| // Copyright lowRISC contributors. |
| // Licensed under the Apache License, Version 2.0, see LICENSE for details. |
| // SPDX-License-Identifier: Apache-2.0 |
| |
| #ifndef OPENTITAN_SW_DEVICE_LIB_CRYPTO_INCLUDE_RSA_H_ |
| #define OPENTITAN_SW_DEVICE_LIB_CRYPTO_INCLUDE_RSA_H_ |
| |
| /** |
| * @file |
| * @brief RSA signature operations for the OpenTitan cryptography library. |
| */ |
| |
| #ifdef __cplusplus |
| extern "C" { |
| #endif // __cplusplus |
| |
| /** |
| * Enum to define padding scheme for RSA data. |
| * |
| * Values are hardened. |
| */ |
| typedef enum rsa_padding { |
| // Pads input data according to the PKCS#1 (v1.5) scheme. |
| kRsaPaddingPkcs = 0x9f44, |
| // Pads input data according to the PKCS#1-PSS scheme. |
| kRsaPaddingPss = 0x88cf, |
| } rsa_padding_t; |
| |
| /** |
| * Enum to define hash modes for RSA schemes. |
| * |
| * Aligning with existing hash modes. Values are hardened. |
| */ |
| typedef enum rsa_hash { |
| // SHA2-256 hashing mode for RSA. |
| kRsaHashSha256 = 0xed4b, |
| // SHA2-384 hashing mode for RSA. |
| kRsaHashSha384 = 0x5dd0, |
| // SHA2-512 hashing mode for RSA. |
| kRsaHashSha512 = 0x0bab, |
| // SHA3-384 hashing mode for RSA. |
| kRsaHashSha3_384 = 0x65b7, |
| } rsa_hash_t; |
| |
| /** |
| * Struct to handle the RSA private exponent and modulus. |
| */ |
| typedef struct rsa_private_key { |
| // Unblinded key struct with RSA modulus. |
| crypto_unblinded_key_t n; |
| // Blinded key struct with RSA private exponent. |
| crypto_blinded_key_t d; |
| } rsa_private_key_t; |
| |
| /** |
| * Enum to define possible lengths of RSA (public) keys. |
| * |
| * Values are hardened. |
| */ |
| typedef enum rsa_key_size { |
| // 2048-bit RSA key. |
| kRsaKeySize2048 = 0xa74d, |
| // 3072-bit RSA key. |
| kRsaKeySize3072 = 0x7fc6, |
| // 4096-bit RSA key. |
| kRsaKeySize4096 = 0xf07a, |
| } rsa_key_size_t; |
| |
| /** |
| * Struct to handle the RSA public exponent and modulus. |
| */ |
| typedef struct rsa_public_key { |
| // Unblinded key struct with RSA modulus. |
| crypto_unblinded_key_t n; |
| // Blinded key struct with RSA public exponent. |
| crypto_unblinded_key_t e; |
| } rsa_public_key_t; |
| |
| /** |
| * Performs the RSA key generation. |
| * |
| * Computes RSA private key (d) and RSA public key exponent (e) and |
| * modulus (n). |
| * |
| * The caller should allocate and partially populate all blinded and unblinded |
| * key structs underneath `rsa_private_key` and `rsa_public_key`. For unblinded |
| * keys, this means setting the key mode, allocating a buffer for the key |
| * material, and recording the length of the allocated buffer in `key_length`. |
| * If the buffer size does not match expectations, this function will return an |
| * error. For blinded key structs, the caller should fully populate the key |
| * configuration and allocate space for the keyblob. As for unblinded keys, the |
| * caller should record the allocated buffer length and this function will |
| * return an error if the keyblob length does not match expectations. The |
| * keyblob should be twice the length of the key. The value in the `checksum` |
| * field of the blinded key struct will be populated by the key generation |
| * function. |
| * |
| * @param required_key_len Requested key length. |
| * @param[out] rsa_public_key Pointer to RSA public exponent struct. |
| * @param[out] rsa_private_key Pointer to RSA private exponent struct. |
| * @return Result of the RSA key generation. |
| */ |
| crypto_status_t otcrypto_rsa_keygen(rsa_key_size_t required_key_len, |
| rsa_public_key_t *rsa_public_key, |
| rsa_private_key_t *rsa_private_key); |
| |
| /** |
| * Computes the digital signature on the input message data. |
| * |
| * The caller should allocate space for the `signature` buffer, |
| * (expected length same as modulus length from `rsa_private_key`), |
| * and set the length of expected output in the `len` field of |
| * `signature`. If the user-set length and the output length does not |
| * match, an error message will be returned. |
| * |
| * @param rsa_private_key Pointer to RSA private exponent struct. |
| * @param input_message Input message to be signed. |
| * @param padding_mode Padding scheme to be used for the data. |
| * @param hash_mode Hashing scheme to be used for the signature scheme. |
| * @param[out] signature Pointer to generated signature struct. |
| * @return The result of the RSA sign generation. |
| */ |
| crypto_status_t otcrypto_rsa_sign(const rsa_private_key_t *rsa_private_key, |
| crypto_const_uint8_buf_t input_message, |
| rsa_padding_t padding_mode, |
| rsa_hash_t hash_mode, |
| crypto_uint8_buf_t *signature); |
| |
| /** |
| * Verifies the authenticity of the input signature. |
| * |
| * The generated signature is compared against the input signature and |
| * PASS / FAIL is returned. |
| * |
| * @param rsa_public_key Pointer to RSA public exponent struct. |
| * @param input_message Input message to be signed for verification. |
| * @param padding_mode Padding scheme to be used for the data. |
| * @param hash_mode Hashing scheme to be used for the signature scheme. |
| * @param signature Pointer to the input signature to be verified. |
| * @param[out] verification_result Result of signature verification |
| * (Pass/Fail). |
| * @return Result of the RSA verify operation. |
| */ |
| crypto_status_t otcrypto_rsa_verify(const rsa_public_key_t *rsa_public_key, |
| crypto_const_uint8_buf_t input_message, |
| rsa_padding_t padding_mode, |
| rsa_hash_t hash_mode, |
| crypto_const_uint8_buf_t signature, |
| verification_status_t *verification_result); |
| |
| /** |
| * Starts the asynchronous RSA key generation function. |
| * |
| * Initializes OTBN and starts the OTBN routine to compute the RSA |
| * private key (d), RSA public key exponent (e) and modulus (n). |
| * |
| * Returns `kCryptoStatusOK` if the operation was successfully |
| * started, or`kCryptoStatusInternalError` if the operation cannot be |
| * started. |
| * |
| * @param required_key_len Requested key length. |
| * @return Result of async RSA keygen start operation. |
| */ |
| crypto_status_t otcrypto_rsa_keygen_async_start( |
| rsa_key_size_t required_key_len); |
| |
| /** |
| * Finalizes the asynchronous RSA key generation function. |
| * |
| * Returns `kCryptoStatusOK` and copies the RSA private key (d), RSA |
| * public key exponent (e) and modulus (n) if the OTBN status is done, |
| * or `kCryptoStatusAsyncIncomplete` if the OTBN is busy or |
| * `kCryptoStatusInternalError` if there is an error. |
| * |
| * @param[out] rsa_public_key Pointer to RSA public exponent struct. |
| * @param[out] rsa_private_key Pointer to RSA private exponent struct. |
| * @return Result of asynchronous RSA keygen finalize operation. |
| */ |
| crypto_status_t otcrypto_rsa_keygen_async_finalize( |
| rsa_public_key_t *rsa_public_key, rsa_private_key_t *rsa_private_key); |
| |
| /** |
| * Starts the asynchronous digital signature generation function. |
| * |
| * Initializes OTBN and starts the OTBN routine to compute the digital |
| * signature on the input message. |
| * |
| * Returns `kCryptoStatusOK` if the operation was successfully |
| * started, or`kCryptoStatusInternalError` if the operation cannot be |
| * started. |
| * |
| * @param rsa_private_key Pointer to RSA private exponent struct. |
| * @param input_message Input message to be signed. |
| * @param padding_mode Padding scheme to be used for the data. |
| * @param hash_mode Hashing scheme to be used for the signature scheme. |
| * @return Result of async RSA sign start operation. |
| */ |
| crypto_status_t otcrypto_rsa_sign_async_start( |
| const rsa_private_key_t *rsa_private_key, |
| crypto_const_uint8_buf_t input_message, rsa_padding_t padding_mode, |
| rsa_hash_t hash_mode); |
| |
| /** |
| * Finalizes the asynchronous digital signature generation function. |
| * |
| * Returns `kCryptoStatusOK` and copies the signature if the OTBN |
| * status is done, or `kCryptoStatusAsyncIncomplete` if the OTBN is |
| * busy or `kCryptoStatusInternalError` if there is an error. |
| * |
| * The caller should allocate space for the `signature` buffer, |
| * (expected length same as modulus length from `rsa_private_key`), |
| * and set the length of expected output in the `len` field of |
| * `signature`. If the user-set length and the output length does not |
| * match, an error message will be returned. |
| * |
| * @param[out] signature Pointer to generated signature struct. |
| * @return Result of async RSA sign finalize operation. |
| */ |
| crypto_status_t otcrypto_rsa_sign_async_finalize(crypto_uint8_buf_t *signature); |
| |
| /** |
| * Starts the asynchronous signature verification function. |
| * |
| * Initializes OTBN and starts the OTBN routine to recover the message |
| * from the input signature. |
| * |
| * @param rsa_public_key Pointer to RSA public exponent struct. |
| * @param signature Pointer to the input signature to be verified. |
| * @return Result of async RSA verify start operation. |
| */ |
| crypto_status_t otcrypto_rsa_verify_async_start( |
| const rsa_public_key_t *rsa_public_key, crypto_const_uint8_buf_t signature); |
| |
| /** |
| * Finalizes the asynchronous signature verification function. |
| * |
| * Returns `kCryptoStatusOK` and populates the `verification result` |
| * if the OTBN status is done, or `kCryptoStatusAsyncIncomplete` if |
| * OTBN is busy or `kCryptoStatusInternalError` if there is an error. |
| * The (hash of) recovered message is compared against the input |
| * message and a PASS or FAIL is returned. |
| * |
| * @param input_message Input message to be signed for verification. |
| * @param padding_mode Padding scheme to be used for the data. |
| * @param hash_mode Hashing scheme to be used for the signature scheme. |
| * @param[out] verification_result Result of signature verification |
| * (Pass/Fail). |
| * @return Result of async RSA verify finalize operation. |
| */ |
| crypto_status_t otcrypto_rsa_verify_async_finalize( |
| crypto_const_uint8_buf_t input_message, rsa_padding_t padding_mode, |
| rsa_hash_t hash_mode, verification_status_t *verification_result); |
| |
| #ifdef __cplusplus |
| } // extern "C" |
| #endif // __cplusplus |
| |
| #endif // OPENTITAN_SW_DEVICE_LIB_CRYPTO_INCLUDE_RSA_H_ |