diff --git a/include/libssh/crypto.h b/include/libssh/crypto.h
index 4cd0cecd..034b4f2e 100644
--- a/include/libssh/crypto.h
+++ b/include/libssh/crypto.h
@@ -45,6 +45,7 @@
 #ifdef HAVE_OPENSSL_ECDH_H
 #include <openssl/ecdh.h>
 #endif
+#include "libssh/dh.h"
 #include "libssh/ecdh.h"
 #include "libssh/kex.h"
 #include "libssh/curve25519.h"
@@ -98,10 +99,11 @@ enum ssh_cipher_e {
     SSH_AEAD_CHACHA20_POLY1305
 };
 
+struct dh_ctx;
+
 struct ssh_crypto_struct {
-    bignum e,f,x,k,y;
-    bignum g, p;
-    int dh_group_is_mutable; /* do free group parameters */
+    bignum shared_secret;
+    struct dh_ctx *dh_ctx;
 #ifdef WITH_GEX
     size_t dh_pmin; int dh_pn; int dh_pmax; /* preferred group parameters */
 #endif /* WITH_GEX */
diff --git a/include/libssh/dh.h b/include/libssh/dh.h
index 25aad47e..2a9be714 100644
--- a/include/libssh/dh.h
+++ b/include/libssh/dh.h
@@ -25,6 +25,18 @@
 
 #include "libssh/crypto.h"
 
+struct dh_keypair {
+    bignum priv_key;
+    bignum pub_key;
+};
+
+struct dh_ctx {
+    struct dh_keypair client;
+    struct dh_keypair server;
+    bignum generator;
+    bignum modulus;
+};
+
 int ssh_dh_init(void);
 void ssh_dh_finalize(void);
 
diff --git a/src/curve25519.c b/src/curve25519.c
index 3a914a41..92f603dd 100644
--- a/src/curve25519.c
+++ b/src/curve25519.c
@@ -95,8 +95,8 @@ static int ssh_curve25519_build_k(ssh_session session) {
 	  crypto_scalarmult(k, session->next_crypto->curve25519_privkey,
 			  session->next_crypto->curve25519_server_pubkey);
 
-  bignum_bin2bn(k, CURVE25519_PUBKEY_SIZE, &session->next_crypto->k);
-  if (session->next_crypto->k == NULL) {
+  bignum_bin2bn(k, CURVE25519_PUBKEY_SIZE, &session->next_crypto->shared_secret);
+  if (session->next_crypto->shared_secret == NULL) {
     return SSH_ERROR;
   }
 
@@ -105,7 +105,7 @@ static int ssh_curve25519_build_k(ssh_session session) {
                    session->next_crypto->server_kex.cookie, 16);
     ssh_print_hexa("Session client cookie",
                    session->next_crypto->client_kex.cookie, 16);
-    ssh_print_bignum("Shared secret key", session->next_crypto->k);
+    ssh_print_bignum("Shared secret key", session->next_crypto->shared_secret);
 #endif
 
   return 0;
diff --git a/src/dh-gex.c b/src/dh-gex.c
index cbe7e02c..02494bb2 100644
--- a/src/dh-gex.c
+++ b/src/dh-gex.c
@@ -128,11 +128,10 @@ SSH_PACKET_CALLBACK(ssh_packet_client_dhgex_group)
         ssh_set_error_oom(session);
         goto error;
     }
-    session->next_crypto->dh_group_is_mutable = 1;
     rc = ssh_buffer_unpack(packet,
                            "BB",
-                           &session->next_crypto->p,
-                           &session->next_crypto->g);
+                           &session->next_crypto->dh_ctx->modulus,
+                           &session->next_crypto->dh_ctx->generator);
     if (rc != SSH_OK) {
         ssh_set_error(session, SSH_FATAL, "Invalid DH_GEX_GROUP packet");
         goto error;
@@ -142,7 +141,7 @@ SSH_PACKET_CALLBACK(ssh_packet_client_dhgex_group)
     if (rc != 1) {
         goto error;
     }
-    blen = bignum_num_bits(session->next_crypto->p);
+    blen = bignum_num_bits(session->next_crypto->dh_ctx->modulus);
     if (blen < DH_PMIN || blen > DH_PMAX) {
         ssh_set_error(session,
                 SSH_FATAL,
@@ -152,36 +151,31 @@ SSH_PACKET_CALLBACK(ssh_packet_client_dhgex_group)
                 DH_PMAX);
         goto error;
     }
-    if (bignum_cmp(session->next_crypto->p, one) <= 0) {
+    if (bignum_cmp(session->next_crypto->dh_ctx->modulus, one) <= 0) {
         /* p must be positive and preferably bigger than one */
         ssh_set_error(session, SSH_FATAL, "Invalid dh group parameter p");
     }
-    if (!bignum_is_bit_set(session->next_crypto->p, 0)) {
+    if (!bignum_is_bit_set(session->next_crypto->dh_ctx->modulus, 0)) {
         /* p must be a prime and therefore not divisible by 2 */
         ssh_set_error(session, SSH_FATAL, "Invalid dh group parameter p");
         goto error;
     }
-    bignum_sub(pmin1, session->next_crypto->p, one);
-    if (bignum_cmp(session->next_crypto->g, one) <= 0 ||
-        bignum_cmp(session->next_crypto->g, pmin1) > 0) {
+    bignum_sub(pmin1, session->next_crypto->dh_ctx->modulus, one);
+    if (bignum_cmp(session->next_crypto->dh_ctx->generator, one) <= 0 ||
+        bignum_cmp(session->next_crypto->dh_ctx->generator, pmin1) > 0) {
         /* generator must be at least 2 and smaller than p-1*/
         ssh_set_error(session, SSH_FATAL, "Invalid dh group parameter g");
         goto error;
     }
     /* compute and send DH public parameter */
-    rc = ssh_dh_generate_secret(session, session->next_crypto->x);
+    rc = ssh_dh_generate_secret(session, session->next_crypto->dh_ctx->client.priv_key);
     if (rc == SSH_ERROR) {
         goto error;
     }
-    session->next_crypto->e = bignum_new();
-    if (session->next_crypto->e == NULL) {
-        ssh_set_error_oom(session);
-        goto error;
-    }
-    rc = bignum_mod_exp(session->next_crypto->e,
-                        session->next_crypto->g,
-                        session->next_crypto->x,
-                        session->next_crypto->p,
+    rc = bignum_mod_exp(session->next_crypto->dh_ctx->client.pub_key,
+                        session->next_crypto->dh_ctx->generator,
+                        session->next_crypto->dh_ctx->client.priv_key,
+                        session->next_crypto->dh_ctx->modulus,
                         ctx);
     if (rc != 1) {
         goto error;
@@ -193,7 +187,7 @@ SSH_PACKET_CALLBACK(ssh_packet_client_dhgex_group)
     rc = ssh_buffer_pack(session->out_buffer,
                          "bB",
                          SSH2_MSG_KEX_DH_GEX_INIT,
-                         session->next_crypto->e);
+                         session->next_crypto->dh_ctx->client.pub_key);
     if (rc != SSH_OK) {
         goto error;
     }
@@ -229,7 +223,7 @@ static SSH_PACKET_CALLBACK(ssh_packet_client_dhgex_reply)
     ssh_packet_remove_callbacks(session, &ssh_dhgex_client_callbacks);
     rc = ssh_buffer_unpack(packet,
                            "SBS",
-                           &pubkey_blob, &crypto->f,
+                           &pubkey_blob, &crypto->dh_ctx->server.pub_key,
                            &crypto->dh_server_signature);
 
     if (rc == SSH_ERROR) {
@@ -584,8 +578,8 @@ static SSH_PACKET_CALLBACK(ssh_packet_server_dhgex_request)
                               pn,
                               pmax,
                               &size,
-                              &session->next_crypto->p,
-                              &session->next_crypto->g);
+                              &session->next_crypto->dh_ctx->modulus,
+                              &session->next_crypto->dh_ctx->generator);
     if (rc == SSH_ERROR) {
         ssh_set_error(session,
                       SSH_FATAL,
@@ -595,12 +589,11 @@ static SSH_PACKET_CALLBACK(ssh_packet_server_dhgex_request)
                       pmax);
         goto error;
     }
-    session->next_crypto->dh_group_is_mutable = 1;
     rc = ssh_buffer_pack(session->out_buffer,
                          "bBB",
                          SSH2_MSG_KEX_DH_GEX_GROUP,
-                         session->next_crypto->p,
-                         session->next_crypto->g);
+                         session->next_crypto->dh_ctx->modulus,
+                         session->next_crypto->dh_ctx->generator);
     if (rc != SSH_OK) {
         ssh_set_error_invalid(session);
         goto error;
diff --git a/src/dh.c b/src/dh.c
index 5bfa8b35..e997d583 100644
--- a/src/dh.c
+++ b/src/dh.c
@@ -294,65 +294,120 @@ void ssh_dh_finalize(void)
     dh_crypto_initialized = 0;
 }
 
+static void ssh_dh_free_dh_keypair(struct dh_keypair *keypair)
+{
+    bignum_safe_free(keypair->priv_key);
+    bignum_safe_free(keypair->pub_key);
+}
+
+static int ssh_dh_init_dh_keypair(struct dh_keypair *keypair)
+{
+    int rc;
+
+    keypair->priv_key = bignum_new();
+    if (keypair->priv_key == NULL) {
+        rc = SSH_ERROR;
+        goto done;
+    }
+    keypair->pub_key = bignum_new();
+    if (keypair->pub_key == NULL) {
+        rc = SSH_ERROR;
+        goto done;
+    }
+
+    rc = SSH_OK;
+done:
+    if (rc != SSH_OK) {
+        ssh_dh_free_dh_keypair(keypair);
+    }
+    return rc;
+}
+
 /**
  * @internal
  * @brief allocate and initialize ephemeral values used in dh kex
  */
-int ssh_dh_init_common(ssh_session session){
-    struct ssh_crypto_struct *crypto=session->next_crypto;
-    crypto->x = bignum_new();
-    crypto->y = bignum_new();
-    crypto->e = NULL;
-    crypto->f = NULL;
-    crypto->k = bignum_new();
-    crypto->g = NULL;
-    crypto->p = NULL;
-    crypto->dh_group_is_mutable = 0;
-    switch(session->next_crypto->kex_type) {
-      case SSH_KEX_DH_GROUP1_SHA1:
-        session->next_crypto->p = p_group1;
-        session->next_crypto->g = g;
-        session->next_crypto->dh_group_is_mutable = 0;
-        break;
-      case SSH_KEX_DH_GROUP14_SHA1:
-        session->next_crypto->p = p_group14;
-        session->next_crypto->g = g;
-        session->next_crypto->dh_group_is_mutable = 0;
-        break;
-      case SSH_KEX_DH_GROUP16_SHA512:
-        session->next_crypto->p = p_group16;
-        session->next_crypto->g = g;
-        session->next_crypto->dh_group_is_mutable = 0;
-        break;
-      case SSH_KEX_DH_GROUP18_SHA512:
-        session->next_crypto->p = p_group18;
-        session->next_crypto->g = g;
-        session->next_crypto->dh_group_is_mutable = 0;
-        break;
-      default:
-        /* fall through */
-        break;
-    }
-    if (crypto->x == NULL || crypto->y == NULL || crypto->k == NULL){
-        bignum_safe_free(crypto->k);
-        bignum_safe_free(crypto->y);
-        bignum_safe_free(crypto->x);
-        ssh_set_error_oom(session);
+int ssh_dh_init_common(ssh_session session)
+{
+    struct ssh_crypto_struct *crypto = session->next_crypto;
+    struct dh_ctx *ctx = NULL;
+    int rc;
+
+    ctx = calloc(1, sizeof(*ctx));
+    if (ctx == NULL) {
         return SSH_ERROR;
-    } else {
-        return SSH_OK;
     }
+
+    switch (crypto->kex_type) {
+    case SSH_KEX_DH_GROUP1_SHA1:
+        ctx->generator = g;
+        ctx->modulus = p_group1;
+        break;
+    case SSH_KEX_DH_GROUP14_SHA1:
+        ctx->generator = g;
+        ctx->modulus = p_group14;
+        break;
+    case SSH_KEX_DH_GROUP16_SHA512:
+        ctx->generator = g;
+        ctx->modulus = p_group16;
+        break;
+    case SSH_KEX_DH_GROUP18_SHA512:
+        ctx->generator = g;
+        ctx->modulus = p_group18;
+        break;
+    default:
+        break;
+    }
+
+    rc = ssh_dh_init_dh_keypair(&ctx->client);
+    if (rc != SSH_OK) {
+        goto done;
+    }
+
+    rc = ssh_dh_init_dh_keypair(&ctx->server);
+    if (rc != SSH_OK) {
+        goto done;
+    }
+
+    crypto->shared_secret = bignum_new();
+    if (crypto->shared_secret == NULL) {
+        goto done;
+    }
+
+    crypto->dh_ctx = ctx;
+    rc = SSH_OK;
+done:
+    if (rc != SSH_OK) {
+        ssh_dh_free_dh_keypair(&ctx->client);
+        ssh_dh_free_dh_keypair(&ctx->server);
+        free(ctx);
+        ssh_set_error_oom(session);
+    }
+    return rc;
 }
 
-void ssh_dh_cleanup(struct ssh_crypto_struct *crypto){
-    bignum_safe_free(crypto->x);
-    bignum_safe_free(crypto->y);
-    bignum_safe_free(crypto->e);
-    bignum_safe_free(crypto->f);
-    if (crypto->dh_group_is_mutable){
-        bignum_safe_free(crypto->p);
-        bignum_safe_free(crypto->g);
+void ssh_dh_cleanup(struct ssh_crypto_struct *crypto)
+{
+    struct dh_ctx *ctx = crypto->dh_ctx;
+
+    if (ctx == NULL) {
+        return;
     }
+
+    ssh_dh_free_dh_keypair(&ctx->client);
+    ssh_dh_free_dh_keypair(&ctx->server);
+
+    if ((ctx->modulus != p_group1) &&
+        (ctx->modulus != p_group14) &&
+        (ctx->modulus != p_group16) &&
+        (ctx->modulus != p_group18)) {
+        bignum_safe_free(ctx->modulus);
+    }
+    if (ctx->generator != g) {
+        bignum_safe_free(ctx->generator);
+    }
+    free(ctx);
+    crypto->dh_ctx = NULL;
 }
 
 int ssh_dh_import_next_pubkey_blob(ssh_session session, ssh_string pubkey_blob)
@@ -365,18 +420,18 @@ int ssh_dh_import_next_pubkey_blob(ssh_session session, ssh_string pubkey_blob)
 #ifdef DEBUG_CRYPTO
 static void ssh_dh_debug(ssh_session session)
 {
-    ssh_print_bignum("p", session->next_crypto->p);
-    ssh_print_bignum("g", session->next_crypto->g);
-    ssh_print_bignum("x", session->next_crypto->x);
-    ssh_print_bignum("y", session->next_crypto->y);
-    ssh_print_bignum("e", session->next_crypto->e);
-    ssh_print_bignum("f", session->next_crypto->f);
+    ssh_print_bignum("p", session->next_crypto->dh_ctx->modulus);
+    ssh_print_bignum("g", session->next_crypto->dh_ctx->generator);
+    ssh_print_bignum("x", session->next_crypto->dh_ctx->client.priv_key);
+    ssh_print_bignum("y", session->next_crypto->dh_ctx->server.priv_key);
+    ssh_print_bignum("e", session->next_crypto->dh_ctx->client.pub_key);
+    ssh_print_bignum("f", session->next_crypto->dh_ctx->server.pub_key);
  
     ssh_print_hexa("Session server cookie",
                    session->next_crypto->server_kex.cookie, 16);
     ssh_print_hexa("Session client cookie",
                    session->next_crypto->client_kex.cookie, 16);
-    ssh_print_bignum("k", session->next_crypto->k);
+    ssh_print_bignum("k", session->next_crypto->shared_secret);
 }
 #else
 #define ssh_dh_debug(session)
@@ -404,7 +459,7 @@ int ssh_dh_generate_secret(ssh_session session, bignum dest)
     if (tmp == NULL) {
         goto error;
     }
-    p_bits = bignum_num_bits(session->next_crypto->p);
+    p_bits = bignum_num_bits(session->next_crypto->dh_ctx->modulus);
     /* we need at most DH_SECURITY_BITS */
     bits = MIN(DH_SECURITY_BITS * 2, p_bits);
     /* ensure we're not too close of p so rnd()%p stays uniform */
@@ -415,7 +470,7 @@ int ssh_dh_generate_secret(ssh_session session, bignum dest)
     if (rc != 1) {
         goto error;
     }
-    rc = bignum_mod(dest, tmp, session->next_crypto->p, ctx);
+    rc = bignum_mod(dest, tmp, session->next_crypto->dh_ctx->modulus, ctx);
     if (rc != 1) {
         goto error;
     }
@@ -439,16 +494,16 @@ int ssh_dh_build_k(ssh_session session)
 
     /* the server and clients don't use the same numbers */
     if (session->client) {
-        rc = bignum_mod_exp(session->next_crypto->k,
-                            session->next_crypto->f,
-                            session->next_crypto->x,
-                            session->next_crypto->p,
+        rc = bignum_mod_exp(session->next_crypto->shared_secret,
+                            session->next_crypto->dh_ctx->server.pub_key,
+                            session->next_crypto->dh_ctx->client.priv_key,
+                            session->next_crypto->dh_ctx->modulus,
                             ctx);
     } else {
-        rc = bignum_mod_exp(session->next_crypto->k,
-                            session->next_crypto->e,
-                            session->next_crypto->y,
-                            session->next_crypto->p,
+        rc = bignum_mod_exp(session->next_crypto->shared_secret,
+                            session->next_crypto->dh_ctx->client.pub_key,
+                            session->next_crypto->dh_ctx->server.priv_key,
+                            session->next_crypto->dh_ctx->modulus,
                             ctx);
     }
 
@@ -488,22 +543,18 @@ int ssh_client_dh_init(ssh_session session){
     goto error;
   }
 
-  rc = ssh_dh_generate_secret(session, session->next_crypto->x);
+  rc = ssh_dh_generate_secret(session, session->next_crypto->dh_ctx->client.priv_key);
   if (rc == SSH_ERROR){
       goto error;
   }
-  session->next_crypto->e = bignum_new();
-  if (session->next_crypto->e == NULL){
-      goto error;
-  }
-  rc = bignum_mod_exp(session->next_crypto->e, session->next_crypto->g, session->next_crypto->x,
-      session->next_crypto->p, ctx);
+  rc = bignum_mod_exp(session->next_crypto->dh_ctx->client.pub_key, session->next_crypto->dh_ctx->generator, session->next_crypto->dh_ctx->client.priv_key,
+      session->next_crypto->dh_ctx->modulus, ctx);
 
   bignum_ctx_free(ctx);
   if (rc != 1) {
     goto error;
   }
-  rc = ssh_buffer_pack(session->out_buffer, "bB", SSH2_MSG_KEXDH_INIT, session->next_crypto->e);
+  rc = ssh_buffer_pack(session->out_buffer, "bB", SSH2_MSG_KEXDH_INIT, session->next_crypto->dh_ctx->client.pub_key);
   if (rc != SSH_OK) {
     goto error;
   }
@@ -529,7 +580,7 @@ SSH_PACKET_CALLBACK(ssh_packet_client_dh_reply){
 
   ssh_packet_remove_callbacks(session, &ssh_dh_client_callbacks);
 
-  rc = ssh_buffer_unpack(packet, "SBS", &pubkey_blob, &crypto->f,
+  rc = ssh_buffer_unpack(packet, "SBS", &pubkey_blob, &crypto->dh_ctx->server.pub_key,
           &crypto->dh_server_signature);
   if (rc == SSH_ERROR) {
       goto error;
@@ -606,25 +657,21 @@ int ssh_server_dh_process_init(ssh_session session, ssh_buffer packet)
     if (bignum_ctx_invalid(ctx)) {
         goto error;
     }
-    rc = ssh_buffer_unpack(packet, "B", &session->next_crypto->e);
+    rc = ssh_buffer_unpack(packet, "B", &session->next_crypto->dh_ctx->client.pub_key);
     if (rc == SSH_ERROR) {
         ssh_set_error(session, SSH_FATAL, "No e number in client request");
         goto error;
     }
 
-    rc = ssh_dh_generate_secret(session, session->next_crypto->y);
+    rc = ssh_dh_generate_secret(session, session->next_crypto->dh_ctx->server.priv_key);
     if (rc == SSH_ERROR){
         goto error;
     }
 
-    session->next_crypto->f = bignum_new();
-    if (session->next_crypto->f == NULL){
-        goto error;
-    }
-    rc = bignum_mod_exp(session->next_crypto->f,
-                        session->next_crypto->g,
-                        session->next_crypto->y,
-                        session->next_crypto->p, ctx);
+    rc = bignum_mod_exp(session->next_crypto->dh_ctx->server.pub_key,
+                        session->next_crypto->dh_ctx->generator,
+                        session->next_crypto->dh_ctx->server.priv_key,
+                        session->next_crypto->dh_ctx->modulus, ctx);
     bignum_ctx_free(ctx);
     ctx = NULL;
     if (rc != 1) {
@@ -677,7 +724,7 @@ int ssh_server_dh_process_init(ssh_session session, ssh_buffer packet)
                          "bSBS",
                          packet_type,
                          pubkey_blob,
-                         session->next_crypto->f,
+                         session->next_crypto->dh_ctx->server.pub_key,
                          sig_blob);
     SSH_STRING_FREE(sig_blob);
     SSH_STRING_FREE(pubkey_blob);
diff --git a/src/ecdh_crypto.c b/src/ecdh_crypto.c
index 0078712e..86e4551c 100644
--- a/src/ecdh_crypto.c
+++ b/src/ecdh_crypto.c
@@ -170,9 +170,9 @@ int ecdh_build_k(ssh_session session) {
       return -1;
   }
 
-  bignum_bin2bn(buffer, len, &session->next_crypto->k);
+  bignum_bin2bn(buffer, len, &session->next_crypto->shared_secret);
   free(buffer);
-  if (session->next_crypto->k == NULL) {
+  if (session->next_crypto->shared_secret == NULL) {
       EC_KEY_free(session->next_crypto->ecdh_privkey);
       session->next_crypto->ecdh_privkey = NULL;
       return -1;
@@ -185,7 +185,7 @@ int ecdh_build_k(ssh_session session) {
                    session->next_crypto->server_kex.cookie, 16);
     ssh_print_hexa("Session client cookie",
                    session->next_crypto->client_kex.cookie, 16);
-    ssh_print_bignum("Shared secret key", session->next_crypto->k);
+    ssh_print_bignum("Shared secret key", session->next_crypto->shared_secret);
 #endif
 
   return 0;
diff --git a/src/ecdh_gcrypt.c b/src/ecdh_gcrypt.c
index 913855c0..473846b8 100644
--- a/src/ecdh_gcrypt.c
+++ b/src/ecdh_gcrypt.c
@@ -198,8 +198,9 @@ int ecdh_build_k(ssh_session session)
         goto out;
     }
 
-    session->next_crypto->k = gcry_mpi_new(0);
-    gcry_mpi_point_snatch_get(session->next_crypto->k, NULL, NULL, point);
+    session->next_crypto->shared_secret = gcry_mpi_new(0);
+    gcry_mpi_point_snatch_get(session->next_crypto->shared_secret,
+                              NULL, NULL, point);
 #else
     s = ssh_sexp_extract_mpi(result, "s", GCRYMPI_FMT_USG, GCRYMPI_FMT_USG);
     if (s == NULL) {
@@ -224,7 +225,7 @@ int ecdh_build_k(ssh_session session)
         goto out;
     }
 
-    err = gcry_mpi_scan(&session->next_crypto->k,
+    err = gcry_mpi_scan(&session->next_crypto->shared_secret,
                         GCRYMPI_FMT_USG,
                         (const char *)ssh_string_data(s) + 1,
                         k_len / 2,
@@ -245,7 +246,7 @@ int ecdh_build_k(ssh_session session)
                    session->next_crypto->server_kex.cookie, 16);
     ssh_print_hexa("Session client cookie",
                    session->next_crypto->client_kex.cookie, 16);
-    ssh_print_bignum("Shared secret key", session->next_crypto->k);
+    ssh_print_bignum("Shared secret key", session->next_crypto->shared_secret);
 #endif
 
  out:
diff --git a/src/ecdh_mbedcrypto.c b/src/ecdh_mbedcrypto.c
index 68033f7d..2c165aaa 100644
--- a/src/ecdh_mbedcrypto.c
+++ b/src/ecdh_mbedcrypto.c
@@ -154,16 +154,16 @@ int ecdh_build_k(ssh_session session)
         goto out;
     }
 
-    session->next_crypto->k = malloc(sizeof(mbedtls_mpi));
-    if (session->next_crypto->k == NULL) {
+    session->next_crypto->shared_secret = malloc(sizeof(mbedtls_mpi));
+    if (session->next_crypto->shared_secret == NULL) {
         rc = SSH_ERROR;
         goto out;
     }
 
-    mbedtls_mpi_init(session->next_crypto->k);
+    mbedtls_mpi_init(session->next_crypto->shared_secret);
 
     rc = mbedtls_ecdh_compute_shared(&grp,
-                                     session->next_crypto->k,
+                                     session->next_crypto->shared_secret,
                                      &pubkey,
                                      &session->next_crypto->ecdh_privkey->d,
                                      mbedtls_ctr_drbg_random,
diff --git a/src/kex.c b/src/kex.c
index 750996b3..618ec88e 100644
--- a/src/kex.c
+++ b/src/kex.c
@@ -1123,8 +1123,8 @@ int ssh_make_sessionid(ssh_session session)
     case SSH_KEX_DH_GROUP18_SHA512:
         rc = ssh_buffer_pack(buf,
                              "BB",
-                             session->next_crypto->e,
-                             session->next_crypto->f);
+                             session->next_crypto->dh_ctx->client.pub_key,
+                             session->next_crypto->dh_ctx->server.pub_key);
         if (rc != SSH_OK) {
             goto error;
         }
@@ -1137,10 +1137,10 @@ int ssh_make_sessionid(ssh_session session)
                     session->next_crypto->dh_pmin,
                     session->next_crypto->dh_pn,
                     session->next_crypto->dh_pmax,
-                    session->next_crypto->p,
-                    session->next_crypto->g,
-                    session->next_crypto->e,
-                    session->next_crypto->f);
+                    session->next_crypto->dh_ctx->modulus,
+                    session->next_crypto->dh_ctx->generator,
+                    session->next_crypto->dh_ctx->client.pub_key,
+                    session->next_crypto->dh_ctx->server.pub_key);
         if (rc != SSH_OK) {
             goto error;
         }
@@ -1180,7 +1180,7 @@ int ssh_make_sessionid(ssh_session session)
         break;
 #endif
     }
-    rc = ssh_buffer_pack(buf, "B", session->next_crypto->k);
+    rc = ssh_buffer_pack(buf, "B", session->next_crypto->shared_secret);
     if (rc != SSH_OK) {
         goto error;
     }
@@ -1365,7 +1365,7 @@ int ssh_generate_session_keys(ssh_session session)
     size_t intkey_srv_to_cli_len = 0;
     int rc = -1;
 
-    k_string = ssh_make_bignum_string(crypto->k);
+    k_string = ssh_make_bignum_string(crypto->shared_secret);
     if (k_string == NULL) {
         ssh_set_error_oom(session);
         goto error;
diff --git a/src/wrapper.c b/src/wrapper.c
index ca04f5b2..299d4f3f 100644
--- a/src/wrapper.c
+++ b/src/wrapper.c
@@ -169,7 +169,7 @@ void crypto_free(struct ssh_crypto_struct *crypto)
     ssh_key_free(crypto->server_pubkey);
 
     ssh_dh_cleanup(crypto);
-    bignum_safe_free(crypto->k);
+    bignum_safe_free(crypto->shared_secret);
 #ifdef HAVE_ECDH
     SAFE_FREE(crypto->ecdh_client_pubkey);
     SAFE_FREE(crypto->ecdh_server_pubkey);
diff --git a/tests/unittests/torture_session_keys.c b/tests/unittests/torture_session_keys.c
index 2a21e63b..e7ef2e44 100644
--- a/tests/unittests/torture_session_keys.c
+++ b/tests/unittests/torture_session_keys.c
@@ -69,7 +69,7 @@ static void torture_session_keys(UNUSED_PARAM(void **state))
 
     k_string = ssh_string_new(32);
     ssh_string_fill(k_string, key, 32);
-    test_crypto.k = ssh_make_string_bn(k_string);
+    test_crypto.shared_secret = ssh_make_string_bn(k_string);
 
     rc = ssh_generate_session_keys(&session);
     assert_int_equal(rc, 0);