Replace the liboqs-based pre-standardization SPHINCS+ implementation
with the native FIPS 205 SLH-DSA implementation across the
certificate / ASN.1 / X.509 layers, and add SLH-DSA-rooted test
certificates plus TLS 1.3 .conf scenarios that exercise the new
verification path. All liboqs SPHINCS+ code is removed.
This enables SLH-DSA for certificate chain authentication: CA
certificates signed with SLH-DSA, certificate signature verification
against an SLH-DSA root. TLS 1.3 entity authentication via
CertificateVerify with SLH-DSA will be added in a follow-up PR.
Follows RFC 9909 (X.509 Algorithm Identifiers for SLH-DSA) and
NIST FIPS 205. Supports both SHAKE and SHA-2 parameter families
across all twelve standardized variants.
DER codec:
- New PrivateKeyDecode, PublicKeyDecode, KeyToDer, PrivateKeyToDer,
PublicKeyToDer with RFC 9909 encoding (bare OCTET STRING containing
4*n raw bytes = SK.seed || SK.prf || PK.seed || PK.root, no nested
wrapper). OID auto-detection across all twelve SHAKE / SHA-2 variants.
- PublicKeyDecode raw-bytes fast path mirrors wc_Falcon_PublicKeyDecode
and wc_Dilithium_PublicKeyDecode so callers (notably
wolfssl_x509_make_der and ConfirmSignature, which pass the raw
BIT STRING contents stashed by StoreKey) decode correctly. Honours
the caller's *inOutIdx start offset.
- Error paths in Private/PublicKeyDecode preserve params/flags/
inOutIdx and only ForceZero the buffer half each helper actually
writes; skip the wipe entirely on BAD_LENGTH_E (no bytes touched).
- ImportPublic uses |= on flags so a Private-then-Public import
sequence retains FLAG_PRIVATE.
OID dispatch:
- 12 standardized NIST OIDs (6 SHAKE + 6 SHA-2) per RFC 9909. The
pre-standardization OID-collision mechanism is removed since NIST
OIDs do not collide.
- wc_SlhDsaOidToParam / wc_SlhDsaOidToCertType return NOT_COMPILED_IN
(rather than -1) for recognised SLH-DSA OIDs whose parameter set
isn't built; wc_IsSlhDsaOid recognises both. The x509 dispatch
surfaces this as a precise diagnostic instead of the generic
"No public key found".
- wc_GetKeyOID picks a placeholder parameter from whatever variant is
compiled in and #errors at compile time if none is.
- asn_orig.c EncodeCert / EncodeCertReq accept SHA-2 SLH-DSA keyTypes
alongside SHAKE.
Tests and fixtures:
- Test cert chain in certs/slhdsa/: SLH-DSA-SHAKE-128s and
SLH-DSA-SHA2-128s self-signed roots that sign reused ML-DSA-44
entity keys (server + client), plus the gen script
(gen-slhdsa-mldsa-certs.sh, OpenSSL >= 3.5).
- New TLS 1.3 .conf scenarios under tests/suites.c dispatch:
test-tls13-slhdsa-shake.conf, test-tls13-slhdsa-sha2.conf, and a
wrong-CA negative test test-tls13-slhdsa-fail.conf.
- DER round-trip and on-disk decode tests; bench_slhdsa_*_key.der
fixtures regenerated with wolfSSL's own encoder so the codec is
pinned to RFC 9909.
- New unit test test_wc_slhdsa_x509_i2d_roundtrip exercises the raw
PublicKeyDecode entry point that wolfssl_x509_make_der relies on.
- test_wc_slhdsa_check_key now tests both Public-then-Private and
Private-then-Public import orderings.
Build / ABI:
- DYNAMIC_TYPE_SPHINCS = 98 kept as RESERVED with a tombstone comment
for ABI stability; new code should use DYNAMIC_TYPE_SLHDSA (107).
- All build system / IDE project files updated; SPHINCS+ sources,
headers, and test data removed.
- Dead bench_slhdsa_*_key arrays removed from gencertbuf.pl and
certs_test.h; the .der files on disk drive the decode tests.
Tobias Frauenschläger
JacobBarthelmeh
Andras Fekete
Daniel Pouzzner
Lealem Amedie