1 /* $OpenBSD: chacha.h,v 1.4 2016/08/27 04:04:56 guenther Exp $ */ 2 3 /* 4 chacha-merged.c version 20080118 5 D. J. Bernstein 6 Public domain. 7 */ 8 9 #ifndef CHACHA_H 10 #define CHACHA_H 11 12 #include <sys/types.h> 13 14 #include "_chacha.h" 15 16 #define CHACHA_MINKEYLEN 16 17 #define CHACHA_NONCELEN 8 18 #define CHACHA_CTRLEN 8 19 #define CHACHA_STATELEN (CHACHA_NONCELEN + CHACHA_CTRLEN) 20 #define CHACHA_BLOCKLEN 64 21 22 #ifdef CHACHA_EMBED 23 #define LOCAL static 24 #else 25 #define LOCAL 26 #endif 27 28 /* 29 * Initialize the context with key <k> of length <kbits> bit. 30 * The recommended key length is 256 bits, although 128-bit keys are 31 * also supported. 32 */ 33 LOCAL void chacha_keysetup(struct chacha_ctx *x, const uint8_t *k, 34 uint32_t kbits); 35 36 /* 37 * Setup the context with a 64-bit IV <iv> and a 64-bit counter 38 * <counter>. If <counter> is NULL, then the value zero (0) is used. 39 * 40 * If CHACHA_NONCE0_CTR128 is defined, then the IV <iv> is ignored 41 * and the counter <counter> must be 128 bits. 42 */ 43 LOCAL void chacha_ivsetup(struct chacha_ctx *x, const uint8_t *iv, 44 const uint8_t *counter); 45 46 /* 47 * Encrypt/decrypt the byte string <m> of length <bytes>, write the 48 * result to <c>. 49 * 50 * The output buffer <c> may point to the same area as the input <m>. 51 * In that case, the encryption/decryption is performed in-place. 52 * 53 * If KEYSTREAM_ONLY is defined, then this function only generates a 54 * key stream of the requested length <bytes> and writes to <c>. 55 * The input <m> is unused and should be NULL in this case. 56 */ 57 LOCAL void chacha_encrypt_bytes(struct chacha_ctx *x, const uint8_t *m, 58 uint8_t *c, uint32_t bytes); 59 60 #ifdef CHACHA_NONCE0_CTR128 61 /* 62 * Save the current value of the 128-bit counter, which can be restored 63 * by calling chacha_ivsetup(x, NULL, counter). 64 */ 65 LOCAL void chacha_ctrsave(const struct chacha_ctx *x, uint8_t *counter) 66 __unused; /* maybe unused */ 67 #endif 68 69 /* 70 * HChaCha20 is an intermediary block to build XChaCha20, similar to 71 * the HSalsa20 defined for XSalsa20. 72 */ 73 LOCAL void hchacha20(uint8_t derived_key[32], const uint8_t nonce[16], 74 const uint8_t key[32]) __unused; /* maybe unused */ 75 76 #endif /* CHACHA_H */ 77