diff options
Diffstat (limited to 'g10/sig-check.c')
| -rw-r--r-- | g10/sig-check.c | 21 |
1 files changed, 15 insertions, 6 deletions
diff --git a/g10/sig-check.c b/g10/sig-check.c index 4cb1ea65e..2de2f7818 100644 --- a/g10/sig-check.c +++ b/g10/sig-check.c @@ -65,17 +65,26 @@ signature_check( PKT_signature *sig, MD_HANDLE digest ) free_public_key( pk ); - if( !rc && is_status_enabled() - && ( sig->pubkey_algo == PUBKEY_ALGO_DSA - || sig->pubkey_algo == PUBKEY_ALGO_ELGAMAL ) ) { - /* If we are using these public key algorithms we can - * calculate an unique signature id, which may be useful - * in an application to prevent replac attacks */ + if( !rc && is_status_enabled() ) { + /* This signature id works best with DLP algorithms because + * they use a random parameter for every signature. Instead of + * this sig-id we could have also used the hash of the document + * and the timestamp, but the drawback of this is, that it is + * not possible to sign more than one identical document within + * one second. Some remote bacth processing applications might + * like this feature here */ MD_HANDLE md; + u32 a = sig->timestamp; int i, nsig = pubkey_get_nsig( sig->pubkey_algo ); byte *p; md = md_open( DIGEST_ALGO_RMD160, 0); + md_putc( digest, sig->pubkey_algo ); + md_putc( digest, sig->digest_algo ); + md_putc( digest, (a >> 24) & 0xff ); + md_putc( digest, (a >> 16) & 0xff ); + md_putc( digest, (a >> 8) & 0xff ); + md_putc( digest, a & 0xff ); for(i=0; i < nsig; i++ ) { unsigned n = mpi_get_nbits( sig->data[i]); |