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ElGamal funktioniert und ist default

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This commit is contained in:
Werner Koch 1997-11-24 22:24:04 +00:00
parent a51cca90b6
commit 46900fbd43
31 changed files with 1273 additions and 409 deletions
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55
g10/pubkey-enc.c
View file

@ -39,24 +39,50 @@ int
get_session_key( PKT_pubkey_enc *k, DEK *dek )
{
int i, j, c, rc = 0;
RSA_secret_key *skey = m_alloc_secure( sizeof *skey );
MPI dek_frame = mpi_alloc_secure(40);
u16 csum, csum2;
PKT_seckey_cert *skc = m_alloc_clear( sizeof *skc );
if( k->pubkey_algo != PUBKEY_ALGO_RSA ) {
skc->pubkey_algo = k->pubkey_algo; /* we want a pubkey with this algo*/
if( (rc = get_seckey( skc, k->keyid )) )
goto leave;
if( k->pubkey_algo == PUBKEY_ALGO_ELGAMAL ) {
ELG_secret_key skey;
if( DBG_CIPHER ) {
log_mpidump("Encr DEK a:", k->d.elg.a );
log_mpidump(" DEK b:", k->d.elg.b );
}
skey.p = skc->d.elg.p;
skey.g = skc->d.elg.g;
skey.y = skc->d.elg.y;
skey.x = skc->d.elg.x;
elg_decipher( dek_frame, k->d.elg.a, k->d.elg.b, &skey );
memset( &skey, 0, sizeof skey );
}
else if( k->pubkey_algo == PUBKEY_ALGO_RSA ) {
RSA_secret_key skey;
if( DBG_CIPHER )
log_mpidump("Encr DEK frame:", k->d.rsa.rsa_integer );
skey.e = skc->d.rsa.rsa_e;
skey.n = skc->d.rsa.rsa_n;
skey.p = skc->d.rsa.rsa_p;
skey.q = skc->d.rsa.rsa_q;
skey.d = skc->d.rsa.rsa_d;
skey.u = skc->d.rsa.rsa_u;
rsa_secret( dek_frame, k->d.rsa.rsa_integer, &skey );
memset( &skey, 0, sizeof skey );
}
else {
rc = G10ERR_PUBKEY_ALGO; /* unsupported algorithm */
goto leave;
}
free_seckey_cert( skc ); skc = NULL;
/* get the secret key for the given public key
* and decode the rsa_integer
*/
if( (rc = get_seckey( skey, k->keyid )) )
goto leave;
if( DBG_CIPHER )
log_mpidump("Encr DEK frame:", k->d.rsa.rsa_integer );
rsa_secret( dek_frame, k->d.rsa.rsa_integer, skey );
/* Now get the DEK (data encryption key) from the dek_frame
*
* Old versions encode the DEK in in this format (msb is left):
@ -87,7 +113,7 @@ get_session_key( PKT_pubkey_enc *k, DEK *dek )
}
if( c != 2 ) /* somethink is wrong */
{ rc = G10ERR_WRONG_SECKEY; goto leave; }
/* look for the zeor byte */
/* look for the zero byte */
for(i--; i > 4 ; i-- )
if( !mpi_getbyte(dek_frame,i) )
break;
@ -95,10 +121,10 @@ get_session_key( PKT_pubkey_enc *k, DEK *dek )
{ rc = G10ERR_WRONG_SECKEY; goto leave; }
/* next byte indicates the used cipher */
switch( mpi_getbyte(dek_frame, --i ) ) {
case 1:
case CIPHER_ALGO_IDEA:
rc = G10ERR_NI_CIPHER;
goto leave;
case 42:
case CIPHER_ALGO_BLOWFISH:
if( i != 22 ) /* length of blowfish is 20 (+2 bytes checksum) */
{ rc = G10ERR_WRONG_SECKEY; goto leave; }
dek->algo = CIPHER_ALGO_BLOWFISH;
@ -122,7 +148,8 @@ get_session_key( PKT_pubkey_enc *k, DEK *dek )
leave:
mpi_free(dek_frame);
m_free(skey);
if( skc )
free_seckey_cert( skc );
return rc;
}