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Commit | Line | Data |
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3cbe1980 DSH |
1 | =pod |
2 | ||
3 | =head1 NAME | |
4 | ||
25191fff | 5 | EVP_MD_CTX_new, EVP_MD_CTX_reset, EVP_MD_CTX_free, EVP_MD_CTX_copy_ex, |
91da5e77 | 6 | EVP_DigestInit_ex, EVP_DigestUpdate, EVP_DigestFinal_ex, |
25191fff | 7 | EVP_DigestInit, EVP_DigestFinal, EVP_MD_CTX_copy, EVP_MD_type, |
aafbe1cc | 8 | EVP_MD_pkey_type, EVP_MD_size, EVP_MD_block_size, EVP_MD_CTX_md, EVP_MD_CTX_size, |
474e469b | 9 | EVP_MD_CTX_block_size, EVP_MD_CTX_type, EVP_md_null, EVP_md2, EVP_md5, EVP_sha1, |
7f572e95 | 10 | EVP_sha224, EVP_sha256, EVP_sha384, EVP_sha512, EVP_mdc2, |
208527a7 | 11 | EVP_ripemd160, EVP_blake2b_512, EVP_blake2s_256, EVP_get_digestbyname, |
2d0b4412 | 12 | EVP_get_digestbynid, EVP_get_digestbyobj - EVP digest routines |
3cbe1980 DSH |
13 | |
14 | =head1 SYNOPSIS | |
15 | ||
16 | #include <openssl/evp.h> | |
17 | ||
25191fff RL |
18 | EVP_MD_CTX *EVP_MD_CTX_new(void); |
19 | int EVP_MD_CTX_reset(EVP_MD_CTX *ctx); | |
20 | void EVP_MD_CTX_free(EVP_MD_CTX *ctx); | |
e72d734d DSH |
21 | |
22 | int EVP_DigestInit_ex(EVP_MD_CTX *ctx, const EVP_MD *type, ENGINE *impl); | |
109d3123 | 23 | int EVP_DigestUpdate(EVP_MD_CTX *ctx, const void *d, size_t cnt); |
e72d734d DSH |
24 | int EVP_DigestFinal_ex(EVP_MD_CTX *ctx, unsigned char *md, |
25 | unsigned int *s); | |
26 | ||
aebb9aac | 27 | int EVP_MD_CTX_copy_ex(EVP_MD_CTX *out, const EVP_MD_CTX *in); |
e72d734d DSH |
28 | |
29 | int EVP_DigestInit(EVP_MD_CTX *ctx, const EVP_MD *type); | |
13588350 | 30 | int EVP_DigestFinal(EVP_MD_CTX *ctx, unsigned char *md, |
4d524e10 | 31 | unsigned int *s); |
3cbe1980 | 32 | |
aebb9aac | 33 | int EVP_MD_CTX_copy(EVP_MD_CTX *out, EVP_MD_CTX *in); |
e72d734d | 34 | |
5a34fcd7 | 35 | int EVP_MD_type(const EVP_MD *md); |
05ea606a | 36 | int EVP_MD_pkey_type(const EVP_MD *md); |
5a34fcd7 DSH |
37 | int EVP_MD_size(const EVP_MD *md); |
38 | int EVP_MD_block_size(const EVP_MD *md); | |
3cbe1980 | 39 | |
5a34fcd7 | 40 | const EVP_MD *EVP_MD_CTX_md(const EVP_MD_CTX *ctx); |
25191fff RL |
41 | int EVP_MD_CTX_size(const EVP_MD *ctx); |
42 | int EVP_MD_CTX_block_size(const EVP_MD *ctx); | |
43 | int EVP_MD_CTX_type(const EVP_MD *ctx); | |
3cbe1980 | 44 | |
13588350 DSH |
45 | const EVP_MD *EVP_md_null(void); |
46 | const EVP_MD *EVP_md2(void); | |
47 | const EVP_MD *EVP_md5(void); | |
13588350 | 48 | const EVP_MD *EVP_sha1(void); |
13588350 DSH |
49 | const EVP_MD *EVP_mdc2(void); |
50 | const EVP_MD *EVP_ripemd160(void); | |
208527a7 KR |
51 | const EVP_MD *EVP_blake2b_512(void); |
52 | const EVP_MD *EVP_blake2s_256(void); | |
3cbe1980 | 53 | |
5a34fcd7 DSH |
54 | const EVP_MD *EVP_sha224(void); |
55 | const EVP_MD *EVP_sha256(void); | |
56 | const EVP_MD *EVP_sha384(void); | |
57 | const EVP_MD *EVP_sha512(void); | |
58 | ||
3cbe1980 | 59 | const EVP_MD *EVP_get_digestbyname(const char *name); |
25191fff RL |
60 | const EVP_MD *EVP_get_digestbynid(int type); |
61 | const EVP_MD *EVP_get_digestbyobj(const ASN1_OBJECT *o); | |
3cbe1980 DSH |
62 | |
63 | =head1 DESCRIPTION | |
64 | ||
c7497f34 RS |
65 | The EVP digest routines are a high level interface to message digests, |
66 | and should be used instead of the cipher-specific functions. | |
3cbe1980 | 67 | |
25191fff RL |
68 | EVP_MD_CTX_new() allocates, initializes and returns a digest context. |
69 | ||
70 | EVP_MD_CTX_reset() resets the digest context B<ctx>. This can be used | |
71 | to reuse an already existing context. | |
e72d734d | 72 | |
25191fff RL |
73 | EVP_MD_CTX_free() cleans up digest context B<ctx> and frees up the |
74 | space allocated to it. | |
e72d734d DSH |
75 | |
76 | EVP_DigestInit_ex() sets up digest context B<ctx> to use a digest | |
77 | B<type> from ENGINE B<impl>. B<ctx> must be initialized before calling this | |
186bb907 | 78 | function. B<type> will typically be supplied by a function such as EVP_sha1(). |
e72d734d | 79 | If B<impl> is NULL then the default implementation of digest B<type> is used. |
3cbe1980 | 80 | |
4facdbb5 | 81 | EVP_DigestUpdate() hashes B<cnt> bytes of data at B<d> into the |
c8973693 | 82 | digest context B<ctx>. This function can be called several times on the |
3cbe1980 DSH |
83 | same B<ctx> to hash additional data. |
84 | ||
e72d734d | 85 | EVP_DigestFinal_ex() retrieves the digest value from B<ctx> and places |
3cbe1980 DSH |
86 | it in B<md>. If the B<s> parameter is not NULL then the number of |
87 | bytes of data written (i.e. the length of the digest) will be written | |
88 | to the integer at B<s>, at most B<EVP_MAX_MD_SIZE> bytes will be written. | |
e72d734d DSH |
89 | After calling EVP_DigestFinal_ex() no additional calls to EVP_DigestUpdate() |
90 | can be made, but EVP_DigestInit_ex() can be called to initialize a new | |
3cbe1980 DSH |
91 | digest operation. |
92 | ||
e72d734d | 93 | EVP_MD_CTX_copy_ex() can be used to copy the message digest state from |
3cbe1980 | 94 | B<in> to B<out>. This is useful if large amounts of data are to be |
e72d734d DSH |
95 | hashed which only differ in the last few bytes. B<out> must be initialized |
96 | before calling this function. | |
97 | ||
98 | EVP_DigestInit() behaves in the same way as EVP_DigestInit_ex() except | |
99 | the passed context B<ctx> does not have to be initialized, and it always | |
100 | uses the default digest implementation. | |
101 | ||
102 | EVP_DigestFinal() is similar to EVP_DigestFinal_ex() except the digest | |
11c4c02c | 103 | context B<ctx> is automatically cleaned up. |
e72d734d DSH |
104 | |
105 | EVP_MD_CTX_copy() is similar to EVP_MD_CTX_copy_ex() except the destination | |
106 | B<out> does not have to be initialized. | |
3cbe1980 | 107 | |
4facdbb5 | 108 | EVP_MD_size() and EVP_MD_CTX_size() return the size of the message digest |
3cbe1980 DSH |
109 | when passed an B<EVP_MD> or an B<EVP_MD_CTX> structure, i.e. the size of the |
110 | hash. | |
111 | ||
4facdbb5 | 112 | EVP_MD_block_size() and EVP_MD_CTX_block_size() return the block size of the |
3cbe1980 DSH |
113 | message digest when passed an B<EVP_MD> or an B<EVP_MD_CTX> structure. |
114 | ||
4facdbb5 | 115 | EVP_MD_type() and EVP_MD_CTX_type() return the NID of the OBJECT IDENTIFIER |
3cbe1980 | 116 | representing the given message digest when passed an B<EVP_MD> structure. |
4facdbb5 | 117 | For example EVP_MD_type(EVP_sha1()) returns B<NID_sha1>. This function is |
3cbe1980 DSH |
118 | normally used when setting ASN1 OIDs. |
119 | ||
72b60351 | 120 | EVP_MD_CTX_md() returns the B<EVP_MD> structure corresponding to the passed |
3cbe1980 DSH |
121 | B<EVP_MD_CTX>. |
122 | ||
4facdbb5 UM |
123 | EVP_MD_pkey_type() returns the NID of the public key signing algorithm associated |
124 | with this digest. For example EVP_sha1() is associated with RSA so this will | |
5a34fcd7 DSH |
125 | return B<NID_sha1WithRSAEncryption>. Since digests and signature algorithms |
126 | are no longer linked this function is only retained for compatibility | |
127 | reasons. | |
3cbe1980 | 128 | |
474e469b | 129 | EVP_md2(), EVP_md5(), EVP_sha1(), EVP_sha224(), EVP_sha256(), |
208527a7 KR |
130 | EVP_sha384(), EVP_sha512(), EVP_mdc2(), EVP_ripemd160(), EVP_blake2b_512(), and |
131 | EVP_blake2s_256() return B<EVP_MD> structures for the MD2, MD5, SHA1, SHA224, | |
132 | SHA256, SHA384, SHA512, MDC2, RIPEMD160, BLAKE2b-512, and BLAKE2s-256 digest | |
133 | algorithms respectively. | |
3cbe1980 | 134 | |
4facdbb5 | 135 | EVP_md_null() is a "null" message digest that does nothing: i.e. the hash it |
3cbe1980 DSH |
136 | returns is of zero length. |
137 | ||
4facdbb5 | 138 | EVP_get_digestbyname(), EVP_get_digestbynid() and EVP_get_digestbyobj() |
3cbe1980 | 139 | return an B<EVP_MD> structure when passed a digest name, a digest NID or |
f672aee4 | 140 | an ASN1_OBJECT structure respectively. |
3cbe1980 DSH |
141 | |
142 | =head1 RETURN VALUES | |
143 | ||
e72d734d | 144 | EVP_DigestInit_ex(), EVP_DigestUpdate() and EVP_DigestFinal_ex() return 1 for |
13588350 | 145 | success and 0 for failure. |
3cbe1980 | 146 | |
e72d734d | 147 | EVP_MD_CTX_copy_ex() returns 1 if successful or 0 for failure. |
3cbe1980 DSH |
148 | |
149 | EVP_MD_type(), EVP_MD_pkey_type() and EVP_MD_type() return the NID of the | |
150 | corresponding OBJECT IDENTIFIER or NID_undef if none exists. | |
151 | ||
fa6bb85a MC |
152 | EVP_MD_size(), EVP_MD_block_size(), EVP_MD_CTX_size() and |
153 | EVP_MD_CTX_block_size() return the digest or block size in bytes. | |
3cbe1980 | 154 | |
625a9baf | 155 | EVP_md_null(), EVP_md2(), EVP_md5(), EVP_sha1(), |
208527a7 KR |
156 | EVP_mdc2(), EVP_ripemd160(), EVP_blake2b_512(), and EVP_blake2s_256() return |
157 | pointers to the corresponding EVP_MD structures. | |
3cbe1980 | 158 | |
4ec19e20 | 159 | EVP_get_digestbyname(), EVP_get_digestbynid() and EVP_get_digestbyobj() |
3cbe1980 DSH |
160 | return either an B<EVP_MD> structure or NULL if an error occurs. |
161 | ||
162 | =head1 NOTES | |
163 | ||
164 | The B<EVP> interface to message digests should almost always be used in | |
165 | preference to the low level interfaces. This is because the code then becomes | |
166 | transparent to the digest used and much more flexible. | |
167 | ||
7b3e11c5 | 168 | New applications should use the SHA2 digest algorithms such as SHA256. |
5a34fcd7 | 169 | The other digest algorithms are still in common use. |
3cbe1980 | 170 | |
e72d734d DSH |
171 | For most applications the B<impl> parameter to EVP_DigestInit_ex() will be |
172 | set to NULL to use the default digest implementation. | |
173 | ||
7b3e11c5 | 174 | The functions EVP_DigestInit(), EVP_DigestFinal() and EVP_MD_CTX_copy() are |
e72d734d | 175 | obsolete but are retained to maintain compatibility with existing code. New |
7b3e11c5 | 176 | applications should use EVP_DigestInit_ex(), EVP_DigestFinal_ex() and |
e72d734d DSH |
177 | EVP_MD_CTX_copy_ex() because they can efficiently reuse a digest context |
178 | instead of initializing and cleaning it up on each call and allow non default | |
179 | implementations of digests to be specified. | |
180 | ||
a528d4f0 | 181 | If digest contexts are not cleaned up after use |
7b3e11c5 | 182 | memory leaks will occur. |
13588350 | 183 | |
25191fff RL |
184 | EVP_MD_CTX_size(), EVP_MD_CTX_block_size(), EVP_MD_CTX_type(), |
185 | EVP_get_digestbynid() and EVP_get_digestbyobj() are defined as | |
186 | macros. | |
5a34fcd7 DSH |
187 | |
188 | ||
3cbe1980 DSH |
189 | =head1 EXAMPLE |
190 | ||
191 | This example digests the data "Test Message\n" and "Hello World\n", using the | |
192 | digest name passed on the command line. | |
193 | ||
194 | #include <stdio.h> | |
195 | #include <openssl/evp.h> | |
196 | ||
197 | main(int argc, char *argv[]) | |
198 | { | |
5a34fcd7 | 199 | EVP_MD_CTX *mdctx; |
3cbe1980 DSH |
200 | const EVP_MD *md; |
201 | char mess1[] = "Test Message\n"; | |
202 | char mess2[] = "Hello World\n"; | |
203 | unsigned char md_value[EVP_MAX_MD_SIZE]; | |
204 | int md_len, i; | |
205 | ||
3cbe1980 | 206 | if(!argv[1]) { |
1bc74519 RS |
207 | printf("Usage: mdtest digestname\n"); |
208 | exit(1); | |
3cbe1980 DSH |
209 | } |
210 | ||
211 | md = EVP_get_digestbyname(argv[1]); | |
212 | ||
213 | if(!md) { | |
1bc74519 RS |
214 | printf("Unknown message digest %s\n", argv[1]); |
215 | exit(1); | |
3cbe1980 DSH |
216 | } |
217 | ||
25191fff | 218 | mdctx = EVP_MD_CTX_new(); |
5a34fcd7 DSH |
219 | EVP_DigestInit_ex(mdctx, md, NULL); |
220 | EVP_DigestUpdate(mdctx, mess1, strlen(mess1)); | |
221 | EVP_DigestUpdate(mdctx, mess2, strlen(mess2)); | |
222 | EVP_DigestFinal_ex(mdctx, md_value, &md_len); | |
25191fff | 223 | EVP_MD_CTX_free(mdctx); |
3cbe1980 DSH |
224 | |
225 | printf("Digest is: "); | |
2f8e53d7 | 226 | for (i = 0; i < md_len; i++) |
1bc74519 | 227 | printf("%02x", md_value[i]); |
3cbe1980 | 228 | printf("\n"); |
7b3e11c5 | 229 | |
7b3e11c5 | 230 | exit(0); |
3cbe1980 DSH |
231 | } |
232 | ||
3cbe1980 DSH |
233 | =head1 SEE ALSO |
234 | ||
9b86974e | 235 | L<dgst(1)>, |
b97fdb57 | 236 | L<evp(7)> |
4facdbb5 | 237 | |
3cbe1980 DSH |
238 | =head1 HISTORY |
239 | ||
25191fff RL |
240 | B<EVP_MD_CTX> became opaque in OpenSSL 1.1. Consequently, stack |
241 | allocated B<EVP_MD_CTX>s are no longer supported. | |
242 | ||
243 | EVP_MD_CTX_create() and EVP_MD_CTX_destroy() were renamed to | |
244 | EVP_MD_CTX_new() and EVP_MD_CTX_free() in OpenSSL 1.1. | |
245 | ||
3fa39ed7 | 246 | The link between digests and signing algorithms was fixed in OpenSSL 1.0 and |
7f572e95 DSH |
247 | later, so now EVP_sha1() can be used with RSA and DSA. The legacy EVP_dss1() |
248 | was removed in OpenSSL 1.1.0 | |
3fa39ed7 | 249 | |
e2f92610 RS |
250 | =head1 COPYRIGHT |
251 | ||
252 | Copyright 2000-2016 The OpenSSL Project Authors. All Rights Reserved. | |
253 | ||
254 | Licensed under the OpenSSL license (the "License"). You may not use | |
255 | this file except in compliance with the License. You can obtain a copy | |
256 | in the file LICENSE in the source distribution or at | |
257 | L<https://www.openssl.org/source/license.html>. | |
258 | ||
259 | =cut |