1/* Copyright (C) 1995-1998 Eric Young (eay@cryptsoft.com) 2 * All rights reserved. 3 * 4 * This package is an SSL implementation written 5 * by Eric Young (eay@cryptsoft.com). 6 * The implementation was written so as to conform with Netscapes SSL. 7 * 8 * This library is free for commercial and non-commercial use as long as 9 * the following conditions are aheared to. The following conditions 10 * apply to all code found in this distribution, be it the RC4, RSA, 11 * lhash, DES, etc., code; not just the SSL code. The SSL documentation 12 * included with this distribution is covered by the same copyright terms 13 * except that the holder is Tim Hudson (tjh@cryptsoft.com). 14 * 15 * Copyright remains Eric Young's, and as such any Copyright notices in 16 * the code are not to be removed. 17 * If this package is used in a product, Eric Young should be given attribution 18 * as the author of the parts of the library used. 19 * This can be in the form of a textual message at program startup or 20 * in documentation (online or textual) provided with the package. 21 * 22 * Redistribution and use in source and binary forms, with or without 23 * modification, are permitted provided that the following conditions 24 * are met: 25 * 1. Redistributions of source code must retain the copyright 26 * notice, this list of conditions and the following disclaimer. 27 * 2. Redistributions in binary form must reproduce the above copyright 28 * notice, this list of conditions and the following disclaimer in the 29 * documentation and/or other materials provided with the distribution. 30 * 3. All advertising materials mentioning features or use of this software 31 * must display the following acknowledgement: 32 * "This product includes cryptographic software written by 33 * Eric Young (eay@cryptsoft.com)" 34 * The word 'cryptographic' can be left out if the rouines from the library 35 * being used are not cryptographic related :-). 36 * 4. If you include any Windows specific code (or a derivative thereof) from 37 * the apps directory (application code) you must include an acknowledgement: 38 * "This product includes software written by Tim Hudson (tjh@cryptsoft.com)" 39 * 40 * THIS SOFTWARE IS PROVIDED BY ERIC YOUNG ``AS IS'' AND 41 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 42 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 43 * ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE 44 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL 45 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS 46 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 47 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 48 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY 49 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 50 * SUCH DAMAGE. 51 * 52 * The licence and distribution terms for any publically available version or 53 * derivative of this code cannot be changed. i.e. this code cannot simply be 54 * copied and put under another distribution licence 55 * [including the GNU Public Licence.] */ 56 57#ifndef OPENSSL_HEADER_DH_H 58#define OPENSSL_HEADER_DH_H 59 60#include <openssl/base.h> 61 62#include <openssl/ex_data.h> 63#include <openssl/thread.h> 64 65#if defined(__cplusplus) 66extern "C" { 67#endif 68 69 70// DH contains functions for performing Diffie-Hellman key agreement in 71// multiplicative groups. 72 73 74// Allocation and destruction. 75 76// DH_new returns a new, empty DH object or NULL on error. 77OPENSSL_EXPORT DH *DH_new(void); 78 79// DH_free decrements the reference count of |dh| and frees it if the reference 80// count drops to zero. 81OPENSSL_EXPORT void DH_free(DH *dh); 82 83// DH_up_ref increments the reference count of |dh| and returns one. 84OPENSSL_EXPORT int DH_up_ref(DH *dh); 85 86 87// Properties. 88 89// DH_get0_key sets |*out_pub_key| and |*out_priv_key|, if non-NULL, to |dh|'s 90// public and private key, respectively. If |dh| is a public key, the private 91// key will be set to NULL. 92OPENSSL_EXPORT void DH_get0_key(const DH *dh, const BIGNUM **out_pub_key, 93 const BIGNUM **out_priv_key); 94 95// DH_set0_key sets |dh|'s public and private key to the specified values. If 96// NULL, the field is left unchanged. On success, it takes ownership of each 97// argument and returns one. Otherwise, it returns zero. 98OPENSSL_EXPORT int DH_set0_key(DH *dh, BIGNUM *pub_key, BIGNUM *priv_key); 99 100// DH_get0_pqg sets |*out_p|, |*out_q|, and |*out_g|, if non-NULL, to |dh|'s p, 101// q, and g parameters, respectively. 102OPENSSL_EXPORT void DH_get0_pqg(const DH *dh, const BIGNUM **out_p, 103 const BIGNUM **out_q, const BIGNUM **out_g); 104 105// DH_set0_pqg sets |dh|'s p, q, and g parameters to the specified values. If 106// NULL, the field is left unchanged. On success, it takes ownership of each 107// argument and returns one. Otherwise, it returns zero. |q| may be NULL, but 108// |p| and |g| must either be specified or already configured on |dh|. 109OPENSSL_EXPORT int DH_set0_pqg(DH *dh, BIGNUM *p, BIGNUM *q, BIGNUM *g); 110 111 112// Standard parameters. 113 114// BN_get_rfc3526_prime_1536 sets |*ret| to the 1536-bit MODP group from RFC 115// 3526 and returns |ret|. If |ret| is NULL then a fresh |BIGNUM| is allocated 116// and returned. It returns NULL on allocation failure. 117OPENSSL_EXPORT BIGNUM *BN_get_rfc3526_prime_1536(BIGNUM *ret); 118 119 120// Parameter generation. 121 122#define DH_GENERATOR_2 2 123#define DH_GENERATOR_5 5 124 125// DH_generate_parameters_ex generates a suitable Diffie-Hellman group with a 126// prime that is |prime_bits| long and stores it in |dh|. The generator of the 127// group will be |generator|, which should be |DH_GENERATOR_2| unless there's a 128// good reason to use a different value. The |cb| argument contains a callback 129// function that will be called during the generation. See the documentation in 130// |bn.h| about this. In addition to the callback invocations from |BN|, |cb| 131// will also be called with |event| equal to three when the generation is 132// complete. 133OPENSSL_EXPORT int DH_generate_parameters_ex(DH *dh, int prime_bits, 134 int generator, BN_GENCB *cb); 135 136 137// Diffie-Hellman operations. 138 139// DH_generate_key generates a new, random, private key and stores it in 140// |dh|. It returns one on success and zero on error. 141OPENSSL_EXPORT int DH_generate_key(DH *dh); 142 143// DH_compute_key calculates the shared key between |dh| and |peers_key| and 144// writes it as a big-endian integer into |out|, which must have |DH_size| 145// bytes of space. It returns the number of bytes written, or a negative number 146// on error. 147OPENSSL_EXPORT int DH_compute_key(uint8_t *out, const BIGNUM *peers_key, 148 DH *dh); 149 150 151// Utility functions. 152 153// DH_size returns the number of bytes in the DH group's prime. 154OPENSSL_EXPORT int DH_size(const DH *dh); 155 156// DH_num_bits returns the minimum number of bits needed to represent the 157// absolute value of the DH group's prime. 158OPENSSL_EXPORT unsigned DH_num_bits(const DH *dh); 159 160#define DH_CHECK_P_NOT_PRIME 0x01 161#define DH_CHECK_P_NOT_SAFE_PRIME 0x02 162#define DH_CHECK_UNABLE_TO_CHECK_GENERATOR 0x04 163#define DH_CHECK_NOT_SUITABLE_GENERATOR 0x08 164#define DH_CHECK_Q_NOT_PRIME 0x10 165#define DH_CHECK_INVALID_Q_VALUE 0x20 166#define DH_CHECK_INVALID_J_VALUE 0x40 167 168// These are compatibility defines. 169#define DH_NOT_SUITABLE_GENERATOR DH_CHECK_NOT_SUITABLE_GENERATOR 170#define DH_UNABLE_TO_CHECK_GENERATOR DH_CHECK_UNABLE_TO_CHECK_GENERATOR 171 172// DH_check checks the suitability of |dh| as a Diffie-Hellman group. and sets 173// |DH_CHECK_*| flags in |*out_flags| if it finds any errors. It returns one if 174// |*out_flags| was successfully set and zero on error. 175// 176// Note: these checks may be quite computationally expensive. 177OPENSSL_EXPORT int DH_check(const DH *dh, int *out_flags); 178 179#define DH_CHECK_PUBKEY_TOO_SMALL 0x1 180#define DH_CHECK_PUBKEY_TOO_LARGE 0x2 181#define DH_CHECK_PUBKEY_INVALID 0x4 182 183// DH_check_pub_key checks the suitability of |pub_key| as a public key for the 184// DH group in |dh| and sets |DH_CHECK_PUBKEY_*| flags in |*out_flags| if it 185// finds any errors. It returns one if |*out_flags| was successfully set and 186// zero on error. 187OPENSSL_EXPORT int DH_check_pub_key(const DH *dh, const BIGNUM *pub_key, 188 int *out_flags); 189 190// DHparams_dup allocates a fresh |DH| and copies the parameters from |dh| into 191// it. It returns the new |DH| or NULL on error. 192OPENSSL_EXPORT DH *DHparams_dup(const DH *dh); 193 194 195// ASN.1 functions. 196 197// DH_parse_parameters decodes a DER-encoded DHParameter structure (PKCS #3) 198// from |cbs| and advances |cbs|. It returns a newly-allocated |DH| or NULL on 199// error. 200OPENSSL_EXPORT DH *DH_parse_parameters(CBS *cbs); 201 202// DH_marshal_parameters marshals |dh| as a DER-encoded DHParameter structure 203// (PKCS #3) and appends the result to |cbb|. It returns one on success and zero 204// on error. 205OPENSSL_EXPORT int DH_marshal_parameters(CBB *cbb, const DH *dh); 206 207 208// ex_data functions. 209// 210// See |ex_data.h| for details. 211 212OPENSSL_EXPORT int DH_get_ex_new_index(long argl, void *argp, 213 CRYPTO_EX_unused *unused, 214 CRYPTO_EX_dup *dup_unused, 215 CRYPTO_EX_free *free_func); 216OPENSSL_EXPORT int DH_set_ex_data(DH *d, int idx, void *arg); 217OPENSSL_EXPORT void *DH_get_ex_data(DH *d, int idx); 218 219 220// Deprecated functions. 221 222// DH_generate_parameters behaves like |DH_generate_parameters_ex|, which is 223// what you should use instead. It returns NULL on error, or a newly-allocated 224// |DH| on success. This function is provided for compatibility only. 225OPENSSL_EXPORT DH *DH_generate_parameters(int prime_len, int generator, 226 void (*callback)(int, int, void *), 227 void *cb_arg); 228 229// d2i_DHparams parses an ASN.1, DER encoded Diffie-Hellman parameters structure 230// from |len| bytes at |*inp|. If |ret| is not NULL then, on exit, a pointer to 231// the result is in |*ret|. Note that, even if |*ret| is already non-NULL on 232// entry, it will not be written to. Rather, a fresh |DH| is allocated and the 233// previous one is freed. 234// 235// On successful exit, |*inp| is advanced past the DER structure. It 236// returns the result or NULL on error. 237// 238// Use |DH_parse_parameters| instead. 239OPENSSL_EXPORT DH *d2i_DHparams(DH **ret, const unsigned char **inp, long len); 240 241// i2d_DHparams marshals |in| to an ASN.1, DER structure. If |outp| is not NULL 242// then the result is written to |*outp| and |*outp| is advanced just past the 243// output. It returns the number of bytes in the result, whether written or 244// not, or a negative value on error. 245// 246// Use |DH_marshal_parameters| instead. 247OPENSSL_EXPORT int i2d_DHparams(const DH *in, unsigned char **outp); 248 249 250struct dh_st { 251 BIGNUM *p; 252 BIGNUM *g; 253 BIGNUM *pub_key; // g^x mod p 254 BIGNUM *priv_key; // x 255 256 // priv_length contains the length, in bits, of the private value. If zero, 257 // the private value will be the same length as |p|. 258 unsigned priv_length; 259 260 CRYPTO_MUTEX method_mont_p_lock; 261 BN_MONT_CTX *method_mont_p; 262 263 // Place holders if we want to do X9.42 DH 264 BIGNUM *q; 265 BIGNUM *j; 266 unsigned char *seed; 267 int seedlen; 268 BIGNUM *counter; 269 270 int flags; 271 CRYPTO_refcount_t references; 272 CRYPTO_EX_DATA ex_data; 273}; 274 275 276#if defined(__cplusplus) 277} // extern C 278 279extern "C++" { 280 281namespace bssl { 282 283BORINGSSL_MAKE_DELETER(DH, DH_free) 284 285} // namespace bssl 286 287} // extern C++ 288 289#endif 290 291#define DH_R_BAD_GENERATOR 100 292#define DH_R_INVALID_PUBKEY 101 293#define DH_R_MODULUS_TOO_LARGE 102 294#define DH_R_NO_PRIVATE_VALUE 103 295#define DH_R_DECODE_ERROR 104 296#define DH_R_ENCODE_ERROR 105 297 298#endif // OPENSSL_HEADER_DH_H 299