58 lines
1.8 KiB
C
58 lines
1.8 KiB
C
/* LibTomCrypt, modular cryptographic library -- Tom St Denis */
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/* SPDX-License-Identifier: Unlicense */
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#include "tomcrypt_private.h"
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#pragma clang diagnostic push
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#pragma clang diagnostic ignored "-Wconversion"
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#pragma clang diagnostic ignored "-Wshorten-64-to-32"
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#ifdef LTC_CHACHA
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/**
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Encrypt (or decrypt) bytes of ciphertext (or plaintext) with ChaCha
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@param key The key
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@param keylen The key length
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@param rounds The number of rounds
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@param iv The initial vector
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@param ivlen The initial vector length
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@param counter initial counter value, either ignored, 32- or 64-bit, depending on ivlen
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@param datain The plaintext (or ciphertext)
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@param datalen The length of the input and output (octets)
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@param dataout [out] The ciphertext (or plaintext)
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@return CRYPT_OK if successful
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*/
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int chacha_memory(const unsigned char *key, unsigned long keylen, unsigned long rounds,
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const unsigned char *iv, unsigned long ivlen, ulong64 counter,
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const unsigned char *datain, unsigned long datalen, unsigned char *dataout)
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{
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chacha_state st;
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int err;
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const unsigned char *iv_ = iv;
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unsigned long ivlen_ = ivlen;
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ulong64 counter_ = counter;
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if (ivlen == 16) {
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LOAD64L(counter_, iv);
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iv_ += 8;
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ivlen_ -=8;
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}
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LTC_ARGCHK(ivlen_ <= 8 || counter_ < CONST64(4294967296)); /* 2**32 */
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if ((err = chacha_setup(&st, key, keylen, rounds)) != CRYPT_OK) goto WIPE_KEY;
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if (ivlen_ > 8) {
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if ((err = chacha_ivctr32(&st, iv_, ivlen_, (ulong32)counter_)) != CRYPT_OK) goto WIPE_KEY;
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} else {
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if ((err = chacha_ivctr64(&st, iv_, ivlen_, counter_)) != CRYPT_OK) goto WIPE_KEY;
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}
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err = chacha_crypt(&st, datain, datalen, dataout);
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WIPE_KEY:
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chacha_done(&st);
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return err;
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}
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#endif /* LTC_CHACHA */
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#pragma clang diagnostic pop
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