5 EVP_MD_CTX_init, EVP_MD_CTX_create, EVP_DigestInit_ex, EVP_DigestUpdate,
6 EVP_DigestFinal_ex, EVP_MD_CTX_cleanup, EVP_MD_CTX_destroy, EVP_MAX_MD_SIZE,
7 EVP_MD_CTX_copy_ex, 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_dss1, EVP_mdc2,
11 EVP_ripemd160, EVP_get_digestbyname, EVP_get_digestbynid, EVP_get_digestbyobj -
16 #include <openssl/evp.h>
18 void EVP_MD_CTX_init(EVP_MD_CTX *ctx);
19 EVP_MD_CTX *EVP_MD_CTX_create(void);
21 int EVP_DigestInit_ex(EVP_MD_CTX *ctx, const EVP_MD *type, ENGINE *impl);
22 int EVP_DigestUpdate(EVP_MD_CTX *ctx, const void *d, size_t cnt);
23 int EVP_DigestFinal_ex(EVP_MD_CTX *ctx, unsigned char *md,
26 int EVP_MD_CTX_cleanup(EVP_MD_CTX *ctx);
27 void EVP_MD_CTX_destroy(EVP_MD_CTX *ctx);
29 int EVP_MD_CTX_copy_ex(EVP_MD_CTX *out,const EVP_MD_CTX *in);
31 int EVP_DigestInit(EVP_MD_CTX *ctx, const EVP_MD *type);
32 int EVP_DigestFinal(EVP_MD_CTX *ctx, unsigned char *md,
35 int EVP_MD_CTX_copy(EVP_MD_CTX *out,EVP_MD_CTX *in);
37 #define EVP_MAX_MD_SIZE 64 /* SHA512 */
39 int EVP_MD_type(const EVP_MD *md);
40 int EVP_MD_pkey_type(const EVP_MD *md);
41 int EVP_MD_size(const EVP_MD *md);
42 int EVP_MD_block_size(const EVP_MD *md);
44 const EVP_MD *EVP_MD_CTX_md(const EVP_MD_CTX *ctx);
45 #define EVP_MD_CTX_size(e) EVP_MD_size(EVP_MD_CTX_md(e))
46 #define EVP_MD_CTX_block_size(e) EVP_MD_block_size((e)->digest)
47 #define EVP_MD_CTX_type(e) EVP_MD_type((e)->digest)
49 const EVP_MD *EVP_md_null(void);
50 const EVP_MD *EVP_md2(void);
51 const EVP_MD *EVP_md5(void);
52 const EVP_MD *EVP_sha1(void);
53 const EVP_MD *EVP_dss1(void);
54 const EVP_MD *EVP_mdc2(void);
55 const EVP_MD *EVP_ripemd160(void);
57 const EVP_MD *EVP_sha224(void);
58 const EVP_MD *EVP_sha256(void);
59 const EVP_MD *EVP_sha384(void);
60 const EVP_MD *EVP_sha512(void);
62 const EVP_MD *EVP_get_digestbyname(const char *name);
63 #define EVP_get_digestbynid(a) EVP_get_digestbyname(OBJ_nid2sn(a))
64 #define EVP_get_digestbyobj(a) EVP_get_digestbynid(OBJ_obj2nid(a))
68 The EVP digest routines are a high level interface to message digests,
69 and should be used instead of the cipher-specific functions.
71 EVP_MD_CTX_init() initializes digest context B<ctx>.
73 EVP_MD_CTX_create() allocates, initializes and returns a digest context.
75 EVP_DigestInit_ex() sets up digest context B<ctx> to use a digest
76 B<type> from ENGINE B<impl>. B<ctx> must be initialized before calling this
77 function. B<type> will typically be supplied by a function such as EVP_sha1().
78 If B<impl> is NULL then the default implementation of digest B<type> is used.
80 EVP_DigestUpdate() hashes B<cnt> bytes of data at B<d> into the
81 digest context B<ctx>. This function can be called several times on the
82 same B<ctx> to hash additional data.
84 EVP_DigestFinal_ex() retrieves the digest value from B<ctx> and places
85 it in B<md>. If the B<s> parameter is not NULL then the number of
86 bytes of data written (i.e. the length of the digest) will be written
87 to the integer at B<s>, at most B<EVP_MAX_MD_SIZE> bytes will be written.
88 After calling EVP_DigestFinal_ex() no additional calls to EVP_DigestUpdate()
89 can be made, but EVP_DigestInit_ex() can be called to initialize a new
92 EVP_MD_CTX_cleanup() cleans up digest context B<ctx>, it should be called
93 after a digest context is no longer needed.
95 EVP_MD_CTX_destroy() cleans up digest context B<ctx> and frees up the
96 space allocated to it, it should be called only on a context created
97 using EVP_MD_CTX_create().
99 EVP_MD_CTX_copy_ex() can be used to copy the message digest state from
100 B<in> to B<out>. This is useful if large amounts of data are to be
101 hashed which only differ in the last few bytes. B<out> must be initialized
102 before calling this function.
104 EVP_DigestInit() behaves in the same way as EVP_DigestInit_ex() except
105 the passed context B<ctx> does not have to be initialized, and it always
106 uses the default digest implementation.
108 EVP_DigestFinal() is similar to EVP_DigestFinal_ex() except the digest
109 context B<ctx> is automatically cleaned up.
111 EVP_MD_CTX_copy() is similar to EVP_MD_CTX_copy_ex() except the destination
112 B<out> does not have to be initialized.
114 EVP_MD_size() and EVP_MD_CTX_size() return the size of the message digest
115 when passed an B<EVP_MD> or an B<EVP_MD_CTX> structure, i.e. the size of the
118 EVP_MD_block_size() and EVP_MD_CTX_block_size() return the block size of the
119 message digest when passed an B<EVP_MD> or an B<EVP_MD_CTX> structure.
121 EVP_MD_type() and EVP_MD_CTX_type() return the NID of the OBJECT IDENTIFIER
122 representing the given message digest when passed an B<EVP_MD> structure.
123 For example EVP_MD_type(EVP_sha1()) returns B<NID_sha1>. This function is
124 normally used when setting ASN1 OIDs.
126 EVP_MD_CTX_md() returns the B<EVP_MD> structure corresponding to the passed
129 EVP_MD_pkey_type() returns the NID of the public key signing algorithm associated
130 with this digest. For example EVP_sha1() is associated with RSA so this will
131 return B<NID_sha1WithRSAEncryption>. Since digests and signature algorithms
132 are no longer linked this function is only retained for compatibility
135 EVP_md2(), EVP_md5(), EVP_sha1(), EVP_sha224(), EVP_sha256(),
136 EVP_sha384(), EVP_sha512(), EVP_mdc2() and EVP_ripemd160() return B<EVP_MD>
137 structures for the MD2, MD5, SHA1, SHA224, SHA256, SHA384, SHA512, MDC2
138 and RIPEMD160 digest algorithms respectively.
140 EVP_dss1() returns B<EVP_MD> an structure the SHA1 digest
141 algorithm but using DSS (DSA) for the signature algorithm. Note: there is
142 no need to use these pseudo-digests in OpenSSL 1.0.0 and later, they are
143 however retained for compatibility.
145 EVP_md_null() is a "null" message digest that does nothing: i.e. the hash it
146 returns is of zero length.
148 EVP_get_digestbyname(), EVP_get_digestbynid() and EVP_get_digestbyobj()
149 return an B<EVP_MD> structure when passed a digest name, a digest NID or
150 an ASN1_OBJECT structure respectively. The digest table must be initialized
151 using, for example, OpenSSL_add_all_digests() for these functions to work.
155 EVP_DigestInit_ex(), EVP_DigestUpdate() and EVP_DigestFinal_ex() return 1 for
156 success and 0 for failure.
158 EVP_MD_CTX_copy_ex() returns 1 if successful or 0 for failure.
160 EVP_MD_type(), EVP_MD_pkey_type() and EVP_MD_type() return the NID of the
161 corresponding OBJECT IDENTIFIER or NID_undef if none exists.
163 EVP_MD_size(), EVP_MD_block_size(), EVP_MD_CTX_size() and
164 EVP_MD_CTX_block_size() return the digest or block size in bytes.
166 EVP_md_null(), EVP_md2(), EVP_md5(), EVP_sha1(),
167 EVP_dss1(), EVP_mdc2() and EVP_ripemd160() return pointers to the
168 corresponding EVP_MD structures.
170 EVP_get_digestbyname(), EVP_get_digestbynid() and EVP_get_digestbyobj()
171 return either an B<EVP_MD> structure or NULL if an error occurs.
175 The B<EVP> interface to message digests should almost always be used in
176 preference to the low level interfaces. This is because the code then becomes
177 transparent to the digest used and much more flexible.
179 New applications should use the SHA2 digest algorithms such as SHA256.
180 The other digest algorithms are still in common use.
182 For most applications the B<impl> parameter to EVP_DigestInit_ex() will be
183 set to NULL to use the default digest implementation.
185 The functions EVP_DigestInit(), EVP_DigestFinal() and EVP_MD_CTX_copy() are
186 obsolete but are retained to maintain compatibility with existing code. New
187 applications should use EVP_DigestInit_ex(), EVP_DigestFinal_ex() and
188 EVP_MD_CTX_copy_ex() because they can efficiently reuse a digest context
189 instead of initializing and cleaning it up on each call and allow non default
190 implementations of digests to be specified.
192 In OpenSSL 0.9.7 and later if digest contexts are not cleaned up after use
193 memory leaks will occur.
195 Stack allocation of EVP_MD_CTX structures is common, for example:
198 EVP_MD_CTX_init(&mctx);
200 This will cause binary compatibility issues if the size of EVP_MD_CTX
201 structure changes (this will only happen with a major release of OpenSSL).
202 Applications wishing to avoid this should use EVP_MD_CTX_create() instead:
205 mctx = EVP_MD_CTX_create();
210 This example digests the data "Test Message\n" and "Hello World\n", using the
211 digest name passed on the command line.
214 #include <openssl/evp.h>
216 main(int argc, char *argv[])
220 char mess1[] = "Test Message\n";
221 char mess2[] = "Hello World\n";
222 unsigned char md_value[EVP_MAX_MD_SIZE];
225 OpenSSL_add_all_digests();
228 printf("Usage: mdtest digestname\n");
232 md = EVP_get_digestbyname(argv[1]);
235 printf("Unknown message digest %s\n", argv[1]);
239 mdctx = EVP_MD_CTX_create();
240 EVP_DigestInit_ex(mdctx, md, NULL);
241 EVP_DigestUpdate(mdctx, mess1, strlen(mess1));
242 EVP_DigestUpdate(mdctx, mess2, strlen(mess2));
243 EVP_DigestFinal_ex(mdctx, md_value, &md_len);
244 EVP_MD_CTX_destroy(mdctx);
246 printf("Digest is: ");
247 for(i = 0; i < md_len; i++)
248 printf("%02x", md_value[i]);
251 /* Call this once before exit. */
263 EVP_DigestInit(), EVP_DigestUpdate() and EVP_DigestFinal() are
264 available in all versions of SSLeay and OpenSSL.
266 EVP_MD_CTX_init(), EVP_MD_CTX_create(), EVP_MD_CTX_copy_ex(),
267 EVP_MD_CTX_cleanup(), EVP_MD_CTX_destroy(), EVP_DigestInit_ex()
268 and EVP_DigestFinal_ex() were added in OpenSSL 0.9.7.
270 EVP_md_null(), EVP_md2(), EVP_md5(), EVP_sha1(),
271 EVP_dss1(), EVP_mdc2() and EVP_ripemd160() were
272 changed to return truly const EVP_MD * in OpenSSL 0.9.7.
274 The link between digests and signing algorithms was fixed in OpenSSL 1.0 and
275 later, so now EVP_sha1() can be used with RSA and DSA; there is no need to
276 use EVP_dss1() any more.
278 OpenSSL 1.0 and later does not include the MD2 digest algorithm in the
279 default configuration due to its security weaknesses.