1 /* 2 * Interface of curve P-256 (ECDH and ECDSA) 3 * 4 * Copyright The Mbed TLS Contributors 5 * Author: Manuel Pégourié-Gonnard. 6 * SPDX-License-Identifier: Apache-2.0 OR GPL-2.0-or-later 7 */ 8 #ifndef P256_M_H 9 #define P256_M_H 10 11 #include <stdint.h> 12 #include <stddef.h> 13 14 /* Status codes */ 15 #define P256_SUCCESS 0 16 #define P256_RANDOM_FAILED -1 17 #define P256_INVALID_PUBKEY -2 18 #define P256_INVALID_PRIVKEY -3 19 #define P256_INVALID_SIGNATURE -4 20 21 #ifdef __cplusplus 22 extern "C" { 23 #endif 24 25 /* 26 * RNG function - must be provided externally and be cryptographically secure. 27 * 28 * in: output - must point to a writable buffer of at least output_size bytes. 29 * output_size - the number of random bytes to write to output. 30 * out: output is filled with output_size random bytes. 31 * return 0 on success, non-zero on errors. 32 */ 33 extern int p256_generate_random(uint8_t * output, unsigned output_size); 34 35 /* 36 * ECDH/ECDSA generate key pair 37 * 38 * [in] draws from p256_generate_random() 39 * [out] priv: on success, holds the private key, as a big-endian integer 40 * [out] pub: on success, holds the public key, as two big-endian integers 41 * 42 * return: P256_SUCCESS on success 43 * P256_RANDOM_FAILED on failure 44 */ 45 int p256_gen_keypair(uint8_t priv[32], uint8_t pub[64]); 46 47 /* 48 * ECDH compute shared secret 49 * 50 * [out] secret: on success, holds the shared secret, as a big-endian integer 51 * [in] priv: our private key as a big-endian integer 52 * [in] pub: the peer's public key, as two big-endian integers 53 * 54 * return: P256_SUCCESS on success 55 * P256_INVALID_PRIVKEY if priv is invalid 56 * P256_INVALID_PUBKEY if pub is invalid 57 */ 58 int p256_ecdh_shared_secret(uint8_t secret[32], 59 const uint8_t priv[32], const uint8_t pub[64]); 60 61 /* 62 * ECDSA sign 63 * 64 * [in] draws from p256_generate_random() 65 * [out] sig: on success, holds the signature, as two big-endian integers 66 * [in] priv: our private key as a big-endian integer 67 * [in] hash: the hash of the message to be signed 68 * [in] hlen: the size of hash in bytes 69 * 70 * return: P256_SUCCESS on success 71 * P256_RANDOM_FAILED on failure 72 * P256_INVALID_PRIVKEY if priv is invalid 73 */ 74 int p256_ecdsa_sign(uint8_t sig[64], const uint8_t priv[32], 75 const uint8_t *hash, size_t hlen); 76 77 /* 78 * ECDSA verify 79 * 80 * [in] sig: the signature to be verified, as two big-endian integers 81 * [in] pub: the associated public key, as two big-endian integers 82 * [in] hash: the hash of the message that was signed 83 * [in] hlen: the size of hash in bytes 84 * 85 * return: P256_SUCCESS on success - the signature was verified as valid 86 * P256_INVALID_PUBKEY if pub is invalid 87 * P256_INVALID_SIGNATURE if the signature was found to be invalid 88 */ 89 int p256_ecdsa_verify(const uint8_t sig[64], const uint8_t pub[64], 90 const uint8_t *hash, size_t hlen); 91 92 /* 93 * Public key validation 94 * 95 * Note: you never need to call this function, as all other functions always 96 * validate their input; however it's availabe if you want to validate the key 97 * without performing an operation. 98 * 99 * [in] pub: the public key, as two big-endian integers 100 * 101 * return: P256_SUCCESS if the key is valid 102 * P256_INVALID_PUBKEY if pub is invalid 103 */ 104 int p256_validate_pubkey(const uint8_t pub[64]); 105 106 /* 107 * Private key validation 108 * 109 * Note: you never need to call this function, as all other functions always 110 * validate their input; however it's availabe if you want to validate the key 111 * without performing an operation. 112 * 113 * [in] priv: the private key, as a big-endian integer 114 * 115 * return: P256_SUCCESS if the key is valid 116 * P256_INVALID_PRIVKEY if priv is invalid 117 */ 118 int p256_validate_privkey(const uint8_t priv[32]); 119 120 /* 121 * Compute public key from private key 122 * 123 * [out] pub: the associated public key, as two big-endian integers 124 * [in] priv: the private key, as a big-endian integer 125 * 126 * return: P256_SUCCESS on success 127 * P256_INVALID_PRIVKEY if priv is invalid 128 */ 129 int p256_public_from_private(uint8_t pub[64], const uint8_t priv[32]); 130 131 #ifdef __cplusplus 132 } 133 #endif 134 135 #endif /* P256_M_H */ 136
