mirror of
https://github.com/Mbed-TLS/mbedtls.git
synced 2025-11-03 20:33:16 +03:00
69 lines
2.5 KiB
Markdown
69 lines
2.5 KiB
Markdown
TLS 1.3 Experimental Developments
|
|
=================================
|
|
|
|
Overview
|
|
--------
|
|
|
|
Mbed TLS doesn't support the TLS 1.3 protocol yet, but a prototype is in development.
|
|
Stable parts of this prototype that can be independently tested are being successively
|
|
upstreamed under the guard of the following macro:
|
|
|
|
```
|
|
MBEDTLS_SSL_PROTO_TLS1_3_EXPERIMENTAL
|
|
```
|
|
|
|
This macro will likely be renamed to `MBEDTLS_SSL_PROTO_TLS1_3` once a minimal viable
|
|
implementation of the TLS 1.3 protocol is available.
|
|
|
|
See the [documentation of `MBEDTLS_SSL_PROTO_TLS1_3_EXPERIMENTAL`](../../include/mbedtls/config.h)
|
|
for more information.
|
|
|
|
Status
|
|
------
|
|
|
|
The following lists which parts of the TLS 1.3 prototype have already been upstreamed
|
|
together with their level of testing:
|
|
|
|
* TLS 1.3 record protection mechanisms
|
|
|
|
The record protection routines `mbedtls_ssl_{encrypt|decrypt}_buf()` have been extended
|
|
to support the modified TLS 1.3 record protection mechanism, including modified computation
|
|
of AAD, IV, and the introduction of a flexible padding.
|
|
|
|
Those record protection routines have unit tests in `test_suite_ssl` alongside the
|
|
tests for the other record protection routines.
|
|
|
|
TODO: Add some test vectors from RFC 8448.
|
|
|
|
- The HKDF key derivation function on which the TLS 1.3 key schedule is based,
|
|
is already present as an independent module controlled by `MBEDTLS_HKDF_C`
|
|
independently of the development of the TLS 1.3 prototype.
|
|
|
|
- The TLS 1.3-specific HKDF-based key derivation functions (see RFC 8446):
|
|
* HKDF-Expand-Label
|
|
* Derive-Secret
|
|
- Secret evolution
|
|
* The traffic {Key,IV} generation from secret
|
|
Those functions are implemented in `library/ssl_tls13_keys.c` and
|
|
tested in `test_suite_ssl` using test vectors from RFC 8448 and
|
|
https://tls13.ulfheim.net/.
|
|
|
|
- New TLS Message Processing Stack (MPS)
|
|
|
|
The TLS 1.3 prototype is developed alongside a rewrite of the TLS messaging layer,
|
|
encompassing low-level details such as record parsing, handshake reassembly, and
|
|
DTLS retransmission state machine.
|
|
|
|
MPS has the following components:
|
|
- Layer 1 (Datagram handling)
|
|
- Layer 2 (Record handling)
|
|
- Layer 3 (Message handling)
|
|
- Layer 4 (Retransmission State Machine)
|
|
- Reader (Abstracted pointer arithmetic and reassembly logic for incoming data)
|
|
- Writer (Abstracted pointer arithmetic and fragmentation logic for outgoing data)
|
|
|
|
Of those components, the following have been upstreamed
|
|
as part of `MBEDTLS_SSL_PROTO_TLS1_3_EXPERIMENTAL`:
|
|
|
|
- Reader ([`library/mps_reader.h`](../../library/mps_reader.h))
|