mbedtls/include/psa/crypto_sizes.h

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/**
* \file psa/crypto_sizes.h
*
* \brief PSA cryptography module: Mbed TLS buffer size macros
*
* This file contains the definitions of macros that are useful to
* compute buffer sizes. The signatures and semantics of these macros
* are standardized, but the definitions are not, because they depend on
* the available algorithms and, in some cases, on permitted tolerances
* on buffer sizes.
*
* Macros that compute sizes whose values do not depend on the
* implementation are in crypto.h.
*/
/*
* Copyright (C) 2018, ARM Limited, All Rights Reserved
* SPDX-License-Identifier: Apache-2.0
*
* 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
*
* http://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.
*
* This file is part of mbed TLS (https://tls.mbed.org)
*/
#ifndef PSA_CRYPTO_SIZES_H
#define PSA_CRYPTO_SIZES_H
/* Include the Mbed TLS configuration file, the way Mbed TLS does it
* in each of its header files. */
#if !defined(MBEDTLS_CONFIG_FILE)
#include "../mbedtls/config.h"
#else
#include MBEDTLS_CONFIG_FILE
#endif
#if defined(MBEDTLS_SHA512_C)
#define PSA_HASH_MAX_SIZE 64
#define PSA_HMAC_MAX_HASH_BLOCK_SIZE 128
#else
#define PSA_HASH_MAX_SIZE 32
#define PSA_HMAC_MAX_HASH_BLOCK_SIZE 64
#endif
/** The size of the output of psa_mac_finish(), in bytes.
*
* This is also the MAC size that psa_mac_verify() expects.
*
* \param key_type The type of the MAC key.
* \param key_bits The size of the MAC key in bits.
* \param alg A MAC algorithm (\c PSA_ALG_XXX value such that
* #PSA_ALG_IS_MAC(alg) is true).
*
* \return The MAC size for the specified algorithm with
* the specified key parameters.
* \return 0 if the MAC algorithm is not recognized.
* \return Either 0 or the correct size for a MAC algorithm that
* the implementation recognizes, but does not support.
* \return Unspecified if the key parameters are not consistent
* with the algorithm.
*/
#define PSA_MAC_FINAL_SIZE(key_type, key_bits, alg) \
(PSA_ALG_IS_HMAC(alg) ? PSA_HASH_SIZE(PSA_ALG_HMAC_HASH(alg)) : \
PSA_ALG_IS_BLOCK_CIPHER_MAC(alg) ? PSA_BLOCK_CIPHER_BLOCK_SIZE(key_type) : \
0)
/** The maximum size of the output of psa_aead_encrypt(), in bytes.
*
* If the size of the ciphertext buffer is at least this large, it is
* guaranteed that psa_aead_encrypt() will not fail due to an
* insufficient buffer size. Depending on the algorithm, the actual size of
* the ciphertext may be smaller.
*
* \param alg An AEAD algorithm
* (\c PSA_ALG_XXX value such that
* #PSA_ALG_IS_AEAD(alg) is true).
* \param plaintext_length Size of the plaintext in bytes.
*
* \return The AEAD ciphertext size for the specified
* algorithm.
* If the AEAD algorithm is not recognized, return 0.
* An implementation may return either 0 or a
* correct size for an AEAD algorithm that it
* recognizes, but does not support.
*/
#define PSA_AEAD_ENCRYPT_OUTPUT_SIZE(alg, plaintext_length) \
(PSA_AEAD_TAG_SIZE(alg) != 0 ? \
(plaintext_length) + PSA_AEAD_TAG_SIZE(alg) : \
0)
/** The maximum size of the output of psa_aead_decrypt(), in bytes.
*
* If the size of the plaintext buffer is at least this large, it is
* guaranteed that psa_aead_decrypt() will not fail due to an
* insufficient buffer size. Depending on the algorithm, the actual size of
* the plaintext may be smaller.
*
* \param alg An AEAD algorithm
* (\c PSA_ALG_XXX value such that
* #PSA_ALG_IS_AEAD(alg) is true).
* \param ciphertext_length Size of the plaintext in bytes.
*
* \return The AEAD ciphertext size for the specified
* algorithm.
* If the AEAD algorithm is not recognized, return 0.
* An implementation may return either 0 or a
* correct size for an AEAD algorithm that it
* recognizes, but does not support.
*/
#define PSA_AEAD_DECRYPT_OUTPUT_SIZE(alg, ciphertext_length) \
(PSA_AEAD_TAG_SIZE(alg) != 0 ? \
(plaintext_length) - PSA_AEAD_TAG_SIZE(alg) : \
0)
/** Safe signature buffer size for psa_asymmetric_sign().
*
* This macro returns a safe buffer size for a signature using a key
* of the specified type and size, with the specified algorithm.
* Note that the actual size of the signature may be smaller
* (some algorithms produce a variable-size signature).
*
* \warning This function may call its arguments multiple times or
* zero times, so you should not pass arguments that contain
* side effects.
*
* \param key_type An asymmetric key type (this may indifferently be a
* key pair type or a public key type).
* \param key_bits The size of the key in bits.
* \param alg The signature algorithm.
*
* \return If the parameters are valid and supported, return
* a buffer size in bytes that guarantees that
* psa_asymmetric_sign() will not fail with
* #PSA_ERROR_BUFFER_TOO_SMALL.
* If the parameters are a valid combination that is not supported
* by the implementation, this macro either shall return either a
* sensible size or 0.
* If the parameters are not valid, the
* return value is unspecified.
*
*/
#define PSA_ASYMMETRIC_SIGN_OUTPUT_SIZE(key_type, key_bits, alg) \
(PSA_KEY_TYPE_IS_RSA(key_type) ? ((void)alg, PSA_BITS_TO_BYTES(key_bits)) : \
PSA_KEY_TYPE_IS_ECC(key_type) ? PSA_ECDSA_SIGNATURE_SIZE(key_bits) : \
((void)alg, 0))
#define PSA_ASYMMETRIC_ENCRYPT_OUTPUT_SIZE(key_type, key_bits, alg) \
(PSA_KEY_TYPE_IS_RSA(key_type) ? \
((void)alg, PSA_BITS_TO_BYTES(key_bits)) : \
0)
#define PSA_ASYMMETRIC_DECRYPT_OUTPUT_SIZE(key_type, key_bits, alg) \
(PSA_KEY_TYPE_IS_RSA(key_type) ? \
PSA_BITS_TO_BYTES(key_bits) - PSA_RSA_MINIMUM_PADDING_SIZE(alg) : \
0)
#endif /* PSA_CRYPTO_SIZES_H */