diff options
Diffstat (limited to 'g10/ecdh.c')
| -rw-r--r-- | g10/ecdh.c | 9 |
1 files changed, 8 insertions, 1 deletions
diff --git a/g10/ecdh.c b/g10/ecdh.c index ac2883cf4..9a1f535a0 100644 --- a/g10/ecdh.c +++ b/g10/ecdh.c @@ -129,6 +129,13 @@ extract_secret_x (byte **r_secret_x, } +/* Build KDF parameters */ +/* RFC 6637 defines the KDF parameters and its encoding in Section + 8. EC DH Algorighm (ECDH). Since it was written for v4 key, it + said "20 octets representing a recipient encryption subkey or a + master key fingerprint". For v5 key, it is considered "adequate" + (in terms of NIST SP 800 56A, see 5.8.2 FixedInfo) to use the first + 20 octets of its 32 octets fingerprint. */ static gpg_error_t build_kdf_params (unsigned char kdf_params[256], size_t *r_size, gcry_mpi_t *pkey, const byte pk_fp[MAX_FINGERPRINT_LEN]) @@ -150,7 +157,7 @@ build_kdf_params (unsigned char kdf_params[256], size_t *r_size, err = (err ? err : gpg_mpi_write_nohdr (obuf, pkey[2])); /* fixed-length field 4 */ iobuf_write (obuf, "Anonymous Sender ", 20); - /* fixed-length field 5, recipient fp */ + /* fixed-length field 5, recipient fp (or first 20 octets of fp) */ iobuf_write (obuf, pk_fp, 20); if (!err) |