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| author | Werner Koch <wk@gnupg.org> | 2014-07-24 12:30:32 +0200 |
|---|---|---|
| committer | Werner Koch <wk@gnupg.org> | 2014-07-25 08:13:56 +0200 |
| commit | 4556f9b19c024f16bdf542da7173395c0741b91d (patch) | |
| tree | 5f8785a6cde5043636d65680a9625852c6133178 /doc | |
| parent | 0e10902ad7584277ac966367efc712b183784532 (diff) | |
| download | libgcrypt-4556f9b19c024f16bdf542da7173395c0741b91d.tar.gz | |
ecc: Support the non-standard 0x40 compression flag for EdDSA.
* cipher/ecc.c (ecc_generate): Check the "comp" flag for EdDSA.
* cipher/ecc-eddsa.c (eddsa_encode_x_y): Add arg WITH_PREFIX.
(_gcry_ecc_eddsa_encodepoint): Ditto.
(_gcry_ecc_eddsa_ensure_compact): Handle the 0x40 compression prefix.
(_gcry_ecc_eddsa_decodepoint): Ditto.
* tests/keygrip.c: Check an compresssed with prefix Ed25519 key.
* tests/t-ed25519.inp: Ditto.
Diffstat (limited to 'doc')
| -rw-r--r-- | doc/gcrypt.texi | 12 |
1 files changed, 8 insertions, 4 deletions
diff --git a/doc/gcrypt.texi b/doc/gcrypt.texi index d59c0958..23efc526 100644 --- a/doc/gcrypt.texi +++ b/doc/gcrypt.texi @@ -2162,7 +2162,9 @@ The private key @math{d} All point values are encoded in standard format; Libgcrypt does in general only support uncompressed points, thus the first byte needs to be @code{0x04}. However ``EdDSA'' describes its own compression -scheme which is used by default. +scheme which is used by default; the non-standard first byte +@code{0x40} may optionally be used to explicit flag the use of the +algorithm’s native compression method. The public key is similar with "private-key" replaced by "public-key" and no @var{d-mpi}. @@ -2232,9 +2234,11 @@ are known: If supported by the algorithm and curve the @code{comp} flag requests that points are returned in compact (compressed) representation. The @code{nocomp} flag requests that points are returned with full -coordinates. The default depends on the the algorithm and curve. -The compact representation requires a small overhead before a point -can be used but halves the size of a to be conveyed public key. +coordinates. The default depends on the the algorithm and curve. The +compact representation requires a small overhead before a point can be +used but halves the size of a to be conveyed public key. If +@code{comp} is used with the ``EdDSA'' algorithm the key generation +prefix the public key with a @code{0x40} byte. @item pkcs1 @cindex PKCS1 |