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#include "Mra.h"
#include "MraSendQueue.h"
void hmac_sha1(BYTE *text,size_t text_len,BYTE *key,size_t key_len,BYTE *digest)
{
mir_sha1_ctx context;
BYTE k_ipad[65]; /* inner padding - key XORd with ipad */
BYTE k_opad[65]; /* outer padding - key XORd with opad */
BYTE tk[MIR_SHA1_HASH_SIZE];
/* if key is longer than 64 bytes reset it to key=SHA1(key) */
if (key_len>64)
{
mir_sha1_ctx tctx;
mir_sha1_init(&tctx);
mir_sha1_append(&tctx,key,key_len);
mir_sha1_finish(&tctx,(BYTE*)&tk);
key=tk;
key_len=MIR_SHA1_HASH_SIZE;
}
/*
* the HMAC_SHA1 transform looks like:
*
* SHA1(K XOR opad, SHA1(K XOR ipad, text))
*
* where K is an n byte key
* ipad is the byte 0x36 repeated 64 times
* opad is the byte 0x5c repeated 64 times
* and text is the data being protected
*/
/* start out by storing key in pads */
memmove(&k_ipad,key,key_len);
memmove(&k_opad,key,key_len);
memset(&k_ipad[key_len], 0, (sizeof(k_ipad)-key_len));
memset(&k_opad[key_len], 0 , (sizeof(k_opad)-key_len));
/* XOR key with ipad and opad values */
for (size_t i=0;i<(64/sizeof(ULONGLONG));i++)
{
((ULONGLONG*)k_ipad)[i]^=0x3636363636363636;
((ULONGLONG*)k_opad)[i]^=0x5C5C5C5C5C5C5C5C;
}
/* perform inner SHA1 */
mir_sha1_init(&context); /* init context for 1st pass */
mir_sha1_append(&context,k_ipad,64); /* start with inner pad */
mir_sha1_append(&context,text,text_len); /* then text of datagram */
mir_sha1_finish(&context,digest); /* finish up 1st pass */
/* perform outer SHA1 */
mir_sha1_init(&context); /* init context for 2nd pass */
mir_sha1_append(&context,k_opad,64); /* start with outer pad */
mir_sha1_append(&context,(BYTE*)digest,MIR_SHA1_HASH_SIZE); /* then results of 1st hash */
mir_sha1_finish(&context,digest); /* finish up 2nd pass */
bzero(k_ipad,sizeof(k_ipad));
bzero(k_opad,sizeof(k_opad));
bzero(tk,sizeof(tk));
}
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