5 EVP_MD_CTX_new, EVP_MD_CTX_reset, EVP_MD_CTX_free, EVP_MD_CTX_copy_ex,
6 EVP_MD_CTX_ctrl, EVP_DigestInit_ex, EVP_DigestUpdate, EVP_DigestFinal_ex,
7 EVP_DigestInit, EVP_DigestFinal, EVP_MD_CTX_copy, EVP_MD_type,
8 EVP_MD_pkey_type, EVP_MD_size, EVP_MD_block_size, EVP_MD_CTX_md, EVP_MD_CTX_size,
9 EVP_MD_CTX_block_size, EVP_MD_CTX_type, EVP_md_null, EVP_md2, EVP_md5, EVP_sha1,
10 EVP_sha224, EVP_sha256, EVP_sha384, EVP_sha512, EVP_mdc2,
11 EVP_ripemd160, EVP_blake2b512, EVP_blake2s256, EVP_get_digestbyname,
12 EVP_get_digestbynid, EVP_get_digestbyobj - EVP digest routines
16 #include <openssl/evp.h>
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);
21 void EVP_MD_CTX_ctrl(EVP_MD_CTX *ctx, int cmd, int p1, void* p2);
23 int EVP_DigestInit_ex(EVP_MD_CTX *ctx, const EVP_MD *type, ENGINE *impl);
24 int EVP_DigestUpdate(EVP_MD_CTX *ctx, const void *d, size_t cnt);
25 int EVP_DigestFinal_ex(EVP_MD_CTX *ctx, unsigned char *md,
28 int EVP_MD_CTX_copy_ex(EVP_MD_CTX *out, const EVP_MD_CTX *in);
30 int EVP_DigestInit(EVP_MD_CTX *ctx, const EVP_MD *type);
31 int EVP_DigestFinal(EVP_MD_CTX *ctx, unsigned char *md,
34 int EVP_MD_CTX_copy(EVP_MD_CTX *out, EVP_MD_CTX *in);
36 int EVP_MD_type(const EVP_MD *md);
37 int EVP_MD_pkey_type(const EVP_MD *md);
38 int EVP_MD_size(const EVP_MD *md);
39 int EVP_MD_block_size(const EVP_MD *md);
41 const EVP_MD *EVP_MD_CTX_md(const EVP_MD_CTX *ctx);
42 int EVP_MD_CTX_size(const EVP_MD *ctx);
43 int EVP_MD_CTX_block_size(const EVP_MD *ctx);
44 int EVP_MD_CTX_type(const EVP_MD *ctx);
46 const EVP_MD *EVP_md_null(void);
47 const EVP_MD *EVP_md2(void);
48 const EVP_MD *EVP_md5(void);
49 const EVP_MD *EVP_sha1(void);
50 const EVP_MD *EVP_mdc2(void);
51 const EVP_MD *EVP_ripemd160(void);
52 const EVP_MD *EVP_blake2b512(void);
53 const EVP_MD *EVP_blake2s256(void);
55 const EVP_MD *EVP_sha224(void);
56 const EVP_MD *EVP_sha256(void);
57 const EVP_MD *EVP_sha384(void);
58 const EVP_MD *EVP_sha512(void);
60 const EVP_MD *EVP_get_digestbyname(const char *name);
61 const EVP_MD *EVP_get_digestbynid(int type);
62 const EVP_MD *EVP_get_digestbyobj(const ASN1_OBJECT *o);
66 The EVP digest routines are a high level interface to message digests,
67 and should be used instead of the cipher-specific functions.
69 EVP_MD_CTX_new() allocates, initializes and returns a digest context.
71 EVP_MD_CTX_reset() resets the digest context B<ctx>. This can be used
72 to reuse an already existing context.
74 EVP_MD_CTX_free() cleans up digest context B<ctx> and frees up the
75 space allocated to it.
77 EVP_MD_CTX_ctrl() performs digest-specific control actions on context B<ctx>.
79 EVP_DigestInit_ex() sets up digest context B<ctx> to use a digest
80 B<type> from ENGINE B<impl>. B<ctx> must be initialized before calling this
81 function. B<type> will typically be supplied by a function such as EVP_sha1().
82 If B<impl> is NULL then the default implementation of digest B<type> is used.
84 EVP_DigestUpdate() hashes B<cnt> bytes of data at B<d> into the
85 digest context B<ctx>. This function can be called several times on the
86 same B<ctx> to hash additional data.
88 EVP_DigestFinal_ex() retrieves the digest value from B<ctx> and places
89 it in B<md>. If the B<s> parameter is not NULL then the number of
90 bytes of data written (i.e. the length of the digest) will be written
91 to the integer at B<s>, at most B<EVP_MAX_MD_SIZE> bytes will be written.
92 After calling EVP_DigestFinal_ex() no additional calls to EVP_DigestUpdate()
93 can be made, but EVP_DigestInit_ex() can be called to initialize a new
96 EVP_MD_CTX_copy_ex() can be used to copy the message digest state from
97 B<in> to B<out>. This is useful if large amounts of data are to be
98 hashed which only differ in the last few bytes. B<out> must be initialized
99 before calling this function.
101 EVP_DigestInit() behaves in the same way as EVP_DigestInit_ex() except
102 the passed context B<ctx> does not have to be initialized, and it always
103 uses the default digest implementation.
105 EVP_DigestFinal() is similar to EVP_DigestFinal_ex() except the digest
106 context B<ctx> is automatically cleaned up.
108 EVP_MD_CTX_copy() is similar to EVP_MD_CTX_copy_ex() except the destination
109 B<out> does not have to be initialized.
111 EVP_MD_size() and EVP_MD_CTX_size() return the size of the message digest
112 when passed an B<EVP_MD> or an B<EVP_MD_CTX> structure, i.e. the size of the
115 EVP_MD_block_size() and EVP_MD_CTX_block_size() return the block size of the
116 message digest when passed an B<EVP_MD> or an B<EVP_MD_CTX> structure.
118 EVP_MD_type() and EVP_MD_CTX_type() return the NID of the OBJECT IDENTIFIER
119 representing the given message digest when passed an B<EVP_MD> structure.
120 For example EVP_MD_type(EVP_sha1()) returns B<NID_sha1>. This function is
121 normally used when setting ASN1 OIDs.
123 EVP_MD_CTX_md() returns the B<EVP_MD> structure corresponding to the passed
126 EVP_MD_pkey_type() returns the NID of the public key signing algorithm associated
127 with this digest. For example EVP_sha1() is associated with RSA so this will
128 return B<NID_sha1WithRSAEncryption>. Since digests and signature algorithms
129 are no longer linked this function is only retained for compatibility
132 EVP_md2(), EVP_md5(), EVP_sha1(), EVP_sha224(), EVP_sha256(),
133 EVP_sha384(), EVP_sha512(), EVP_mdc2(), EVP_ripemd160(), EVP_blake2b512(), and
134 EVP_blake2s256() return B<EVP_MD> structures for the MD2, MD5, SHA1, SHA224,
135 SHA256, SHA384, SHA512, MDC2, RIPEMD160, BLAKE2b-512, and BLAKE2s-256 digest
136 algorithms respectively.
138 EVP_md_null() is a "null" message digest that does nothing: i.e. the hash it
139 returns is of zero length.
141 EVP_get_digestbyname(), EVP_get_digestbynid() and EVP_get_digestbyobj()
142 return an B<EVP_MD> structure when passed a digest name, a digest NID or
143 an ASN1_OBJECT structure respectively.
147 EVP_DigestInit_ex(), EVP_DigestUpdate() and EVP_DigestFinal_ex() return 1 for
148 success and 0 for failure.
150 EVP_MD_CTX_ctrl() returns 1 if successful or 0 for failure.
152 EVP_MD_CTX_copy_ex() returns 1 if successful or 0 for failure.
154 EVP_MD_type(), EVP_MD_pkey_type() and EVP_MD_type() return the NID of the
155 corresponding OBJECT IDENTIFIER or NID_undef if none exists.
157 EVP_MD_size(), EVP_MD_block_size(), EVP_MD_CTX_size() and
158 EVP_MD_CTX_block_size() return the digest or block size in bytes.
160 EVP_md_null(), EVP_md2(), EVP_md5(), EVP_sha1(),
161 EVP_mdc2(), EVP_ripemd160(), EVP_blake2b512(), and EVP_blake2s256() return
162 pointers to the corresponding EVP_MD structures.
164 EVP_get_digestbyname(), EVP_get_digestbynid() and EVP_get_digestbyobj()
165 return either an B<EVP_MD> structure or NULL if an error occurs.
169 The B<EVP> interface to message digests should almost always be used in
170 preference to the low level interfaces. This is because the code then becomes
171 transparent to the digest used and much more flexible.
173 New applications should use the SHA2 digest algorithms such as SHA256.
174 The other digest algorithms are still in common use.
176 For most applications the B<impl> parameter to EVP_DigestInit_ex() will be
177 set to NULL to use the default digest implementation.
179 The functions EVP_DigestInit(), EVP_DigestFinal() and EVP_MD_CTX_copy() are
180 obsolete but are retained to maintain compatibility with existing code. New
181 applications should use EVP_DigestInit_ex(), EVP_DigestFinal_ex() and
182 EVP_MD_CTX_copy_ex() because they can efficiently reuse a digest context
183 instead of initializing and cleaning it up on each call and allow non default
184 implementations of digests to be specified.
186 If digest contexts are not cleaned up after use
187 memory leaks will occur.
189 EVP_MD_CTX_size(), EVP_MD_CTX_block_size(), EVP_MD_CTX_type(),
190 EVP_get_digestbynid() and EVP_get_digestbyobj() are defined as
193 EVP_MD_CTX_ctrl() sends commands to message digests for additional configuration
198 This example digests the data "Test Message\n" and "Hello World\n", using the
199 digest name passed on the command line.
202 #include <openssl/evp.h>
204 main(int argc, char *argv[])
208 char mess1[] = "Test Message\n";
209 char mess2[] = "Hello World\n";
210 unsigned char md_value[EVP_MAX_MD_SIZE];
213 if (argv[1] == NULL) {
214 printf("Usage: mdtest digestname\n");
218 md = EVP_get_digestbyname(argv[1]);
220 printf("Unknown message digest %s\n", argv[1]);
224 mdctx = EVP_MD_CTX_new();
225 EVP_DigestInit_ex(mdctx, md, NULL);
226 EVP_DigestUpdate(mdctx, mess1, strlen(mess1));
227 EVP_DigestUpdate(mdctx, mess2, strlen(mess2));
228 EVP_DigestFinal_ex(mdctx, md_value, &md_len);
229 EVP_MD_CTX_free(mdctx);
231 printf("Digest is: ");
232 for (i = 0; i < md_len; i++)
233 printf("%02x", md_value[i]);
246 B<EVP_MD_CTX> became opaque in OpenSSL 1.1. Consequently, stack
247 allocated B<EVP_MD_CTX>s are no longer supported.
249 EVP_MD_CTX_create() and EVP_MD_CTX_destroy() were renamed to
250 EVP_MD_CTX_new() and EVP_MD_CTX_free() in OpenSSL 1.1.
252 The link between digests and signing algorithms was fixed in OpenSSL 1.0 and
253 later, so now EVP_sha1() can be used with RSA and DSA. The legacy EVP_dss1()
254 was removed in OpenSSL 1.1.0
258 Copyright 2000-2016 The OpenSSL Project Authors. All Rights Reserved.
260 Licensed under the OpenSSL license (the "License"). You may not use
261 this file except in compliance with the License. You can obtain a copy
262 in the file LICENSE in the source distribution or at
263 L<https://www.openssl.org/source/license.html>.