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diff --git a/test/monniaux/BearSSL/inc/bearssl_rsa.h b/test/monniaux/BearSSL/inc/bearssl_rsa.h new file mode 100644 index 00000000..0a069fd3 --- /dev/null +++ b/test/monniaux/BearSSL/inc/bearssl_rsa.h @@ -0,0 +1,1655 @@ +/* + * Copyright (c) 2016 Thomas Pornin <pornin@bolet.org> + * + * Permission is hereby granted, free of charge, to any person obtaining + * a copy of this software and associated documentation files (the + * "Software"), to deal in the Software without restriction, including + * without limitation the rights to use, copy, modify, merge, publish, + * distribute, sublicense, and/or sell copies of the Software, and to + * permit persons to whom the Software is furnished to do so, subject to + * the following conditions: + * + * The above copyright notice and this permission notice shall be + * included in all copies or substantial portions of the Software. + * + * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, + * EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF + * MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND + * NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS + * BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN + * ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN + * CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE + * SOFTWARE. + */ + +#ifndef BR_BEARSSL_RSA_H__ +#define BR_BEARSSL_RSA_H__ + +#include <stddef.h> +#include <stdint.h> + +#include "bearssl_hash.h" +#include "bearssl_rand.h" + +#ifdef __cplusplus +extern "C" { +#endif + +/** \file bearssl_rsa.h + * + * # RSA + * + * This file documents the RSA implementations provided with BearSSL. + * Note that the SSL engine accesses these implementations through a + * configurable API, so it is possible to, for instance, run a SSL + * server which uses a RSA engine which is not based on this code. + * + * ## Key Elements + * + * RSA public and private keys consist in lists of big integers. All + * such integers are represented with big-endian unsigned notation: + * first byte is the most significant, and the value is positive (so + * there is no dedicated "sign bit"). Public and private key structures + * thus contain, for each such integer, a pointer to the first value byte + * (`unsigned char *`), and a length (`size_t`) which is the number of + * relevant bytes. As a general rule, minimal-length encoding is not + * enforced: values may have extra leading bytes of value 0. + * + * RSA public keys consist in two integers: + * + * - the modulus (`n`); + * - the public exponent (`e`). + * + * RSA private keys, as defined in + * [PKCS#1](https://tools.ietf.org/html/rfc3447), contain eight integers: + * + * - the modulus (`n`); + * - the public exponent (`e`); + * - the private exponent (`d`); + * - the first prime factor (`p`); + * - the second prime factor (`q`); + * - the first reduced exponent (`dp`, which is `d` modulo `p-1`); + * - the second reduced exponent (`dq`, which is `d` modulo `q-1`); + * - the CRT coefficient (`iq`, the inverse of `q` modulo `p`). + * + * However, the implementations defined in BearSSL use only five of + * these integers: `p`, `q`, `dp`, `dq` and `iq`. + * + * ## Security Features and Limitations + * + * The implementations contained in BearSSL have the following limitations + * and features: + * + * - They are constant-time. This means that the execution time and + * memory access pattern may depend on the _lengths_ of the private + * key components, but not on their value, nor on the value of + * the operand. Note that this property is not achieved through + * random masking, but "true" constant-time code. + * + * - They support only private keys with two prime factors. RSA private + * keys with three or more prime factors are nominally supported, but + * rarely used; they may offer faster operations, at the expense of + * more code and potentially a reduction in security if there are + * "too many" prime factors. + * + * - The public exponent may have arbitrary length. Of course, it is + * a good idea to keep public exponents small, so that public key + * operations are fast; but, contrary to some widely deployed + * implementations, BearSSL has no problem with public exponents + * longer than 32 bits. + * + * - The two prime factors of the modulus need not have the same length + * (but severely imbalanced factor lengths might reduce security). + * Similarly, there is no requirement that the first factor (`p`) + * be greater than the second factor (`q`). + * + * - Prime factors and modulus must be smaller than a compile-time limit. + * This is made necessary by the use of fixed-size stack buffers, and + * the limit has been adjusted to keep stack usage under 2 kB for the + * RSA operations. Currently, the maximum modulus size is 4096 bits, + * and the maximum prime factor size is 2080 bits. + * + * - The RSA functions themselves do not enforce lower size limits, + * except that which is absolutely necessary for the operation to + * mathematically make sense (e.g. a PKCS#1 v1.5 signature with + * SHA-1 requires a modulus of at least 361 bits). It is up to users + * of this code to enforce size limitations when appropriate (e.g. + * the X.509 validation engine, by default, rejects RSA keys of + * less than 1017 bits). + * + * - Within the size constraints expressed above, arbitrary bit lengths + * are supported. There is no requirement that prime factors or + * modulus have a size multiple of 8 or 16. + * + * - When verifying PKCS#1 v1.5 signatures, both variants of the hash + * function identifying header (with and without the ASN.1 NULL) are + * supported. When producing such signatures, the variant with the + * ASN.1 NULL is used. + * + * ## Implementations + * + * Three RSA implementations are included: + * + * - The **i32** implementation internally represents big integers + * as arrays of 32-bit integers. It is perfunctory and portable, + * but not very efficient. + * + * - The **i31** implementation uses 32-bit integers, each containing + * 31 bits worth of integer data. The i31 implementation is somewhat + * faster than the i32 implementation (the reduced integer size makes + * carry propagation easier) for a similar code footprint, but uses + * very slightly larger stack buffers (about 4% bigger). + * + * - The **i62** implementation is similar to the i31 implementation, + * except that it internally leverages the 64x64->128 multiplication + * opcode. This implementation is available only on architectures + * where such an opcode exists. It is much faster than i31. + * + * - The **i15** implementation uses 16-bit integers, each containing + * 15 bits worth of integer data. Multiplication results fit on + * 32 bits, so this won't use the "widening" multiplication routine + * on ARM Cortex M0/M0+, for much better performance and constant-time + * execution. + */ + +/** + * \brief RSA public key. + * + * The structure references the modulus and the public exponent. Both + * integers use unsigned big-endian representation; extra leading bytes + * of value 0 are allowed. + */ +typedef struct { + /** \brief Modulus. */ + unsigned char *n; + /** \brief Modulus length (in bytes). */ + size_t nlen; + /** \brief Public exponent. */ + unsigned char *e; + /** \brief Public exponent length (in bytes). */ + size_t elen; +} br_rsa_public_key; + +/** + * \brief RSA private key. + * + * The structure references the private factors, reduced private + * exponents, and CRT coefficient. It also contains the bit length of + * the modulus. The big integers use unsigned big-endian representation; + * extra leading bytes of value 0 are allowed. However, the modulus bit + * length (`n_bitlen`) MUST be exact. + */ +typedef struct { + /** \brief Modulus bit length (in bits, exact value). */ + uint32_t n_bitlen; + /** \brief First prime factor. */ + unsigned char *p; + /** \brief First prime factor length (in bytes). */ + size_t plen; + /** \brief Second prime factor. */ + unsigned char *q; + /** \brief Second prime factor length (in bytes). */ + size_t qlen; + /** \brief First reduced private exponent. */ + unsigned char *dp; + /** \brief First reduced private exponent length (in bytes). */ + size_t dplen; + /** \brief Second reduced private exponent. */ + unsigned char *dq; + /** \brief Second reduced private exponent length (in bytes). */ + size_t dqlen; + /** \brief CRT coefficient. */ + unsigned char *iq; + /** \brief CRT coefficient length (in bytes). */ + size_t iqlen; +} br_rsa_private_key; + +/** + * \brief Type for a RSA public key engine. + * + * The public key engine performs the modular exponentiation of the + * provided value with the public exponent. The value is modified in + * place. + * + * The value length (`xlen`) is verified to have _exactly_ the same + * length as the modulus (actual modulus length, without extra leading + * zeros in the modulus representation in memory). If the length does + * not match, then this function returns 0 and `x[]` is unmodified. + * + * It `xlen` is correct, then `x[]` is modified. Returned value is 1 + * on success, 0 on error. Error conditions include an oversized `x[]` + * (the array has the same length as the modulus, but the numerical value + * is not lower than the modulus) and an invalid modulus (e.g. an even + * integer). If an error is reported, then the new contents of `x[]` are + * unspecified. + * + * \param x operand to exponentiate. + * \param xlen length of the operand (in bytes). + * \param pk RSA public key. + * \return 1 on success, 0 on error. + */ +typedef uint32_t (*br_rsa_public)(unsigned char *x, size_t xlen, + const br_rsa_public_key *pk); + +/** + * \brief Type for a RSA signature verification engine (PKCS#1 v1.5). + * + * Parameters are: + * + * - The signature itself. The provided array is NOT modified. + * + * - The encoded OID for the hash function. The provided array must begin + * with a single byte that contains the length of the OID value (in + * bytes), followed by exactly that many bytes. This parameter may + * also be `NULL`, in which case the raw hash value should be used + * with the PKCS#1 v1.5 "type 1" padding (as used in SSL/TLS up + * to TLS-1.1, with a 36-byte hash value). + * + * - The hash output length, in bytes. + * + * - The public key. + * + * - An output buffer for the hash value. The caller must still compare + * it with the hash of the data over which the signature is computed. + * + * **Constraints:** + * + * - Hash length MUST be no more than 64 bytes. + * + * - OID value length MUST be no more than 32 bytes (i.e. `hash_oid[0]` + * must have a value in the 0..32 range, inclusive). + * + * This function verifies that the signature length (`xlen`) matches the + * modulus length (this function returns 0 on mismatch). If the modulus + * size exceeds the maximum supported RSA size, then the function also + * returns 0. + * + * Returned value is 1 on success, 0 on error. + * + * Implementations of this type need not be constant-time. + * + * \param x signature buffer. + * \param xlen signature length (in bytes). + * \param hash_oid encoded hash algorithm OID (or `NULL`). + * \param hash_len expected hash value length (in bytes). + * \param pk RSA public key. + * \param hash_out output buffer for the hash value. + * \return 1 on success, 0 on error. + */ +typedef uint32_t (*br_rsa_pkcs1_vrfy)(const unsigned char *x, size_t xlen, + const unsigned char *hash_oid, size_t hash_len, + const br_rsa_public_key *pk, unsigned char *hash_out); + +/** + * \brief Type for a RSA signature verification engine (PSS). + * + * Parameters are: + * + * - The signature itself. The provided array is NOT modified. + * + * - The hash function which was used to hash the message. + * + * - The hash function to use with MGF1 within the PSS padding. This + * is not necessarily the same hash function as the one which was + * used to hash the signed message. + * + * - The hashed message (as an array of bytes). + * + * - The PSS salt length (in bytes). + * + * - The public key. + * + * **Constraints:** + * + * - Hash message length MUST be no more than 64 bytes. + * + * Note that, contrary to PKCS#1 v1.5 signature, the hash value of the + * signed data cannot be extracted from the signature; it must be + * provided to the verification function. + * + * This function verifies that the signature length (`xlen`) matches the + * modulus length (this function returns 0 on mismatch). If the modulus + * size exceeds the maximum supported RSA size, then the function also + * returns 0. + * + * Returned value is 1 on success, 0 on error. + * + * Implementations of this type need not be constant-time. + * + * \param x signature buffer. + * \param xlen signature length (in bytes). + * \param hf_data hash function applied on the message. + * \param hf_mgf1 hash function to use with MGF1. + * \param hash hash value of the signed message. + * \param salt_len PSS salt length (in bytes). + * \param pk RSA public key. + * \return 1 on success, 0 on error. + */ +typedef uint32_t (*br_rsa_pss_vrfy)(const unsigned char *x, size_t xlen, + const br_hash_class *hf_data, const br_hash_class *hf_mgf1, + const void *hash, size_t salt_len, const br_rsa_public_key *pk); + +/** + * \brief Type for a RSA encryption engine (OAEP). + * + * Parameters are: + * + * - A source of random bytes. The source must be already initialized. + * + * - A hash function, used internally with the mask generation function + * (MGF1). + * + * - A label. The `label` pointer may be `NULL` if `label_len` is zero + * (an empty label, which is the default in PKCS#1 v2.2). + * + * - The public key. + * + * - The destination buffer. Its maximum length (in bytes) is provided; + * if that length is lower than the public key length, then an error + * is reported. + * + * - The source message. + * + * The encrypted message output has exactly the same length as the modulus + * (mathematical length, in bytes, not counting extra leading zeros in the + * modulus representation in the public key). + * + * The source message (`src`, length `src_len`) may overlap with the + * destination buffer (`dst`, length `dst_max_len`). + * + * This function returns the actual encrypted message length, in bytes; + * on error, zero is returned. An error is reported if the output buffer + * is not large enough, or the public is invalid, or the public key + * modulus exceeds the maximum supported RSA size. + * + * \param rnd source of random bytes. + * \param dig hash function to use with MGF1. + * \param label label value (may be `NULL` if `label_len` is zero). + * \param label_len label length, in bytes. + * \param pk RSA public key. + * \param dst destination buffer. + * \param dst_max_len destination buffer length (maximum encrypted data size). + * \param src message to encrypt. + * \param src_len source message length (in bytes). + * \return encrypted message length (in bytes), or 0 on error. + */ +typedef size_t (*br_rsa_oaep_encrypt)( + const br_prng_class **rnd, const br_hash_class *dig, + const void *label, size_t label_len, + const br_rsa_public_key *pk, + void *dst, size_t dst_max_len, + const void *src, size_t src_len); + +/** + * \brief Type for a RSA private key engine. + * + * The `x[]` buffer is modified in place, and its length is inferred from + * the modulus length (`x[]` is assumed to have a length of + * `(sk->n_bitlen+7)/8` bytes). + * + * Returned value is 1 on success, 0 on error. + * + * \param x operand to exponentiate. + * \param sk RSA private key. + * \return 1 on success, 0 on error. + */ +typedef uint32_t (*br_rsa_private)(unsigned char *x, + const br_rsa_private_key *sk); + +/** + * \brief Type for a RSA signature generation engine (PKCS#1 v1.5). + * + * Parameters are: + * + * - The encoded OID for the hash function. The provided array must begin + * with a single byte that contains the length of the OID value (in + * bytes), followed by exactly that many bytes. This parameter may + * also be `NULL`, in which case the raw hash value should be used + * with the PKCS#1 v1.5 "type 1" padding (as used in SSL/TLS up + * to TLS-1.1, with a 36-byte hash value). + * + * - The hash value computes over the data to sign (its length is + * expressed in bytes). + * + * - The RSA private key. + * + * - The output buffer, that receives the signature. + * + * Returned value is 1 on success, 0 on error. Error conditions include + * a too small modulus for the provided hash OID and value, or some + * invalid key parameters. The signature length is exactly + * `(sk->n_bitlen+7)/8` bytes. + * + * This function is expected to be constant-time with regards to the + * private key bytes (lengths of the modulus and the individual factors + * may leak, though) and to the hashed data. + * + * \param hash_oid encoded hash algorithm OID (or `NULL`). + * \param hash hash value. + * \param hash_len hash value length (in bytes). + * \param sk RSA private key. + * \param x output buffer for the signature value. + * \return 1 on success, 0 on error. + */ +typedef uint32_t (*br_rsa_pkcs1_sign)(const unsigned char *hash_oid, + const unsigned char *hash, size_t hash_len, + const br_rsa_private_key *sk, unsigned char *x); + +/** + * \brief Type for a RSA signature generation engine (PSS). + * + * Parameters are: + * + * - An initialized PRNG for salt generation. If the salt length is + * zero (`salt_len` parameter), then the PRNG is optional (this is + * not the typical case, as the security proof of RSA/PSS is + * tighter when a non-empty salt is used). + * + * - The hash function which was used to hash the message. + * + * - The hash function to use with MGF1 within the PSS padding. This + * is not necessarily the same function as the one used to hash the + * message. + * + * - The hashed message. + * + * - The salt length, in bytes. + * + * - The RSA private key. + * + * - The output buffer, that receives the signature. + * + * Returned value is 1 on success, 0 on error. Error conditions include + * a too small modulus for the provided hash and salt lengths, or some + * invalid key parameters. The signature length is exactly + * `(sk->n_bitlen+7)/8` bytes. + * + * This function is expected to be constant-time with regards to the + * private key bytes (lengths of the modulus and the individual factors + * may leak, though) and to the hashed data. + * + * \param rng PRNG for salt generation (`NULL` if `salt_len` is zero). + * \param hf_data hash function used to hash the signed data. + * \param hf_mgf1 hash function to use with MGF1. + * \param hash hashed message. + * \param salt_len salt length (in bytes). + * \param sk RSA private key. + * \param x output buffer for the signature value. + * \return 1 on success, 0 on error. + */ +typedef uint32_t (*br_rsa_pss_sign)(const br_prng_class **rng, + const br_hash_class *hf_data, const br_hash_class *hf_mgf1, + const unsigned char *hash_value, size_t salt_len, + const br_rsa_private_key *sk, unsigned char *x); + +/** + * \brief Encoded OID for SHA-1 (in RSA PKCS#1 signatures). + */ +#define BR_HASH_OID_SHA1 \ + ((const unsigned char *)"\x05\x2B\x0E\x03\x02\x1A") + +/** + * \brief Encoded OID for SHA-224 (in RSA PKCS#1 signatures). + */ +#define BR_HASH_OID_SHA224 \ + ((const unsigned char *)"\x09\x60\x86\x48\x01\x65\x03\x04\x02\x04") + +/** + * \brief Encoded OID for SHA-256 (in RSA PKCS#1 signatures). + */ +#define BR_HASH_OID_SHA256 \ + ((const unsigned char *)"\x09\x60\x86\x48\x01\x65\x03\x04\x02\x01") + +/** + * \brief Encoded OID for SHA-384 (in RSA PKCS#1 signatures). + */ +#define BR_HASH_OID_SHA384 \ + ((const unsigned char *)"\x09\x60\x86\x48\x01\x65\x03\x04\x02\x02") + +/** + * \brief Encoded OID for SHA-512 (in RSA PKCS#1 signatures). + */ +#define BR_HASH_OID_SHA512 \ + ((const unsigned char *)"\x09\x60\x86\x48\x01\x65\x03\x04\x02\x03") + +/** + * \brief Type for a RSA decryption engine (OAEP). + * + * Parameters are: + * + * - A hash function, used internally with the mask generation function + * (MGF1). + * + * - A label. The `label` pointer may be `NULL` if `label_len` is zero + * (an empty label, which is the default in PKCS#1 v2.2). + * + * - The private key. + * + * - The source and destination buffer. The buffer initially contains + * the encrypted message; the buffer contents are altered, and the + * decrypted message is written at the start of that buffer + * (decrypted message is always shorter than the encrypted message). + * + * If decryption fails in any way, then `*len` is unmodified, and the + * function returns 0. Otherwise, `*len` is set to the decrypted message + * length, and 1 is returned. The implementation is responsible for + * checking that the input message length matches the key modulus length, + * and that the padding is correct. + * + * Implementations MUST use constant-time check of the validity of the + * OAEP padding, at least until the leading byte and hash value have + * been checked. Whether overall decryption worked, and the length of + * the decrypted message, may leak. + * + * \param dig hash function to use with MGF1. + * \param label label value (may be `NULL` if `label_len` is zero). + * \param label_len label length, in bytes. + * \param sk RSA private key. + * \param data input/output buffer. + * \param len encrypted/decrypted message length. + * \return 1 on success, 0 on error. + */ +typedef uint32_t (*br_rsa_oaep_decrypt)( + const br_hash_class *dig, const void *label, size_t label_len, + const br_rsa_private_key *sk, void *data, size_t *len); + +/* + * RSA "i32" engine. Integers are internally represented as arrays of + * 32-bit integers, and the core multiplication primitive is the + * 32x32->64 multiplication. + */ + +/** + * \brief RSA public key engine "i32". + * + * \see br_rsa_public + * + * \param x operand to exponentiate. + * \param xlen length of the operand (in bytes). + * \param pk RSA public key. + * \return 1 on success, 0 on error. + */ +uint32_t br_rsa_i32_public(unsigned char *x, size_t xlen, + const br_rsa_public_key *pk); + +/** + * \brief RSA signature verification engine "i32" (PKCS#1 v1.5 signatures). + * + * \see br_rsa_pkcs1_vrfy + * + * \param x signature buffer. + * \param xlen signature length (in bytes). + * \param hash_oid encoded hash algorithm OID (or `NULL`). + * \param hash_len expected hash value length (in bytes). + * \param pk RSA public key. + * \param hash_out output buffer for the hash value. + * \return 1 on success, 0 on error. + */ +uint32_t br_rsa_i32_pkcs1_vrfy(const unsigned char *x, size_t xlen, + const unsigned char *hash_oid, size_t hash_len, + const br_rsa_public_key *pk, unsigned char *hash_out); + +/** + * \brief RSA signature verification engine "i32" (PSS signatures). + * + * \see br_rsa_pss_vrfy + * + * \param x signature buffer. + * \param xlen signature length (in bytes). + * \param hf_data hash function applied on the message. + * \param hf_mgf1 hash function to use with MGF1. + * \param hash hash value of the signed message. + * \param salt_len PSS salt length (in bytes). + * \param pk RSA public key. + * \return 1 on success, 0 on error. + */ +uint32_t br_rsa_i32_pss_vrfy(const unsigned char *x, size_t xlen, + const br_hash_class *hf_data, const br_hash_class *hf_mgf1, + const void *hash, size_t salt_len, const br_rsa_public_key *pk); + +/** + * \brief RSA private key engine "i32". + * + * \see br_rsa_private + * + * \param x operand to exponentiate. + * \param sk RSA private key. + * \return 1 on success, 0 on error. + */ +uint32_t br_rsa_i32_private(unsigned char *x, + const br_rsa_private_key *sk); + +/** + * \brief RSA signature generation engine "i32" (PKCS#1 v1.5 signatures). + * + * \see br_rsa_pkcs1_sign + * + * \param hash_oid encoded hash algorithm OID (or `NULL`). + * \param hash hash value. + * \param hash_len hash value length (in bytes). + * \param sk RSA private key. + * \param x output buffer for the hash value. + * \return 1 on success, 0 on error. + */ +uint32_t br_rsa_i32_pkcs1_sign(const unsigned char *hash_oid, + const unsigned char *hash, size_t hash_len, + const br_rsa_private_key *sk, unsigned char *x); + +/** + * \brief RSA signature generation engine "i32" (PSS signatures). + * + * \see br_rsa_pss_sign + * + * \param rng PRNG for salt generation (`NULL` if `salt_len` is zero). + * \param hf_data hash function used to hash the signed data. + * \param hf_mgf1 hash function to use with MGF1. + * \param hash hashed message. + * \param salt_len salt length (in bytes). + * \param sk RSA private key. + * \param x output buffer for the signature value. + * \return 1 on success, 0 on error. + */ +uint32_t br_rsa_i32_pss_sign(const br_prng_class **rng, + const br_hash_class *hf_data, const br_hash_class *hf_mgf1, + const unsigned char *hash_value, size_t salt_len, + const br_rsa_private_key *sk, unsigned char *x); + +/* + * RSA "i31" engine. Similar to i32, but only 31 bits are used per 32-bit + * word. This uses slightly more stack space (about 4% more) and code + * space, but it quite faster. + */ + +/** + * \brief RSA public key engine "i31". + * + * \see br_rsa_public + * + * \param x operand to exponentiate. + * \param xlen length of the operand (in bytes). + * \param pk RSA public key. + * \return 1 on success, 0 on error. + */ +uint32_t br_rsa_i31_public(unsigned char *x, size_t xlen, + const br_rsa_public_key *pk); + +/** + * \brief RSA signature verification engine "i31" (PKCS#1 v1.5 signatures). + * + * \see br_rsa_pkcs1_vrfy + * + * \param x signature buffer. + * \param xlen signature length (in bytes). + * \param hash_oid encoded hash algorithm OID (or `NULL`). + * \param hash_len expected hash value length (in bytes). + * \param pk RSA public key. + * \param hash_out output buffer for the hash value. + * \return 1 on success, 0 on error. + */ +uint32_t br_rsa_i31_pkcs1_vrfy(const unsigned char *x, size_t xlen, + const unsigned char *hash_oid, size_t hash_len, + const br_rsa_public_key *pk, unsigned char *hash_out); + +/** + * \brief RSA signature verification engine "i31" (PSS signatures). + * + * \see br_rsa_pss_vrfy + * + * \param x signature buffer. + * \param xlen signature length (in bytes). + * \param hf_data hash function applied on the message. + * \param hf_mgf1 hash function to use with MGF1. + * \param hash hash value of the signed message. + * \param salt_len PSS salt length (in bytes). + * \param pk RSA public key. + * \return 1 on success, 0 on error. + */ +uint32_t br_rsa_i31_pss_vrfy(const unsigned char *x, size_t xlen, + const br_hash_class *hf_data, const br_hash_class *hf_mgf1, + const void *hash, size_t salt_len, const br_rsa_public_key *pk); + +/** + * \brief RSA private key engine "i31". + * + * \see br_rsa_private + * + * \param x operand to exponentiate. + * \param sk RSA private key. + * \return 1 on success, 0 on error. + */ +uint32_t br_rsa_i31_private(unsigned char *x, + const br_rsa_private_key *sk); + +/** + * \brief RSA signature generation engine "i31" (PKCS#1 v1.5 signatures). + * + * \see br_rsa_pkcs1_sign + * + * \param hash_oid encoded hash algorithm OID (or `NULL`). + * \param hash hash value. + * \param hash_len hash value length (in bytes). + * \param sk RSA private key. + * \param x output buffer for the hash value. + * \return 1 on success, 0 on error. + */ +uint32_t br_rsa_i31_pkcs1_sign(const unsigned char *hash_oid, + const unsigned char *hash, size_t hash_len, + const br_rsa_private_key *sk, unsigned char *x); + +/** + * \brief RSA signature generation engine "i31" (PSS signatures). + * + * \see br_rsa_pss_sign + * + * \param rng PRNG for salt generation (`NULL` if `salt_len` is zero). + * \param hf_data hash function used to hash the signed data. + * \param hf_mgf1 hash function to use with MGF1. + * \param hash hashed message. + * \param salt_len salt length (in bytes). + * \param sk RSA private key. + * \param x output buffer for the signature value. + * \return 1 on success, 0 on error. + */ +uint32_t br_rsa_i31_pss_sign(const br_prng_class **rng, + const br_hash_class *hf_data, const br_hash_class *hf_mgf1, + const unsigned char *hash_value, size_t salt_len, + const br_rsa_private_key *sk, unsigned char *x); + +/* + * RSA "i62" engine. Similar to i31, but internal multiplication use + * 64x64->128 multiplications. This is available only on architecture + * that offer such an opcode. + */ + +/** + * \brief RSA public key engine "i62". + * + * This function is defined only on architecture that offer a 64x64->128 + * opcode. Use `br_rsa_i62_public_get()` to dynamically obtain a pointer + * to that function. + * + * \see br_rsa_public + * + * \param x operand to exponentiate. + * \param xlen length of the operand (in bytes). + * \param pk RSA public key. + * \return 1 on success, 0 on error. + */ +uint32_t br_rsa_i62_public(unsigned char *x, size_t xlen, + const br_rsa_public_key *pk); + +/** + * \brief RSA signature verification engine "i62" (PKCS#1 v1.5 signatures). + * + * This function is defined only on architecture that offer a 64x64->128 + * opcode. Use `br_rsa_i62_pkcs1_vrfy_get()` to dynamically obtain a pointer + * to that function. + * + * \see br_rsa_pkcs1_vrfy + * + * \param x signature buffer. + * \param xlen signature length (in bytes). + * \param hash_oid encoded hash algorithm OID (or `NULL`). + * \param hash_len expected hash value length (in bytes). + * \param pk RSA public key. + * \param hash_out output buffer for the hash value. + * \return 1 on success, 0 on error. + */ +uint32_t br_rsa_i62_pkcs1_vrfy(const unsigned char *x, size_t xlen, + const unsigned char *hash_oid, size_t hash_len, + const br_rsa_public_key *pk, unsigned char *hash_out); + +/** + * \brief RSA signature verification engine "i62" (PSS signatures). + * + * This function is defined only on architecture that offer a 64x64->128 + * opcode. Use `br_rsa_i62_pss_vrfy_get()` to dynamically obtain a pointer + * to that function. + * + * \see br_rsa_pss_vrfy + * + * \param x signature buffer. + * \param xlen signature length (in bytes). + * \param hf_data hash function applied on the message. + * \param hf_mgf1 hash function to use with MGF1. + * \param hash hash value of the signed message. + * \param salt_len PSS salt length (in bytes). + * \param pk RSA public key. + * \return 1 on success, 0 on error. + */ +uint32_t br_rsa_i62_pss_vrfy(const unsigned char *x, size_t xlen, + const br_hash_class *hf_data, const br_hash_class *hf_mgf1, + const void *hash, size_t salt_len, const br_rsa_public_key *pk); + +/** + * \brief RSA private key engine "i62". + * + * This function is defined only on architecture that offer a 64x64->128 + * opcode. Use `br_rsa_i62_private_get()` to dynamically obtain a pointer + * to that function. + * + * \see br_rsa_private + * + * \param x operand to exponentiate. + * \param sk RSA private key. + * \return 1 on success, 0 on error. + */ +uint32_t br_rsa_i62_private(unsigned char *x, + const br_rsa_private_key *sk); + +/** + * \brief RSA signature generation engine "i62" (PKCS#1 v1.5 signatures). + * + * This function is defined only on architecture that offer a 64x64->128 + * opcode. Use `br_rsa_i62_pkcs1_sign_get()` to dynamically obtain a pointer + * to that function. + * + * \see br_rsa_pkcs1_sign + * + * \param hash_oid encoded hash algorithm OID (or `NULL`). + * \param hash hash value. + * \param hash_len hash value length (in bytes). + * \param sk RSA private key. + * \param x output buffer for the hash value. + * \return 1 on success, 0 on error. + */ +uint32_t br_rsa_i62_pkcs1_sign(const unsigned char *hash_oid, + const unsigned char *hash, size_t hash_len, + const br_rsa_private_key *sk, unsigned char *x); + +/** + * \brief RSA signature generation engine "i62" (PSS signatures). + * + * This function is defined only on architecture that offer a 64x64->128 + * opcode. Use `br_rsa_i62_pss_sign_get()` to dynamically obtain a pointer + * to that function. + * + * \see br_rsa_pss_sign + * + * \param rng PRNG for salt generation (`NULL` if `salt_len` is zero). + * \param hf_data hash function used to hash the signed data. + * \param hf_mgf1 hash function to use with MGF1. + * \param hash hashed message. + * \param salt_len salt length (in bytes). + * \param sk RSA private key. + * \param x output buffer for the signature value. + * \return 1 on success, 0 on error. + */ +uint32_t br_rsa_i62_pss_sign(const br_prng_class **rng, + const br_hash_class *hf_data, const br_hash_class *hf_mgf1, + const unsigned char *hash_value, size_t salt_len, + const br_rsa_private_key *sk, unsigned char *x); + +/** + * \brief Get the RSA "i62" implementation (public key operations), + * if available. + * + * \return the implementation, or 0. + */ +br_rsa_public br_rsa_i62_public_get(void); + +/** + * \brief Get the RSA "i62" implementation (PKCS#1 v1.5 signature verification), + * if available. + * + * \return the implementation, or 0. + */ +br_rsa_pkcs1_vrfy br_rsa_i62_pkcs1_vrfy_get(void); + +/** + * \brief Get the RSA "i62" implementation (PSS signature verification), + * if available. + * + * \return the implementation, or 0. + */ +br_rsa_pss_vrfy br_rsa_i62_pss_vrfy_get(void); + +/** + * \brief Get the RSA "i62" implementation (private key operations), + * if available. + * + * \return the implementation, or 0. + */ +br_rsa_private br_rsa_i62_private_get(void); + +/** + * \brief Get the RSA "i62" implementation (PKCS#1 v1.5 signature generation), + * if available. + * + * \return the implementation, or 0. + */ +br_rsa_pkcs1_sign br_rsa_i62_pkcs1_sign_get(void); + +/** + * \brief Get the RSA "i62" implementation (PSS signature generation), + * if available. + * + * \return the implementation, or 0. + */ +br_rsa_pss_sign br_rsa_i62_pss_sign_get(void); + +/** + * \brief Get the RSA "i62" implementation (OAEP encryption), + * if available. + * + * \return the implementation, or 0. + */ +br_rsa_oaep_encrypt br_rsa_i62_oaep_encrypt_get(void); + +/** + * \brief Get the RSA "i62" implementation (OAEP decryption), + * if available. + * + * \return the implementation, or 0. + */ +br_rsa_oaep_decrypt br_rsa_i62_oaep_decrypt_get(void); + +/* + * RSA "i15" engine. Integers are represented as 15-bit integers, so + * the code uses only 32-bit multiplication (no 64-bit result), which + * is vastly faster (and constant-time) on the ARM Cortex M0/M0+. + */ + +/** + * \brief RSA public key engine "i15". + * + * \see br_rsa_public + * + * \param x operand to exponentiate. + * \param xlen length of the operand (in bytes). + * \param pk RSA public key. + * \return 1 on success, 0 on error. + */ +uint32_t br_rsa_i15_public(unsigned char *x, size_t xlen, + const br_rsa_public_key *pk); + +/** + * \brief RSA signature verification engine "i15" (PKCS#1 v1.5 signatures). + * + * \see br_rsa_pkcs1_vrfy + * + * \param x signature buffer. + * \param xlen signature length (in bytes). + * \param hash_oid encoded hash algorithm OID (or `NULL`). + * \param hash_len expected hash value length (in bytes). + * \param pk RSA public key. + * \param hash_out output buffer for the hash value. + * \return 1 on success, 0 on error. + */ +uint32_t br_rsa_i15_pkcs1_vrfy(const unsigned char *x, size_t xlen, + const unsigned char *hash_oid, size_t hash_len, + const br_rsa_public_key *pk, unsigned char *hash_out); + +/** + * \brief RSA signature verification engine "i15" (PSS signatures). + * + * \see br_rsa_pss_vrfy + * + * \param x signature buffer. + * \param xlen signature length (in bytes). + * \param hf_data hash function applied on the message. + * \param hf_mgf1 hash function to use with MGF1. + * \param hash hash value of the signed message. + * \param salt_len PSS salt length (in bytes). + * \param pk RSA public key. + * \return 1 on success, 0 on error. + */ +uint32_t br_rsa_i15_pss_vrfy(const unsigned char *x, size_t xlen, + const br_hash_class *hf_data, const br_hash_class *hf_mgf1, + const void *hash, size_t salt_len, const br_rsa_public_key *pk); + +/** + * \brief RSA private key engine "i15". + * + * \see br_rsa_private + * + * \param x operand to exponentiate. + * \param sk RSA private key. + * \return 1 on success, 0 on error. + */ +uint32_t br_rsa_i15_private(unsigned char *x, + const br_rsa_private_key *sk); + +/** + * \brief RSA signature generation engine "i15" (PKCS#1 v1.5 signatures). + * + * \see br_rsa_pkcs1_sign + * + * \param hash_oid encoded hash algorithm OID (or `NULL`). + * \param hash hash value. + * \param hash_len hash value length (in bytes). + * \param sk RSA private key. + * \param x output buffer for the hash value. + * \return 1 on success, 0 on error. + */ +uint32_t br_rsa_i15_pkcs1_sign(const unsigned char *hash_oid, + const unsigned char *hash, size_t hash_len, + const br_rsa_private_key *sk, unsigned char *x); + +/** + * \brief RSA signature generation engine "i15" (PSS signatures). + * + * \see br_rsa_pss_sign + * + * \param rng PRNG for salt generation (`NULL` if `salt_len` is zero). + * \param hf_data hash function used to hash the signed data. + * \param hf_mgf1 hash function to use with MGF1. + * \param hash hashed message. + * \param salt_len salt length (in bytes). + * \param sk RSA private key. + * \param x output buffer for the signature value. + * \return 1 on success, 0 on error. + */ +uint32_t br_rsa_i15_pss_sign(const br_prng_class **rng, + const br_hash_class *hf_data, const br_hash_class *hf_mgf1, + const unsigned char *hash_value, size_t salt_len, + const br_rsa_private_key *sk, unsigned char *x); + +/** + * \brief Get "default" RSA implementation (public-key operations). + * + * This returns the preferred implementation of RSA (public-key operations) + * on the current system. + * + * \return the default implementation. + */ +br_rsa_public br_rsa_public_get_default(void); + +/** + * \brief Get "default" RSA implementation (private-key operations). + * + * This returns the preferred implementation of RSA (private-key operations) + * on the current system. + * + * \return the default implementation. + */ +br_rsa_private br_rsa_private_get_default(void); + +/** + * \brief Get "default" RSA implementation (PKCS#1 v1.5 signature verification). + * + * This returns the preferred implementation of RSA (signature verification) + * on the current system. + * + * \return the default implementation. + */ +br_rsa_pkcs1_vrfy br_rsa_pkcs1_vrfy_get_default(void); + +/** + * \brief Get "default" RSA implementation (PSS signature verification). + * + * This returns the preferred implementation of RSA (signature verification) + * on the current system. + * + * \return the default implementation. + */ +br_rsa_pss_vrfy br_rsa_pss_vrfy_get_default(void); + +/** + * \brief Get "default" RSA implementation (PKCS#1 v1.5 signature generation). + * + * This returns the preferred implementation of RSA (signature generation) + * on the current system. + * + * \return the default implementation. + */ +br_rsa_pkcs1_sign br_rsa_pkcs1_sign_get_default(void); + +/** + * \brief Get "default" RSA implementation (PSS signature generation). + * + * This returns the preferred implementation of RSA (signature generation) + * on the current system. + * + * \return the default implementation. + */ +br_rsa_pss_sign br_rsa_pss_sign_get_default(void); + +/** + * \brief Get "default" RSA implementation (OAEP encryption). + * + * This returns the preferred implementation of RSA (OAEP encryption) + * on the current system. + * + * \return the default implementation. + */ +br_rsa_oaep_encrypt br_rsa_oaep_encrypt_get_default(void); + +/** + * \brief Get "default" RSA implementation (OAEP decryption). + * + * This returns the preferred implementation of RSA (OAEP decryption) + * on the current system. + * + * \return the default implementation. + */ +br_rsa_oaep_decrypt br_rsa_oaep_decrypt_get_default(void); + +/** + * \brief RSA decryption helper, for SSL/TLS. + * + * This function performs the RSA decryption for a RSA-based key exchange + * in a SSL/TLS server. The provided RSA engine is used. The `data` + * parameter points to the value to decrypt, of length `len` bytes. On + * success, the 48-byte pre-master secret is copied into `data`, starting + * at the first byte of that buffer; on error, the contents of `data` + * become indeterminate. + * + * This function first checks that the provided value length (`len`) is + * not lower than 59 bytes, and matches the RSA modulus length; if neither + * of this property is met, then this function returns 0 and the buffer + * is unmodified. + * + * Otherwise, decryption and then padding verification are performed, both + * in constant-time. A decryption error, or a bad padding, or an + * incorrect decrypted value length are reported with a returned value of + * 0; on success, 1 is returned. The caller (SSL server engine) is supposed + * to proceed with a random pre-master secret in case of error. + * + * \param core RSA private key engine. + * \param sk RSA private key. + * \param data input/output buffer. + * \param len length (in bytes) of the data to decrypt. + * \return 1 on success, 0 on error. + */ +uint32_t br_rsa_ssl_decrypt(br_rsa_private core, const br_rsa_private_key *sk, + unsigned char *data, size_t len); + +/** + * \brief RSA encryption (OAEP) with the "i15" engine. + * + * \see br_rsa_oaep_encrypt + * + * \param rnd source of random bytes. + * \param dig hash function to use with MGF1. + * \param label label value (may be `NULL` if `label_len` is zero). + * \param label_len label length, in bytes. + * \param pk RSA public key. + * \param dst destination buffer. + * \param dst_max_len destination buffer length (maximum encrypted data size). + * \param src message to encrypt. + * \param src_len source message length (in bytes). + * \return encrypted message length (in bytes), or 0 on error. + */ +size_t br_rsa_i15_oaep_encrypt( + const br_prng_class **rnd, const br_hash_class *dig, + const void *label, size_t label_len, + const br_rsa_public_key *pk, + void *dst, size_t dst_max_len, + const void *src, size_t src_len); + +/** + * \brief RSA decryption (OAEP) with the "i15" engine. + * + * \see br_rsa_oaep_decrypt + * + * \param dig hash function to use with MGF1. + * \param label label value (may be `NULL` if `label_len` is zero). + * \param label_len label length, in bytes. + * \param sk RSA private key. + * \param data input/output buffer. + * \param len encrypted/decrypted message length. + * \return 1 on success, 0 on error. + */ +uint32_t br_rsa_i15_oaep_decrypt( + const br_hash_class *dig, const void *label, size_t label_len, + const br_rsa_private_key *sk, void *data, size_t *len); + +/** + * \brief RSA encryption (OAEP) with the "i31" engine. + * + * \see br_rsa_oaep_encrypt + * + * \param rnd source of random bytes. + * \param dig hash function to use with MGF1. + * \param label label value (may be `NULL` if `label_len` is zero). + * \param label_len label length, in bytes. + * \param pk RSA public key. + * \param dst destination buffer. + * \param dst_max_len destination buffer length (maximum encrypted data size). + * \param src message to encrypt. + * \param src_len source message length (in bytes). + * \return encrypted message length (in bytes), or 0 on error. + */ +size_t br_rsa_i31_oaep_encrypt( + const br_prng_class **rnd, const br_hash_class *dig, + const void *label, size_t label_len, + const br_rsa_public_key *pk, + void *dst, size_t dst_max_len, + const void *src, size_t src_len); + +/** + * \brief RSA decryption (OAEP) with the "i31" engine. + * + * \see br_rsa_oaep_decrypt + * + * \param dig hash function to use with MGF1. + * \param label label value (may be `NULL` if `label_len` is zero). + * \param label_len label length, in bytes. + * \param sk RSA private key. + * \param data input/output buffer. + * \param len encrypted/decrypted message length. + * \return 1 on success, 0 on error. + */ +uint32_t br_rsa_i31_oaep_decrypt( + const br_hash_class *dig, const void *label, size_t label_len, + const br_rsa_private_key *sk, void *data, size_t *len); + +/** + * \brief RSA encryption (OAEP) with the "i32" engine. + * + * \see br_rsa_oaep_encrypt + * + * \param rnd source of random bytes. + * \param dig hash function to use with MGF1. + * \param label label value (may be `NULL` if `label_len` is zero). + * \param label_len label length, in bytes. + * \param pk RSA public key. + * \param dst destination buffer. + * \param dst_max_len destination buffer length (maximum encrypted data size). + * \param src message to encrypt. + * \param src_len source message length (in bytes). + * \return encrypted message length (in bytes), or 0 on error. + */ +size_t br_rsa_i32_oaep_encrypt( + const br_prng_class **rnd, const br_hash_class *dig, + const void *label, size_t label_len, + const br_rsa_public_key *pk, + void *dst, size_t dst_max_len, + const void *src, size_t src_len); + +/** + * \brief RSA decryption (OAEP) with the "i32" engine. + * + * \see br_rsa_oaep_decrypt + * + * \param dig hash function to use with MGF1. + * \param label label value (may be `NULL` if `label_len` is zero). + * \param label_len label length, in bytes. + * \param sk RSA private key. + * \param data input/output buffer. + * \param len encrypted/decrypted message length. + * \return 1 on success, 0 on error. + */ +uint32_t br_rsa_i32_oaep_decrypt( + const br_hash_class *dig, const void *label, size_t label_len, + const br_rsa_private_key *sk, void *data, size_t *len); + +/** + * \brief RSA encryption (OAEP) with the "i62" engine. + * + * This function is defined only on architecture that offer a 64x64->128 + * opcode. Use `br_rsa_i62_oaep_encrypt_get()` to dynamically obtain a pointer + * to that function. + * + * \see br_rsa_oaep_encrypt + * + * \param rnd source of random bytes. + * \param dig hash function to use with MGF1. + * \param label label value (may be `NULL` if `label_len` is zero). + * \param label_len label length, in bytes. + * \param pk RSA public key. + * \param dst destination buffer. + * \param dst_max_len destination buffer length (maximum encrypted data size). + * \param src message to encrypt. + * \param src_len source message length (in bytes). + * \return encrypted message length (in bytes), or 0 on error. + */ +size_t br_rsa_i62_oaep_encrypt( + const br_prng_class **rnd, const br_hash_class *dig, + const void *label, size_t label_len, + const br_rsa_public_key *pk, + void *dst, size_t dst_max_len, + const void *src, size_t src_len); + +/** + * \brief RSA decryption (OAEP) with the "i62" engine. + * + * This function is defined only on architecture that offer a 64x64->128 + * opcode. Use `br_rsa_i62_oaep_decrypt_get()` to dynamically obtain a pointer + * to that function. + * + * \see br_rsa_oaep_decrypt + * + * \param dig hash function to use with MGF1. + * \param label label value (may be `NULL` if `label_len` is zero). + * \param label_len label length, in bytes. + * \param sk RSA private key. + * \param data input/output buffer. + * \param len encrypted/decrypted message length. + * \return 1 on success, 0 on error. + */ +uint32_t br_rsa_i62_oaep_decrypt( + const br_hash_class *dig, const void *label, size_t label_len, + const br_rsa_private_key *sk, void *data, size_t *len); + +/** + * \brief Get buffer size to hold RSA private key elements. + * + * This macro returns the length (in bytes) of the buffer needed to + * receive the elements of a RSA private key, as generated by one of + * the `br_rsa_*_keygen()` functions. If the provided size is a constant + * expression, then the whole macro evaluates to a constant expression. + * + * \param size target key size (modulus size, in bits) + * \return the length of the private key buffer, in bytes. + */ +#define BR_RSA_KBUF_PRIV_SIZE(size) (5 * (((size) + 15) >> 4)) + +/** + * \brief Get buffer size to hold RSA public key elements. + * + * This macro returns the length (in bytes) of the buffer needed to + * receive the elements of a RSA public key, as generated by one of + * the `br_rsa_*_keygen()` functions. If the provided size is a constant + * expression, then the whole macro evaluates to a constant expression. + * + * \param size target key size (modulus size, in bits) + * \return the length of the public key buffer, in bytes. + */ +#define BR_RSA_KBUF_PUB_SIZE(size) (4 + (((size) + 7) >> 3)) + +/** + * \brief Type for RSA key pair generator implementation. + * + * This function generates a new RSA key pair whose modulus has bit + * length `size` bits. The private key elements are written in the + * `kbuf_priv` buffer, and pointer values and length fields to these + * elements are populated in the provided private key structure `sk`. + * Similarly, the public key elements are written in `kbuf_pub`, with + * pointers and lengths set in `pk`. + * + * If `pk` is `NULL`, then `kbuf_pub` may be `NULL`, and only the + * private key is set. + * + * If `pubexp` is not zero, then its value will be used as public + * exponent. Valid RSA public exponent values are odd integers + * greater than 1. If `pubexp` is zero, then the public exponent will + * have value 3. + * + * The provided PRNG (`rng_ctx`) must have already been initialized + * and seeded. + * + * Returned value is 1 on success, 0 on error. An error is reported + * if the requested range is outside of the supported key sizes, or + * if an invalid non-zero public exponent value is provided. Supported + * range starts at 512 bits, and up to an implementation-defined + * maximum (by default 4096 bits). Note that key sizes up to 768 bits + * have been broken in practice, and sizes lower than 2048 bits are + * usually considered to be weak and should not be used. + * + * \param rng_ctx source PRNG context (already initialized) + * \param sk RSA private key structure (destination) + * \param kbuf_priv buffer for private key elements + * \param pk RSA public key structure (destination), or `NULL` + * \param kbuf_pub buffer for public key elements, or `NULL` + * \param size target RSA modulus size (in bits) + * \param pubexp public exponent to use, or zero + * \return 1 on success, 0 on error (invalid parameters) + */ +typedef uint32_t (*br_rsa_keygen)( + const br_prng_class **rng_ctx, + br_rsa_private_key *sk, void *kbuf_priv, + br_rsa_public_key *pk, void *kbuf_pub, + unsigned size, uint32_t pubexp); + +/** + * \brief RSA key pair generation with the "i15" engine. + * + * \see br_rsa_keygen + * + * \param rng_ctx source PRNG context (already initialized) + * \param sk RSA private key structure (destination) + * \param kbuf_priv buffer for private key elements + * \param pk RSA public key structure (destination), or `NULL` + * \param kbuf_pub buffer for public key elements, or `NULL` + * \param size target RSA modulus size (in bits) + * \param pubexp public exponent to use, or zero + * \return 1 on success, 0 on error (invalid parameters) + */ +uint32_t br_rsa_i15_keygen( + const br_prng_class **rng_ctx, + br_rsa_private_key *sk, void *kbuf_priv, + br_rsa_public_key *pk, void *kbuf_pub, + unsigned size, uint32_t pubexp); + +/** + * \brief RSA key pair generation with the "i31" engine. + * + * \see br_rsa_keygen + * + * \param rng_ctx source PRNG context (already initialized) + * \param sk RSA private key structure (destination) + * \param kbuf_priv buffer for private key elements + * \param pk RSA public key structure (destination), or `NULL` + * \param kbuf_pub buffer for public key elements, or `NULL` + * \param size target RSA modulus size (in bits) + * \param pubexp public exponent to use, or zero + * \return 1 on success, 0 on error (invalid parameters) + */ +uint32_t br_rsa_i31_keygen( + const br_prng_class **rng_ctx, + br_rsa_private_key *sk, void *kbuf_priv, + br_rsa_public_key *pk, void *kbuf_pub, + unsigned size, uint32_t pubexp); + +/** + * \brief RSA key pair generation with the "i62" engine. + * + * This function is defined only on architecture that offer a 64x64->128 + * opcode. Use `br_rsa_i62_keygen_get()` to dynamically obtain a pointer + * to that function. + * + * \see br_rsa_keygen + * + * \param rng_ctx source PRNG context (already initialized) + * \param sk RSA private key structure (destination) + * \param kbuf_priv buffer for private key elements + * \param pk RSA public key structure (destination), or `NULL` + * \param kbuf_pub buffer for public key elements, or `NULL` + * \param size target RSA modulus size (in bits) + * \param pubexp public exponent to use, or zero + * \return 1 on success, 0 on error (invalid parameters) + */ +uint32_t br_rsa_i62_keygen( + const br_prng_class **rng_ctx, + br_rsa_private_key *sk, void *kbuf_priv, + br_rsa_public_key *pk, void *kbuf_pub, + unsigned size, uint32_t pubexp); + +/** + * \brief Get the RSA "i62" implementation (key pair generation), + * if available. + * + * \return the implementation, or 0. + */ +br_rsa_keygen br_rsa_i62_keygen_get(void); + +/** + * \brief Get "default" RSA implementation (key pair generation). + * + * This returns the preferred implementation of RSA (key pair generation) + * on the current system. + * + * \return the default implementation. + */ +br_rsa_keygen br_rsa_keygen_get_default(void); + +/** + * \brief Type for a modulus computing function. + * + * Such a function computes the public modulus from the private key. The + * encoded modulus (unsigned big-endian) is written on `n`, and the size + * (in bytes) is returned. If `n` is `NULL`, then the size is returned but + * the modulus itself is not computed. + * + * If the key size exceeds an internal limit, 0 is returned. + * + * \param n destination buffer (or `NULL`). + * \param sk RSA private key. + * \return the modulus length (in bytes), or 0. + */ +typedef size_t (*br_rsa_compute_modulus)(void *n, const br_rsa_private_key *sk); + +/** + * \brief Recompute RSA modulus ("i15" engine). + * + * \see br_rsa_compute_modulus + * + * \param n destination buffer (or `NULL`). + * \param sk RSA private key. + * \return the modulus length (in bytes), or 0. + */ +size_t br_rsa_i15_compute_modulus(void *n, const br_rsa_private_key *sk); + +/** + * \brief Recompute RSA modulus ("i31" engine). + * + * \see br_rsa_compute_modulus + * + * \param n destination buffer (or `NULL`). + * \param sk RSA private key. + * \return the modulus length (in bytes), or 0. + */ +size_t br_rsa_i31_compute_modulus(void *n, const br_rsa_private_key *sk); + +/** + * \brief Get "default" RSA implementation (recompute modulus). + * + * This returns the preferred implementation of RSA (recompute modulus) + * on the current system. + * + * \return the default implementation. + */ +br_rsa_compute_modulus br_rsa_compute_modulus_get_default(void); + +/** + * \brief Type for a public exponent computing function. + * + * Such a function recomputes the public exponent from the private key. + * 0 is returned if any of the following occurs: + * + * - Either `p` or `q` is not equal to 3 modulo 4. + * + * - The public exponent does not fit on 32 bits. + * + * - An internal limit is exceeded. + * + * - The private key is invalid in some way. + * + * For all private keys produced by the key generator functions + * (`br_rsa_keygen` type), this function succeeds and returns the true + * public exponent. The public exponent is always an odd integer greater + * than 1. + * + * \return the public exponent, or 0. + */ +typedef uint32_t (*br_rsa_compute_pubexp)(const br_rsa_private_key *sk); + +/** + * \brief Recompute RSA public exponent ("i15" engine). + * + * \see br_rsa_compute_pubexp + * + * \return the public exponent, or 0. + */ +uint32_t br_rsa_i15_compute_pubexp(const br_rsa_private_key *sk); + +/** + * \brief Recompute RSA public exponent ("i31" engine). + * + * \see br_rsa_compute_pubexp + * + * \return the public exponent, or 0. + */ +uint32_t br_rsa_i31_compute_pubexp(const br_rsa_private_key *sk); + +/** + * \brief Get "default" RSA implementation (recompute public exponent). + * + * This returns the preferred implementation of RSA (recompute public + * exponent) on the current system. + * + * \return the default implementation. + */ +br_rsa_compute_pubexp br_rsa_compute_pubexp_get_default(void); + +/** + * \brief Type for a private exponent computing function. + * + * An RSA private key (`br_rsa_private_key`) contains two reduced + * private exponents, which are sufficient to perform private key + * operations. However, standard encoding formats for RSA private keys + * require also a copy of the complete private exponent (non-reduced), + * which this function recomputes. + * + * This function suceeds if all the following conditions hold: + * + * - Both private factors `p` and `q` are equal to 3 modulo 4. + * + * - The provided public exponent `pubexp` is correct, and, in particular, + * is odd, relatively prime to `p-1` and `q-1`, and greater than 1. + * + * - No internal storage limit is exceeded. + * + * For all private keys produced by the key generator functions + * (`br_rsa_keygen` type), this function succeeds. Note that the API + * restricts the public exponent to a maximum size of 32 bits. + * + * The encoded private exponent is written in `d` (unsigned big-endian + * convention), and the length (in bytes) is returned. If `d` is `NULL`, + * then the exponent is not written anywhere, but the length is still + * returned. On error, 0 is returned. + * + * Not all error conditions are detected when `d` is `NULL`; therefore, the + * returned value shall be checked also when actually producing the value. + * + * \param d destination buffer (or `NULL`). + * \param sk RSA private key. + * \param pubexp the public exponent. + * \return the private exponent length (in bytes), or 0. + */ +typedef size_t (*br_rsa_compute_privexp)(void *d, + const br_rsa_private_key *sk, uint32_t pubexp); + +/** + * \brief Recompute RSA private exponent ("i15" engine). + * + * \see br_rsa_compute_privexp + * + * \param d destination buffer (or `NULL`). + * \param sk RSA private key. + * \param pubexp the public exponent. + * \return the private exponent length (in bytes), or 0. + */ +size_t br_rsa_i15_compute_privexp(void *d, + const br_rsa_private_key *sk, uint32_t pubexp); + +/** + * \brief Recompute RSA private exponent ("i31" engine). + * + * \see br_rsa_compute_privexp + * + * \param d destination buffer (or `NULL`). + * \param sk RSA private key. + * \param pubexp the public exponent. + * \return the private exponent length (in bytes), or 0. + */ +size_t br_rsa_i31_compute_privexp(void *d, + const br_rsa_private_key *sk, uint32_t pubexp); + +/** + * \brief Get "default" RSA implementation (recompute private exponent). + * + * This returns the preferred implementation of RSA (recompute private + * exponent) on the current system. + * + * \return the default implementation. + */ +br_rsa_compute_privexp br_rsa_compute_privexp_get_default(void); + +#ifdef __cplusplus +} +#endif + +#endif |