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 /*
  35  * validate key length for AES algorithms
  36  */
  37 static inline int aes_check_keylen(unsigned int keylen)
  38 {
  39         switch (keylen) {
  40         case AES_KEYSIZE_128:
  41         case AES_KEYSIZE_192:
  42         case AES_KEYSIZE_256:
  43                 break;
  44         default:
  45                 return -EINVAL;
  46         }
  47
  48         return 0;
  49 }
  50
  51 int crypto_aes_set_key(struct crypto_tfm *tfm, const u8 *in_key,
  52                 unsigned int key_len);
  53
  54 /**
  55  * aes_expandkey - Expands the AES key as described in FIPS-197
  56  * @ctx:        The location where the computed key will be stored.
  57  * @in_key:     The supplied key.
  58  * @key_len:    The length of the supplied key.
  59  *
  60  * Returns 0 on success. The function fails only if an invalid key size (or
  61  * pointer) is supplied.
  62  * The expanded key size is 240 bytes (max of 14 rounds with a unique 16 bytes
  63  * key schedule plus a 16 bytes key which is used before the first round).
  64  * The decryption key is prepared for the "Equivalent Inverse Cipher" as
  65  * described in FIPS-197. The first slot (16 bytes) of each key (enc or dec) is
  66  * for the initial combination, the second slot for the first round and so on.
  67  */
  68 int aes_expandkey(struct crypto_aes_ctx *ctx, const u8 *in_key,
  69                   unsigned int key_len);
  70
  71 /**
  72  * aes_encrypt - Encrypt a single AES block
  73  * @ctx:        Context struct containing the key schedule
  74  * @out:        Buffer to store the ciphertext
  75  * @in:         Buffer containing the plaintext
  76  */
  77 void aes_encrypt(const struct crypto_aes_ctx *ctx, u8 *out, const u8 *in);
  78
  79 /**
  80  * aes_decrypt - Decrypt a single AES block
  81  * @ctx:        Context struct containing the key schedule
  82  * @out:        Buffer to store the plaintext
  83  * @in:         Buffer containing the ciphertext
  84  */
  85 void aes_decrypt(const struct crypto_aes_ctx *ctx, u8 *out, const u8 *in);
  86
  87 extern const u8 crypto_aes_sbox[];
  88 extern const u8 crypto_aes_inv_sbox[];
  89
  90 #endif