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_DigestInit, EVP_DigestUpdate,
7 EVP_DigestFinal_ex, EVP_DigestFinalXOF, EVP_DigestFinal,
8 EVP_MD_CTX_copy, EVP_MD_type, EVP_MD_pkey_type, EVP_MD_size,
9 EVP_MD_block_size, EVP_MD_CTX_md, EVP_MD_CTX_size,
10 EVP_MD_CTX_block_size, EVP_MD_CTX_type, EVP_md_null, EVP_md2, EVP_md5, EVP_sha1,
11 EVP_sha224, EVP_sha256, EVP_sha384, EVP_sha512, EVP_sha3_224, EVP_sha3_256,
12 EVP_sha3_384, EVP_sha3_512, EVP_mdc2, EVP_ripemd160, EVP_blake2b512,
13 EVP_blake2s256, EVP_get_digestbyname, EVP_get_digestbynid,
14 EVP_get_digestbyobj - EVP digest routines
18 #include <openssl/evp.h>
20 EVP_MD_CTX *EVP_MD_CTX_new(void);
21 int EVP_MD_CTX_reset(EVP_MD_CTX *ctx);
22 void EVP_MD_CTX_free(EVP_MD_CTX *ctx);
23 void EVP_MD_CTX_ctrl(EVP_MD_CTX *ctx, int cmd, int p1, void* p2);
25 int EVP_DigestInit_ex(EVP_MD_CTX *ctx, const EVP_MD *type, ENGINE *impl);
26 int EVP_DigestUpdate(EVP_MD_CTX *ctx, const void *d, size_t cnt);
27 int EVP_DigestFinal_ex(EVP_MD_CTX *ctx, unsigned char *md, unsigned int *s);
28 int EVP_DigestFinalXOF(EVP_MD_CTX *ctx, unsigned char *md, size_t len);
30 int EVP_MD_CTX_copy_ex(EVP_MD_CTX *out, const EVP_MD_CTX *in);
32 int EVP_DigestInit(EVP_MD_CTX *ctx, const EVP_MD *type);
33 int EVP_DigestFinal(EVP_MD_CTX *ctx, unsigned char *md, unsigned int *s);
35 int EVP_MD_CTX_copy(EVP_MD_CTX *out, EVP_MD_CTX *in);
37 int EVP_MD_type(const EVP_MD *md);
38 int EVP_MD_pkey_type(const EVP_MD *md);
39 int EVP_MD_size(const EVP_MD *md);
40 int EVP_MD_block_size(const EVP_MD *md);
42 const EVP_MD *EVP_MD_CTX_md(const EVP_MD_CTX *ctx);
43 int EVP_MD_CTX_size(const EVP_MD *ctx);
44 int EVP_MD_CTX_block_size(const EVP_MD *ctx);
45 int EVP_MD_CTX_type(const EVP_MD *ctx);
47 const EVP_MD *EVP_md_null(void);
48 const EVP_MD *EVP_md2(void);
49 const EVP_MD *EVP_md5(void);
50 const EVP_MD *EVP_sha1(void);
51 const EVP_MD *EVP_mdc2(void);
52 const EVP_MD *EVP_ripemd160(void);
53 const EVP_MD *EVP_blake2b512(void);
54 const EVP_MD *EVP_blake2s256(void);
56 const EVP_MD *EVP_sha224(void);
57 const EVP_MD *EVP_sha256(void);
58 const EVP_MD *EVP_sha384(void);
59 const EVP_MD *EVP_sha512(void);
61 const EVP_MD *EVP_sha3_224(void);
62 const EVP_MD *EVP_sha3_256(void);
63 const EVP_MD *EVP_sha3_384(void);
64 const EVP_MD *EVP_sha3_512(void);
66 const EVP_MD *EVP_get_digestbyname(const char *name);
67 const EVP_MD *EVP_get_digestbynid(int type);
68 const EVP_MD *EVP_get_digestbyobj(const ASN1_OBJECT *o);
72 The EVP digest routines are a high level interface to message digests,
73 and should be used instead of the cipher-specific functions.
75 EVP_MD_CTX_new() allocates, initializes and returns a digest context.
77 EVP_MD_CTX_reset() resets the digest context B<ctx>. This can be used
78 to reuse an already existing context.
80 EVP_MD_CTX_free() cleans up digest context B<ctx> and frees up the
81 space allocated to it.
83 EVP_MD_CTX_ctrl() performs digest-specific control actions on context B<ctx>.
85 EVP_DigestInit_ex() sets up digest context B<ctx> to use a digest
86 B<type> from ENGINE B<impl>. B<ctx> must be initialized before calling this
87 function. B<type> will typically be supplied by a function such as EVP_sha1().
88 If B<impl> is NULL then the default implementation of digest B<type> is used.
90 EVP_DigestUpdate() hashes B<cnt> bytes of data at B<d> into the
91 digest context B<ctx>. This function can be called several times on the
92 same B<ctx> to hash additional data.
94 EVP_DigestFinal_ex() retrieves the digest value from B<ctx> and places
95 it in B<md>. If the B<s> parameter is not NULL then the number of
96 bytes of data written (i.e. the length of the digest) will be written
97 to the integer at B<s>, at most B<EVP_MAX_MD_SIZE> bytes will be written.
98 After calling EVP_DigestFinal_ex() no additional calls to EVP_DigestUpdate()
99 can be made, but EVP_DigestInit_ex() can be called to initialize a new
102 EVP_DigestFinalXOF() interfaces to extendable-output functions, XOFs,
103 such as SHAKE128 and SHAKE256. It retrieves the digest value from
104 B<ctx> and places it in B<len>-sized <B>md. After calling this function
105 no additional calls to EVP_DigestUpdate() can be made, but
106 EVP_DigestInit_ex() can be called to initialize a new operation.
108 EVP_MD_CTX_copy_ex() can be used to copy the message digest state from
109 B<in> to B<out>. This is useful if large amounts of data are to be
110 hashed which only differ in the last few bytes. B<out> must be initialized
111 before calling this function.
113 EVP_DigestInit() behaves in the same way as EVP_DigestInit_ex() except
114 the passed context B<ctx> does not have to be initialized, and it always
115 uses the default digest implementation.
117 EVP_DigestFinal() is similar to EVP_DigestFinal_ex() except the digest
118 context B<ctx> is automatically cleaned up.
120 EVP_MD_CTX_copy() is similar to EVP_MD_CTX_copy_ex() except the destination
121 B<out> does not have to be initialized.
123 EVP_MD_size() and EVP_MD_CTX_size() return the size of the message digest
124 when passed an B<EVP_MD> or an B<EVP_MD_CTX> structure, i.e. the size of the
127 EVP_MD_block_size() and EVP_MD_CTX_block_size() return the block size of the
128 message digest when passed an B<EVP_MD> or an B<EVP_MD_CTX> structure.
130 EVP_MD_type() and EVP_MD_CTX_type() return the NID of the OBJECT IDENTIFIER
131 representing the given message digest when passed an B<EVP_MD> structure.
132 For example EVP_MD_type(EVP_sha1()) returns B<NID_sha1>. This function is
133 normally used when setting ASN1 OIDs.
135 EVP_MD_CTX_md() returns the B<EVP_MD> structure corresponding to the passed
138 EVP_MD_pkey_type() returns the NID of the public key signing algorithm associated
139 with this digest. For example EVP_sha1() is associated with RSA so this will
140 return B<NID_sha1WithRSAEncryption>. Since digests and signature algorithms
141 are no longer linked this function is only retained for compatibility
144 EVP_md2(), EVP_md5(), EVP_sha1(), EVP_sha224(), EVP_sha256(),
145 EVP_sha384(), EVP_sha512(), EVP_sha3_224(), EVP_sha3_256(),
146 EVP_sha3_384(), EVP_sha3_512(), EVP_mdc2(), EVP_ripemd160(),
147 EVP_blake2b512(), and EVP_blake2s256() return B<EVP_MD> structures for
148 the MD2, MD5, SHA1, SHA224, SHA256, SHA384, SHA512, SHA3-224, SHA3-256,
149 SHA3-384, SHA3-512, MDC2, RIPEMD160, BLAKE2b-512, and BLAKE2s-256 digest
150 algorithms respectively.
152 EVP_md_null() is a "null" message digest that does nothing: i.e. the hash it
153 returns is of zero length.
155 EVP_get_digestbyname(), EVP_get_digestbynid() and EVP_get_digestbyobj()
156 return an B<EVP_MD> structure when passed a digest name, a digest NID or
157 an ASN1_OBJECT structure respectively.
161 EVP_DigestInit_ex(), EVP_DigestUpdate() and EVP_DigestFinal_ex() return 1 for
162 success and 0 for failure.
164 EVP_MD_CTX_ctrl() returns 1 if successful or 0 for failure.
166 EVP_MD_CTX_copy_ex() returns 1 if successful or 0 for failure.
168 EVP_MD_type(), EVP_MD_pkey_type() and EVP_MD_type() return the NID of the
169 corresponding OBJECT IDENTIFIER or NID_undef if none exists.
171 EVP_MD_size(), EVP_MD_block_size(), EVP_MD_CTX_size() and
172 EVP_MD_CTX_block_size() return the digest or block size in bytes.
174 EVP_md_null(), EVP_md2(), EVP_md5(), EVP_sha1(),
175 EVP_mdc2(), EVP_ripemd160(), EVP_blake2b512(), and EVP_blake2s256() return
176 pointers to the corresponding EVP_MD structures.
178 EVP_get_digestbyname(), EVP_get_digestbynid() and EVP_get_digestbyobj()
179 return either an B<EVP_MD> structure or NULL if an error occurs.
183 The B<EVP> interface to message digests should almost always be used in
184 preference to the low level interfaces. This is because the code then becomes
185 transparent to the digest used and much more flexible.
187 New applications should use the SHA2 digest algorithms such as SHA256.
188 The other digest algorithms are still in common use.
190 For most applications the B<impl> parameter to EVP_DigestInit_ex() will be
191 set to NULL to use the default digest implementation.
193 The functions EVP_DigestInit(), EVP_DigestFinal() and EVP_MD_CTX_copy() are
194 obsolete but are retained to maintain compatibility with existing code. New
195 applications should use EVP_DigestInit_ex(), EVP_DigestFinal_ex() and
196 EVP_MD_CTX_copy_ex() because they can efficiently reuse a digest context
197 instead of initializing and cleaning it up on each call and allow non default
198 implementations of digests to be specified.
200 If digest contexts are not cleaned up after use
201 memory leaks will occur.
203 EVP_MD_CTX_size(), EVP_MD_CTX_block_size(), EVP_MD_CTX_type(),
204 EVP_get_digestbynid() and EVP_get_digestbyobj() are defined as
207 EVP_MD_CTX_ctrl() sends commands to message digests for additional configuration
212 This example digests the data "Test Message\n" and "Hello World\n", using the
213 digest name passed on the command line.
216 #include <openssl/evp.h>
218 main(int argc, char *argv[])
222 char mess1[] = "Test Message\n";
223 char mess2[] = "Hello World\n";
224 unsigned char md_value[EVP_MAX_MD_SIZE];
227 if (argv[1] == NULL) {
228 printf("Usage: mdtest digestname\n");
232 md = EVP_get_digestbyname(argv[1]);
234 printf("Unknown message digest %s\n", argv[1]);
238 mdctx = EVP_MD_CTX_new();
239 EVP_DigestInit_ex(mdctx, md, NULL);
240 EVP_DigestUpdate(mdctx, mess1, strlen(mess1));
241 EVP_DigestUpdate(mdctx, mess2, strlen(mess2));
242 EVP_DigestFinal_ex(mdctx, md_value, &md_len);
243 EVP_MD_CTX_free(mdctx);
245 printf("Digest is: ");
246 for (i = 0; i < md_len; i++)
247 printf("%02x", md_value[i]);
260 EVP_MD_CTX_create() and EVP_MD_CTX_destroy() were renamed to
261 EVP_MD_CTX_new() and EVP_MD_CTX_free() in OpenSSL 1.1.0.
263 The link between digests and signing algorithms was fixed in OpenSSL 1.0 and
264 later, so now EVP_sha1() can be used with RSA and DSA.
266 EVP_dss1() was removed in OpenSSL 1.1.0
270 Copyright 2000-2016 The OpenSSL Project Authors. All Rights Reserved.
272 Licensed under the OpenSSL license (the "License"). You may not use
273 this file except in compliance with the License. You can obtain a copy
274 in the file LICENSE in the source distribution or at
275 L<https://www.openssl.org/source/license.html>.