Mercurial > dropbear
view libtomcrypt/src/modes/f8/f8_start.c @ 1552:e46f7f1da56a
CHANGES for 2018.76
author | Matt Johnston <matt@ucc.asn.au> |
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date | Tue, 27 Feb 2018 22:14:04 +0800 |
parents | 6dba84798cd5 |
children |
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/* 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. */ #include "tomcrypt.h" /** @file f8_start.c F8 implementation, start chain, Tom St Denis */ #ifdef LTC_F8_MODE /** Initialize an F8 context @param cipher The index of the cipher desired @param IV The initialization vector @param key The secret key @param keylen The length of the secret key (octets) @param salt_key The salting key for the IV @param skeylen The length of the salting key (octets) @param num_rounds Number of rounds in the cipher desired (0 for default) @param f8 The F8 state to initialize @return CRYPT_OK if successful */ int f8_start( int cipher, const unsigned char *IV, const unsigned char *key, int keylen, const unsigned char *salt_key, int skeylen, int num_rounds, symmetric_F8 *f8) { int x, err; unsigned char tkey[MAXBLOCKSIZE]; LTC_ARGCHK(IV != NULL); LTC_ARGCHK(key != NULL); LTC_ARGCHK(salt_key != NULL); LTC_ARGCHK(f8 != NULL); if ((err = cipher_is_valid(cipher)) != CRYPT_OK) { return err; } #ifdef LTC_FAST if (cipher_descriptor[cipher].block_length % sizeof(LTC_FAST_TYPE)) { return CRYPT_INVALID_ARG; } #endif /* copy details */ f8->blockcnt = 0; f8->cipher = cipher; f8->blocklen = cipher_descriptor[cipher].block_length; f8->padlen = f8->blocklen; /* now get key ^ salt_key [extend salt_ket with 0x55 as required to match length] */ zeromem(tkey, sizeof(tkey)); for (x = 0; x < keylen && x < (int)sizeof(tkey); x++) { tkey[x] = key[x]; } for (x = 0; x < skeylen && x < (int)sizeof(tkey); x++) { tkey[x] ^= salt_key[x]; } for (; x < keylen && x < (int)sizeof(tkey); x++) { tkey[x] ^= 0x55; } /* now encrypt with tkey[0..keylen-1] the IV and use that as the IV */ if ((err = cipher_descriptor[cipher].setup(tkey, keylen, num_rounds, &f8->key)) != CRYPT_OK) { return err; } /* encrypt IV */ if ((err = cipher_descriptor[f8->cipher].ecb_encrypt(IV, f8->MIV, &f8->key)) != CRYPT_OK) { cipher_descriptor[f8->cipher].done(&f8->key); return err; } zeromem(tkey, sizeof(tkey)); zeromem(f8->IV, sizeof(f8->IV)); /* terminate this cipher */ cipher_descriptor[f8->cipher].done(&f8->key); /* init the cipher */ return cipher_descriptor[cipher].setup(key, keylen, num_rounds, &f8->key); } #endif /* ref: $Format:%D$ */ /* git commit: $Format:%H$ */ /* commit time: $Format:%ai$ */