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/engine.h> 63#include <openssl/ex_data.h> 64#include <openssl/thread.h> 65 66#if defined(__cplusplus) 67extern "C" { 68#endif 69 70 71/* DH contains functions for performing Diffie-Hellman key agreement in 72 * multiplicative groups. */ 73 74 75/* Allocation and destruction. */ 76 77/* DH_new returns a new, empty DH object or NULL on error. */ 78OPENSSL_EXPORT DH *DH_new(void); 79 80/* DH_new_method acts the same as |DH_new| but takes an explicit |ENGINE|. */ 81OPENSSL_EXPORT DH *DH_new_method(const ENGINE *engine); 82 83/* DH_free decrements the reference count of |dh| and frees it if the reference 84 * count drops to zero. */ 85OPENSSL_EXPORT void DH_free(DH *dh); 86 87/* DH_up_ref increments the reference count of |dh|. */ 88OPENSSL_EXPORT int DH_up_ref(DH *dh); 89 90 91/* Standard parameters. 92 * 93 * These functions return new DH objects with standard parameters configured 94 * that use the given ENGINE, which may be NULL. They return NULL on allocation 95 * failure. */ 96 97/* These parameters are taken from RFC 5114. */ 98 99OPENSSL_EXPORT DH *DH_get_1024_160(const ENGINE *engine); 100OPENSSL_EXPORT DH *DH_get_2048_224(const ENGINE *engine); 101OPENSSL_EXPORT DH *DH_get_2048_256(const ENGINE *engine); 102 103 104/* Parameter generation. */ 105 106#define DH_GENERATOR_2 2 107#define DH_GENERATOR_5 5 108 109/* DH_generate_parameters_ex generates a suitable Diffie-Hellman group with a 110 * prime that is |prime_bits| long and stores it in |dh|. The generator of the 111 * group will be |generator|, which should be |DH_GENERATOR_2| unless there's a 112 * good reason to use a different value. The |cb| argument contains a callback 113 * function that will be called during the generation. See the documentation in 114 * |bn.h| about this. In addition to the callback invocations from |BN|, |cb| 115 * will also be called with |event| equal to three when the generation is 116 * complete. */ 117OPENSSL_EXPORT int DH_generate_parameters_ex(DH *dh, int prime_bits, 118 int generator, BN_GENCB *cb); 119 120 121/* Diffie-Hellman operations. */ 122 123/* DH_generate_key generates a new, random, private key and stores it in 124 * |dh|. It returns one on success and zero on error. */ 125OPENSSL_EXPORT int DH_generate_key(DH *dh); 126 127/* DH_compute_key calculates the shared key between |dh| and |peers_key| and 128 * writes it as a big-endian integer into |out|, which must have |DH_size| 129 * bytes of space. It returns the number of bytes written, or a negative number 130 * on error. */ 131OPENSSL_EXPORT int DH_compute_key(uint8_t *out, const BIGNUM *peers_key, 132 DH *dh); 133 134 135/* Utility functions. */ 136 137/* DH_size returns the number of bytes in the DH group's prime. */ 138OPENSSL_EXPORT int DH_size(const DH *dh); 139 140/* DH_num_bits returns the minimum number of bits needed to represent the 141 * absolute value of the DH group's prime. */ 142OPENSSL_EXPORT unsigned DH_num_bits(const DH *dh); 143 144#define DH_CHECK_P_NOT_PRIME 0x01 145#define DH_CHECK_P_NOT_SAFE_PRIME 0x02 146#define DH_CHECK_UNABLE_TO_CHECK_GENERATOR 0x04 147#define DH_CHECK_NOT_SUITABLE_GENERATOR 0x08 148#define DH_CHECK_Q_NOT_PRIME 0x10 149#define DH_CHECK_INVALID_Q_VALUE 0x20 150#define DH_CHECK_INVALID_J_VALUE 0x40 151 152/* These are compatibility defines. */ 153#define DH_NOT_SUITABLE_GENERATOR DH_CHECK_NOT_SUITABLE_GENERATOR 154#define DH_UNABLE_TO_CHECK_GENERATOR DH_CHECK_UNABLE_TO_CHECK_GENERATOR 155 156/* DH_check checks the suitability of |dh| as a Diffie-Hellman group. and sets 157 * |DH_CHECK_*| flags in |*out_flags| if it finds any errors. It returns one if 158 * |*out_flags| was successfully set and zero on error. 159 * 160 * Note: these checks may be quite computationally expensive. */ 161OPENSSL_EXPORT int DH_check(const DH *dh, int *out_flags); 162 163#define DH_CHECK_PUBKEY_TOO_SMALL 1 164#define DH_CHECK_PUBKEY_TOO_LARGE 2 165 166/* DH_check_pub_key checks the suitability of |pub_key| as a public key for the 167 * DH group in |dh| and sets |DH_CHECK_PUBKEY_*| flags in |*out_flags| if it 168 * finds any errors. It returns one if |*out_flags| was successfully set and 169 * zero on error. */ 170OPENSSL_EXPORT int DH_check_pub_key(const DH *dh, const BIGNUM *pub_key, 171 int *out_flags); 172 173/* DHparams_dup allocates a fresh |DH| and copies the parameters from |dh| into 174 * it. It returns the new |DH| or NULL on error. */ 175OPENSSL_EXPORT DH *DHparams_dup(const DH *dh); 176 177 178/* ASN.1 functions. */ 179 180/* d2i_DHparams parses an ASN.1, DER encoded Diffie-Hellman parameters 181 * structure from |len| bytes at |*inp|. If |ret| is not NULL then, on exit, a 182 * pointer to the result is in |*ret|. If |*ret| is already non-NULL on entry 183 * then the result is written directly into |*ret|, otherwise a fresh |DH| is 184 * allocated. On successful exit, |*inp| is advanced past the DER structure. It 185 * returns the result or NULL on error. */ 186OPENSSL_EXPORT DH *d2i_DHparams(DH **ret, const unsigned char **inp, long len); 187 188/* i2d_DHparams marshals |in| to an ASN.1, DER structure. If |outp| is not NULL 189 * then the result is written to |*outp| and |*outp| is advanced just past the 190 * output. It returns the number of bytes in the result, whether written or 191 * not, or a negative value on error. */ 192OPENSSL_EXPORT int i2d_DHparams(const DH *in, unsigned char **outp); 193 194 195/* ex_data functions. 196 * 197 * See |ex_data.h| for details. */ 198 199OPENSSL_EXPORT int DH_get_ex_new_index(long argl, void *argp, 200 CRYPTO_EX_new *new_func, 201 CRYPTO_EX_dup *dup_func, 202 CRYPTO_EX_free *free_func); 203OPENSSL_EXPORT int DH_set_ex_data(DH *d, int idx, void *arg); 204OPENSSL_EXPORT void *DH_get_ex_data(DH *d, int idx); 205 206 207/* dh_method contains function pointers to override the implementation of DH. 208 * See |engine.h| for details. */ 209struct dh_method { 210 struct openssl_method_common_st common; 211 212 /* app_data is an opaque pointer for the method to use. */ 213 void *app_data; 214 215 /* init is called just before the return of |DH_new_method|. It returns one 216 * on success or zero on error. */ 217 int (*init)(DH *dh); 218 219 /* finish is called before |dh| is destructed. */ 220 void (*finish)(DH *dh); 221 222 /* generate_parameters is called by |DH_generate_parameters_ex|. */ 223 int (*generate_parameters)(DH *dh, int prime_bits, int generator, 224 BN_GENCB *cb); 225 226 /* generate_parameters is called by |DH_generate_key|. */ 227 int (*generate_key)(DH *dh); 228 229 /* compute_key is called by |DH_compute_key|. */ 230 int (*compute_key)(DH *dh, uint8_t *out, const BIGNUM *pub_key); 231}; 232 233struct dh_st { 234 DH_METHOD *meth; 235 236 BIGNUM *p; 237 BIGNUM *g; 238 BIGNUM *pub_key; /* g^x */ 239 BIGNUM *priv_key; /* x */ 240 241 /* priv_length contains the length, in bits, of the private value. If zero, 242 * the private value will be the same length as |p|. */ 243 unsigned priv_length; 244 245 CRYPTO_MUTEX method_mont_p_lock; 246 BN_MONT_CTX *method_mont_p; 247 248 /* Place holders if we want to do X9.42 DH */ 249 BIGNUM *q; 250 BIGNUM *j; 251 unsigned char *seed; 252 int seedlen; 253 BIGNUM *counter; 254 255 int flags; 256 CRYPTO_refcount_t references; 257 CRYPTO_EX_DATA ex_data; 258}; 259 260 261#if defined(__cplusplus) 262} /* extern C */ 263#endif 264 265#define DH_F_DH_new_method 100 266#define DH_F_compute_key 101 267#define DH_F_generate_key 102 268#define DH_F_generate_parameters 103 269#define DH_R_BAD_GENERATOR 100 270#define DH_R_INVALID_PUBKEY 101 271#define DH_R_MODULUS_TOO_LARGE 102 272#define DH_R_NO_PRIVATE_VALUE 103 273 274#endif /* OPENSSL_HEADER_DH_H */ 275