1 /* 2 * Copyright (C) 2008, Damien Miller 3 * Copyright (C) 2011, Alex Hornung 4 * 5 * Permission to use, copy, and modify this software with or without fee 6 * is hereby granted, provided that this entire notice is included in 7 * all copies of any software which is or includes a copy or 8 * modification of this software. 9 * You may use this code under the GNU public license if you so wish. Please 10 * contribute changes back to the authors under this freer than GPL license 11 * so that we may further the use of strong encryption without limitations to 12 * all. 13 * 14 * THIS SOFTWARE IS BEING PROVIDED "AS IS", WITHOUT ANY EXPRESS OR 15 * IMPLIED WARRANTY. IN PARTICULAR, NONE OF THE AUTHORS MAKES ANY 16 * REPRESENTATION OR WARRANTY OF ANY KIND CONCERNING THE 17 * MERCHANTABILITY OF THIS SOFTWARE OR ITS FITNESS FOR ANY PARTICULAR 18 * PURPOSE. 19 */ 20 21 #include <inttypes.h> 22 #define XTS_MAX_BLOCKSIZE 16 23 #define XTS_IVSIZE 8 24 #define XTS_ALPHA 0x87 /* GF(2^128) generator polynomial */ 25 26 typedef int (*encrypt_decrypt_fn)(void *, size_t, const uint8_t *, uint8_t *); 27 typedef int (*set_key_fn)(void **, void *, void *, const uint8_t *, int); 28 typedef int (*zero_key_fn)(void **); 29 30 31 struct xts_ctx { 32 encrypt_decrypt_fn encrypt_fn; 33 encrypt_decrypt_fn decrypt_fn; 34 set_key_fn set_key_fn; 35 zero_key_fn zero_key_fn; 36 37 void *ctx1; 38 void *ctx2; 39 uint8_t tweak[XTS_MAX_BLOCKSIZE]; 40 uint32_t blk_sz; 41 }; 42 43 int xts_init(struct xts_ctx *ctxp, void *arg1, void *arg2, set_key_fn set_key_fn, 44 zero_key_fn zero_key_fn, encrypt_decrypt_fn encrypt_fn, 45 encrypt_decrypt_fn decrypt_fn, uint32_t blk_sz, uint8_t *key, int len); 46 int xts_encrypt(struct xts_ctx *ctx, uint8_t *data, size_t len, uint8_t *iv); 47 int xts_decrypt(struct xts_ctx *ctx, uint8_t *data, size_t len, uint8_t *iv); 48 int xts_uninit(struct xts_ctx *ctxp); 49 50