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, unsigned int *s);
27 int EVP_MD_CTX_copy_ex(EVP_MD_CTX *out, const EVP_MD_CTX *in);
29 int EVP_DigestInit(EVP_MD_CTX *ctx, const EVP_MD *type);
30 int EVP_DigestFinal(EVP_MD_CTX *ctx, unsigned char *md, unsigned int *s);
32 int EVP_MD_CTX_copy(EVP_MD_CTX *out, EVP_MD_CTX *in);
34 int EVP_MD_type(const EVP_MD *md);
35 int EVP_MD_pkey_type(const EVP_MD *md);
36 int EVP_MD_size(const EVP_MD *md);
37 int EVP_MD_block_size(const EVP_MD *md);
39 const EVP_MD *EVP_MD_CTX_md(const EVP_MD_CTX *ctx);
40 int EVP_MD_CTX_size(const EVP_MD *ctx);
41 int EVP_MD_CTX_block_size(const EVP_MD *ctx);
42 int EVP_MD_CTX_type(const EVP_MD *ctx);
44 const EVP_MD *EVP_md_null(void);
45 const EVP_MD *EVP_md2(void);
46 const EVP_MD *EVP_md5(void);
47 const EVP_MD *EVP_sha1(void);
48 const EVP_MD *EVP_mdc2(void);
49 const EVP_MD *EVP_ripemd160(void);
50 const EVP_MD *EVP_blake2b512(void);
51 const EVP_MD *EVP_blake2s256(void);
53 const EVP_MD *EVP_sha224(void);
54 const EVP_MD *EVP_sha256(void);
55 const EVP_MD *EVP_sha384(void);
56 const EVP_MD *EVP_sha512(void);
58 const EVP_MD *EVP_get_digestbyname(const char *name);
59 const EVP_MD *EVP_get_digestbynid(int type);
60 const EVP_MD *EVP_get_digestbyobj(const ASN1_OBJECT *o);
64 The EVP digest routines are a high level interface to message digests,
65 and should be used instead of the cipher-specific functions.
67 EVP_MD_CTX_new() allocates, initializes and returns a digest context.
69 EVP_MD_CTX_reset() resets the digest context B<ctx>. This can be used
70 to reuse an already existing context.
72 EVP_MD_CTX_free() cleans up digest context B<ctx> and frees up the
73 space allocated to it.
75 EVP_MD_CTX_ctrl() performs digest-specific control actions on context B<ctx>.
77 EVP_DigestInit_ex() sets up digest context B<ctx> to use a digest
78 B<type> from ENGINE B<impl>. B<ctx> must be initialized before calling this
79 function. B<type> will typically be supplied by a function such as EVP_sha1().
80 If B<impl> is NULL then the default implementation of digest B<type> is used.
82 EVP_DigestUpdate() hashes B<cnt> bytes of data at B<d> into the
83 digest context B<ctx>. This function can be called several times on the
84 same B<ctx> to hash additional data.
86 EVP_DigestFinal_ex() retrieves the digest value from B<ctx> and places
87 it in B<md>. If the B<s> parameter is not NULL then the number of
88 bytes of data written (i.e. the length of the digest) will be written
89 to the integer at B<s>, at most B<EVP_MAX_MD_SIZE> bytes will be written.
90 After calling EVP_DigestFinal_ex() no additional calls to EVP_DigestUpdate()
91 can be made, but EVP_DigestInit_ex() can be called to initialize a new
94 EVP_MD_CTX_copy_ex() can be used to copy the message digest state from
95 B<in> to B<out>. This is useful if large amounts of data are to be
96 hashed which only differ in the last few bytes. B<out> must be initialized
97 before calling this function.
99 EVP_DigestInit() behaves in the same way as EVP_DigestInit_ex() except
100 the passed context B<ctx> does not have to be initialized, and it always
101 uses the default digest implementation.
103 EVP_DigestFinal() is similar to EVP_DigestFinal_ex() except the digest
104 context B<ctx> is automatically cleaned up.
106 EVP_MD_CTX_copy() is similar to EVP_MD_CTX_copy_ex() except the destination
107 B<out> does not have to be initialized.
109 EVP_MD_size() and EVP_MD_CTX_size() return the size of the message digest
110 when passed an B<EVP_MD> or an B<EVP_MD_CTX> structure, i.e. the size of the
113 EVP_MD_block_size() and EVP_MD_CTX_block_size() return the block size of the
114 message digest when passed an B<EVP_MD> or an B<EVP_MD_CTX> structure.
116 EVP_MD_type() and EVP_MD_CTX_type() return the NID of the OBJECT IDENTIFIER
117 representing the given message digest when passed an B<EVP_MD> structure.
118 For example EVP_MD_type(EVP_sha1()) returns B<NID_sha1>. This function is
119 normally used when setting ASN1 OIDs.
121 EVP_MD_CTX_md() returns the B<EVP_MD> structure corresponding to the passed
124 EVP_MD_pkey_type() returns the NID of the public key signing algorithm associated
125 with this digest. For example EVP_sha1() is associated with RSA so this will
126 return B<NID_sha1WithRSAEncryption>. Since digests and signature algorithms
127 are no longer linked this function is only retained for compatibility
130 EVP_md2(), EVP_md5(), EVP_sha1(), EVP_sha224(), EVP_sha256(),
131 EVP_sha384(), EVP_sha512(), EVP_mdc2(), EVP_ripemd160(), EVP_blake2b512(), and
132 EVP_blake2s256() return B<EVP_MD> structures for the MD2, MD5, SHA1, SHA224,
133 SHA256, SHA384, SHA512, MDC2, RIPEMD160, BLAKE2b-512, and BLAKE2s-256 digest
134 algorithms respectively.
136 EVP_md_null() is a "null" message digest that does nothing: i.e. the hash it
137 returns is of zero length.
139 EVP_get_digestbyname(), EVP_get_digestbynid() and EVP_get_digestbyobj()
140 return an B<EVP_MD> structure when passed a digest name, a digest NID or
141 an ASN1_OBJECT structure respectively.
145 EVP_DigestInit_ex(), EVP_DigestUpdate() and EVP_DigestFinal_ex() return 1 for
146 success and 0 for failure.
148 EVP_MD_CTX_ctrl() returns 1 if successful or 0 for failure.
150 EVP_MD_CTX_copy_ex() returns 1 if successful or 0 for failure.
152 EVP_MD_type(), EVP_MD_pkey_type() and EVP_MD_type() return the NID of the
153 corresponding OBJECT IDENTIFIER or NID_undef if none exists.
155 EVP_MD_size(), EVP_MD_block_size(), EVP_MD_CTX_size() and
156 EVP_MD_CTX_block_size() return the digest or block size in bytes.
158 EVP_md_null(), EVP_md2(), EVP_md5(), EVP_sha1(),
159 EVP_mdc2(), EVP_ripemd160(), EVP_blake2b512(), and EVP_blake2s256() return
160 pointers to the corresponding EVP_MD structures.
162 EVP_get_digestbyname(), EVP_get_digestbynid() and EVP_get_digestbyobj()
163 return either an B<EVP_MD> structure or NULL if an error occurs.
167 The B<EVP> interface to message digests should almost always be used in
168 preference to the low level interfaces. This is because the code then becomes
169 transparent to the digest used and much more flexible.
171 New applications should use the SHA2 digest algorithms such as SHA256.
172 The other digest algorithms are still in common use.
174 For most applications the B<impl> parameter to EVP_DigestInit_ex() will be
175 set to NULL to use the default digest implementation.
177 The functions EVP_DigestInit(), EVP_DigestFinal() and EVP_MD_CTX_copy() are
178 obsolete but are retained to maintain compatibility with existing code. New
179 applications should use EVP_DigestInit_ex(), EVP_DigestFinal_ex() and
180 EVP_MD_CTX_copy_ex() because they can efficiently reuse a digest context
181 instead of initializing and cleaning it up on each call and allow non default
182 implementations of digests to be specified.
184 If digest contexts are not cleaned up after use
185 memory leaks will occur.
187 EVP_MD_CTX_size(), EVP_MD_CTX_block_size(), EVP_MD_CTX_type(),
188 EVP_get_digestbynid() and EVP_get_digestbyobj() are defined as
191 EVP_MD_CTX_ctrl() sends commands to message digests for additional configuration
196 This example digests the data "Test Message\n" and "Hello World\n", using the
197 digest name passed on the command line.
200 #include <openssl/evp.h>
202 main(int argc, char *argv[])
206 char mess1[] = "Test Message\n";
207 char mess2[] = "Hello World\n";
208 unsigned char md_value[EVP_MAX_MD_SIZE];
211 if (argv[1] == NULL) {
212 printf("Usage: mdtest digestname\n");
216 md = EVP_get_digestbyname(argv[1]);
218 printf("Unknown message digest %s\n", argv[1]);
222 mdctx = EVP_MD_CTX_new();
223 EVP_DigestInit_ex(mdctx, md, NULL);
224 EVP_DigestUpdate(mdctx, mess1, strlen(mess1));
225 EVP_DigestUpdate(mdctx, mess2, strlen(mess2));
226 EVP_DigestFinal_ex(mdctx, md_value, &md_len);
227 EVP_MD_CTX_free(mdctx);
229 printf("Digest is: ");
230 for (i = 0; i < md_len; i++)
231 printf("%02x", md_value[i]);
244 B<EVP_MD_CTX> became opaque in OpenSSL 1.1. Consequently, stack
245 allocated B<EVP_MD_CTX>s are no longer supported.
247 EVP_MD_CTX_create() and EVP_MD_CTX_destroy() were renamed to
248 EVP_MD_CTX_new() and EVP_MD_CTX_free() in OpenSSL 1.1.
250 The link between digests and signing algorithms was fixed in OpenSSL 1.0 and
251 later, so now EVP_sha1() can be used with RSA and DSA. The legacy EVP_dss1()
252 was removed in OpenSSL 1.1.0
256 Copyright 2000-2016 The OpenSSL Project Authors. All Rights Reserved.
258 Licensed under the OpenSSL license (the "License"). You may not use
259 this file except in compliance with the License. You can obtain a copy
260 in the file LICENSE in the source distribution or at
261 L<https://www.openssl.org/source/license.html>.