1*3cbcf6a2SEric Biggers /* SPDX-License-Identifier: GPL-2.0 */ 2*3cbcf6a2SEric Biggers /* 3*3cbcf6a2SEric Biggers * AES-CBC and AES-CBC-CTS unauthenticated encryption and decryption 4*3cbcf6a2SEric Biggers * 5*3cbcf6a2SEric Biggers * Copyright 2026 Google LLC 6*3cbcf6a2SEric Biggers */ 7*3cbcf6a2SEric Biggers #ifndef _CRYPTO_AES_CBC_H 8*3cbcf6a2SEric Biggers #define _CRYPTO_AES_CBC_H 9*3cbcf6a2SEric Biggers 10*3cbcf6a2SEric Biggers #include <crypto/aes.h> 11*3cbcf6a2SEric Biggers 12*3cbcf6a2SEric Biggers /** 13*3cbcf6a2SEric Biggers * aes_cbc_encrypt() - Encrypt data using AES-CBC 14*3cbcf6a2SEric Biggers * @dst: The destination buffer. Can be in-place or out-of-place. For other 15*3cbcf6a2SEric Biggers * overlaps the behavior is unspecified. 16*3cbcf6a2SEric Biggers * @src: The source data 17*3cbcf6a2SEric Biggers * @len: Number of bytes to encrypt. Must be a multiple of AES_BLOCK_SIZE. 18*3cbcf6a2SEric Biggers * @iv: The initialization vector. It is updated with the next value, i.e. the 19*3cbcf6a2SEric Biggers * last ciphertext block (or left unchanged if @len == 0). 20*3cbcf6a2SEric Biggers * @key: The key, already prepared using aes_preparekey() or aes_prepareenckey() 21*3cbcf6a2SEric Biggers * 22*3cbcf6a2SEric Biggers * This supports incremental encryption. The length of each chunk must be a 23*3cbcf6a2SEric Biggers * multiple of AES_BLOCK_SIZE, and the updated @iv must be passed in each time. 24*3cbcf6a2SEric Biggers * 25*3cbcf6a2SEric Biggers * Context: Any context. 26*3cbcf6a2SEric Biggers */ 27*3cbcf6a2SEric Biggers void aes_cbc_encrypt(u8 *dst, const u8 *src, size_t len, 28*3cbcf6a2SEric Biggers u8 iv[at_least AES_BLOCK_SIZE], aes_encrypt_arg key); 29*3cbcf6a2SEric Biggers 30*3cbcf6a2SEric Biggers /** 31*3cbcf6a2SEric Biggers * aes_cbc_decrypt() - Decrypt data using AES-CBC 32*3cbcf6a2SEric Biggers * @dst: The destination buffer. Can be in-place or out-of-place. For other 33*3cbcf6a2SEric Biggers * overlaps the behavior is unspecified. 34*3cbcf6a2SEric Biggers * @src: The source data 35*3cbcf6a2SEric Biggers * @len: Number of bytes to decrypt. Must be a multiple of AES_BLOCK_SIZE. 36*3cbcf6a2SEric Biggers * @iv: The initialization vector. It is updated with the next value, i.e. the 37*3cbcf6a2SEric Biggers * last ciphertext block (or left unchanged if @len == 0). 38*3cbcf6a2SEric Biggers * @key: The key, already prepared using aes_preparekey() 39*3cbcf6a2SEric Biggers * 40*3cbcf6a2SEric Biggers * This supports incremental decryption. The length of each chunk must be a 41*3cbcf6a2SEric Biggers * multiple of AES_BLOCK_SIZE, and the updated @iv must be passed in each time. 42*3cbcf6a2SEric Biggers * 43*3cbcf6a2SEric Biggers * Context: Any context. 44*3cbcf6a2SEric Biggers */ 45*3cbcf6a2SEric Biggers void aes_cbc_decrypt(u8 *dst, const u8 *src, size_t len, 46*3cbcf6a2SEric Biggers u8 iv[at_least AES_BLOCK_SIZE], const struct aes_key *key); 47*3cbcf6a2SEric Biggers 48*3cbcf6a2SEric Biggers /** 49*3cbcf6a2SEric Biggers * aes_cbc_cts_encrypt() - Encrypt data using AES-CBC-CTS (CS3 variant) 50*3cbcf6a2SEric Biggers * @dst: The destination buffer. Can be in-place or out-of-place. For other 51*3cbcf6a2SEric Biggers * overlaps the behavior is unspecified. 52*3cbcf6a2SEric Biggers * @src: The source data 53*3cbcf6a2SEric Biggers * @len: Number of bytes to encrypt, at least AES_BLOCK_SIZE 54*3cbcf6a2SEric Biggers * @iv: The initialization vector, clobbered by this function 55*3cbcf6a2SEric Biggers * @key: The key, already prepared using aes_preparekey() or aes_prepareenckey() 56*3cbcf6a2SEric Biggers * 57*3cbcf6a2SEric Biggers * Context: Any context. 58*3cbcf6a2SEric Biggers */ 59*3cbcf6a2SEric Biggers void aes_cbc_cts_encrypt(u8 *dst, const u8 *src, size_t len, 60*3cbcf6a2SEric Biggers u8 iv[at_least AES_BLOCK_SIZE], aes_encrypt_arg key); 61*3cbcf6a2SEric Biggers 62*3cbcf6a2SEric Biggers /** 63*3cbcf6a2SEric Biggers * aes_cbc_cts_decrypt() - Decrypt data using AES-CBC-CTS (CS3 variant) 64*3cbcf6a2SEric Biggers * @dst: The destination buffer. Can be in-place or out-of-place. For other 65*3cbcf6a2SEric Biggers * overlaps the behavior is unspecified. 66*3cbcf6a2SEric Biggers * @src: The source data 67*3cbcf6a2SEric Biggers * @len: Number of bytes to decrypt, at least AES_BLOCK_SIZE 68*3cbcf6a2SEric Biggers * @iv: The initialization vector, clobbered by this function 69*3cbcf6a2SEric Biggers * @key: The key, already prepared using aes_preparekey() 70*3cbcf6a2SEric Biggers * 71*3cbcf6a2SEric Biggers * Context: Any context. 72*3cbcf6a2SEric Biggers */ 73*3cbcf6a2SEric Biggers void aes_cbc_cts_decrypt(u8 *dst, const u8 *src, size_t len, 74*3cbcf6a2SEric Biggers u8 iv[at_least AES_BLOCK_SIZE], 75*3cbcf6a2SEric Biggers const struct aes_key *key); 76*3cbcf6a2SEric Biggers 77*3cbcf6a2SEric Biggers #endif /* _CRYPTO_AES_CBC_H */ 78