// Copyright 2023 The BoringSSL Authors

//

// Licensed under the Apache License, Version 2.0 (the "License");

// you may not use this file except in compliance with the License.

// You may obtain a copy of the License at

//

//     https://www.apache.org/licenses/LICENSE-2.0

//

// Unless required by applicable law or agreed to in writing, software

// distributed under the License is distributed on an "AS IS" BASIS,

// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.

// See the License for the specific language governing permissions and

// limitations under the License.

#ifndef OPENSSL_HEADER_CRYPTO_FIPSMODULE_KECCAK_INTERNAL_H

#define OPENSSL_HEADER_CRYPTO_FIPSMODULE_KECCAK_INTERNAL_H

#include <openssl/base.h>

#include "../../internal.h"

BSSL_NAMESPACE_BEGIN

#define BITS_TO_BYTES(BITS) ((BITS) / 8)

#define SHA3_256_DIGEST_LENGTH BITS_TO_BYTES(256)

#define SHA3_384_DIGEST_LENGTH BITS_TO_BYTES(384)

#define SHA3_512_DIGEST_LENGTH BITS_TO_BYTES(512)

#define SHA3_BLOCK_SIZE(BITS) BITS_TO_BYTES(1600 - 2 * (BITS))

#define SHA3_256_CBLOCK SHA3_BLOCK_SIZE(256)

#define SHA3_384_CBLOCK SHA3_BLOCK_SIZE(384)

#define SHA3_512_CBLOCK SHA3_BLOCK_SIZE(512)

enum boringssl_keccak_config_t : int32_t {

  boringssl_sha3_256,

  boringssl_sha3_384,

  boringssl_sha3_512,

  boringssl_shake128,

  boringssl_shake256,

  boringssl_turboshake128,

  boringssl_turboshake256,

  boringssl_cshake128,

  boringssl_cshake256,

};

enum boringssl_keccak_phase_t : int32_t {

  boringssl_keccak_phase_absorb,

  boringssl_keccak_phase_squeeze,

};

struct BORINGSSL_keccak_st {

  // Note: the state with 64-bit integers comes first so that the size of this

  // struct is easy to compute on all architectures without padding surprises

  // due to alignment.

  uint64_t state[25];

  enum boringssl_keccak_config_t config;

  enum boringssl_keccak_phase_t phase;

  size_t required_out_len;

  size_t rate_bytes;

  size_t absorb_offset;

  size_t squeeze_offset;

};

// BORINGSSL_keccak hashes `in_len` bytes from `in` and writes `out_len` bytes

// of output to `out`. If the `config` specifies a fixed-output function, like

// SHA3-256, then `out_len` must be the correct length for that function. The

// cSHAKE configurations are only valid with the BORINGSSL_cshake functions.

OPENSSL_EXPORT void BORINGSSL_keccak(uint8_t *out, size_t out_len,

                                     const uint8_t *in, size_t in_len,

                                     enum boringssl_keccak_config_t config);

// BORINGSSL_keccak_init prepares `ctx` for absorbing. If the `config` specifies

// a fixed-output function, like SHA3-256, then the output must be squeezed in a

// single call to `BORINGSSL_keccak_squeeze`. In that case, it is recommended to

// use `BORINGSSL_keccak` if the input can be absorbed in a single call.

OPENSSL_EXPORT void BORINGSSL_keccak_init(

    struct BORINGSSL_keccak_st *ctx, enum boringssl_keccak_config_t config);

// BORINGSSL_cshake_init prepares `ctx` for cSHAKE, including absorbing the

// function-name and customization strings. `config` must be

// `boringssl_cshake128` or `boringssl_cshake256`. The message may then be

// absorbed and output squeezed with the usual Keccak functions.

OPENSSL_EXPORT void BORINGSSL_cshake_init(struct BORINGSSL_keccak_st *ctx,

                                          enum boringssl_keccak_config_t config,

                                          const uint8_t *function_name,

                                          size_t function_name_len,

                                          const uint8_t *customization,

                                          size_t customization_len);

// BORINGSSL_cshake is the one-shot form of BORINGSSL_cshake_init.

OPENSSL_EXPORT void BORINGSSL_cshake(uint8_t *out, size_t out_len,

                                     const uint8_t *in, size_t in_len,

                                     enum boringssl_keccak_config_t config,

                                     const uint8_t *function_name,

                                     size_t function_name_len,

                                     const uint8_t *customization,

                                     size_t customization_len);

// BORINGSSL_keccak_absorb absorbs `in_len` bytes from `in`.

OPENSSL_EXPORT void BORINGSSL_keccak_absorb(struct BORINGSSL_keccak_st *ctx,

                                            const uint8_t *in, size_t in_len);

// BORINGSSL_keccak_squeeze writes `out_len` bytes to `out` from `ctx`. If the

// configuration previously passed in `BORINGSSL_keccak_init` specifies a

// fixed-output function, then a single call to `BORINGSSL_keccak_squeeze` is

// allowed, where `out_len` must be the correct length for that function.

OPENSSL_EXPORT void BORINGSSL_keccak_squeeze(struct BORINGSSL_keccak_st *ctx,

                                             uint8_t *out, size_t out_len);

#if defined(__has_attribute)

#if __has_attribute(vector_size)

#define HAVE_KECCAK_X2

#if defined(OPENSSL_AARCH64)

#define HAVE_KECCAK_X4

#define KECCAK_X4_TARGET

#endif

#if defined(OPENSSL_X86_64)

#define HAVE_KECCAK_X4

#define KECCAK_X4_TARGET __attribute__((target("avx2")))

#endif

#endif  // vector_size

#endif  // __has_attribute

#if defined(HAVE_KECCAK_X2)

// BORINGSSL_keccak_squeeze_x2 performs BORINGSSL_keccak_squeeze in parallel

// with two same-length outputs. The contexts must be in equivalent state (i.e.

// same config, same amount of bytes absorbed and squeezed).

// This function is not compatible with cSHAKE nor TurboSHAKE.

OPENSSL_EXPORT void BORINGSSL_keccak_squeeze_x2(

    struct BORINGSSL_keccak_st ctx[2], uint8_t *outs[2], size_t out_len);

// BORINGSSL_keccak_short_x2 performs BORINGSSL_keccak in parallel on two

// same-length strings with same-length outputs. `in_len` must be less than 72

// (or actually `rate_bytes`).

// This function is not compatible with cSHAKE nor TurboSHAKE.

OPENSSL_EXPORT void BORINGSSL_keccak_short_x2(

    uint8_t *outs[2], size_t out_len, const uint8_t *ins[2], size_t in_len,

    enum boringssl_keccak_config_t config);

#endif

#if defined(HAVE_KECCAK_X4)

// BORINGSSL_have_keccak_x4 needs to return true before using any of the _x4

// variants here, as they may require additional CPU features.

// This function is not compatible with cSHAKE nor TurboSHAKE.

inline bool BORINGSSL_have_keccak_x4() {

#if defined(OPENSSL_X86_64)

  return CRYPTO_is_AVX2_capable();

#else

  return true;

#endif

}

// BORINGSSL_keccak_squeeze_x4 performs BORINGSSL_keccak_squeeze in parallel

// with four same-length outputs. The contexts must be in equivalent state (i.e.

// same config, same amount of bytes absorbed and squeezed).

// This function is not compatible with cSHAKE nor TurboSHAKE.

OPENSSL_EXPORT void BORINGSSL_keccak_squeeze_x4(

    struct BORINGSSL_keccak_st ctx[4], uint8_t *outs[4], size_t out_len);

// BORINGSSL_keccak_short_x4 performs BORINGSSL_keccak in parallel on four

// same-length strings with same-length outputs. in_len must be less than 72

// (or actually `rate_bytes`).

// This function is not compatible with cSHAKE nor TurboSHAKE.

OPENSSL_EXPORT void BORINGSSL_keccak_short_x4(

    uint8_t *outs[4], size_t out_len, const uint8_t *ins[4], size_t in_len,

    enum boringssl_keccak_config_t config);

#endif

BSSL_NAMESPACE_END

#endif  // OPENSSL_HEADER_CRYPTO_FIPSMODULE_KECCAK_INTERNAL_H