5 EVP_MD_CTX_new, EVP_MD_CTX_reset, EVP_MD_CTX_free, EVP_MD_CTX_copy_ex,
6 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_blake2b_512, EVP_blake2s_256, 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);
22 int EVP_DigestInit_ex(EVP_MD_CTX *ctx, const EVP_MD *type, ENGINE *impl);
23 int EVP_DigestUpdate(EVP_MD_CTX *ctx, const void *d, size_t cnt);
24 int EVP_DigestFinal_ex(EVP_MD_CTX *ctx, unsigned char *md,
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,
33 int EVP_MD_CTX_copy(EVP_MD_CTX *out, EVP_MD_CTX *in);
35 int EVP_MD_type(const EVP_MD *md);
36 int EVP_MD_pkey_type(const EVP_MD *md);
37 int EVP_MD_size(const EVP_MD *md);
38 int EVP_MD_block_size(const EVP_MD *md);
40 const EVP_MD *EVP_MD_CTX_md(const EVP_MD_CTX *ctx);
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);
45 const EVP_MD *EVP_md_null(void);
46 const EVP_MD *EVP_md2(void);
47 const EVP_MD *EVP_md5(void);
48 const EVP_MD *EVP_sha1(void);
49 const EVP_MD *EVP_mdc2(void);
50 const EVP_MD *EVP_ripemd160(void);
51 const EVP_MD *EVP_blake2b_512(void);
52 const EVP_MD *EVP_blake2s_256(void);
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);
59 const EVP_MD *EVP_get_digestbyname(const char *name);
60 const EVP_MD *EVP_get_digestbynid(int type);
61 const EVP_MD *EVP_get_digestbyobj(const ASN1_OBJECT *o);
65 The EVP digest routines are a high level interface to message digests,
66 and should be used instead of the cipher-specific functions.
68 EVP_MD_CTX_new() allocates, initializes and returns a digest context.
70 EVP_MD_CTX_reset() resets the digest context B<ctx>. This can be used
71 to reuse an already existing context.
73 EVP_MD_CTX_free() cleans up digest context B<ctx> and frees up the
74 space allocated to it.
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
78 function. B<type> will typically be supplied by a function such as EVP_sha1().
79 If B<impl> is NULL then the default implementation of digest B<type> is used.
81 EVP_DigestUpdate() hashes B<cnt> bytes of data at B<d> into the
82 digest context B<ctx>. This function can be called several times on the
83 same B<ctx> to hash additional data.
85 EVP_DigestFinal_ex() retrieves the digest value from B<ctx> and places
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.
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
93 EVP_MD_CTX_copy_ex() can be used to copy the message digest state from
94 B<in> to B<out>. This is useful if large amounts of data are to be
95 hashed which only differ in the last few bytes. B<out> must be initialized
96 before calling this function.
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.
102 EVP_DigestFinal() is similar to EVP_DigestFinal_ex() except the digest
103 context B<ctx> is automatically cleaned up.
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.
108 EVP_MD_size() and EVP_MD_CTX_size() return the size of the message digest
109 when passed an B<EVP_MD> or an B<EVP_MD_CTX> structure, i.e. the size of the
112 EVP_MD_block_size() and EVP_MD_CTX_block_size() return the block size of the
113 message digest when passed an B<EVP_MD> or an B<EVP_MD_CTX> structure.
115 EVP_MD_type() and EVP_MD_CTX_type() return the NID of the OBJECT IDENTIFIER
116 representing the given message digest when passed an B<EVP_MD> structure.
117 For example EVP_MD_type(EVP_sha1()) returns B<NID_sha1>. This function is
118 normally used when setting ASN1 OIDs.
120 EVP_MD_CTX_md() returns the B<EVP_MD> structure corresponding to the passed
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
125 return B<NID_sha1WithRSAEncryption>. Since digests and signature algorithms
126 are no longer linked this function is only retained for compatibility
129 EVP_md2(), EVP_md5(), EVP_sha1(), EVP_sha224(), EVP_sha256(),
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.
135 EVP_md_null() is a "null" message digest that does nothing: i.e. the hash it
136 returns is of zero length.
138 EVP_get_digestbyname(), EVP_get_digestbynid() and EVP_get_digestbyobj()
139 return an B<EVP_MD> structure when passed a digest name, a digest NID or
140 an ASN1_OBJECT structure respectively.
144 EVP_DigestInit_ex(), EVP_DigestUpdate() and EVP_DigestFinal_ex() return 1 for
145 success and 0 for failure.
147 EVP_MD_CTX_copy_ex() returns 1 if successful or 0 for failure.
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.
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.
155 EVP_md_null(), EVP_md2(), EVP_md5(), EVP_sha1(),
156 EVP_mdc2(), EVP_ripemd160(), EVP_blake2b_512(), and EVP_blake2s_256() return
157 pointers to the corresponding EVP_MD structures.
159 EVP_get_digestbyname(), EVP_get_digestbynid() and EVP_get_digestbyobj()
160 return either an B<EVP_MD> structure or NULL if an error occurs.
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.
168 New applications should use the SHA2 digest algorithms such as SHA256.
169 The other digest algorithms are still in common use.
171 For most applications the B<impl> parameter to EVP_DigestInit_ex() will be
172 set to NULL to use the default digest implementation.
174 The functions EVP_DigestInit(), EVP_DigestFinal() and EVP_MD_CTX_copy() are
175 obsolete but are retained to maintain compatibility with existing code. New
176 applications should use EVP_DigestInit_ex(), EVP_DigestFinal_ex() and
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.
181 If digest contexts are not cleaned up after use
182 memory leaks will occur.
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
191 This example digests the data "Test Message\n" and "Hello World\n", using the
192 digest name passed on the command line.
195 #include <openssl/evp.h>
197 main(int argc, char *argv[])
201 char mess1[] = "Test Message\n";
202 char mess2[] = "Hello World\n";
203 unsigned char md_value[EVP_MAX_MD_SIZE];
207 printf("Usage: mdtest digestname\n");
211 md = EVP_get_digestbyname(argv[1]);
214 printf("Unknown message digest %s\n", argv[1]);
218 mdctx = EVP_MD_CTX_new();
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);
223 EVP_MD_CTX_free(mdctx);
225 printf("Digest is: ");
226 for (i = 0; i < md_len; i++)
227 printf("%02x", md_value[i]);
240 B<EVP_MD_CTX> became opaque in OpenSSL 1.1. Consequently, stack
241 allocated B<EVP_MD_CTX>s are no longer supported.
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.
246 The link between digests and signing algorithms was fixed in OpenSSL 1.0 and
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
252 Copyright 2000-2016 The OpenSSL Project Authors. All Rights Reserved.
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>.