diff options
Diffstat (limited to '')
| -rw-r--r-- | cipher/cipher.c | 51 |
1 files changed, 51 insertions, 0 deletions
diff --git a/cipher/cipher.c b/cipher/cipher.c index a44dcc4a7..59b6f2efb 100644 --- a/cipher/cipher.c +++ b/cipher/cipher.c @@ -408,6 +408,49 @@ do_ecb_decrypt( CIPHER_HANDLE c, byte *outbuf, byte *inbuf, unsigned nblocks ) } } +static void +do_cbc_encrypt( CIPHER_HANDLE c, byte *outbuf, byte *inbuf, unsigned nblocks ) +{ + unsigned int n; + byte *ivp; + int i; + size_t blocksize = c->blocksize; + + for(n=0; n < nblocks; n++ ) { + /* fixme: the xor should works on words and not on + * bytes. Maybe it is a good idea to enhance the cipher backend + * API to allow for CBC handling in the backend */ + for(ivp=c->iv,i=0; i < blocksize; i++ ) + outbuf[i] ^= *ivp++; + (*c->encrypt)( &c->context.c, outbuf, outbuf ); + memcpy(c->iv, outbuf, blocksize ); + inbuf += c->blocksize; + outbuf += c->blocksize; + } +} + +static void +do_cbc_decrypt( CIPHER_HANDLE c, byte *outbuf, byte *inbuf, unsigned nblocks ) +{ + unsigned int n; + byte *ivp; + int i; + size_t blocksize = c->blocksize; + + for(n=0; n < nblocks; n++ ) { + /* because outbuf and inbuf might be the same, we have + * to save the original ciphertext block. We use lastiv + * for this here because it is not used otherwise */ + memcpy(c->lastiv, inbuf, blocksize ); + (*c->decrypt)( &c->context.c, outbuf, inbuf ); + for(ivp=c->iv,i=0; i < blocksize; i++ ) + outbuf[i] ^= *ivp++; + memcpy(c->iv, c->lastiv, blocksize ); + inbuf += c->blocksize; + outbuf += c->blocksize; + } +} + static void do_cfb_encrypt( CIPHER_HANDLE c, byte *outbuf, byte *inbuf, unsigned nbytes ) @@ -524,6 +567,10 @@ cipher_encrypt( CIPHER_HANDLE c, byte *outbuf, byte *inbuf, unsigned nbytes ) assert(!(nbytes%8)); do_ecb_encrypt(c, outbuf, inbuf, nbytes/8 ); break; + case CIPHER_MODE_CBC: + assert(!(nbytes%8)); /* fixme: should be blocksize */ + do_cbc_encrypt(c, outbuf, inbuf, nbytes/8 ); + break; case CIPHER_MODE_CFB: case CIPHER_MODE_PHILS_CFB: do_cfb_encrypt(c, outbuf, inbuf, nbytes ); @@ -550,6 +597,10 @@ cipher_decrypt( CIPHER_HANDLE c, byte *outbuf, byte *inbuf, unsigned nbytes ) assert(!(nbytes%8)); do_ecb_decrypt(c, outbuf, inbuf, nbytes/8 ); break; + case CIPHER_MODE_CBC: + assert(!(nbytes%8)); /* fixme: should assert on blocksize */ + do_cbc_decrypt(c, outbuf, inbuf, nbytes/8 ); + break; case CIPHER_MODE_CFB: case CIPHER_MODE_PHILS_CFB: do_cfb_decrypt(c, outbuf, inbuf, nbytes ); |