1 /* Copyright (C) 1995-1998 Eric Young (eay (at) cryptsoft.com) 2 * All rights reserved. 3 * 4 * This package is an SSL implementation written 5 * by Eric Young (eay (at) 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 (at) 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 (at) 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 (at) 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) 67 extern "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. */ 78 OPENSSL_EXPORT DH *DH_new(void); 79 80 /* DH_free decrements the reference count of |dh| and frees it if the reference 81 * count drops to zero. */ 82 OPENSSL_EXPORT void DH_free(DH *dh); 83 84 /* DH_up_ref increments the reference count of |dh|. */ 85 OPENSSL_EXPORT int DH_up_ref(DH *dh); 86 87 88 /* Standard parameters. 89 * 90 * These functions return new DH objects with standard parameters. They return 91 * NULL on allocation failure. The |engine| parameter is ignored. */ 92 93 /* These parameters are taken from RFC 5114. */ 94 95 OPENSSL_EXPORT DH *DH_get_1024_160(const ENGINE *engine); 96 OPENSSL_EXPORT DH *DH_get_2048_224(const ENGINE *engine); 97 OPENSSL_EXPORT DH *DH_get_2048_256(const ENGINE *engine); 98 99 100 /* Parameter generation. */ 101 102 #define DH_GENERATOR_2 2 103 #define DH_GENERATOR_5 5 104 105 /* DH_generate_parameters_ex generates a suitable Diffie-Hellman group with a 106 * prime that is |prime_bits| long and stores it in |dh|. The generator of the 107 * group will be |generator|, which should be |DH_GENERATOR_2| unless there's a 108 * good reason to use a different value. The |cb| argument contains a callback 109 * function that will be called during the generation. See the documentation in 110 * |bn.h| about this. In addition to the callback invocations from |BN|, |cb| 111 * will also be called with |event| equal to three when the generation is 112 * complete. */ 113 OPENSSL_EXPORT int DH_generate_parameters_ex(DH *dh, int prime_bits, 114 int generator, BN_GENCB *cb); 115 116 117 /* Diffie-Hellman operations. */ 118 119 /* DH_generate_key generates a new, random, private key and stores it in 120 * |dh|. It returns one on success and zero on error. */ 121 OPENSSL_EXPORT int DH_generate_key(DH *dh); 122 123 /* DH_compute_key calculates the shared key between |dh| and |peers_key| and 124 * writes it as a big-endian integer into |out|, which must have |DH_size| 125 * bytes of space. It returns the number of bytes written, or a negative number 126 * on error. */ 127 OPENSSL_EXPORT int DH_compute_key(uint8_t *out, const BIGNUM *peers_key, 128 DH *dh); 129 130 131 /* Utility functions. */ 132 133 /* DH_size returns the number of bytes in the DH group's prime. */ 134 OPENSSL_EXPORT int DH_size(const DH *dh); 135 136 /* DH_num_bits returns the minimum number of bits needed to represent the 137 * absolute value of the DH group's prime. */ 138 OPENSSL_EXPORT unsigned DH_num_bits(const DH *dh); 139 140 #define DH_CHECK_P_NOT_PRIME 0x01 141 #define DH_CHECK_P_NOT_SAFE_PRIME 0x02 142 #define DH_CHECK_UNABLE_TO_CHECK_GENERATOR 0x04 143 #define DH_CHECK_NOT_SUITABLE_GENERATOR 0x08 144 #define DH_CHECK_Q_NOT_PRIME 0x10 145 #define DH_CHECK_INVALID_Q_VALUE 0x20 146 #define DH_CHECK_INVALID_J_VALUE 0x40 147 148 /* These are compatibility defines. */ 149 #define DH_NOT_SUITABLE_GENERATOR DH_CHECK_NOT_SUITABLE_GENERATOR 150 #define DH_UNABLE_TO_CHECK_GENERATOR DH_CHECK_UNABLE_TO_CHECK_GENERATOR 151 152 /* DH_check checks the suitability of |dh| as a Diffie-Hellman group. and sets 153 * |DH_CHECK_*| flags in |*out_flags| if it finds any errors. It returns one if 154 * |*out_flags| was successfully set and zero on error. 155 * 156 * Note: these checks may be quite computationally expensive. */ 157 OPENSSL_EXPORT int DH_check(const DH *dh, int *out_flags); 158 159 #define DH_CHECK_PUBKEY_TOO_SMALL 1 160 #define DH_CHECK_PUBKEY_TOO_LARGE 2 161 162 /* DH_check_pub_key checks the suitability of |pub_key| as a public key for the 163 * DH group in |dh| and sets |DH_CHECK_PUBKEY_*| flags in |*out_flags| if it 164 * finds any errors. It returns one if |*out_flags| was successfully set and 165 * zero on error. */ 166 OPENSSL_EXPORT int DH_check_pub_key(const DH *dh, const BIGNUM *pub_key, 167 int *out_flags); 168 169 /* DHparams_dup allocates a fresh |DH| and copies the parameters from |dh| into 170 * it. It returns the new |DH| or NULL on error. */ 171 OPENSSL_EXPORT DH *DHparams_dup(const DH *dh); 172 173 174 /* ASN.1 functions. */ 175 176 /* d2i_DHparams parses an ASN.1, DER encoded Diffie-Hellman parameters 177 * structure from |len| bytes at |*inp|. If |ret| is not NULL then, on exit, a 178 * pointer to the result is in |*ret|. If |*ret| is already non-NULL on entry 179 * then the result is written directly into |*ret|, otherwise a fresh |DH| is 180 * allocated. On successful exit, |*inp| is advanced past the DER structure. It 181 * returns the result or NULL on error. */ 182 OPENSSL_EXPORT DH *d2i_DHparams(DH **ret, const unsigned char **inp, long len); 183 184 /* i2d_DHparams marshals |in| to an ASN.1, DER structure. If |outp| is not NULL 185 * then the result is written to |*outp| and |*outp| is advanced just past the 186 * output. It returns the number of bytes in the result, whether written or 187 * not, or a negative value on error. */ 188 OPENSSL_EXPORT int i2d_DHparams(const DH *in, unsigned char **outp); 189 190 191 /* ex_data functions. 192 * 193 * See |ex_data.h| for details. */ 194 195 OPENSSL_EXPORT int DH_get_ex_new_index(long argl, void *argp, 196 CRYPTO_EX_unused *unused, 197 CRYPTO_EX_dup *dup_func, 198 CRYPTO_EX_free *free_func); 199 OPENSSL_EXPORT int DH_set_ex_data(DH *d, int idx, void *arg); 200 OPENSSL_EXPORT void *DH_get_ex_data(DH *d, int idx); 201 202 203 struct dh_st { 204 BIGNUM *p; 205 BIGNUM *g; 206 BIGNUM *pub_key; /* g^x mod p */ 207 BIGNUM *priv_key; /* x */ 208 209 /* priv_length contains the length, in bits, of the private value. If zero, 210 * the private value will be the same length as |p|. */ 211 unsigned priv_length; 212 213 CRYPTO_MUTEX method_mont_p_lock; 214 BN_MONT_CTX *method_mont_p; 215 216 /* Place holders if we want to do X9.42 DH */ 217 BIGNUM *q; 218 BIGNUM *j; 219 unsigned char *seed; 220 int seedlen; 221 BIGNUM *counter; 222 223 int flags; 224 CRYPTO_refcount_t references; 225 CRYPTO_EX_DATA ex_data; 226 }; 227 228 229 #if defined(__cplusplus) 230 } /* extern C */ 231 #endif 232 233 #define DH_R_BAD_GENERATOR 100 234 #define DH_R_INVALID_PUBKEY 101 235 #define DH_R_MODULUS_TOO_LARGE 102 236 #define DH_R_NO_PRIVATE_VALUE 103 237 238 #endif /* OPENSSL_HEADER_DH_H */ 239
