generic-library/openssl
1
0
Fork 0
Code Issues Pull Requests Releases Wiki Activity

Add untested CFB-r mode. Will be tested soon.

Browse Source
This commit is contained in:
Ben Laurie 2003-07-27 13:46:57 +00:00
parent 5cc2658cff
commit a052dd6532
2 changed files with 60 additions and 0 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

3
crypto/aes/aes.h
View File

@ -95,6 +95,9 @@ void AES_cbc_encrypt(const unsigned char *in, unsigned char *out,
void AES_cfb128_encrypt(const unsigned char *in, unsigned char *out,
const unsigned long length, const AES_KEY *key,
unsigned char *ivec, int *num, const int enc);
void AES_cfbr_encrypt_block(const unsigned char *in,unsigned char *out,
const int nbits,const AES_KEY *key,
unsigned char *ivec,const int enc);
void AES_ofb128_encrypt(const unsigned char *in, unsigned char *out,
const unsigned long length, const AES_KEY *key,
unsigned char *ivec, int *num);

57
crypto/aes/aes_cfb.c
View File

@ -155,3 +155,60 @@ void AES_cfb128_encrypt(const unsigned char *in, unsigned char *out,
*num=n;
}
/* This expects a single block of size nbits for both in and out. Note that
it corrupts any extra bits in the last byte of out */
/* Untested, once it is working, it will be optimised */
void AES_cfbr_encrypt_block(const unsigned char *in,unsigned char *out,
const int nbits,const AES_KEY *key,
unsigned char *ivec,const int enc)
{
unsigned int n;
unsigned char ovec[AES_BLOCK_SIZE*2];
assert(in && out && key && ivec);
if(enc)
{
/* construct the new IV in the second half of ovec */
AES_encrypt(ivec,ovec+AES_BLOCK_SIZE,key);
/* encrypt the input */
for(n=0 ; n < (nbits+7)/8 ; ++n)
out[n]=in[n]^ovec[n+AES_BLOCK_SIZE];
/* fill in the first half of the new IV with the current IV */
memcpy(ovec,ivec,AES_BLOCK_SIZE);
/* shift ovec left most of the bits... */
memmove(ovec,ovec+nbits/8,AES_BLOCK_SIZE+(nbits%8 ? 1 : 0));
/* now the remaining bits */
if(nbits%8 != 0)
for(n=0 ; n < AES_BLOCK_SIZE ; ++n)
{
ovec[n]<<=nbits%8;
ovec[n]|=ovec[n+1]>>(8-nbits%8);
}
/* finally, move it back into place */
memcpy(ivec,ovec,AES_BLOCK_SIZE);
}
else
{
/* construct the new IV in the first half of ovec */
AES_encrypt(ivec,ovec,key);
/* decrypt the input */
for(n=0 ; n < (nbits+7)/8 ; ++n)
out[n]=in[n]^ovec[n];
/* fill in the first half of the new IV with the current IV */
memcpy(ovec,ivec,AES_BLOCK_SIZE);
/* append the ciphertext */
memcpy(ovec+AES_BLOCK_SIZE,in,(nbits+7)/8);
/* shift ovec left most of the bits... */
memmove(ovec,ovec+nbits/8,AES_BLOCK_SIZE+(nbits%8 ? 1 : 0));
/* now the remaining bits */
if(nbits%8 != 0)
for(n=0 ; n < AES_BLOCK_SIZE ; ++n)
{
ovec[n]<<=nbits%8;
ovec[n]|=ovec[n+1]>>(8-nbits%8);
}
/* finally, move it back into place */
memcpy(ivec,ovec,AES_BLOCK_SIZE);
}
/* it is not necessary to cleanse ovec, since the IV is not secret */
}