diff --git a/Cargo.lock b/Cargo.lock
index 95b5c584..b5c2ed41 100644
--- a/Cargo.lock
+++ b/Cargo.lock
@@ -2468,6 +2468,8 @@ dependencies = [
  "opentelemetry-semantic-conventions",
  "opentelemetry-zipkin",
  "prometheus",
+ "rand",
+ "rand_chacha",
  "rustls",
  "serde_json",
  "serde_yaml",
@@ -2497,6 +2499,7 @@ dependencies = [
  "mas-keystore",
  "pem-rfc7468",
  "rand",
+ "rand_chacha",
  "rustls-pemfile",
  "schemars",
  "serde",
@@ -2567,6 +2570,7 @@ dependencies = [
  "mime",
  "oauth2-types",
  "rand",
+ "rand_chacha",
  "serde",
  "serde_json",
  "serde_urlencoded",
@@ -2779,6 +2783,7 @@ dependencies = [
  "oauth2-types",
  "password-hash",
  "rand",
+ "rand_chacha",
  "serde",
  "serde_json",
  "sqlx",
@@ -3068,7 +3073,7 @@ checksum = "86f0b0d4bf799edbc74508c1e8bf170ff5f41238e5f8225603ca7caaae2b7860"
 [[package]]
 name = "opa-wasm"
 version = "0.1.0"
-source = "git+https://github.com/matrix-org/rust-opa-wasm.git#325071ee8a2a7d18cc611365edd3235945a8cdf4"
+source = "git+https://github.com/matrix-org/rust-opa-wasm.git#f838595670747b0644b6bfd9829fca5d63bbee66"
 dependencies = [
  "anyhow",
  "base64",
@@ -3079,6 +3084,7 @@ dependencies = [
  "md-5",
  "parse-size",
  "rand",
+ "rayon-core",
  "semver",
  "serde",
  "serde_json",
diff --git a/clippy.toml b/clippy.toml
index 87582113..93fce8d5 100644
--- a/clippy.toml
+++ b/clippy.toml
@@ -1,2 +1,11 @@
 msrv = "1.61.0"
 doc-valid-idents = ["OpenID", "OAuth", ".."]
+
+disallowed-methods = [
+    { path = "rand::thread_rng", reason = "do not create rngs on the fly, pass them as parameters" },
+    { path = "chrono::Utc::now", reason = "source the current time from the clock instead" },
+]
+
+disallowed-types = [
+    "rand::OsRng",
+]
diff --git a/crates/axum-utils/src/csrf.rs b/crates/axum-utils/src/csrf.rs
index b69f935d..c12a2ed8 100644
--- a/crates/axum-utils/src/csrf.rs
+++ b/crates/axum-utils/src/csrf.rs
@@ -15,6 +15,7 @@
 use axum_extra::extract::cookie::{Cookie, PrivateCookieJar};
 use chrono::{DateTime, Duration, Utc};
 use data_encoding::{DecodeError, BASE64URL_NOPAD};
+use rand::{thread_rng, Rng};
 use serde::{Deserialize, Serialize};
 use serde_with::{serde_as, TimestampSeconds};
 use thiserror::Error;
@@ -56,20 +57,20 @@ pub struct CsrfToken {
 
 impl CsrfToken {
     /// Create a new token from a defined value valid for a specified duration
-    fn new(token: [u8; 32], ttl: Duration) -> Self {
-        let expiration = Utc::now() + ttl;
+    fn new(token: [u8; 32], now: DateTime<Utc>, ttl: Duration) -> Self {
+        let expiration = now + ttl;
         Self { expiration, token }
     }
 
     /// Generate a new random token valid for a specified duration
-    fn generate(ttl: Duration) -> Self {
-        let token = rand::random();
-        Self::new(token, ttl)
+    fn generate(now: DateTime<Utc>, mut rng: impl Rng, ttl: Duration) -> Self {
+        let token = rng.gen();
+        Self::new(token, now, ttl)
     }
 
     /// Generate a new token with the same value but an up to date expiration
-    fn refresh(self, ttl: Duration) -> Self {
-        Self::new(self.token, ttl)
+    fn refresh(self, now: DateTime<Utc>, ttl: Duration) -> Self {
+        Self::new(self.token, now, ttl)
     }
 
     /// Get the value to include in HTML forms
@@ -88,8 +89,8 @@ impl CsrfToken {
         }
     }
 
-    fn verify_expiration(self) -> Result<Self, CsrfError> {
-        if Utc::now() < self.expiration {
+    fn verify_expiration(self, now: DateTime<Utc>) -> Result<Self, CsrfError> {
+        if now < self.expiration {
             Ok(self)
         } else {
             Err(CsrfError::Expired)
@@ -118,12 +119,18 @@ impl<K> CsrfExt for PrivateCookieJar<K> {
         cookie.set_path("/");
         cookie.set_http_only(true);
 
+        // XXX: the rng source and clock should come from somewhere else
+        #[allow(clippy::disallowed_methods)]
+        let now = Utc::now();
+        #[allow(clippy::disallowed_methods)]
+        let rng = thread_rng();
+
         let new_token = cookie
             .decode()
             .ok()
-            .and_then(|token: CsrfToken| token.verify_expiration().ok())
-            .unwrap_or_else(|| CsrfToken::generate(Duration::hours(1)))
-            .refresh(Duration::hours(1));
+            .and_then(|token: CsrfToken| token.verify_expiration(now).ok())
+            .unwrap_or_else(|| CsrfToken::generate(now, rng, Duration::hours(1)))
+            .refresh(now, Duration::hours(1));
 
         let cookie = cookie.encode(&new_token);
         let jar = jar.add(cookie);
@@ -131,9 +138,13 @@ impl<K> CsrfExt for PrivateCookieJar<K> {
     }
 
     fn verify_form<T>(&self, form: ProtectedForm<T>) -> Result<T, CsrfError> {
+        // XXX: the clock should come from somewhere else
+        #[allow(clippy::disallowed_methods)]
+        let now = Utc::now();
+
         let cookie = self.get("csrf").ok_or(CsrfError::Missing)?;
         let token: CsrfToken = cookie.decode()?;
-        let token = token.verify_expiration()?;
+        let token = token.verify_expiration(now)?;
         token.verify_form_value(&form.csrf)?;
         Ok(form.inner)
     }
diff --git a/crates/cli/Cargo.toml b/crates/cli/Cargo.toml
index b3484ef0..3a588157 100644
--- a/crates/cli/Cargo.toml
+++ b/crates/cli/Cargo.toml
@@ -6,23 +6,25 @@ edition = "2021"
 license = "Apache-2.0"
 
 [dependencies]
-axum = "0.6.0-rc.2"
-tokio = { version = "1.21.2", features = ["full"] }
-futures-util = "0.3.25"
 anyhow = "1.0.66"
+argon2 = { version = "0.4.1", features = ["password-hash"] }
+atty = "0.2.14"
+axum = "0.6.0-rc.2"
 clap = { version = "4.0.18", features = ["derive"] }
 dotenv = "0.15.0"
-tower = { version = "0.4.13", features = ["full"] }
+futures-util = "0.3.25"
 hyper = { version = "0.14.22", features = ["full"] }
-serde_yaml = "0.9.14"
-serde_json = "1.0.87"
-url = "2.3.1"
-argon2 = { version = "0.4.1", features = ["password-hash"] }
-watchman_client = "0.8.0"
-atty = "0.2.14"
-listenfd = "1.0.0"
-rustls = "0.20.7"
 itertools = "0.10.5"
+listenfd = "1.0.0"
+rand = "0.8.5"
+rand_chacha = "0.3.1"
+rustls = "0.20.7"
+serde_json = "1.0.87"
+serde_yaml = "0.9.14"
+tokio = { version = "1.21.2", features = ["full"] }
+tower = { version = "0.4.13", features = ["full"] }
+url = "2.3.1"
+watchman_client = "0.8.0"
 
 tracing = "0.1.37"
 tracing-appender = "0.2.2"
diff --git a/crates/cli/src/commands/manage.rs b/crates/cli/src/commands/manage.rs
index 3cd5f38d..8afd3b5a 100644
--- a/crates/cli/src/commands/manage.rs
+++ b/crates/cli/src/commands/manage.rs
@@ -20,7 +20,9 @@ use mas_storage::{
     user::{
         lookup_user_by_username, lookup_user_email, mark_user_email_as_verified, register_user,
     },
+    Clock,
 };
+use rand::SeedableRng;
 use tracing::{info, warn};
 
 #[derive(Parser, Debug)]
@@ -51,14 +53,17 @@ enum Subcommand {
 impl Options {
     pub async fn run(&self, root: &super::Options) -> anyhow::Result<()> {
         use Subcommand as SC;
+        let clock = Clock::default();
+
         match &self.subcommand {
             SC::Register { username, password } => {
                 let config: DatabaseConfig = root.load_config()?;
                 let pool = config.connect().await?;
                 let mut txn = pool.begin().await?;
                 let hasher = Argon2::default();
+                let rng = rand_chacha::ChaChaRng::from_entropy();
 
-                let user = register_user(&mut txn, hasher, username, password).await?;
+                let user = register_user(&mut txn, rng, &clock, hasher, username, password).await?;
                 txn.commit().await?;
                 info!(?user, "User registered");
 
@@ -76,7 +81,7 @@ impl Options {
 
                 let user = lookup_user_by_username(&mut txn, username).await?;
                 let email = lookup_user_email(&mut txn, &user, email).await?;
-                let email = mark_user_email_as_verified(&mut txn, email).await?;
+                let email = mark_user_email_as_verified(&mut txn, &clock, email).await?;
 
                 txn.commit().await?;
                 info!(?email, "Email marked as verified");
diff --git a/crates/config/Cargo.toml b/crates/config/Cargo.toml
index b78d401b..ddaf3db9 100644
--- a/crates/config/Cargo.toml
+++ b/crates/config/Cargo.toml
@@ -28,6 +28,7 @@ lettre = { version = "0.10.1", default-features = false, features = ["serde", "b
 pem-rfc7468 = "0.6.0"
 rustls-pemfile = "1.0.1"
 rand = "0.8.5"
+rand_chacha = "0.3.1"
 
 indoc = "1.0.7"
 
diff --git a/crates/config/src/sections/secrets.rs b/crates/config/src/sections/secrets.rs
index f9fc9905..8ba5e667 100644
--- a/crates/config/src/sections/secrets.rs
+++ b/crates/config/src/sections/secrets.rs
@@ -20,7 +20,7 @@ use mas_jose::jwk::{JsonWebKey, JsonWebKeySet};
 use mas_keystore::{Encrypter, Keystore, PrivateKey};
 use rand::{
     distributions::{Alphanumeric, DistString},
-    thread_rng,
+    thread_rng, SeedableRng,
 };
 use schemars::JsonSchema;
 use serde::{Deserialize, Serialize};
@@ -139,64 +139,72 @@ impl ConfigurationSection<'_> for SecretsConfig {
 
     #[tracing::instrument]
     async fn generate() -> anyhow::Result<Self> {
+        // XXX: that RNG should come from somewhere else
+        #[allow(clippy::disallowed_methods)]
+        let mut rng = rand_chacha::ChaChaRng::from_rng(thread_rng())?;
+
         info!("Generating keys...");
 
         let span = tracing::info_span!("rsa");
+        let key_rng = rand_chacha::ChaChaRng::from_rng(&mut rng)?;
         let rsa_key = task::spawn_blocking(move || {
             let _entered = span.enter();
-            let ret = PrivateKey::generate_rsa(thread_rng()).unwrap();
+            let ret = PrivateKey::generate_rsa(key_rng).unwrap();
             info!("Done generating RSA key");
             ret
         })
         .await
         .context("could not join blocking task")?;
         let rsa_key = KeyConfig {
-            kid: Alphanumeric.sample_string(&mut thread_rng(), 10),
+            kid: Alphanumeric.sample_string(&mut rng, 10),
             password: None,
             key: KeyOrFile::Key(rsa_key.to_pem(pem_rfc7468::LineEnding::LF)?.to_string()),
         };
 
         let span = tracing::info_span!("ec_p256");
+        let key_rng = rand_chacha::ChaChaRng::from_rng(&mut rng)?;
         let ec_p256_key = task::spawn_blocking(move || {
             let _entered = span.enter();
-            let ret = PrivateKey::generate_ec_p256(thread_rng());
+            let ret = PrivateKey::generate_ec_p256(key_rng);
             info!("Done generating EC P-256 key");
             ret
         })
         .await
         .context("could not join blocking task")?;
         let ec_p256_key = KeyConfig {
-            kid: Alphanumeric.sample_string(&mut thread_rng(), 10),
+            kid: Alphanumeric.sample_string(&mut rng, 10),
             password: None,
             key: KeyOrFile::Key(ec_p256_key.to_pem(pem_rfc7468::LineEnding::LF)?.to_string()),
         };
 
         let span = tracing::info_span!("ec_p384");
+        let key_rng = rand_chacha::ChaChaRng::from_rng(&mut rng)?;
         let ec_p384_key = task::spawn_blocking(move || {
             let _entered = span.enter();
-            let ret = PrivateKey::generate_ec_p384(thread_rng());
+            let ret = PrivateKey::generate_ec_p384(key_rng);
             info!("Done generating EC P-256 key");
             ret
         })
         .await
         .context("could not join blocking task")?;
         let ec_p384_key = KeyConfig {
-            kid: Alphanumeric.sample_string(&mut thread_rng(), 10),
+            kid: Alphanumeric.sample_string(&mut rng, 10),
             password: None,
             key: KeyOrFile::Key(ec_p384_key.to_pem(pem_rfc7468::LineEnding::LF)?.to_string()),
         };
 
         let span = tracing::info_span!("ec_k256");
+        let key_rng = rand_chacha::ChaChaRng::from_rng(&mut rng)?;
         let ec_k256_key = task::spawn_blocking(move || {
             let _entered = span.enter();
-            let ret = PrivateKey::generate_ec_k256(thread_rng());
+            let ret = PrivateKey::generate_ec_k256(key_rng);
             info!("Done generating EC secp256k1 key");
             ret
         })
         .await
         .context("could not join blocking task")?;
         let ec_k256_key = KeyConfig {
-            kid: Alphanumeric.sample_string(&mut thread_rng(), 10),
+            kid: Alphanumeric.sample_string(&mut rng, 10),
             password: None,
             key: KeyOrFile::Key(ec_k256_key.to_pem(pem_rfc7468::LineEnding::LF)?.to_string()),
         };
diff --git a/crates/data-model/src/tokens.rs b/crates/data-model/src/tokens.rs
index f11ccb0a..6e1c7658 100644
--- a/crates/data-model/src/tokens.rs
+++ b/crates/data-model/src/tokens.rs
@@ -263,6 +263,8 @@ mod tests {
     #[test]
     fn test_generate_and_check() {
         const COUNT: usize = 500; // Generate 500 of each token type
+
+        #[allow(clippy::disallowed_methods)]
         let mut rng = thread_rng();
 
         for t in [
diff --git a/crates/handlers/Cargo.toml b/crates/handlers/Cargo.toml
index e64cd379..43c736f2 100644
--- a/crates/handlers/Cargo.toml
+++ b/crates/handlers/Cargo.toml
@@ -44,6 +44,7 @@ chrono = { version = "0.4.22", features = ["serde"] }
 url = { version = "2.3.1", features = ["serde"] }
 mime = "0.3.16"
 rand = "0.8.5"
+rand_chacha = "0.3.1"
 headers = "0.3.8"
 ulid = "1.0.0"
 
diff --git a/crates/handlers/src/compat/login.rs b/crates/handlers/src/compat/login.rs
index 490e097d..d3af3402 100644
--- a/crates/handlers/src/compat/login.rs
+++ b/crates/handlers/src/compat/login.rs
@@ -13,7 +13,7 @@
 // limitations under the License.
 
 use axum::{extract::State, response::IntoResponse, Json};
-use chrono::{Duration, Utc};
+use chrono::Duration;
 use hyper::StatusCode;
 use mas_data_model::{CompatSession, CompatSsoLoginState, Device, TokenType};
 use mas_storage::{
@@ -22,9 +22,8 @@ use mas_storage::{
         get_compat_sso_login_by_token, mark_compat_sso_login_as_exchanged,
         CompatSsoLoginLookupError,
     },
-    PostgresqlBackend,
+    Clock, PostgresqlBackend,
 };
-use rand::thread_rng;
 use serde::{Deserialize, Serialize};
 use serde_with::{serde_as, skip_serializing_none, DurationMilliSeconds};
 use sqlx::{PgPool, Postgres, Transaction};
@@ -201,6 +200,7 @@ pub(crate) async fn post(
     State(homeserver): State<MatrixHomeserver>,
     Json(input): Json<RequestBody>,
 ) -> Result<impl IntoResponse, RouteError> {
+    let (clock, mut rng) = crate::rng_and_clock()?;
     let mut txn = pool.begin().await?;
     let session = match input.credentials {
         Credentials::Password {
@@ -208,7 +208,7 @@ pub(crate) async fn post(
             password,
         } => user_password_login(&mut txn, user, password).await?,
 
-        Credentials::Token { token } => token_login(&mut txn, &token).await?,
+        Credentials::Token { token } => token_login(&mut txn, &clock, &token).await?,
 
         _ => {
             return Err(RouteError::Unsupported);
@@ -225,14 +225,28 @@ pub(crate) async fn post(
         None
     };
 
-    let access_token = TokenType::CompatAccessToken.generate(&mut thread_rng());
-    let access_token =
-        add_compat_access_token(&mut txn, &session, access_token, expires_in).await?;
+    let access_token = TokenType::CompatAccessToken.generate(&mut rng);
+    let access_token = add_compat_access_token(
+        &mut txn,
+        &mut rng,
+        &clock,
+        &session,
+        access_token,
+        expires_in,
+    )
+    .await?;
 
     let refresh_token = if input.refresh_token {
-        let refresh_token = TokenType::CompatRefreshToken.generate(&mut thread_rng());
-        let refresh_token =
-            add_compat_refresh_token(&mut txn, &session, &access_token, refresh_token).await?;
+        let refresh_token = TokenType::CompatRefreshToken.generate(&mut rng);
+        let refresh_token = add_compat_refresh_token(
+            &mut txn,
+            &mut rng,
+            &clock,
+            &session,
+            &access_token,
+            refresh_token,
+        )
+        .await?;
         Some(refresh_token.token)
     } else {
         None
@@ -251,11 +265,12 @@ pub(crate) async fn post(
 
 async fn token_login(
     txn: &mut Transaction<'_, Postgres>,
+    clock: &Clock,
     token: &str,
 ) -> Result<CompatSession<PostgresqlBackend>, RouteError> {
     let login = get_compat_sso_login_by_token(&mut *txn, token).await?;
 
-    let now = Utc::now();
+    let now = clock.now();
     match login.state {
         CompatSsoLoginState::Pending => {
             tracing::error!(
@@ -285,7 +300,7 @@ async fn token_login(
         }
     }
 
-    let login = mark_compat_sso_login_as_exchanged(&mut *txn, login).await?;
+    let login = mark_compat_sso_login_as_exchanged(&mut *txn, clock, login).await?;
 
     match login.state {
         CompatSsoLoginState::Exchanged { session, .. } => Ok(session),
@@ -298,8 +313,10 @@ async fn user_password_login(
     username: String,
     password: String,
 ) -> Result<CompatSession<PostgresqlBackend>, RouteError> {
-    let device = Device::generate(&mut thread_rng());
-    let session = compat_login(txn, &username, &password, device)
+    let (clock, mut rng) = crate::rng_and_clock()?;
+
+    let device = Device::generate(&mut rng);
+    let session = compat_login(txn, &mut rng, &clock, &username, &password, device)
         .await
         .map_err(|_| RouteError::LoginFailed)?;
 
diff --git a/crates/handlers/src/compat/login_sso_complete.rs b/crates/handlers/src/compat/login_sso_complete.rs
index 6083d944..97dd0e00 100644
--- a/crates/handlers/src/compat/login_sso_complete.rs
+++ b/crates/handlers/src/compat/login_sso_complete.rs
@@ -20,7 +20,7 @@ use axum::{
     response::{Html, IntoResponse, Redirect, Response},
 };
 use axum_extra::extract::PrivateCookieJar;
-use chrono::{Duration, Utc};
+use chrono::Duration;
 use mas_axum_utils::{
     csrf::{CsrfExt, ProtectedForm},
     FancyError, SessionInfoExt,
@@ -28,9 +28,11 @@ use mas_axum_utils::{
 use mas_data_model::Device;
 use mas_keystore::Encrypter;
 use mas_router::{CompatLoginSsoAction, PostAuthAction, Route};
-use mas_storage::compat::{fullfill_compat_sso_login, get_compat_sso_login_by_id};
+use mas_storage::{
+    compat::{fullfill_compat_sso_login, get_compat_sso_login_by_id},
+    Clock,
+};
 use mas_templates::{CompatSsoContext, ErrorContext, TemplateContext, Templates};
-use rand::thread_rng;
 use serde::{Deserialize, Serialize};
 use sqlx::PgPool;
 use ulid::Ulid;
@@ -56,6 +58,7 @@ pub async fn get(
     Path(id): Path<Ulid>,
     Query(params): Query<Params>,
 ) -> Result<Response, FancyError> {
+    let clock = Clock::default();
     let mut conn = pool.acquire().await?;
 
     let (session_info, cookie_jar) = cookie_jar.session_info();
@@ -95,7 +98,7 @@ pub async fn get(
     let login = get_compat_sso_login_by_id(&mut conn, id).await?;
 
     // Bail out if that login session is more than 30min old
-    if Utc::now() > login.created_at + Duration::minutes(30) {
+    if clock.now() > login.created_at + Duration::minutes(30) {
         let ctx = ErrorContext::new()
             .with_code("compat_sso_login_expired")
             .with_description("This login session expired.".to_owned());
@@ -121,6 +124,7 @@ pub async fn post(
     Query(params): Query<Params>,
     Form(form): Form<ProtectedForm<()>>,
 ) -> Result<Response, FancyError> {
+    let (clock, mut rng) = crate::rng_and_clock()?;
     let mut txn = pool.begin().await?;
 
     let (session_info, cookie_jar) = cookie_jar.session_info();
@@ -160,7 +164,7 @@ pub async fn post(
     let login = get_compat_sso_login_by_id(&mut txn, id).await?;
 
     // Bail out if that login session is more than 30min old
-    if Utc::now() > login.created_at + Duration::minutes(30) {
+    if clock.now() > login.created_at + Duration::minutes(30) {
         let ctx = ErrorContext::new()
             .with_code("compat_sso_login_expired")
             .with_description("This login session expired.".to_owned());
@@ -186,8 +190,9 @@ pub async fn post(
         redirect_uri
     };
 
-    let device = Device::generate(&mut thread_rng());
-    let _login = fullfill_compat_sso_login(&mut txn, session.user, login, device).await?;
+    let device = Device::generate(&mut rng);
+    let _login =
+        fullfill_compat_sso_login(&mut txn, &mut rng, &clock, session.user, login, device).await?;
 
     txn.commit().await?;
 
diff --git a/crates/handlers/src/compat/login_sso_redirect.rs b/crates/handlers/src/compat/login_sso_redirect.rs
index 2a4c4676..9a146cd4 100644
--- a/crates/handlers/src/compat/login_sso_redirect.rs
+++ b/crates/handlers/src/compat/login_sso_redirect.rs
@@ -20,10 +20,7 @@ use axum::{
 use hyper::StatusCode;
 use mas_router::{CompatLoginSsoAction, CompatLoginSsoComplete, UrlBuilder};
 use mas_storage::compat::insert_compat_sso_login;
-use rand::{
-    distributions::{Alphanumeric, DistString},
-    thread_rng,
-};
+use rand::distributions::{Alphanumeric, DistString};
 use serde::Deserialize;
 use serde_with::serde;
 use sqlx::PgPool;
@@ -70,6 +67,8 @@ pub async fn get(
     State(url_builder): State<UrlBuilder>,
     Query(params): Query<Params>,
 ) -> Result<impl IntoResponse, RouteError> {
+    let (clock, mut rng) = crate::rng_and_clock()?;
+
     // Check the redirectUrl parameter
     let redirect_url = params.redirect_url.ok_or(RouteError::MissingRedirectUrl)?;
     let redirect_url = Url::parse(&redirect_url).map_err(|_| RouteError::InvalidRedirectUrl)?;
@@ -84,9 +83,9 @@ pub async fn get(
         return Err(RouteError::InvalidRedirectUrl);
     }
 
-    let token = Alphanumeric.sample_string(&mut thread_rng(), 32);
+    let token = Alphanumeric.sample_string(&mut rng, 32);
     let mut conn = pool.acquire().await?;
-    let login = insert_compat_sso_login(&mut conn, token, redirect_url).await?;
+    let login = insert_compat_sso_login(&mut conn, &mut rng, &clock, token, redirect_url).await?;
 
     Ok(url_builder.absolute_redirect(&CompatLoginSsoComplete::new(login.data, params.action)))
 }
diff --git a/crates/handlers/src/compat/logout.rs b/crates/handlers/src/compat/logout.rs
index 36e64c47..e613376c 100644
--- a/crates/handlers/src/compat/logout.rs
+++ b/crates/handlers/src/compat/logout.rs
@@ -16,7 +16,7 @@ use axum::{extract::State, response::IntoResponse, Json, TypedHeader};
 use headers::{authorization::Bearer, Authorization};
 use hyper::StatusCode;
 use mas_data_model::{TokenFormatError, TokenType};
-use mas_storage::compat::compat_logout;
+use mas_storage::{compat::compat_logout, Clock};
 use sqlx::PgPool;
 
 use super::MatrixError;
@@ -67,6 +67,7 @@ pub(crate) async fn post(
     State(pool): State<PgPool>,
     maybe_authorization: Option<TypedHeader<Authorization<Bearer>>>,
 ) -> Result<impl IntoResponse, RouteError> {
+    let clock = Clock::default();
     let mut conn = pool.acquire().await?;
 
     let TypedHeader(authorization) = maybe_authorization.ok_or(RouteError::MissingAuthorization)?;
@@ -78,7 +79,7 @@ pub(crate) async fn post(
         return Err(RouteError::InvalidAuthorization);
     }
 
-    compat_logout(&mut conn, token)
+    compat_logout(&mut conn, &clock, token)
         .await
         .map_err(|_| RouteError::LogoutFailed)?;
 
diff --git a/crates/handlers/src/compat/refresh.rs b/crates/handlers/src/compat/refresh.rs
index e07a5768..fb1297bb 100644
--- a/crates/handlers/src/compat/refresh.rs
+++ b/crates/handlers/src/compat/refresh.rs
@@ -20,7 +20,6 @@ use mas_storage::compat::{
     add_compat_access_token, add_compat_refresh_token, consume_compat_refresh_token,
     expire_compat_access_token, lookup_active_compat_refresh_token, CompatRefreshTokenLookupError,
 };
-use rand::thread_rng;
 use serde::{Deserialize, Serialize};
 use serde_with::{serde_as, DurationMilliSeconds};
 use sqlx::PgPool;
@@ -98,6 +97,7 @@ pub(crate) async fn post(
     State(pool): State<PgPool>,
     Json(input): Json<RequestBody>,
 ) -> Result<impl IntoResponse, RouteError> {
+    let (clock, mut rng) = crate::rng_and_clock()?;
     let mut txn = pool.begin().await?;
 
     let token_type = TokenType::check(&input.refresh_token)?;
@@ -109,23 +109,31 @@ pub(crate) async fn post(
     let (refresh_token, access_token, session) =
         lookup_active_compat_refresh_token(&mut txn, &input.refresh_token).await?;
 
-    let (new_refresh_token_str, new_access_token_str) = {
-        let mut rng = thread_rng();
-        (
-            TokenType::CompatRefreshToken.generate(&mut rng),
-            TokenType::CompatAccessToken.generate(&mut rng),
-        )
-    };
+    let new_refresh_token_str = TokenType::CompatRefreshToken.generate(&mut rng);
+    let new_access_token_str = TokenType::CompatAccessToken.generate(&mut rng);
 
     let expires_in = Duration::minutes(5);
-    let new_access_token =
-        add_compat_access_token(&mut txn, &session, new_access_token_str, Some(expires_in)).await?;
-    let new_refresh_token =
-        add_compat_refresh_token(&mut txn, &session, &new_access_token, new_refresh_token_str)
-            .await?;
+    let new_access_token = add_compat_access_token(
+        &mut txn,
+        &mut rng,
+        &clock,
+        &session,
+        new_access_token_str,
+        Some(expires_in),
+    )
+    .await?;
+    let new_refresh_token = add_compat_refresh_token(
+        &mut txn,
+        &mut rng,
+        &clock,
+        &session,
+        &new_access_token,
+        new_refresh_token_str,
+    )
+    .await?;
 
-    consume_compat_refresh_token(&mut txn, refresh_token).await?;
-    expire_compat_access_token(&mut txn, access_token).await?;
+    consume_compat_refresh_token(&mut txn, &clock, refresh_token).await?;
+    expire_compat_access_token(&mut txn, &clock, access_token).await?;
 
     txn.commit().await?;
 
diff --git a/crates/handlers/src/lib.rs b/crates/handlers/src/lib.rs
index 18aca49e..730055f6 100644
--- a/crates/handlers/src/lib.rs
+++ b/crates/handlers/src/lib.rs
@@ -21,6 +21,7 @@
 
 use std::{convert::Infallible, sync::Arc, time::Duration};
 
+use anyhow::Context;
 use axum::{
     body::HttpBody,
     extract::FromRef,
@@ -36,6 +37,7 @@ use mas_keystore::{Encrypter, Keystore};
 use mas_policy::PolicyFactory;
 use mas_router::{Route, UrlBuilder};
 use mas_templates::{ErrorContext, Templates};
+use rand::SeedableRng;
 use sqlx::PgPool;
 use tower::util::AndThenLayer;
 use tower_http::cors::{Any, CorsLayer};
@@ -356,3 +358,15 @@ async fn test_state(pool: PgPool) -> Result<Arc<AppState>, anyhow::Error> {
         policy_factory,
     }))
 }
+
+// XXX: that should be moved somewhere else
+fn rng_and_clock() -> Result<(mas_storage::Clock, rand_chacha::ChaChaRng), anyhow::Error> {
+    let clock = mas_storage::Clock::default();
+
+    // This rng is used to source the local rng
+    #[allow(clippy::disallowed_methods)]
+    let rng = rand::thread_rng();
+
+    let rng = rand_chacha::ChaChaRng::from_rng(rng).context("Failed to seed RNG")?;
+    Ok((clock, rng))
+}
diff --git a/crates/handlers/src/oauth2/authorization/complete.rs b/crates/handlers/src/oauth2/authorization/complete.rs
index 23709c2f..a592dc40 100644
--- a/crates/handlers/src/oauth2/authorization/complete.rs
+++ b/crates/handlers/src/oauth2/authorization/complete.rs
@@ -190,6 +190,8 @@ pub(crate) async fn complete(
     policy_factory: &PolicyFactory,
     mut txn: Transaction<'_, Postgres>,
 ) -> Result<AuthorizationResponse<Option<AccessTokenResponse>>, GrantCompletionError> {
+    let (clock, mut rng) = crate::rng_and_clock()?;
+
     // Verify that the grant is in a pending stage
     if !grant.stage.is_pending() {
         return Err(GrantCompletionError::NotPending);
@@ -226,7 +228,7 @@ pub(crate) async fn complete(
     }
 
     // All good, let's start the session
-    let session = derive_session(&mut txn, &grant, browser_session).await?;
+    let session = derive_session(&mut txn, &mut rng, &clock, &grant, browser_session).await?;
 
     let grant = fulfill_grant(&mut txn, grant, session.clone()).await?;
 
diff --git a/crates/handlers/src/oauth2/authorization/mod.rs b/crates/handlers/src/oauth2/authorization/mod.rs
index ad5a347b..69149206 100644
--- a/crates/handlers/src/oauth2/authorization/mod.rs
+++ b/crates/handlers/src/oauth2/authorization/mod.rs
@@ -37,7 +37,7 @@ use oauth2_types::{
     requests::{AuthorizationRequest, GrantType, Prompt, ResponseMode},
     response_type::ResponseType,
 };
-use rand::{distributions::Alphanumeric, thread_rng, Rng};
+use rand::{distributions::Alphanumeric, Rng};
 use serde::Deserialize;
 use sqlx::PgPool;
 use thiserror::Error;
@@ -159,6 +159,7 @@ pub(crate) async fn get(
     cookie_jar: PrivateCookieJar<Encrypter>,
     Form(params): Form<Params>,
 ) -> Result<Response, RouteError> {
+    let (clock, mut rng) = crate::rng_and_clock()?;
     let mut txn = pool.begin().await?;
 
     // First, figure out what client it is
@@ -265,7 +266,7 @@ pub(crate) async fn get(
                 }
 
                 // 32 random alphanumeric characters, about 190bit of entropy
-                let code: String = thread_rng()
+                let code: String = (&mut rng)
                     .sample_iter(&Alphanumeric)
                     .take(32)
                     .map(char::from)
@@ -296,6 +297,8 @@ pub(crate) async fn get(
 
             let grant = new_authorization_grant(
                 &mut txn,
+                &mut rng,
+                &clock,
                 client,
                 redirect_uri.clone(),
                 params.auth.scope,
diff --git a/crates/handlers/src/oauth2/consent.rs b/crates/handlers/src/oauth2/consent.rs
index 1fa88ad6..e3f9f0bf 100644
--- a/crates/handlers/src/oauth2/consent.rs
+++ b/crates/handlers/src/oauth2/consent.rs
@@ -119,6 +119,7 @@ pub(crate) async fn post(
     Path(grant_id): Path<Ulid>,
     Form(form): Form<ProtectedForm<()>>,
 ) -> Result<Response, RouteError> {
+    let (clock, mut rng) = crate::rng_and_clock()?;
     let mut txn = pool
         .begin()
         .await
@@ -163,6 +164,8 @@ pub(crate) async fn post(
         .collect();
     insert_client_consent(
         &mut txn,
+        &mut rng,
+        &clock,
         &session.user,
         &grant.client,
         &scope_without_device,
diff --git a/crates/handlers/src/oauth2/introspection.rs b/crates/handlers/src/oauth2/introspection.rs
index edbd01d9..c99ad063 100644
--- a/crates/handlers/src/oauth2/introspection.rs
+++ b/crates/handlers/src/oauth2/introspection.rs
@@ -28,6 +28,7 @@ use mas_storage::{
         client::ClientFetchError,
         refresh_token::{lookup_active_refresh_token, RefreshTokenLookupError},
     },
+    Clock,
 };
 use oauth2_types::requests::{IntrospectionRequest, IntrospectionResponse};
 use sqlx::PgPool;
@@ -158,6 +159,7 @@ pub(crate) async fn post(
     State(encrypter): State<Encrypter>,
     client_authorization: ClientAuthorization<IntrospectionRequest>,
 ) -> Result<impl IntoResponse, RouteError> {
+    let clock = Clock::default();
     let mut conn = pool.acquire().await?;
 
     let client = client_authorization.credentials.fetch(&mut conn).await?;
@@ -227,7 +229,8 @@ pub(crate) async fn post(
             }
         }
         TokenType::CompatAccessToken => {
-            let (token, session) = lookup_active_compat_access_token(&mut conn, token).await?;
+            let (token, session) =
+                lookup_active_compat_access_token(&mut conn, &clock, token).await?;
 
             let device_scope = session.device.to_scope_token();
             let scope = [device_scope].into_iter().collect();
diff --git a/crates/handlers/src/oauth2/token.rs b/crates/handlers/src/oauth2/token.rs
index fb70e7fd..0b14cedf 100644
--- a/crates/handlers/src/oauth2/token.rs
+++ b/crates/handlers/src/oauth2/token.rs
@@ -50,7 +50,6 @@ use oauth2_types::{
     },
     scope,
 };
-use rand::thread_rng;
 use serde::Serialize;
 use serde_with::{serde_as, skip_serializing_none};
 use sqlx::{PgPool, Postgres, Transaction};
@@ -235,12 +234,13 @@ async fn authorization_code_grant(
     url_builder: &UrlBuilder,
     mut txn: Transaction<'_, Postgres>,
 ) -> Result<AccessTokenResponse, RouteError> {
+    let (clock, mut rng) = crate::rng_and_clock()?;
+
     // TODO: there is a bunch of unnecessary cloning here
     // TODO: handle "not found" cases
     let authz_grant = lookup_grant_by_code(&mut txn, &grant.code).await?;
 
-    // TODO: that's not a timestamp from the DB. Let's assume they are in sync
-    let now = Utc::now();
+    let now = clock.now();
 
     let session = match authz_grant.stage {
         AuthorizationGrantStage::Cancelled { cancelled_at } => {
@@ -257,7 +257,7 @@ async fn authorization_code_grant(
             // Ending the session if the token was already exchanged more than 20s ago
             if now - exchanged_at > Duration::seconds(20) {
                 debug!("Ending potentially compromised session");
-                end_oauth_session(&mut txn, session).await?;
+                end_oauth_session(&mut txn, &clock, session).await?;
                 txn.commit().await?;
             }
 
@@ -303,22 +303,32 @@ async fn authorization_code_grant(
     let browser_session = &session.browser_session;
 
     let ttl = Duration::minutes(5);
-    let (access_token_str, refresh_token_str) = {
-        let mut rng = thread_rng();
-        (
-            TokenType::AccessToken.generate(&mut rng),
-            TokenType::RefreshToken.generate(&mut rng),
-        )
-    };
+    let access_token_str = TokenType::AccessToken.generate(&mut rng);
+    let refresh_token_str = TokenType::RefreshToken.generate(&mut rng);
 
-    let access_token = add_access_token(&mut txn, session, access_token_str.clone(), ttl).await?;
+    let access_token = add_access_token(
+        &mut txn,
+        &mut rng,
+        &clock,
+        session,
+        access_token_str.clone(),
+        ttl,
+    )
+    .await?;
 
-    let _refresh_token =
-        add_refresh_token(&mut txn, session, access_token, refresh_token_str.clone()).await?;
+    let _refresh_token = add_refresh_token(
+        &mut txn,
+        &mut rng,
+        &clock,
+        session,
+        access_token,
+        refresh_token_str.clone(),
+    )
+    .await?;
 
     let id_token = if session.scope.contains(&scope::OPENID) {
         let mut claims = HashMap::new();
-        let now = Utc::now();
+        let now = clock.now();
         claims::ISS.insert(&mut claims, url_builder.oidc_issuer().to_string())?;
         claims::SUB.insert(&mut claims, &browser_session.user.sub)?;
         claims::AUD.insert(&mut claims, client.client_id.clone())?;
@@ -346,7 +356,7 @@ async fn authorization_code_grant(
         let signer = key.params().signing_key_for_alg(&alg)?;
         let header = JsonWebSignatureHeader::new(alg)
             .with_kid(key.kid().context("key has no `kid` for some reason")?);
-        let id_token = Jwt::sign(header, claims, &signer)?;
+        let id_token = Jwt::sign_with_rng(&mut rng, header, claims, &signer)?;
 
         Some(id_token.as_str().to_owned())
     } else {
@@ -362,7 +372,7 @@ async fn authorization_code_grant(
         params = params.with_id_token(id_token);
     }
 
-    exchange_grant(&mut txn, authz_grant).await?;
+    exchange_grant(&mut txn, &clock, authz_grant).await?;
 
     txn.commit().await?;
 
@@ -374,6 +384,8 @@ async fn refresh_token_grant(
     client: &Client<PostgresqlBackend>,
     mut txn: Transaction<'_, Postgres>,
 ) -> Result<AccessTokenResponse, RouteError> {
+    let (clock, mut rng) = crate::rng_and_clock()?;
+
     let (refresh_token, session) =
         lookup_active_refresh_token(&mut txn, &grant.refresh_token).await?;
 
@@ -383,24 +395,33 @@ async fn refresh_token_grant(
     }
 
     let ttl = Duration::minutes(5);
-    let (access_token_str, refresh_token_str) = {
-        let mut rng = thread_rng();
-        (
-            TokenType::AccessToken.generate(&mut rng),
-            TokenType::RefreshToken.generate(&mut rng),
-        )
-    };
+    let access_token_str = TokenType::AccessToken.generate(&mut rng);
+    let refresh_token_str = TokenType::RefreshToken.generate(&mut rng);
 
-    let new_access_token =
-        add_access_token(&mut txn, &session, access_token_str.clone(), ttl).await?;
+    let new_access_token = add_access_token(
+        &mut txn,
+        &mut rng,
+        &clock,
+        &session,
+        access_token_str.clone(),
+        ttl,
+    )
+    .await?;
 
-    let new_refresh_token =
-        add_refresh_token(&mut txn, &session, new_access_token, refresh_token_str).await?;
+    let new_refresh_token = add_refresh_token(
+        &mut txn,
+        &mut rng,
+        &clock,
+        &session,
+        new_access_token,
+        refresh_token_str,
+    )
+    .await?;
 
-    consume_refresh_token(&mut txn, &refresh_token).await?;
+    consume_refresh_token(&mut txn, &clock, &refresh_token).await?;
 
     if let Some(access_token) = refresh_token.access_token {
-        revoke_access_token(&mut txn, access_token).await?;
+        revoke_access_token(&mut txn, &clock, access_token).await?;
     }
 
     let params = AccessTokenResponse::new(access_token_str)
diff --git a/crates/handlers/src/oauth2/userinfo.rs b/crates/handlers/src/oauth2/userinfo.rs
index a2c1bf69..3c47bcb4 100644
--- a/crates/handlers/src/oauth2/userinfo.rs
+++ b/crates/handlers/src/oauth2/userinfo.rs
@@ -54,6 +54,7 @@ pub async fn get(
     user_authorization: UserAuthorization,
 ) -> Result<Response, FancyError> {
     // TODO: error handling
+    let (_clock, mut rng) = crate::rng_and_clock()?;
     let mut conn = pool.acquire().await?;
 
     let session = user_authorization.protected(&mut conn).await?;
@@ -88,7 +89,7 @@ pub async fn get(
             user_info,
         };
 
-        let token = Jwt::sign(header, user_info, &signer)?;
+        let token = Jwt::sign_with_rng(&mut rng, header, user_info, &signer)?;
         Ok(JwtResponse(token).into_response())
     } else {
         Ok(Json(user_info).into_response())
diff --git a/crates/handlers/src/views/account/emails/add.rs b/crates/handlers/src/views/account/emails/add.rs
index 1165d02c..805f2e5a 100644
--- a/crates/handlers/src/views/account/emails/add.rs
+++ b/crates/handlers/src/views/account/emails/add.rs
@@ -72,6 +72,7 @@ pub(crate) async fn post(
     Query(query): Query<OptionalPostAuthAction>,
     Form(form): Form<ProtectedForm<EmailForm>>,
 ) -> Result<Response, FancyError> {
+    let (clock, mut rng) = crate::rng_and_clock()?;
     let mut txn = pool.begin().await?;
 
     let form = cookie_jar.verify_form(form)?;
@@ -86,14 +87,22 @@ pub(crate) async fn post(
         return Ok((cookie_jar, login.go()).into_response());
     };
 
-    let user_email = add_user_email(&mut txn, &session.user, form.email).await?;
+    let user_email = add_user_email(&mut txn, &mut rng, &clock, &session.user, form.email).await?;
     let next = mas_router::AccountVerifyEmail::new(user_email.data);
     let next = if let Some(action) = query.post_auth_action {
         next.and_then(action)
     } else {
         next
     };
-    start_email_verification(&mailer, &mut txn, &session.user, user_email).await?;
+    start_email_verification(
+        &mailer,
+        &mut txn,
+        &mut rng,
+        &clock,
+        &session.user,
+        user_email,
+    )
+    .await?;
 
     txn.commit().await?;
 
diff --git a/crates/handlers/src/views/account/emails/mod.rs b/crates/handlers/src/views/account/emails/mod.rs
index 3ab0b950..8d7b6d2b 100644
--- a/crates/handlers/src/views/account/emails/mod.rs
+++ b/crates/handlers/src/views/account/emails/mod.rs
@@ -32,10 +32,10 @@ use mas_storage::{
         add_user_email, add_user_email_verification_code, get_user_email, get_user_emails,
         remove_user_email, set_user_email_as_primary,
     },
-    PostgresqlBackend,
+    Clock, PostgresqlBackend,
 };
 use mas_templates::{AccountEmailsContext, EmailVerificationContext, TemplateContext, Templates};
-use rand::{distributions::Uniform, thread_rng, Rng};
+use rand::{distributions::Uniform, Rng};
 use serde::Deserialize;
 use sqlx::{PgExecutor, PgPool};
 use tracing::info;
@@ -93,17 +93,26 @@ async fn render(
 async fn start_email_verification(
     mailer: &Mailer,
     executor: impl PgExecutor<'_>,
+    mut rng: impl Rng + Send,
+    clock: &Clock,
     user: &User<PostgresqlBackend>,
     user_email: UserEmail<PostgresqlBackend>,
 ) -> anyhow::Result<()> {
     // First, generate a code
     let range = Uniform::<u32>::from(0..1_000_000);
-    let code = thread_rng().sample(range).to_string();
+    let code = rng.sample(range).to_string();
 
     let address: Address = user_email.email.parse()?;
 
-    let verification =
-        add_user_email_verification_code(executor, user_email, Duration::hours(8), code).await?;
+    let verification = add_user_email_verification_code(
+        executor,
+        &mut rng,
+        clock,
+        user_email,
+        Duration::hours(8),
+        code,
+    )
+    .await?;
 
     // And send the verification email
     let mailbox = Mailbox::new(Some(user.username.clone()), address);
@@ -126,6 +135,7 @@ pub(crate) async fn post(
     cookie_jar: PrivateCookieJar<Encrypter>,
     Form(form): Form<ProtectedForm<ManagementForm>>,
 ) -> Result<Response, FancyError> {
+    let (clock, mut rng) = crate::rng_and_clock()?;
     let mut txn = pool.begin().await?;
 
     let (session_info, cookie_jar) = cookie_jar.session_info();
@@ -143,9 +153,18 @@ pub(crate) async fn post(
 
     match form {
         ManagementForm::Add { email } => {
-            let user_email = add_user_email(&mut txn, &session.user, email).await?;
+            let user_email =
+                add_user_email(&mut txn, &mut rng, &clock, &session.user, email).await?;
             let next = mas_router::AccountVerifyEmail::new(user_email.data);
-            start_email_verification(&mailer, &mut txn, &session.user, user_email).await?;
+            start_email_verification(
+                &mailer,
+                &mut txn,
+                &mut rng,
+                &clock,
+                &session.user,
+                user_email,
+            )
+            .await?;
             txn.commit().await?;
             return Ok((cookie_jar, next.go()).into_response());
         }
@@ -154,7 +173,15 @@ pub(crate) async fn post(
 
             let user_email = get_user_email(&mut txn, &session.user, id).await?;
             let next = mas_router::AccountVerifyEmail::new(user_email.data);
-            start_email_verification(&mailer, &mut txn, &session.user, user_email).await?;
+            start_email_verification(
+                &mailer,
+                &mut txn,
+                &mut rng,
+                &clock,
+                &session.user,
+                user_email,
+            )
+            .await?;
             txn.commit().await?;
             return Ok((cookie_jar, next.go()).into_response());
         }
diff --git a/crates/handlers/src/views/account/emails/verify.rs b/crates/handlers/src/views/account/emails/verify.rs
index 22e427d3..ff1addea 100644
--- a/crates/handlers/src/views/account/emails/verify.rs
+++ b/crates/handlers/src/views/account/emails/verify.rs
@@ -23,9 +23,12 @@ use mas_axum_utils::{
 };
 use mas_keystore::Encrypter;
 use mas_router::Route;
-use mas_storage::user::{
-    consume_email_verification, lookup_user_email_by_id, lookup_user_email_verification_code,
-    mark_user_email_as_verified, set_user_email_as_primary,
+use mas_storage::{
+    user::{
+        consume_email_verification, lookup_user_email_by_id, lookup_user_email_verification_code,
+        mark_user_email_as_verified, set_user_email_as_primary,
+    },
+    Clock,
 };
 use mas_templates::{EmailVerificationPageContext, TemplateContext, Templates};
 use serde::Deserialize;
@@ -84,6 +87,7 @@ pub(crate) async fn post(
     Path(id): Path<Ulid>,
     Form(form): Form<ProtectedForm<CodeForm>>,
 ) -> Result<Response, FancyError> {
+    let clock = Clock::default();
     let mut txn = pool.begin().await?;
 
     let form = cookie_jar.verify_form(form)?;
@@ -105,12 +109,13 @@ pub(crate) async fn post(
     }
 
     // TODO: make those 8 hours configurable
-    let verification = lookup_user_email_verification_code(&mut txn, email, &form.code).await?;
+    let verification =
+        lookup_user_email_verification_code(&mut txn, &clock, email, &form.code).await?;
 
     // TODO: display nice errors if the code was already consumed or expired
-    let verification = consume_email_verification(&mut txn, verification).await?;
+    let verification = consume_email_verification(&mut txn, &clock, verification).await?;
 
-    let _email = mark_user_email_as_verified(&mut txn, verification.email).await?;
+    let _email = mark_user_email_as_verified(&mut txn, &clock, verification.email).await?;
 
     txn.commit().await?;
 
diff --git a/crates/handlers/src/views/account/password.rs b/crates/handlers/src/views/account/password.rs
index 55fcecd4..7f317868 100644
--- a/crates/handlers/src/views/account/password.rs
+++ b/crates/handlers/src/views/account/password.rs
@@ -81,6 +81,7 @@ pub(crate) async fn post(
     cookie_jar: PrivateCookieJar<Encrypter>,
     Form(form): Form<ProtectedForm<ChangeForm>>,
 ) -> Result<Response, FancyError> {
+    let (clock, mut rng) = crate::rng_and_clock()?;
     let mut txn = pool.begin().await?;
 
     let form = cookie_jar.verify_form(form)?;
@@ -96,7 +97,14 @@ pub(crate) async fn post(
         return Ok((cookie_jar, login.go()).into_response());
     };
 
-    authenticate_session(&mut txn, &mut session, &form.current_password).await?;
+    authenticate_session(
+        &mut txn,
+        &mut rng,
+        &clock,
+        &mut session,
+        &form.current_password,
+    )
+    .await?;
 
     // TODO: display nice form errors
     if form.new_password != form.new_password_confirm {
@@ -104,7 +112,15 @@ pub(crate) async fn post(
     }
 
     let phf = Argon2::default();
-    set_password(&mut txn, phf, &session.user, &form.new_password).await?;
+    set_password(
+        &mut txn,
+        &mut rng,
+        &clock,
+        phf,
+        &session.user,
+        &form.new_password,
+    )
+    .await?;
 
     let reply = render(templates.clone(), session, cookie_jar).await?;
 
diff --git a/crates/handlers/src/views/login.rs b/crates/handlers/src/views/login.rs
index b43932b4..c62f5098 100644
--- a/crates/handlers/src/views/login.rs
+++ b/crates/handlers/src/views/login.rs
@@ -80,6 +80,7 @@ pub(crate) async fn post(
     cookie_jar: PrivateCookieJar<Encrypter>,
     Form(form): Form<ProtectedForm<LoginForm>>,
 ) -> Result<Response, FancyError> {
+    let (clock, mut rng) = crate::rng_and_clock()?;
     let mut conn = pool.acquire().await?;
 
     let form = cookie_jar.verify_form(form)?;
@@ -114,7 +115,7 @@ pub(crate) async fn post(
         return Ok((cookie_jar, Html(content)).into_response());
     }
 
-    match login(&mut conn, &form.username, &form.password).await {
+    match login(&mut conn, &mut rng, &clock, &form.username, &form.password).await {
         Ok(session_info) => {
             let cookie_jar = cookie_jar.set_session(&session_info);
             let reply = query.go_next();
diff --git a/crates/handlers/src/views/logout.rs b/crates/handlers/src/views/logout.rs
index 34d4a69c..a742a9f3 100644
--- a/crates/handlers/src/views/logout.rs
+++ b/crates/handlers/src/views/logout.rs
@@ -23,7 +23,7 @@ use mas_axum_utils::{
 };
 use mas_keystore::Encrypter;
 use mas_router::{PostAuthAction, Route};
-use mas_storage::user::end_session;
+use mas_storage::{user::end_session, Clock};
 use sqlx::PgPool;
 
 pub(crate) async fn post(
@@ -31,6 +31,7 @@ pub(crate) async fn post(
     cookie_jar: PrivateCookieJar<Encrypter>,
     Form(form): Form<ProtectedForm<Option<PostAuthAction>>>,
 ) -> Result<impl IntoResponse, FancyError> {
+    let clock = Clock::default();
     let mut txn = pool.begin().await?;
 
     let form = cookie_jar.verify_form(form)?;
@@ -40,7 +41,7 @@ pub(crate) async fn post(
     let maybe_session = session_info.load_session(&mut txn).await?;
 
     if let Some(session) = maybe_session {
-        end_session(&mut txn, &session).await?;
+        end_session(&mut txn, &clock, &session).await?;
         cookie_jar = cookie_jar.update_session_info(&session_info.mark_session_ended());
     }
 
diff --git a/crates/handlers/src/views/reauth.rs b/crates/handlers/src/views/reauth.rs
index 8cb2463f..dfaa8e0e 100644
--- a/crates/handlers/src/views/reauth.rs
+++ b/crates/handlers/src/views/reauth.rs
@@ -80,6 +80,7 @@ pub(crate) async fn post(
     cookie_jar: PrivateCookieJar<Encrypter>,
     Form(form): Form<ProtectedForm<ReauthForm>>,
 ) -> Result<Response, FancyError> {
+    let (clock, mut rng) = crate::rng_and_clock()?;
     let mut txn = pool.begin().await?;
 
     let form = cookie_jar.verify_form(form)?;
@@ -98,7 +99,7 @@ pub(crate) async fn post(
     };
 
     // TODO: recover from errors here
-    authenticate_session(&mut txn, &mut session, &form.password).await?;
+    authenticate_session(&mut txn, &mut rng, &clock, &mut session, &form.password).await?;
     let cookie_jar = cookie_jar.set_session(&session);
     txn.commit().await?;
 
diff --git a/crates/handlers/src/views/register.rs b/crates/handlers/src/views/register.rs
index 57da405b..d1957d33 100644
--- a/crates/handlers/src/views/register.rs
+++ b/crates/handlers/src/views/register.rs
@@ -39,7 +39,7 @@ use mas_templates::{
     EmailVerificationContext, FieldError, FormError, RegisterContext, RegisterFormField,
     TemplateContext, Templates, ToFormState,
 };
-use rand::{distributions::Uniform, thread_rng, Rng};
+use rand::{distributions::Uniform, Rng};
 use serde::{Deserialize, Serialize};
 use sqlx::{PgConnection, PgPool};
 
@@ -87,6 +87,7 @@ pub(crate) async fn get(
     }
 }
 
+#[allow(clippy::too_many_lines)]
 pub(crate) async fn post(
     State(mailer): State<Mailer>,
     State(policy_factory): State<Arc<PolicyFactory>>,
@@ -96,6 +97,7 @@ pub(crate) async fn post(
     cookie_jar: PrivateCookieJar<Encrypter>,
     Form(form): Form<ProtectedForm<RegisterForm>>,
 ) -> Result<Response, FancyError> {
+    let (clock, mut rng) = crate::rng_and_clock()?;
     let mut txn = pool.begin().await?;
 
     let form = cookie_jar.verify_form(form)?;
@@ -180,18 +182,34 @@ pub(crate) async fn post(
     }
 
     let pfh = Argon2::default();
-    let user = register_user(&mut txn, pfh, &form.username, &form.password).await?;
+    let user = register_user(
+        &mut txn,
+        &mut rng,
+        &clock,
+        pfh,
+        &form.username,
+        &form.password,
+    )
+    .await?;
 
-    let user_email = add_user_email(&mut txn, &user, form.email).await?;
+    let user_email = add_user_email(&mut txn, &mut rng, &clock, &user, form.email).await?;
 
     // First, generate a code
     let range = Uniform::<u32>::from(0..1_000_000);
-    let code = thread_rng().sample(range).to_string();
+    let code = rng.sample(range);
+    let code = format!("{code:06}");
 
     let address: Address = user_email.email.parse()?;
 
-    let verification =
-        add_user_email_verification_code(&mut txn, user_email, Duration::hours(8), code).await?;
+    let verification = add_user_email_verification_code(
+        &mut txn,
+        &mut rng,
+        &clock,
+        user_email,
+        Duration::hours(8),
+        code,
+    )
+    .await?;
 
     // And send the verification email
     let mailbox = Mailbox::new(Some(user.username.clone()), address);
@@ -203,7 +221,7 @@ pub(crate) async fn post(
     let next = mas_router::AccountVerifyEmail::new(verification.email.data)
         .and_maybe(query.post_auth_action);
 
-    let session = start_session(&mut txn, user).await?;
+    let session = start_session(&mut txn, &mut rng, &clock, user).await?;
 
     txn.commit().await?;
 
diff --git a/crates/jose/src/jwt/signed.rs b/crates/jose/src/jwt/signed.rs
index c55a8e3c..89a794bb 100644
--- a/crates/jose/src/jwt/signed.rs
+++ b/crates/jose/src/jwt/signed.rs
@@ -309,6 +309,7 @@ impl<T> Jwt<'static, T> {
         S: Signature,
         T: Serialize,
     {
+        #[allow(clippy::disallowed_methods)]
         Self::sign_with_rng(thread_rng(), header, payload, key)
     }
 
@@ -357,6 +358,7 @@ impl<T> Jwt<'static, T> {
 
 #[cfg(test)]
 mod tests {
+    #![allow(clippy::disallowed_methods)]
     use mas_iana::jose::JsonWebSignatureAlg;
     use rand::thread_rng;
 
diff --git a/crates/storage/Cargo.toml b/crates/storage/Cargo.toml
index f3a154b8..05f7aaa1 100644
--- a/crates/storage/Cargo.toml
+++ b/crates/storage/Cargo.toml
@@ -19,6 +19,7 @@ tracing = "0.1.37"
 argon2 = { version = "0.4.1", features = ["password-hash"] }
 password-hash = { version = "0.4.2", features = ["std"] }
 rand = "0.8.5"
+rand_chacha = "0.3.1"
 url = { version = "2.3.1", features = ["serde"] }
 uuid = "1.2.1"
 ulid = { version = "1.0.0", features = ["uuid", "serde"] }
diff --git a/crates/storage/src/compat.rs b/crates/storage/src/compat.rs
index f8084b56..6b0b9679 100644
--- a/crates/storage/src/compat.rs
+++ b/crates/storage/src/compat.rs
@@ -19,6 +19,7 @@ use mas_data_model::{
     CompatAccessToken, CompatRefreshToken, CompatSession, CompatSsoLogin, CompatSsoLoginState,
     Device, User, UserEmail,
 };
+use rand::Rng;
 use sqlx::{Acquire, PgExecutor, Postgres};
 use thiserror::Error;
 use tokio::task;
@@ -27,7 +28,7 @@ use ulid::Ulid;
 use url::Url;
 use uuid::Uuid;
 
-use crate::{user::lookup_user_by_username, DatabaseInconsistencyError, PostgresqlBackend};
+use crate::{user::lookup_user_by_username, Clock, DatabaseInconsistencyError, PostgresqlBackend};
 
 struct CompatAccessTokenLookup {
     compat_access_token_id: Uuid,
@@ -67,6 +68,7 @@ impl CompatAccessTokenLookupError {
 #[tracing::instrument(skip_all, err)]
 pub async fn lookup_active_compat_access_token(
     executor: impl PgExecutor<'_>,
+    clock: &Clock,
     token: &str,
 ) -> Result<
     (
@@ -112,7 +114,7 @@ pub async fn lookup_active_compat_access_token(
 
     // Check for token expiration
     if let Some(expires_at) = res.compat_access_token_expires_at {
-        if expires_at < Utc::now() {
+        if expires_at < clock.now() {
             return Err(CompatAccessTokenLookupError::Expired { when: expires_at });
         }
     }
@@ -311,7 +313,9 @@ pub async fn lookup_active_compat_refresh_token(
     err(Display),
 )]
 pub async fn compat_login(
-    conn: impl Acquire<'_, Database = Postgres>,
+    conn: impl Acquire<'_, Database = Postgres> + Send,
+    mut rng: impl Rng + Send,
+    clock: &Clock,
     username: &str,
     password: &str,
     device: Device,
@@ -348,8 +352,8 @@ pub async fn compat_login(
     .instrument(tracing::info_span!("Verify hashed password"))
     .await??;
 
-    let created_at = Utc::now();
-    let id = Ulid::from_datetime(created_at.into());
+    let created_at = clock.now();
+    let id = Ulid::from_datetime_with_source(created_at.into(), &mut rng);
     tracing::Span::current().record("compat_session.id", tracing::field::display(id));
 
     sqlx::query!(
@@ -392,12 +396,14 @@ pub async fn compat_login(
 )]
 pub async fn add_compat_access_token(
     executor: impl PgExecutor<'_>,
+    mut rng: impl Rng + Send,
+    clock: &Clock,
     session: &CompatSession<PostgresqlBackend>,
     token: String,
     expires_after: Option<Duration>,
 ) -> Result<CompatAccessToken<PostgresqlBackend>, anyhow::Error> {
-    let created_at = Utc::now();
-    let id = Ulid::from_datetime(created_at.into());
+    let created_at = clock.now();
+    let id = Ulid::from_datetime_with_source(created_at.into(), &mut rng);
     tracing::Span::current().record("compat_access_token.id", tracing::field::display(id));
 
     let expires_at = expires_after.map(|expires_after| created_at + expires_after);
@@ -436,9 +442,10 @@ pub async fn add_compat_access_token(
 )]
 pub async fn expire_compat_access_token(
     executor: impl PgExecutor<'_>,
+    clock: &Clock,
     access_token: CompatAccessToken<PostgresqlBackend>,
 ) -> Result<(), anyhow::Error> {
-    let expires_at = Utc::now();
+    let expires_at = clock.now();
     let res = sqlx::query!(
         r#"
             UPDATE compat_access_tokens
@@ -474,12 +481,14 @@ pub async fn expire_compat_access_token(
 )]
 pub async fn add_compat_refresh_token(
     executor: impl PgExecutor<'_>,
+    mut rng: impl Rng + Send,
+    clock: &Clock,
     session: &CompatSession<PostgresqlBackend>,
     access_token: &CompatAccessToken<PostgresqlBackend>,
     token: String,
 ) -> Result<CompatRefreshToken<PostgresqlBackend>, anyhow::Error> {
-    let created_at = Utc::now();
-    let id = Ulid::from_datetime(created_at.into());
+    let created_at = clock.now();
+    let id = Ulid::from_datetime_with_source(created_at.into(), &mut rng);
     tracing::Span::current().record("compat_refresh_token.id", tracing::field::display(id));
 
     sqlx::query!(
@@ -514,9 +523,10 @@ pub async fn add_compat_refresh_token(
 )]
 pub async fn compat_logout(
     executor: impl PgExecutor<'_>,
+    clock: &Clock,
     token: &str,
 ) -> Result<(), anyhow::Error> {
-    let finished_at = Utc::now();
+    let finished_at = clock.now();
     // TODO: this does not check for token expiration
     let compat_session_id = sqlx::query_scalar!(
         r#"
@@ -552,9 +562,10 @@ pub async fn compat_logout(
 )]
 pub async fn consume_compat_refresh_token(
     executor: impl PgExecutor<'_>,
+    clock: &Clock,
     refresh_token: CompatRefreshToken<PostgresqlBackend>,
 ) -> Result<(), anyhow::Error> {
-    let consumed_at = Utc::now();
+    let consumed_at = clock.now();
     let res = sqlx::query!(
         r#"
             UPDATE compat_refresh_tokens
@@ -587,11 +598,13 @@ pub async fn consume_compat_refresh_token(
 )]
 pub async fn insert_compat_sso_login(
     executor: impl PgExecutor<'_>,
+    mut rng: impl Rng + Send,
+    clock: &Clock,
     login_token: String,
     redirect_uri: Url,
 ) -> Result<CompatSsoLogin<PostgresqlBackend>, anyhow::Error> {
-    let created_at = Utc::now();
-    let id = Ulid::from_datetime(created_at.into());
+    let created_at = clock.now();
+    let id = Ulid::from_datetime_with_source(created_at.into(), &mut rng);
     tracing::Span::current().record("compat_sso_login.id", tracing::field::display(id));
 
     sqlx::query!(
@@ -845,7 +858,9 @@ pub async fn get_compat_sso_login_by_token(
     err(Display),
 )]
 pub async fn fullfill_compat_sso_login(
-    conn: impl Acquire<'_, Database = Postgres>,
+    conn: impl Acquire<'_, Database = Postgres> + Send,
+    mut rng: impl Rng + Send,
+    clock: &Clock,
     user: User<PostgresqlBackend>,
     mut login: CompatSsoLogin<PostgresqlBackend>,
     device: Device,
@@ -856,8 +871,8 @@ pub async fn fullfill_compat_sso_login(
 
     let mut txn = conn.begin().await.context("could not start transaction")?;
 
-    let created_at = Utc::now();
-    let id = Ulid::from_datetime(created_at.into());
+    let created_at = clock.now();
+    let id = Ulid::from_datetime_with_source(created_at.into(), &mut rng);
     tracing::Span::current().record("user.id", tracing::field::display(user.data));
 
     sqlx::query!(
@@ -883,7 +898,7 @@ pub async fn fullfill_compat_sso_login(
         finished_at: None,
     };
 
-    let fulfilled_at = Utc::now();
+    let fulfilled_at = clock.now();
     sqlx::query!(
         r#"
             UPDATE compat_sso_logins
@@ -924,6 +939,7 @@ pub async fn fullfill_compat_sso_login(
 )]
 pub async fn mark_compat_sso_login_as_exchanged(
     executor: impl PgExecutor<'_>,
+    clock: &Clock,
     mut login: CompatSsoLogin<PostgresqlBackend>,
 ) -> Result<CompatSsoLogin<PostgresqlBackend>, anyhow::Error> {
     let (fulfilled_at, session) = match login.state {
@@ -934,7 +950,7 @@ pub async fn mark_compat_sso_login_as_exchanged(
         _ => bail!("sso login in wrong state"),
     };
 
-    let exchanged_at = Utc::now();
+    let exchanged_at = clock.now();
     sqlx::query!(
         r#"
             UPDATE compat_sso_logins
diff --git a/crates/storage/src/lib.rs b/crates/storage/src/lib.rs
index 6c5d8471..06a71bb7 100644
--- a/crates/storage/src/lib.rs
+++ b/crates/storage/src/lib.rs
@@ -15,7 +15,12 @@
 //! Interactions with the database
 
 #![forbid(unsafe_code)]
-#![deny(clippy::all, clippy::str_to_string, rustdoc::broken_intra_doc_links)]
+#![deny(
+    clippy::all,
+    clippy::str_to_string,
+    clippy::future_not_send,
+    rustdoc::broken_intra_doc_links
+)]
 #![warn(clippy::pedantic)]
 #![allow(
     clippy::missing_errors_doc,
@@ -23,12 +28,27 @@
     clippy::module_name_repetitions
 )]
 
+use chrono::{DateTime, Utc};
 use mas_data_model::{StorageBackend, StorageBackendMarker};
 use serde::Serialize;
 use sqlx::migrate::Migrator;
 use thiserror::Error;
 use ulid::Ulid;
 
+#[derive(Default, Debug, Clone, Copy)]
+pub struct Clock {
+    _private: (),
+}
+
+impl Clock {
+    #[must_use]
+    pub fn now(&self) -> DateTime<Utc> {
+        // This is the clock used elsewhere, it's fine to call Utc::now here
+        #[allow(clippy::disallowed_methods)]
+        Utc::now()
+    }
+}
+
 #[derive(Debug, Error)]
 #[error("database query returned an inconsistent state")]
 pub struct DatabaseInconsistencyError;
diff --git a/crates/storage/src/oauth2/access_token.rs b/crates/storage/src/oauth2/access_token.rs
index b7702b5c..1e57637c 100644
--- a/crates/storage/src/oauth2/access_token.rs
+++ b/crates/storage/src/oauth2/access_token.rs
@@ -15,13 +15,14 @@
 use anyhow::Context;
 use chrono::{DateTime, Duration, Utc};
 use mas_data_model::{AccessToken, Authentication, BrowserSession, Session, User, UserEmail};
+use rand::Rng;
 use sqlx::{Acquire, PgExecutor, Postgres};
 use thiserror::Error;
 use ulid::Ulid;
 use uuid::Uuid;
 
 use super::client::{lookup_client, ClientFetchError};
-use crate::{DatabaseInconsistencyError, PostgresqlBackend};
+use crate::{Clock, DatabaseInconsistencyError, PostgresqlBackend};
 
 #[tracing::instrument(
     skip_all,
@@ -35,13 +36,15 @@ use crate::{DatabaseInconsistencyError, PostgresqlBackend};
 )]
 pub async fn add_access_token(
     executor: impl PgExecutor<'_>,
+    mut rng: impl Rng + Send,
+    clock: &Clock,
     session: &Session<PostgresqlBackend>,
     access_token: String,
     expires_after: Duration,
 ) -> Result<AccessToken<PostgresqlBackend>, anyhow::Error> {
-    let created_at = Utc::now();
+    let created_at = clock.now();
     let expires_at = created_at + expires_after;
-    let id = Ulid::from_datetime(created_at.into());
+    let id = Ulid::from_datetime_with_source(created_at.into(), &mut rng);
 
     tracing::Span::current().record("access_token.id", tracing::field::display(id));
 
@@ -243,9 +246,10 @@ where
 )]
 pub async fn revoke_access_token(
     executor: impl PgExecutor<'_>,
+    clock: &Clock,
     access_token: AccessToken<PostgresqlBackend>,
 ) -> anyhow::Result<()> {
-    let revoked_at = Utc::now();
+    let revoked_at = clock.now();
     let res = sqlx::query!(
         r#"
             UPDATE oauth2_access_tokens
@@ -266,9 +270,9 @@ pub async fn revoke_access_token(
     }
 }
 
-pub async fn cleanup_expired(executor: impl PgExecutor<'_>) -> anyhow::Result<u64> {
+pub async fn cleanup_expired(executor: impl PgExecutor<'_>, clock: &Clock) -> anyhow::Result<u64> {
     // Cleanup token which expired more than 15 minutes ago
-    let threshold = Utc::now() - Duration::minutes(15);
+    let threshold = clock.now() - Duration::minutes(15);
     let res = sqlx::query!(
         r#"
             DELETE FROM oauth2_access_tokens
diff --git a/crates/storage/src/oauth2/authorization_grant.rs b/crates/storage/src/oauth2/authorization_grant.rs
index 850e6bea..f8a7041b 100644
--- a/crates/storage/src/oauth2/authorization_grant.rs
+++ b/crates/storage/src/oauth2/authorization_grant.rs
@@ -24,13 +24,14 @@ use mas_data_model::{
 };
 use mas_iana::oauth::PkceCodeChallengeMethod;
 use oauth2_types::{requests::ResponseMode, scope::Scope};
+use rand::Rng;
 use sqlx::{PgConnection, PgExecutor};
 use ulid::Ulid;
 use url::Url;
 use uuid::Uuid;
 
 use super::client::lookup_client;
-use crate::{DatabaseInconsistencyError, PostgresqlBackend};
+use crate::{Clock, DatabaseInconsistencyError, PostgresqlBackend};
 
 #[tracing::instrument(
     skip_all,
@@ -43,6 +44,8 @@ use crate::{DatabaseInconsistencyError, PostgresqlBackend};
 #[allow(clippy::too_many_arguments)]
 pub async fn new_authorization_grant(
     executor: impl PgExecutor<'_>,
+    mut rng: impl Rng + Send,
+    clock: &Clock,
     client: Client<PostgresqlBackend>,
     redirect_uri: Url,
     scope: Scope,
@@ -67,8 +70,8 @@ pub async fn new_authorization_grant(
     let max_age_i32 = max_age.map(|x| i32::try_from(u32::from(x)).unwrap_or(i32::MAX));
     let code_str = code.as_ref().map(|c| &c.code);
 
-    let created_at = Utc::now();
-    let id = Ulid::from_datetime(created_at.into());
+    let created_at = clock.now();
+    let id = Ulid::from_datetime_with_source(created_at.into(), &mut rng);
     tracing::Span::current().record("grant.id", tracing::field::display(id));
 
     sqlx::query!(
@@ -504,11 +507,13 @@ pub async fn lookup_grant_by_code(
 )]
 pub async fn derive_session(
     executor: impl PgExecutor<'_>,
+    mut rng: impl Rng + Send,
+    clock: &Clock,
     grant: &AuthorizationGrant<PostgresqlBackend>,
     browser_session: BrowserSession<PostgresqlBackend>,
 ) -> Result<Session<PostgresqlBackend>, anyhow::Error> {
-    let created_at = Utc::now();
-    let id = Ulid::from_datetime(created_at.into());
+    let created_at = clock.now();
+    let id = Ulid::from_datetime_with_source(created_at.into(), &mut rng);
     tracing::Span::current().record("session.id", tracing::field::display(id));
 
     sqlx::query!(
@@ -623,9 +628,10 @@ pub async fn give_consent_to_grant(
 )]
 pub async fn exchange_grant(
     executor: impl PgExecutor<'_>,
+    clock: &Clock,
     mut grant: AuthorizationGrant<PostgresqlBackend>,
 ) -> Result<AuthorizationGrant<PostgresqlBackend>, anyhow::Error> {
-    let exchanged_at = Utc::now();
+    let exchanged_at = clock.now();
     sqlx::query!(
         r#"
             UPDATE oauth2_authorization_grants
diff --git a/crates/storage/src/oauth2/consent.rs b/crates/storage/src/oauth2/consent.rs
index dd531994..b19100db 100644
--- a/crates/storage/src/oauth2/consent.rs
+++ b/crates/storage/src/oauth2/consent.rs
@@ -14,14 +14,14 @@
 
 use std::str::FromStr;
 
-use chrono::Utc;
 use mas_data_model::{Client, User};
 use oauth2_types::scope::{Scope, ScopeToken};
+use rand::Rng;
 use sqlx::PgExecutor;
 use ulid::Ulid;
 use uuid::Uuid;
 
-use crate::PostgresqlBackend;
+use crate::{Clock, PostgresqlBackend};
 
 #[tracing::instrument(
     skip_all,
@@ -67,17 +67,19 @@ pub async fn fetch_client_consent(
 )]
 pub async fn insert_client_consent(
     executor: impl PgExecutor<'_>,
+    mut rng: impl Rng + Send,
+    clock: &Clock,
     user: &User<PostgresqlBackend>,
     client: &Client<PostgresqlBackend>,
     scope: &Scope,
 ) -> Result<(), anyhow::Error> {
-    let now = Utc::now();
+    let now = clock.now();
     let (tokens, ids): (Vec<String>, Vec<Uuid>) = scope
         .iter()
         .map(|token| {
             (
                 token.to_string(),
-                Uuid::from(Ulid::from_datetime(now.into())),
+                Uuid::from(Ulid::from_datetime_with_source(now.into(), &mut rng)),
             )
         })
         .unzip();
diff --git a/crates/storage/src/oauth2/mod.rs b/crates/storage/src/oauth2/mod.rs
index 38f59f22..6b5822b1 100644
--- a/crates/storage/src/oauth2/mod.rs
+++ b/crates/storage/src/oauth2/mod.rs
@@ -12,12 +12,11 @@
 // See the License for the specific language governing permissions and
 // limitations under the License.
 
-use chrono::Utc;
 use mas_data_model::Session;
 use sqlx::PgExecutor;
 use uuid::Uuid;
 
-use crate::PostgresqlBackend;
+use crate::{Clock, PostgresqlBackend};
 
 pub mod access_token;
 pub mod authorization_grant;
@@ -37,9 +36,10 @@ pub mod refresh_token;
 )]
 pub async fn end_oauth_session(
     executor: impl PgExecutor<'_>,
+    clock: &Clock,
     session: Session<PostgresqlBackend>,
 ) -> Result<(), anyhow::Error> {
-    let finished_at = Utc::now();
+    let finished_at = clock.now();
     let res = sqlx::query!(
         r#"
             UPDATE oauth2_sessions
diff --git a/crates/storage/src/oauth2/refresh_token.rs b/crates/storage/src/oauth2/refresh_token.rs
index 9423e21b..94c2cef7 100644
--- a/crates/storage/src/oauth2/refresh_token.rs
+++ b/crates/storage/src/oauth2/refresh_token.rs
@@ -17,13 +17,14 @@ use chrono::{DateTime, Utc};
 use mas_data_model::{
     AccessToken, Authentication, BrowserSession, RefreshToken, Session, User, UserEmail,
 };
+use rand::Rng;
 use sqlx::{PgConnection, PgExecutor};
 use thiserror::Error;
 use ulid::Ulid;
 use uuid::Uuid;
 
 use super::client::{lookup_client, ClientFetchError};
-use crate::{DatabaseInconsistencyError, PostgresqlBackend};
+use crate::{Clock, DatabaseInconsistencyError, PostgresqlBackend};
 
 #[tracing::instrument(
     skip_all,
@@ -38,12 +39,14 @@ use crate::{DatabaseInconsistencyError, PostgresqlBackend};
 )]
 pub async fn add_refresh_token(
     executor: impl PgExecutor<'_>,
+    mut rng: impl Rng + Send,
+    clock: &Clock,
     session: &Session<PostgresqlBackend>,
     access_token: AccessToken<PostgresqlBackend>,
     refresh_token: String,
 ) -> anyhow::Result<RefreshToken<PostgresqlBackend>> {
-    let created_at = Utc::now();
-    let id = Ulid::from_datetime(created_at.into());
+    let created_at = clock.now();
+    let id = Ulid::from_datetime_with_source(created_at.into(), &mut rng);
     tracing::Span::current().record("refresh_token.id", tracing::field::display(id));
 
     sqlx::query!(
@@ -263,9 +266,10 @@ pub async fn lookup_active_refresh_token(
 )]
 pub async fn consume_refresh_token(
     executor: impl PgExecutor<'_>,
+    clock: &Clock,
     refresh_token: &RefreshToken<PostgresqlBackend>,
 ) -> Result<(), anyhow::Error> {
-    let consumed_at = Utc::now();
+    let consumed_at = clock.now();
     let res = sqlx::query!(
         r#"
             UPDATE oauth2_refresh_tokens
diff --git a/crates/storage/src/user.rs b/crates/storage/src/user.rs
index 6d5f3816..b9070ec6 100644
--- a/crates/storage/src/user.rs
+++ b/crates/storage/src/user.rs
@@ -22,7 +22,7 @@ use mas_data_model::{
     UserEmailVerificationState,
 };
 use password_hash::{PasswordHash, PasswordHasher, SaltString};
-use rand::thread_rng;
+use rand::{CryptoRng, Rng};
 use sqlx::{Acquire, PgExecutor, Postgres, Transaction};
 use thiserror::Error;
 use tokio::task;
@@ -31,6 +31,7 @@ use ulid::Ulid;
 use uuid::Uuid;
 
 use super::{DatabaseInconsistencyError, PostgresqlBackend};
+use crate::Clock;
 
 #[derive(Debug, Clone)]
 struct UserLookup {
@@ -68,7 +69,9 @@ pub enum LoginError {
     err,
 )]
 pub async fn login(
-    conn: impl Acquire<'_, Database = Postgres>,
+    conn: impl Acquire<'_, Database = Postgres> + Send,
+    mut rng: impl Rng + Send,
+    clock: &Clock,
     username: &str,
     password: &str,
 ) -> Result<BrowserSession<PostgresqlBackend>, LoginError> {
@@ -86,8 +89,8 @@ pub async fn login(
             }
         })?;
 
-    let mut session = start_session(&mut txn, user).await?;
-    authenticate_session(&mut txn, &mut session, password)
+    let mut session = start_session(&mut txn, &mut rng, clock, user).await?;
+    authenticate_session(&mut txn, &mut rng, clock, &mut session, password)
         .await
         .map_err(|source| {
             if matches!(source, AuthenticationError::Password { .. }) {
@@ -230,10 +233,12 @@ pub async fn lookup_active_session(
 )]
 pub async fn start_session(
     executor: impl PgExecutor<'_>,
+    mut rng: impl Rng + Send,
+    clock: &Clock,
     user: User<PostgresqlBackend>,
 ) -> Result<BrowserSession<PostgresqlBackend>, anyhow::Error> {
-    let created_at = Utc::now();
-    let id = Ulid::from_datetime(created_at.into());
+    let created_at = clock.now();
+    let id = Ulid::from_datetime_with_source(created_at.into(), &mut rng);
     tracing::Span::current().record("user_session.id", tracing::field::display(id));
 
     sqlx::query!(
@@ -301,13 +306,16 @@ pub enum AuthenticationError {
 #[tracing::instrument(
     skip_all,
     fields(
-        session.id = %session.data,
-        user.id = %session.user.data
+        user.id = %session.user.data,
+        user_session.id = %session.data,
+        user_session_authentication.id,
     ),
     err,
 )]
 pub async fn authenticate_session(
     txn: &mut Transaction<'_, Postgres>,
+    mut rng: impl Rng + Send,
+    clock: &Clock,
     session: &mut BrowserSession<PostgresqlBackend>,
     password: &str,
 ) -> Result<(), AuthenticationError> {
@@ -341,8 +349,13 @@ pub async fn authenticate_session(
     .await??;
 
     // That went well, let's insert the auth info
-    let created_at = Utc::now();
-    let id = Ulid::from_datetime(created_at.into());
+    let created_at = clock.now();
+    let id = Ulid::from_datetime_with_source(created_at.into(), &mut rng);
+    tracing::Span::current().record(
+        "user_session_authentication.id",
+        tracing::field::display(id),
+    );
+
     sqlx::query!(
         r#"
             INSERT INTO user_session_authentications
@@ -376,12 +389,14 @@ pub async fn authenticate_session(
 )]
 pub async fn register_user(
     txn: &mut Transaction<'_, Postgres>,
-    phf: impl PasswordHasher,
+    mut rng: impl CryptoRng + Rng + Send,
+    clock: &Clock,
+    phf: impl PasswordHasher + Send,
     username: &str,
     password: &str,
 ) -> Result<User<PostgresqlBackend>, anyhow::Error> {
-    let created_at = Utc::now();
-    let id = Ulid::from_datetime(created_at.into());
+    let created_at = clock.now();
+    let id = Ulid::from_datetime_with_source(created_at.into(), &mut rng);
     tracing::Span::current().record("user.id", tracing::field::display(id));
 
     sqlx::query!(
@@ -405,7 +420,7 @@ pub async fn register_user(
         primary_email: None,
     };
 
-    set_password(txn.borrow_mut(), phf, &user, password).await?;
+    set_password(txn.borrow_mut(), &mut rng, clock, phf, &user, password).await?;
 
     Ok(user)
 }
@@ -420,15 +435,17 @@ pub async fn register_user(
 )]
 pub async fn set_password(
     executor: impl PgExecutor<'_>,
-    phf: impl PasswordHasher,
+    mut rng: impl CryptoRng + Rng + Send,
+    clock: &Clock,
+    phf: impl PasswordHasher + Send,
     user: &User<PostgresqlBackend>,
     password: &str,
 ) -> Result<(), anyhow::Error> {
-    let created_at = Utc::now();
+    let created_at = clock.now();
     let id = Ulid::from_datetime(created_at.into());
     tracing::Span::current().record("user_password.id", tracing::field::display(id));
 
-    let salt = SaltString::generate(thread_rng());
+    let salt = SaltString::generate(&mut rng);
     let hashed_password = PasswordHash::generate(phf, password, salt.as_str())?;
 
     sqlx::query_scalar!(
@@ -456,9 +473,10 @@ pub async fn set_password(
 )]
 pub async fn end_session(
     executor: impl PgExecutor<'_>,
+    clock: &Clock,
     session: &BrowserSession<PostgresqlBackend>,
 ) -> Result<(), anyhow::Error> {
-    let now = Utc::now();
+    let now = clock.now();
     let res = sqlx::query!(
         r#"
             UPDATE user_sessions
@@ -672,11 +690,13 @@ pub async fn get_user_email(
 )]
 pub async fn add_user_email(
     executor: impl PgExecutor<'_>,
+    mut rng: impl Rng + Send,
+    clock: &Clock,
     user: &User<PostgresqlBackend>,
     email: String,
 ) -> Result<UserEmail<PostgresqlBackend>, anyhow::Error> {
-    let created_at = Utc::now();
-    let id = Ulid::from_datetime(created_at.into());
+    let created_at = clock.now();
+    let id = Ulid::from_datetime_with_source(created_at.into(), &mut rng);
     tracing::Span::current().record("user_email.id", tracing::field::display(id));
 
     sqlx::query!(
@@ -842,9 +862,10 @@ pub async fn lookup_user_email_by_id(
 )]
 pub async fn mark_user_email_as_verified(
     executor: impl PgExecutor<'_>,
+    clock: &Clock,
     mut email: UserEmail<PostgresqlBackend>,
 ) -> Result<UserEmail<PostgresqlBackend>, anyhow::Error> {
-    let confirmed_at = Utc::now();
+    let confirmed_at = clock.now();
     sqlx::query!(
         r#"
             UPDATE user_emails
@@ -881,10 +902,11 @@ struct UserEmailConfirmationCodeLookup {
 )]
 pub async fn lookup_user_email_verification_code(
     executor: impl PgExecutor<'_>,
+    clock: &Clock,
     email: UserEmail<PostgresqlBackend>,
     code: &str,
 ) -> Result<UserEmailVerification<PostgresqlBackend>, anyhow::Error> {
-    let now = Utc::now();
+    let now = clock.now();
 
     let res = sqlx::query_as!(
         UserEmailConfirmationCodeLookup,
@@ -935,13 +957,14 @@ pub async fn lookup_user_email_verification_code(
 )]
 pub async fn consume_email_verification(
     executor: impl PgExecutor<'_>,
+    clock: &Clock,
     mut verification: UserEmailVerification<PostgresqlBackend>,
 ) -> Result<UserEmailVerification<PostgresqlBackend>, anyhow::Error> {
     if !matches!(verification.state, UserEmailVerificationState::Valid) {
         bail!("user email verification in wrong state");
     }
 
-    let consumed_at = Utc::now();
+    let consumed_at = clock.now();
 
     sqlx::query!(
         r#"
@@ -974,12 +997,14 @@ pub async fn consume_email_verification(
 )]
 pub async fn add_user_email_verification_code(
     executor: impl PgExecutor<'_>,
+    mut rng: impl Rng + Send,
+    clock: &Clock,
     email: UserEmail<PostgresqlBackend>,
     max_age: chrono::Duration,
     code: String,
 ) -> Result<UserEmailVerification<PostgresqlBackend>, anyhow::Error> {
-    let created_at = Utc::now();
-    let id = Ulid::from_datetime(created_at.into());
+    let created_at = clock.now();
+    let id = Ulid::from_datetime_with_source(created_at.into(), &mut rng);
     tracing::Span::current().record("user_email_confirmation.id", tracing::field::display(id));
     let expires_at = created_at + max_age;
 
@@ -1013,23 +1038,27 @@ pub async fn add_user_email_verification_code(
 
 #[cfg(test)]
 mod tests {
+    use rand::SeedableRng;
+
     use super::*;
 
     #[sqlx::test(migrator = "crate::MIGRATOR")]
     async fn test_user_registration_and_login(pool: sqlx::PgPool) -> anyhow::Result<()> {
+        let clock = Clock::default();
+        let mut rng = rand_chacha::ChaChaRng::seed_from_u64(42);
         let mut txn = pool.begin().await?;
 
         let exists = username_exists(&mut txn, "john").await?;
         assert!(!exists);
 
         let hasher = Argon2::default();
-        let user = register_user(&mut txn, hasher, "john", "hunter2").await?;
+        let user = register_user(&mut txn, &mut rng, &clock, hasher, "john", "hunter2").await?;
         assert_eq!(user.username, "john");
 
         let exists = username_exists(&mut txn, "john").await?;
         assert!(exists);
 
-        let session = login(&mut txn, "john", "hunter2").await?;
+        let session = login(&mut txn, &mut rng, &clock, "john", "hunter2").await?;
         assert_eq!(session.user.data, user.data);
 
         let user2 = lookup_user_by_username(&mut txn, "john").await?;
diff --git a/crates/tasks/src/database.rs b/crates/tasks/src/database.rs
index b80eec0d..5e72141e 100644
--- a/crates/tasks/src/database.rs
+++ b/crates/tasks/src/database.rs
@@ -14,13 +14,14 @@
 
 //! Database-related tasks
 
+use mas_storage::Clock;
 use sqlx::{Pool, Postgres};
 use tracing::{debug, error, info};
 
 use super::Task;
 
 #[derive(Clone)]
-struct CleanupExpired(Pool<Postgres>);
+struct CleanupExpired(Pool<Postgres>, Clock);
 
 impl std::fmt::Debug for CleanupExpired {
     fn fmt(&self, f: &mut std::fmt::Formatter<'_>) -> std::fmt::Result {
@@ -31,7 +32,7 @@ impl std::fmt::Debug for CleanupExpired {
 #[async_trait::async_trait]
 impl Task for CleanupExpired {
     async fn run(&self) {
-        let res = mas_storage::oauth2::access_token::cleanup_expired(&self.0).await;
+        let res = mas_storage::oauth2::access_token::cleanup_expired(&self.0, &self.1).await;
         match res {
             Ok(0) => {
                 debug!("no token to clean up");
@@ -49,5 +50,6 @@ impl Task for CleanupExpired {
 /// Cleanup expired tokens
 #[must_use]
 pub fn cleanup_expired(pool: &Pool<Postgres>) -> impl Task + Clone {
-    CleanupExpired(pool.clone())
+    // XXX: the clock should come from somewhere else
+    CleanupExpired(pool.clone(), Clock::default())
 }