include/crypto/aes.h

   1 /* SPDX-License-Identifier: GPL-2.0 */
   2 /*
   3  * Common values for AES algorithms
   4  */
   5
   6 #ifndef _CRYPTO_AES_H
   7 #define _CRYPTO_AES_H
   8
   9 #include <linux/types.h>
  10 #include <linux/crypto.h>
  11
  12 #define AES_MIN_KEY_SIZE        16
  13 #define AES_MAX_KEY_SIZE        32
  14 #define AES_KEYSIZE_128         16
  15 #define AES_KEYSIZE_192         24
  16 #define AES_KEYSIZE_256         32
  17 #define AES_BLOCK_SIZE          16
  18 #define AES_MAX_KEYLENGTH       (15 * 16)
  19 #define AES_MAX_KEYLENGTH_U32   (AES_MAX_KEYLENGTH / sizeof(u32))
  20
  21 /*
  22  * Please ensure that the first two fields are 16-byte aligned
  23  * relative to the start of the structure, i.e., don't move them!
  24  */
  25 struct crypto_aes_ctx {
  26         u32 key_enc[AES_MAX_KEYLENGTH_U32];
  27         u32 key_dec[AES_MAX_KEYLENGTH_U32];
  28         u32 key_length;
  29 };
  30
  31 extern const u32 crypto_ft_tab[4][256] ____cacheline_aligned;
  32 extern const u32 crypto_it_tab[4][256] ____cacheline_aligned;
  33
  34 int crypto_aes_set_key(struct crypto_tfm *tfm, const u8 *in_key,
  35                 unsigned int key_len);
  36
  37 /**
  38  * aes_expandkey - Expands the AES key as described in FIPS-197
  39  * @ctx:        The location where the computed key will be stored.
  40  * @in_key:     The supplied key.
  41  * @key_len:    The length of the supplied key.
  42  *
  43  * Returns 0 on success. The function fails only if an invalid key size (or
  44  * pointer) is supplied.
  45  * The expanded key size is 240 bytes (max of 14 rounds with a unique 16 bytes
  46  * key schedule plus a 16 bytes key which is used before the first round).
  47  * The decryption key is prepared for the "Equivalent Inverse Cipher" as
  48  * described in FIPS-197. The first slot (16 bytes) of each key (enc or dec) is
  49  * for the initial combination, the second slot for the first round and so on.
  50  */
  51 int aes_expandkey(struct crypto_aes_ctx *ctx, const u8 *in_key,
  52                   unsigned int key_len);
  53
  54 /**
  55  * aes_encrypt - Encrypt a single AES block
  56  * @ctx:        Context struct containing the key schedule
  57  * @out:        Buffer to store the ciphertext
  58  * @in:         Buffer containing the plaintext
  59  */
  60 void aes_encrypt(const struct crypto_aes_ctx *ctx, u8 *out, const u8 *in);
  61
  62 /**
  63  * aes_decrypt - Decrypt a single AES block
  64  * @ctx:        Context struct containing the key schedule
  65  * @out:        Buffer to store the plaintext
  66  * @in:         Buffer containing the ciphertext
  67  */
  68 void aes_decrypt(const struct crypto_aes_ctx *ctx, u8 *out, const u8 *in);
  69
  70 #endif