48 lines
1.3 KiB
C

/* LibTomCrypt, modular cryptographic library -- Tom St Denis
*
* LibTomCrypt is a library that provides various cryptographic
* algorithms in a highly modular and flexible manner.
*
* The library is free for all purposes without any express
* guarantee it works.
*/
/* The implementation is based on:
* chacha-ref.c version 20080118
* Public domain from D. J. Bernstein
*/
#include "tomcrypt.h"
#ifdef LTC_CHACHA
/**
Set IV + counter data to the ChaCha state
@param st The ChaCha20 state
@param iv The IV data to add
@param ivlen The length of the IV (must be 8)
@param counter 64bit (unsigned) initial counter value
@return CRYPT_OK on success
*/
int chacha_ivctr64(chacha_state *st, const unsigned char *iv, unsigned long ivlen, ulong64 counter)
{
LTC_ARGCHK(st != NULL);
LTC_ARGCHK(iv != NULL);
/* 64bit IV + 64bit counter */
LTC_ARGCHK(ivlen == 8);
st->input[12] = (ulong32)(counter & 0xFFFFFFFF);
st->input[13] = (ulong32)(counter >> 32);
LOAD32L(st->input[14], iv + 0);
LOAD32L(st->input[15], iv + 4);
st->ksleft = 0;
st->ivlen = ivlen;
return CRYPT_OK;
}
#endif
/* ref: HEAD -> master, tag: v1.18.2 */
/* git commit: 7e7eb695d581782f04b24dc444cbfde86af59853 */
/* commit time: 2018-07-01 22:49:01 +0200 */