This introduces support for ML-KEM-512 and ML-KEM-1024 using the same
underlying implementation parameterised by a few macros for the
associated types and constants.
KAT tests are added for ML-KEM 512 and 1024, to complement the previous
tests for ML-KEM-768.
MLKEM{512,768,1024} TLS "group" codepoints are updated to match the
final IANA assigments and to make the additional KEMs known to the TLS
layer.
The pure-QC MLKEMs are not in the default list of supported groups, and
need to be explicitly enabled by the application. Future work will
introduce support for hybrids, and for more fine-grained policy of
which keyshares a client should send by default, and when a server
should request (HRR) a new mutually-supported group that was not
sent.
Tests for ML-KEM key exchange added to sslapitest to make sure that our
TLS client MLKEM{512,768,1024} implementations interoperate with our TLS
server, and that MLKEM* are not negotiated in TLS 1.2.
Tests also added to excercise non-derandomised ML-KEM APIs, both
directly (bypassing the provider layer), and through the generic EVP KEM
API (exercising the provider). These make sure that RNG input is used
correctly (KAT tests bypass the RNG by specifying seeds).
The API interface to the provider takes an "const ML_KEM_VINFO" pointer,
(obtained from ossl_ml_kem_get_vinfo()). This checks input and output
buffer sizes before passing control to internal code that assumes
correctly sized (for each variant) buffers.
The original BoringSSL API was refactored to eliminate the opaque
public/private key structure wrappers, since these structures are an
internal detail between libcrypto and the provider, they are not part of
the public (EVP) API.
New "clangover" counter-measures added, refined with much appreciated
input from David Benjamin (Chromium).
The internal steps of "encrypt_cpa" were reordered to reduce the
working-set size of the algorithm, now needs space for just two
temporary "vectors" rather than three. The "decap" function now process
the decrypted message in one call, rather than three separate calls to
scalar_decode_1, scalar_decompress and scalar_add.
Some loops were unrolled, improving performance of en/decapsulate
(pre-expanded vectors and matrix) by around 5%.
To handle, however unlikely, the SHA3 primitives not behaving like
"pure" functions and failing, the implementation of `decap` was modifed:
- To use the KDF to compute the Fujisaki-Okamoto (FO) failure secret
first thing, and if that fails, bail out returning an error, a shared
secret is still returned at random from the RNG, but it is OK for the
caller to not use it.
- If any of the subsequently used hash primitives fail, use the computed
FO failure secret (OK, despite no longer constant-time) and return
success (otherwise the RNG would replace the result).
- We quite reasonably assume that chosen-ciphertext attacks (of the
correct length) cannot cause hash functions to fail in a manner the
depends on the private key content.
Support for ML-KEM-512 required adding a centered binomial distribution
helper function to deal with η_1 == 3 in just that variant.
Some additional comments were added to highlight how the code relates to
the ML-KEM specification in FIPS 203.
Reviewed-by: Paul Dale <ppzgs1@gmail.com>
Reviewed-by: Tim Hudson <tjh@openssl.org>
Reviewed-by: Matt Caswell <matt@openssl.org>
Reviewed-by: Tomas Mraz <tomas@openssl.org>
(Merged from https://github.com/openssl/openssl/pull/26172)
d2136d9e73