5 EVP_MD_CTX_new, EVP_MD_CTX_reset, EVP_MD_CTX_free, EVP_MD_CTX_copy_ex,
6 EVP_MD_CTX_set_flags, EVP_MD_CTX_clear_flags, EVP_MD_CTX_test_flags,
7 EVP_DigestInit_ex, EVP_DigestUpdate, EVP_DigestFinal_ex,
8 EVP_DigestInit, EVP_DigestFinal, EVP_MD_CTX_copy, EVP_MD_type,
9 EVP_MD_pkey_type, EVP_MD_size, EVP_MD_block_size, EVP_MD_CTX_md, EVP_MD_CTX_size,
10 EVP_MD_CTX_block_size, EVP_MD_CTX_type, EVP_MD_CTX_md_data, EVP_md_null, EVP_md2,
11 EVP_md5, EVP_sha1, EVP_sha224, EVP_sha256, EVP_sha384, EVP_sha512, EVP_mdc2,
12 EVP_ripemd160, EVP_blake2b512, EVP_blake2s256, EVP_get_digestbyname,
13 EVP_get_digestbynid, EVP_get_digestbyobj - EVP digest routines
17 #include <openssl/evp.h>
19 EVP_MD_CTX *EVP_MD_CTX_new(void);
20 int EVP_MD_CTX_reset(EVP_MD_CTX *ctx);
21 void EVP_MD_CTX_free(EVP_MD_CTX *ctx);
22 void EVP_MD_CTX_set_flags(EVP_MD_CTX *ctx, int flags);
23 void EVP_MD_CTX_clear_flags(EVP_MD_CTX *ctx, int flags);
24 int EVP_MD_CTX_test_flags(const EVP_MD_CTX *ctx, int flags);
26 int EVP_DigestInit_ex(EVP_MD_CTX *ctx, const EVP_MD *type, ENGINE *impl);
27 int EVP_DigestUpdate(EVP_MD_CTX *ctx, const void *d, size_t cnt);
28 int EVP_DigestFinal_ex(EVP_MD_CTX *ctx, unsigned char *md,
31 int EVP_MD_CTX_copy_ex(EVP_MD_CTX *out, const EVP_MD_CTX *in);
33 int EVP_DigestInit(EVP_MD_CTX *ctx, const EVP_MD *type);
34 int EVP_DigestFinal(EVP_MD_CTX *ctx, unsigned char *md,
37 int EVP_MD_CTX_copy(EVP_MD_CTX *out, EVP_MD_CTX *in);
39 int EVP_MD_type(const EVP_MD *md);
40 int EVP_MD_pkey_type(const EVP_MD *md);
41 int EVP_MD_size(const EVP_MD *md);
42 int EVP_MD_block_size(const EVP_MD *md);
44 const EVP_MD *EVP_MD_CTX_md(const EVP_MD_CTX *ctx);
45 int EVP_MD_CTX_size(const EVP_MD *ctx);
46 int EVP_MD_CTX_block_size(const EVP_MD *ctx);
47 int EVP_MD_CTX_type(const EVP_MD *ctx);
48 void *EVP_MD_CTX_md_data(const EVP_MD_CTX *ctx);
50 const EVP_MD *EVP_md_null(void);
51 const EVP_MD *EVP_md2(void);
52 const EVP_MD *EVP_md5(void);
53 const EVP_MD *EVP_sha1(void);
54 const EVP_MD *EVP_mdc2(void);
55 const EVP_MD *EVP_ripemd160(void);
56 const EVP_MD *EVP_blake2b512(void);
57 const EVP_MD *EVP_blake2s256(void);
59 const EVP_MD *EVP_sha224(void);
60 const EVP_MD *EVP_sha256(void);
61 const EVP_MD *EVP_sha384(void);
62 const EVP_MD *EVP_sha512(void);
64 const EVP_MD *EVP_get_digestbyname(const char *name);
65 const EVP_MD *EVP_get_digestbynid(int type);
66 const EVP_MD *EVP_get_digestbyobj(const ASN1_OBJECT *o);
70 The EVP digest routines are a high level interface to message digests,
71 and should be used instead of the cipher-specific functions.
73 EVP_MD_CTX_new() allocates, initializes and returns a digest context.
75 EVP_MD_CTX_reset() resets the digest context B<ctx>. This can be used
76 to reuse an already existing context.
78 EVP_MD_CTX_free() cleans up digest context B<ctx> and frees up the
79 space allocated to it.
81 EVP_MD_CTX_set_flags(), EVP_MD_CTX_clear_flags() and EVP_MD_CTX_test_flags()
82 sets, clears and tests B<ctx> flags. See L</FLAGS> below for more information.
84 EVP_DigestInit_ex() sets up digest context B<ctx> to use a digest
85 B<type> from ENGINE B<impl>. B<ctx> must be initialized before calling this
86 function. B<type> will typically be supplied by a function such as EVP_sha1().
87 If B<impl> is NULL then the default implementation of digest B<type> is used.
89 EVP_DigestUpdate() hashes B<cnt> bytes of data at B<d> into the
90 digest context B<ctx>. This function can be called several times on the
91 same B<ctx> to hash additional data.
93 EVP_DigestFinal_ex() retrieves the digest value from B<ctx> and places
94 it in B<md>. If the B<s> parameter is not NULL then the number of
95 bytes of data written (i.e. the length of the digest) will be written
96 to the integer at B<s>, at most B<EVP_MAX_MD_SIZE> bytes will be written.
97 After calling EVP_DigestFinal_ex() no additional calls to EVP_DigestUpdate()
98 can be made, but EVP_DigestInit_ex() can be called to initialize a new
101 EVP_MD_CTX_copy_ex() can be used to copy the message digest state from
102 B<in> to B<out>. This is useful if large amounts of data are to be
103 hashed which only differ in the last few bytes. B<out> must be initialized
104 before calling this function.
106 EVP_DigestInit() behaves in the same way as EVP_DigestInit_ex() except
107 the passed context B<ctx> does not have to be initialized, and it always
108 uses the default digest implementation.
110 EVP_DigestFinal() is similar to EVP_DigestFinal_ex() except the digest
111 context B<ctx> is automatically cleaned up.
113 EVP_MD_CTX_copy() is similar to EVP_MD_CTX_copy_ex() except the destination
114 B<out> does not have to be initialized.
116 EVP_MD_size() and EVP_MD_CTX_size() return the size of the message digest
117 when passed an B<EVP_MD> or an B<EVP_MD_CTX> structure, i.e. the size of the
120 EVP_MD_block_size() and EVP_MD_CTX_block_size() return the block size of the
121 message digest when passed an B<EVP_MD> or an B<EVP_MD_CTX> structure.
123 EVP_MD_type() and EVP_MD_CTX_type() return the NID of the OBJECT IDENTIFIER
124 representing the given message digest when passed an B<EVP_MD> structure.
125 For example EVP_MD_type(EVP_sha1()) returns B<NID_sha1>. This function is
126 normally used when setting ASN1 OIDs.
128 EVP_MD_CTX_md_data() return the digest method private data for the passed
130 The space is allocated by OpenSSL and has the size originally set with
131 EVP_MD_meth_set_app_datasize().
133 EVP_MD_CTX_md() returns the B<EVP_MD> structure corresponding to the passed
136 EVP_MD_pkey_type() returns the NID of the public key signing algorithm associated
137 with this digest. For example EVP_sha1() is associated with RSA so this will
138 return B<NID_sha1WithRSAEncryption>. Since digests and signature algorithms
139 are no longer linked this function is only retained for compatibility
142 EVP_md2(), EVP_md5(), EVP_sha1(), EVP_sha224(), EVP_sha256(),
143 EVP_sha384(), EVP_sha512(), EVP_mdc2(), EVP_ripemd160(), EVP_blake2b512(), and
144 EVP_blake2s256() return B<EVP_MD> structures for the MD2, MD5, SHA1, SHA224,
145 SHA256, SHA384, SHA512, MDC2, RIPEMD160, BLAKE2b-512, and BLAKE2s-256 digest
146 algorithms respectively.
148 EVP_md_null() is a "null" message digest that does nothing: i.e. the hash it
149 returns is of zero length.
151 EVP_get_digestbyname(), EVP_get_digestbynid() and EVP_get_digestbyobj()
152 return an B<EVP_MD> structure when passed a digest name, a digest NID or
153 an ASN1_OBJECT structure respectively.
157 EVP_MD_CTX_set_flags(), EVP_MD_CTX_clear_flags() and EVP_MD_CTX_test_flags()
158 can be used the manipulate and test these B<EVP_MD_CTX> flags:
162 =item EVP_MD_CTX_FLAG_ONESHOT
164 This flag instructs the digest to optimize for one update only, if possible.
166 =for comment EVP_MD_CTX_FLAG_CLEANED is internal, don't mention it
168 =for comment EVP_MD_CTX_FLAG_REUSE is internal, don't mention it
170 =for comment We currently avoid documenting flags that are only bit holder:
171 EVP_MD_CTX_FLAG_NON_FIPS_ALLOW, EVP_MD_CTX_FLAGS_PAD_*
173 =item EVP_MD_CTX_FLAG_NO_INIT
175 This flag instructs EVP_DigestInit() and similar not to initialise the
176 implementation specific data.
178 =item EVP_MD_CTX_FLAG_FINALISE
180 Some functions such as EVP_DigestSign only finalise copies of internal
181 contexts so additional data can be included after the finalisation call.
182 This is inefficient if this functionality is not required, and can be
183 disabled with this flag.
189 EVP_DigestInit_ex(), EVP_DigestUpdate() and EVP_DigestFinal_ex() return 1 for
190 success and 0 for failure.
192 EVP_MD_CTX_copy_ex() returns 1 if successful or 0 for failure.
194 EVP_MD_type(), EVP_MD_pkey_type() and EVP_MD_type() return the NID of the
195 corresponding OBJECT IDENTIFIER or NID_undef if none exists.
197 EVP_MD_size(), EVP_MD_block_size(), EVP_MD_CTX_size() and
198 EVP_MD_CTX_block_size() return the digest or block size in bytes.
200 EVP_md_null(), EVP_md2(), EVP_md5(), EVP_sha1(),
201 EVP_mdc2(), EVP_ripemd160(), EVP_blake2b512(), and EVP_blake2s256() return
202 pointers to the corresponding EVP_MD structures.
204 EVP_get_digestbyname(), EVP_get_digestbynid() and EVP_get_digestbyobj()
205 return either an B<EVP_MD> structure or NULL if an error occurs.
209 The B<EVP> interface to message digests should almost always be used in
210 preference to the low level interfaces. This is because the code then becomes
211 transparent to the digest used and much more flexible.
213 New applications should use the SHA2 digest algorithms such as SHA256.
214 The other digest algorithms are still in common use.
216 For most applications the B<impl> parameter to EVP_DigestInit_ex() will be
217 set to NULL to use the default digest implementation.
219 The functions EVP_DigestInit(), EVP_DigestFinal() and EVP_MD_CTX_copy() are
220 obsolete but are retained to maintain compatibility with existing code. New
221 applications should use EVP_DigestInit_ex(), EVP_DigestFinal_ex() and
222 EVP_MD_CTX_copy_ex() because they can efficiently reuse a digest context
223 instead of initializing and cleaning it up on each call and allow non default
224 implementations of digests to be specified.
226 If digest contexts are not cleaned up after use,
227 memory leaks will occur.
229 EVP_MD_CTX_size(), EVP_MD_CTX_block_size(), EVP_MD_CTX_type(),
230 EVP_get_digestbynid() and EVP_get_digestbyobj() are defined as
236 This example digests the data "Test Message\n" and "Hello World\n", using the
237 digest name passed on the command line.
240 #include <openssl/evp.h>
242 main(int argc, char *argv[])
246 char mess1[] = "Test Message\n";
247 char mess2[] = "Hello World\n";
248 unsigned char md_value[EVP_MAX_MD_SIZE];
252 printf("Usage: mdtest digestname\n");
256 md = EVP_get_digestbyname(argv[1]);
259 printf("Unknown message digest %s\n", argv[1]);
263 mdctx = EVP_MD_CTX_new();
264 EVP_DigestInit_ex(mdctx, md, NULL);
265 EVP_DigestUpdate(mdctx, mess1, strlen(mess1));
266 EVP_DigestUpdate(mdctx, mess2, strlen(mess2));
267 EVP_DigestFinal_ex(mdctx, md_value, &md_len);
268 EVP_MD_CTX_free(mdctx);
270 printf("Digest is: ");
271 for (i = 0; i < md_len; i++)
272 printf("%02x", md_value[i]);
285 B<EVP_MD_CTX> became opaque in OpenSSL 1.1. Consequently, stack
286 allocated B<EVP_MD_CTX>s are no longer supported.
288 EVP_MD_CTX_create() and EVP_MD_CTX_destroy() were renamed to
289 EVP_MD_CTX_new() and EVP_MD_CTX_free() in OpenSSL 1.1.
291 The link between digests and signing algorithms was fixed in OpenSSL 1.0 and
292 later, so now EVP_sha1() can be used with RSA and DSA. The legacy EVP_dss1()
293 was removed in OpenSSL 1.1.0
297 Copyright 2000-2018 The OpenSSL Project Authors. All Rights Reserved.
299 Licensed under the OpenSSL license (the "License"). You may not use
300 this file except in compliance with the License. You can obtain a copy
301 in the file LICENSE in the source distribution or at
302 L<https://www.openssl.org/source/license.html>.