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, EVP_MAX_MD_SIZE,
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, EVP_blake2s, 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 #define EVP_MAX_MD_SIZE 64 /* SHA512 */
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_update_fn(EVP_MD_CTX *ctx))(EVP_MD_CTX *ctx,
44 const void *data, size_t count);
45 void EVP_MD_CTX_set_update_fn(EVP_MD_CTX *ctx,
46 int (*update) (EVP_MD_CTX *ctx,
47 const void *data, size_t count));
48 int EVP_MD_CTX_size(const EVP_MD *ctx);
49 int EVP_MD_CTX_block_size(const EVP_MD *ctx);
50 int EVP_MD_CTX_type(const EVP_MD *ctx);
51 EVP_PKEY_CTX *EVP_MD_CTX_pkey_ctx(const EVP_MD_CTX *ctx);
52 void *EVP_MD_CTX_md_data(const EVP_MD_CTX *ctx);
54 const EVP_MD *EVP_md_null(void);
55 const EVP_MD *EVP_md2(void);
56 const EVP_MD *EVP_md5(void);
57 const EVP_MD *EVP_sha1(void);
58 const EVP_MD *EVP_mdc2(void);
59 const EVP_MD *EVP_ripemd160(void);
60 const EVP_MD *EVP_blake2b(void);
61 const EVP_MD *EVP_blake2s(void);
63 const EVP_MD *EVP_sha224(void);
64 const EVP_MD *EVP_sha256(void);
65 const EVP_MD *EVP_sha384(void);
66 const EVP_MD *EVP_sha512(void);
68 const EVP_MD *EVP_get_digestbyname(const char *name);
69 const EVP_MD *EVP_get_digestbynid(int type);
70 const EVP_MD *EVP_get_digestbyobj(const ASN1_OBJECT *o);
74 The EVP digest routines are a high level interface to message digests,
75 and should be used instead of the cipher-specific functions.
77 EVP_MD_CTX_new() allocates, initializes and returns a digest context.
79 EVP_MD_CTX_reset() resets the digest context B<ctx>. This can be used
80 to reuse an already existing context.
82 EVP_MD_CTX_free() cleans up digest context B<ctx> and frees up the
83 space allocated to it.
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_MD_CTX_copy_ex() can be used to copy the message digest state from
103 B<in> to B<out>. This is useful if large amounts of data are to be
104 hashed which only differ in the last few bytes. B<out> must be initialized
105 before calling this function.
107 EVP_DigestInit() behaves in the same way as EVP_DigestInit_ex() except
108 the passed context B<ctx> does not have to be initialized, and it always
109 uses the default digest implementation.
111 EVP_DigestFinal() is similar to EVP_DigestFinal_ex() except the digest
112 context B<ctx> is automatically cleaned up.
114 EVP_MD_CTX_copy() is similar to EVP_MD_CTX_copy_ex() except the destination
115 B<out> does not have to be initialized.
117 EVP_MD_size() and EVP_MD_CTX_size() return the size of the message digest
118 when passed an B<EVP_MD> or an B<EVP_MD_CTX> structure, i.e. the size of the
121 EVP_MD_block_size() and EVP_MD_CTX_block_size() return the block size of the
122 message digest when passed an B<EVP_MD> or an B<EVP_MD_CTX> structure.
124 EVP_MD_type() and EVP_MD_CTX_type() return the NID of the OBJECT IDENTIFIER
125 representing the given message digest when passed an B<EVP_MD> structure.
126 For example EVP_MD_type(EVP_sha1()) returns B<NID_sha1>. This function is
127 normally used when setting ASN1 OIDs.
129 EVP_MD_CTX_md() returns the B<EVP_MD> structure corresponding to the passed
132 EVP_MD_pkey_type() returns the NID of the public key signing algorithm associated
133 with this digest. For example EVP_sha1() is associated with RSA so this will
134 return B<NID_sha1WithRSAEncryption>. Since digests and signature algorithms
135 are no longer linked this function is only retained for compatibility
138 EVP_md2(), EVP_md5(), EVP_sha1(), EVP_sha224(), EVP_sha256(),
139 EVP_sha384(), EVP_sha512(), EVP_mdc2(), EVP_ripemd160(), EVP_blake2b, and
140 EVP_blake2s return B<EVP_MD> structures for the MD2, MD5, SHA1, SHA224, SHA256,
141 SHA384, SHA512, MDC2, RIPEMD160, BLAKE2b, and BLAKE2s digest algorithms
144 EVP_md_null() is a "null" message digest that does nothing: i.e. the hash it
145 returns is of zero length.
147 EVP_get_digestbyname(), EVP_get_digestbynid() and EVP_get_digestbyobj()
148 return an B<EVP_MD> structure when passed a digest name, a digest NID or
149 an ASN1_OBJECT structure respectively.
153 EVP_DigestInit_ex(), EVP_DigestUpdate() and EVP_DigestFinal_ex() return 1 for
154 success and 0 for failure.
156 EVP_MD_CTX_copy_ex() returns 1 if successful or 0 for failure.
158 EVP_MD_type(), EVP_MD_pkey_type() and EVP_MD_type() return the NID of the
159 corresponding OBJECT IDENTIFIER or NID_undef if none exists.
161 EVP_MD_size(), EVP_MD_block_size(), EVP_MD_CTX_size() and
162 EVP_MD_CTX_block_size() return the digest or block size in bytes.
164 EVP_md_null(), EVP_md2(), EVP_md5(), EVP_sha1(),
165 EVP_mdc2(), EVP_ripemd160(), EVP_blake2b(), and EVP_blake2s() return pointers
166 to the corresponding EVP_MD structures.
168 EVP_get_digestbyname(), EVP_get_digestbynid() and EVP_get_digestbyobj()
169 return either an B<EVP_MD> structure or NULL if an error occurs.
173 The B<EVP> interface to message digests should almost always be used in
174 preference to the low level interfaces. This is because the code then becomes
175 transparent to the digest used and much more flexible.
177 New applications should use the SHA2 digest algorithms such as SHA256.
178 The other digest algorithms are still in common use.
180 For most applications the B<impl> parameter to EVP_DigestInit_ex() will be
181 set to NULL to use the default digest implementation.
183 The functions EVP_DigestInit(), EVP_DigestFinal() and EVP_MD_CTX_copy() are
184 obsolete but are retained to maintain compatibility with existing code. New
185 applications should use EVP_DigestInit_ex(), EVP_DigestFinal_ex() and
186 EVP_MD_CTX_copy_ex() because they can efficiently reuse a digest context
187 instead of initializing and cleaning it up on each call and allow non default
188 implementations of digests to be specified.
190 If digest contexts are not cleaned up after use
191 memory leaks will occur.
193 EVP_MD_CTX_size(), EVP_MD_CTX_block_size(), EVP_MD_CTX_type(),
194 EVP_get_digestbynid() and EVP_get_digestbyobj() are defined as
200 This example digests the data "Test Message\n" and "Hello World\n", using the
201 digest name passed on the command line.
204 #include <openssl/evp.h>
206 main(int argc, char *argv[])
210 char mess1[] = "Test Message\n";
211 char mess2[] = "Hello World\n";
212 unsigned char md_value[EVP_MAX_MD_SIZE];
216 printf("Usage: mdtest digestname\n");
220 md = EVP_get_digestbyname(argv[1]);
223 printf("Unknown message digest %s\n", argv[1]);
227 mdctx = EVP_MD_CTX_new();
228 EVP_DigestInit_ex(mdctx, md, NULL);
229 EVP_DigestUpdate(mdctx, mess1, strlen(mess1));
230 EVP_DigestUpdate(mdctx, mess2, strlen(mess2));
231 EVP_DigestFinal_ex(mdctx, md_value, &md_len);
232 EVP_MD_CTX_free(mdctx);
234 printf("Digest is: ");
235 for(i = 0; i < md_len; i++)
236 printf("%02x", md_value[i]);
239 /* Call this once before exit. */
251 B<EVP_MD_CTX> became opaque in OpenSSL 1.1. Consequently, stack
252 allocated B<EVP_MD_CTX>s are no longer supported.
254 EVP_MD_CTX_create() and EVP_MD_CTX_destroy() were renamed to
255 EVP_MD_CTX_new() and EVP_MD_CTX_free() in OpenSSL 1.1.
257 The link between digests and signing algorithms was fixed in OpenSSL 1.0 and
258 later, so now EVP_sha1() can be used with RSA and DSA. The legacy EVP_dss1()
259 was removed in OpenSSL 1.1.0