1 /* LibTomCrypt, modular cryptographic library -- Tom St Denis */ 2 /* SPDX-License-Identifier: Unlicense */ 3 4 /* The implementation is based on: 5 * chacha-ref.c version 20080118 6 * Public domain from D. J. Bernstein 7 */ 8 9 #include "tomcrypt_private.h" 10 11 #ifdef LTC_CHACHA 12 13 /** 14 Set IV + counter data to the ChaCha state 15 @param st The ChaCha20 state 16 @param iv The IV data to add 17 @param ivlen The length of the IV (must be 8) 18 @param counter 64bit (unsigned) initial counter value 19 @return CRYPT_OK on success 20 */ chacha_ivctr64(chacha_state * st,const unsigned char * iv,unsigned long ivlen,ulong64 counter)21int chacha_ivctr64(chacha_state *st, const unsigned char *iv, unsigned long ivlen, ulong64 counter) 22 { 23 LTC_ARGCHK(st != NULL); 24 LTC_ARGCHK(iv != NULL); 25 /* 64bit IV + 64bit counter */ 26 LTC_ARGCHK(ivlen == 8); 27 28 st->input[12] = (ulong32)(counter & 0xFFFFFFFF); 29 st->input[13] = (ulong32)(counter >> 32); 30 LOAD32L(st->input[14], iv + 0); 31 LOAD32L(st->input[15], iv + 4); 32 st->ksleft = 0; 33 st->ivlen = ivlen; 34 return CRYPT_OK; 35 } 36 37 #endif 38