// Copyright lowRISC contributors.
// Licensed under the Apache License, Version 2.0, see LICENSE for details.
// SPDX-License-Identifier: Apache-2.0

#ifndef AES_H_
#define AES_H_

/**
 * Encrypt one data block (16 Bytes) in ECB mode.
 *
 * @param  plain_text  Input block to enrypt
 * @param  key         Initial encryption key
 * @param  key_len     Key length in bytes (16, 24, 32)
 * @param  cipher_text Encrypted output block
 * @return 0 on success, -ERRNO otherwise
 */
int aes_encrypt_block(const unsigned char *plain_text, const unsigned char *key,
                      const int key_len, unsigned char *cipher_text);

/**
 * Decrypt one data block (16 Bytes) in ECB mode.
 *
 * @param  plain_text  Encrypted input block
 * @param  key         Initial encryption key
 * @param  key_len     Key length in bytes (16, 24, 32)
 * @param  cipher_text Decrypted output block
 * @return 0 on success, -ERRNO otherwise
 */
int aes_decrypt_block(const unsigned char *cipher_text,
                      const unsigned char *key, const int key_len,
                      unsigned char *plain_text);

/**
 * Print block of data in readable format to stdout
 *
 * @param  num_bytes Number of bytes to print
 */
void aes_print_block(const unsigned char *data, const int num_bytes);

/**
 * Get number of cipher rounds
 *
 * @param  key_len   Key length in bytes (16, 24, 32)
 * @return Number of cipher rounds, -EINVAL for unsupported key lengths
 */
int aes_get_num_rounds(const int key_len);

/**
 * Add (XOR) round key to state
 *
 * @param  state     State
 * @param  round_key 128-bit round key
 */
void aes_add_round_key(unsigned char *state, const unsigned char *round_key);

/**
 * Substitute bytes in state
 *
 * @param  state State
 */
void aes_sub_bytes(unsigned char *state);

/**
 * Inverse byte substitution in state
 *
 * @param  state State
 */
void aes_inv_sub_bytes(unsigned char *state);

/**
 * Shift rows operation on state
 *
 * @param  state State
 */
void aes_shift_rows(unsigned char *state);

/**
 * Inverse shift rows operation on state
 *
 * @param  state State
 */
void aes_inv_shift_rows(unsigned char *state);

/**
 * Mix columns operation on state
 *
 * @param  state State
 */
void aes_mix_columns(unsigned char *state);

/**
 * Inverse mix columns operation on state
 *
 * @param  state State
 */
void aes_inv_mix_columns(unsigned char *state);

/**
 * Generate full key and round key for next round during encryption.
 *
 * @param  round_key Round key of previous/next round
 * @param  key       Full key of previous/next round
 * @param  key_len   Key length in bytes (16, 24, 32)
 * @param  rcon      Rcon of previous/next round
 * @param  rnd       Current round index
 */
void aes_key_expand(unsigned char *round_key, unsigned char *key,
                    const int key_len, unsigned char *rcon, const int rnd);

/**
 * Generate full key and round key for next round during decryption.
 *
 * @param  round_key Round key of previous/next round
 * @param  key       Full key of previous/next round
 * @param  key_len   Key length in bytes (16, 24, 32)
 * @param  rcon      Rcon of previous/next round
 * @param  rnd       Current round index
 */
void aes_inv_key_expand(unsigned char *round_key, unsigned char *key,
                        const int key_len, unsigned char *rcon, const int rnd);

/**
 * Update Rcon value for next round during encryption.
 * If the input value is 0, rcon is initialized to the start value.
 *
 * @param  rcon Rcon value
 */
void aes_rcon_next(unsigned char *rcon);

/**
 * Update Rcon value for next round during decryption.
 * If the input value is 0, rcon is initialized to the start value
 * depening on key length.
 *
 * @param  rcon    Rcon value
 * @param  key_len Key length in bytes (16, 24, 32)
 */
void aes_rcon_prev(unsigned char *rcon, int key_len);

static const unsigned char sbox[256] = {
    0x63, 0x7C, 0x77, 0x7B, 0xF2, 0x6B, 0x6F, 0xC5,
    0x30, 0x01, 0x67, 0x2B, 0xFE, 0xD7, 0xAB, 0x76,

    0xCA, 0x82, 0xC9, 0x7D, 0xFA, 0x59, 0x47, 0xF0,
    0xAD, 0xD4, 0xA2, 0xAF, 0x9C, 0xA4, 0x72, 0xC0,

    0xB7, 0xFD, 0x93, 0x26, 0x36, 0x3F, 0xF7, 0xCC,
    0x34, 0xA5, 0xE5, 0xF1, 0x71, 0xD8, 0x31, 0x15,

    0x04, 0xC7, 0x23, 0xC3, 0x18, 0x96, 0x05, 0x9A,
    0x07, 0x12, 0x80, 0xE2, 0xEB, 0x27, 0xB2, 0x75,

    0x09, 0x83, 0x2C, 0x1A, 0x1B, 0x6E, 0x5A, 0xA0,
    0x52, 0x3B, 0xD6, 0xB3, 0x29, 0xE3, 0x2F, 0x84,

    0x53, 0xD1, 0x00, 0xED, 0x20, 0xFC, 0xB1, 0x5B,
    0x6A, 0xCB, 0xBE, 0x39, 0x4A, 0x4C, 0x58, 0xCF,

    0xD0, 0xEF, 0xAA, 0xFB, 0x43, 0x4D, 0x33, 0x85,
    0x45, 0xF9, 0x02, 0x7F, 0x50, 0x3C, 0x9F, 0xA8,

    0x51, 0xA3, 0x40, 0x8F, 0x92, 0x9D, 0x38, 0xF5,
    0xBC, 0xB6, 0xDA, 0x21, 0x10, 0xFF, 0xF3, 0xD2,

    0xCD, 0x0C, 0x13, 0xEC, 0x5F, 0x97, 0x44, 0x17,
    0xC4, 0xA7, 0x7E, 0x3D, 0x64, 0x5D, 0x19, 0x73,

    0x60, 0x81, 0x4F, 0xDC, 0x22, 0x2A, 0x90, 0x88,
    0x46, 0xEE, 0xB8, 0x14, 0xDE, 0x5E, 0x0B, 0xDB,

    0xE0, 0x32, 0x3A, 0x0A, 0x49, 0x06, 0x24, 0x5C,
    0xC2, 0xD3, 0xAC, 0x62, 0x91, 0x95, 0xE4, 0x79,

    0xE7, 0xC8, 0x37, 0x6D, 0x8D, 0xD5, 0x4E, 0xA9,
    0x6C, 0x56, 0xF4, 0xEA, 0x65, 0x7A, 0xAE, 0x08,

    0xBA, 0x78, 0x25, 0x2E, 0x1C, 0xA6, 0xB4, 0xC6,
    0xE8, 0xDD, 0x74, 0x1F, 0x4B, 0xBD, 0x8B, 0x8A,

    0x70, 0x3E, 0xB5, 0x66, 0x48, 0x03, 0xF6, 0x0E,
    0x61, 0x35, 0x57, 0xB9, 0x86, 0xC1, 0x1D, 0x9E,

    0xE1, 0xF8, 0x98, 0x11, 0x69, 0xD9, 0x8E, 0x94,
    0x9B, 0x1E, 0x87, 0xE9, 0xCE, 0x55, 0x28, 0xDF,

    0x8C, 0xA1, 0x89, 0x0D, 0xBF, 0xE6, 0x42, 0x68,
    0x41, 0x99, 0x2D, 0x0F, 0xB0, 0x54, 0xBB, 0x16};

static const unsigned char inv_sbox[256] = {
    0x52, 0x09, 0x6a, 0xd5, 0x30, 0x36, 0xa5, 0x38,
    0xbf, 0x40, 0xa3, 0x9e, 0x81, 0xf3, 0xd7, 0xfb,

    0x7c, 0xe3, 0x39, 0x82, 0x9b, 0x2f, 0xff, 0x87,
    0x34, 0x8e, 0x43, 0x44, 0xc4, 0xde, 0xe9, 0xcb,

    0x54, 0x7b, 0x94, 0x32, 0xa6, 0xc2, 0x23, 0x3d,
    0xee, 0x4c, 0x95, 0x0b, 0x42, 0xfa, 0xc3, 0x4e,

    0x08, 0x2e, 0xa1, 0x66, 0x28, 0xd9, 0x24, 0xb2,
    0x76, 0x5b, 0xa2, 0x49, 0x6d, 0x8b, 0xd1, 0x25,

    0x72, 0xf8, 0xf6, 0x64, 0x86, 0x68, 0x98, 0x16,
    0xd4, 0xa4, 0x5c, 0xcc, 0x5d, 0x65, 0xb6, 0x92,

    0x6c, 0x70, 0x48, 0x50, 0xfd, 0xed, 0xb9, 0xda,
    0x5e, 0x15, 0x46, 0x57, 0xa7, 0x8d, 0x9d, 0x84,

    0x90, 0xd8, 0xab, 0x00, 0x8c, 0xbc, 0xd3, 0x0a,
    0xf7, 0xe4, 0x58, 0x05, 0xb8, 0xb3, 0x45, 0x06,

    0xd0, 0x2c, 0x1e, 0x8f, 0xca, 0x3f, 0x0f, 0x02,
    0xc1, 0xaf, 0xbd, 0x03, 0x01, 0x13, 0x8a, 0x6b,

    0x3a, 0x91, 0x11, 0x41, 0x4f, 0x67, 0xdc, 0xea,
    0x97, 0xf2, 0xcf, 0xce, 0xf0, 0xb4, 0xe6, 0x73,

    0x96, 0xac, 0x74, 0x22, 0xe7, 0xad, 0x35, 0x85,
    0xe2, 0xf9, 0x37, 0xe8, 0x1c, 0x75, 0xdf, 0x6e,

    0x47, 0xf1, 0x1a, 0x71, 0x1d, 0x29, 0xc5, 0x89,
    0x6f, 0xb7, 0x62, 0x0e, 0xaa, 0x18, 0xbe, 0x1b,

    0xfc, 0x56, 0x3e, 0x4b, 0xc6, 0xd2, 0x79, 0x20,
    0x9a, 0xdb, 0xc0, 0xfe, 0x78, 0xcd, 0x5a, 0xf4,

    0x1f, 0xdd, 0xa8, 0x33, 0x88, 0x07, 0xc7, 0x31,
    0xb1, 0x12, 0x10, 0x59, 0x27, 0x80, 0xec, 0x5f,

    0x60, 0x51, 0x7f, 0xa9, 0x19, 0xb5, 0x4a, 0x0d,
    0x2d, 0xe5, 0x7a, 0x9f, 0x93, 0xc9, 0x9c, 0xef,

    0xa0, 0xe0, 0x3b, 0x4d, 0xae, 0x2a, 0xf5, 0xb0,
    0xc8, 0xeb, 0xbb, 0x3c, 0x83, 0x53, 0x99, 0x61,

    0x17, 0x2b, 0x04, 0x7e, 0xba, 0x77, 0xd6, 0x26,
    0xe1, 0x69, 0x14, 0x63, 0x55, 0x21, 0x0c, 0x7d};

#endif  // AES_H_