LXR linux/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 */
  25struct 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
  31extern const u32 crypto_ft_tab[4][256] ____cacheline_aligned;
  32extern const u32 crypto_it_tab[4][256] ____cacheline_aligned;
  33
  34/*
  35 * validate key length for AES algorithms
  36 */
  37static 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
  51int 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 */
  68int 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 */
  77void 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 */
  85void aes_decrypt(const struct crypto_aes_ctx *ctx, u8 *out, const u8 *in);
  86
  87extern const u8 crypto_aes_sbox[];
  88extern const u8 crypto_aes_inv_sbox[];
  89
  90#endif
  91