OpenSSL EVP_DigestInit(3openssl)
NNNNAAAAMMMMEEEEEVP_MD_CTX_init, EVP_MD_CTX_create, EVP_DigestInit_ex,
EVP_DigestUpdate, EVP_DigestFinal_ex, EVP_MD_CTX_cleanup,
EVP_MD_CTX_destroy, EVP_MAX_MD_SIZE, EVP_MD_CTX_copy_ex,
EVP_MD_CTX_copy, EVP_MD_type, EVP_MD_pkey_type, EVP_MD_size,
EVP_MD_block_size, EVP_MD_CTX_md, EVP_MD_CTX_size,
EVP_MD_CTX_block_size, EVP_MD_CTX_type, EVP_md_null,
EVP_md2, EVP_md5, EVP_sha, EVP_sha1, EVP_dss, EVP_dss1,
EVP_mdc2, EVP_ripemd160, EVP_get_digestbyname,
EVP_get_digestbynid, EVP_get_digestbyobj - EVP digest
routines SSSSYYYYNNNNOOOOPPPPSSSSIIIISSSS#include
void EVP_MD_CTX_init(EVP_MD_CTX *ctx);
EVP_MD_CTX *EVP_MD_CTX_create(void);
int EVP_DigestInit_ex(EVP_MD_CTX *ctx, const EVP_MD *type, ENGINE *impl);
int EVP_DigestUpdate(EVP_MD_CTX *ctx, const void *d, size_t cnt);
int EVP_DigestFinal_ex(EVP_MD_CTX *ctx, unsigned char *md,
unsigned int *s);int EVP_MD_CTX_cleanup(EVP_MD_CTX *ctx);
void EVP_MD_CTX_destroy(EVP_MD_CTX *ctx);
int EVP_MD_CTX_copy_ex(EVP_MD_CTX *out,const EVP_MD_CTX *in);
int EVP_DigestInit(EVP_MD_CTX *ctx, const EVP_MD *type);
int EVP_DigestFinal(EVP_MD_CTX *ctx, unsigned char *md,
unsigned int *s);int EVP_MD_CTX_copy(EVP_MD_CTX *out,EVP_MD_CTX *in);
#define EVP_MAX_MD_SIZE (16+20) /* The SSLv3 md5+sha1 type */
#define EVP_MD_type(e) ((e)->type)
#define EVP_MD_pkey_type(e) ((e)->pkey_type)
#define EVP_MD_size(e) ((e)->md_size)
#define EVP_MD_block_size(e) ((e)->block_size)
#define EVP_MD_CTX_md(e) (e)->digest)
#define EVP_MD_CTX_size(e) EVP_MD_size((e)->digest)
#define EVP_MD_CTX_block_size(e) EVP_MD_block_size((e)->digest)
#define EVP_MD_CTX_type(e) EVP_MD_type((e)->digest)
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OpenSSL EVP_DigestInit(3openssl)
const EVP_MD *EVP_md_null(void);
const EVP_MD *EVP_md2(void);
const EVP_MD *EVP_md5(void);
const EVP_MD *EVP_sha(void);
const EVP_MD *EVP_sha1(void);
const EVP_MD *EVP_dss(void);
const EVP_MD *EVP_dss1(void);
const EVP_MD *EVP_mdc2(void);
const EVP_MD *EVP_ripemd160(void);
const EVP_MD *EVP_get_digestbyname(const char *name);
#define EVP_get_digestbynid(a) EVP_get_digestbyname(OBJ_nid2sn(a))
#define EVP_get_digestbyobj(a) EVP_get_digestbynid(OBJ_obj2nid(a))
DDDDEEEESSSSCCCCRRRRIIIIPPPPTTTTIIIIOOOONNNN The EVP digest routines are a high level interface to message digests.EVP_MD_CTX_init() initializes digest context ccccttttxxxx.
EVP_MD_CTX_create() allocates, initializes and returns a
digest context.EVP_DigestInit_ex() sets up digest context ccccttttxxxx to use a
digest ttttyyyyppppeeee from ENGINE iiiimmmmppppllll. ccccttttxxxx must be initialized before calling this function. ttttyyyyppppeeee will typically be supplied by afunctionsuch as EVP_sha1(). If iiiimmmmppppllll is NULL then the
default implementation of digest ttttyyyyppppeeee is used.EVP_DigestUpdate() hashes ccccnnnntttt bytes of data at dddd into the
digest context ccccttttxxxx. This function can be called several times on the same ccccttttxxxx to hash additional data.EVP_DigestFinal_ex() retrieves the digest value from ccccttttxxxx and
places it in mmmmdddd. If the ssss parameter is not NULL then the number of bytes of data written (i.e. the length of the digest) will be written to the integer at ssss, at mostEEEEVVVVPPPP_MMMMAAAAXXXX_MMMMDDDD_SSSSIIIIZZZZEEEE bytes will be written. After calling
EVP_DigestFinal_ex() no additional calls to
EVP_DigestUpdate() can be made, but EVP_DigestInit_ex() can
be called to initialize a new digest operation.EVP_MD_CTX_cleanup() cleans up digest context ccccttttxxxx, it should
be called after a digest context is no longer needed.EVP_MD_CTX_destroy() cleans up digest context ccccttttxxxx and frees
up the space allocated to it, it should be called only on acontext created using EVP_MD_CTX_create().
EVP_MD_CTX_copy_ex() can be used to copy the message digest
state from iiiinnnn to oooouuuutttt. This is useful if large amounts of16/Oct/2009 Last change: 0.9.8o 2
OpenSSL EVP_DigestInit(3openssl)
data are to be hashed which only differ in the last few bytes. oooouuuutttt must be initialized before calling this function.EVP_DigestInit() behaves in the same way as
EVP_DigestInit_ex() except the passed context ccccttttxxxx does not
have to be initialized, and it always uses the default digest implementation.EVP_DigestFinal() is similar to EVP_DigestFinal_ex() except
the digest context ccccttttxxxx is automatically cleaned up.EVP_MD_CTX_copy() is similar to EVP_MD_CTX_copy_ex() except
the destination oooouuuutttt does not have to be initialized.EVP_MD_size() and EVP_MD_CTX_size() return the size of the
message digest when passed an EEEEVVVVPPPP_MMMMDDDD or an EEEEVVVVPPPP_MMMMDDDD_CCCCTTTTXXXX
structure, i.e. the size of the hash.EVP_MD_block_size() and EVP_MD_CTX_block_size() return the
block size of the message digest when passed an EEEEVVVVPPPP_MMMMDDDD or an
EEEEVVVVPPPP_MMMMDDDD_CCCCTTTTXXXX structure.
EVP_MD_type() and EVP_MD_CTX_type() return the NID of the
OBJECT IDENTIFIER representing the given message digest whenpassed an EEEEVVVVPPPP_MMMMDDDD structure. For example
EVP_MD_type(EVP_sha1()) returns NNNNIIIIDDDD_sssshhhhaaaa1111. This function is
normally used when setting ASN1 OIDs.EVP_MD_CTX_md() returns the EEEEVVVVPPPP_MMMMDDDD structure corresponding
to the passed EEEEVVVVPPPP_MMMMDDDD_CCCCTTTTXXXX.
EVP_MD_pkey_type() returns the NID of the public key signing
algorithm associated with this digest. For exampleEVP_sha1() is associated with RSA so this will return
NNNNIIIIDDDD_sssshhhhaaaa1111WWWWiiiitttthhhhRRRRSSSSAAAAEEEEnnnnccccrrrryyyyppppttttiiiioooonnnn. This "link" between digests and
signature algorithms may not be retained in future versions of OpenSSL.EVP_md2(), EVP_md5(), EVP_sha(), EVP_sha1(), EVP_mdc2() and
EVP_ripemd160() return EEEEVVVVPPPP_MMMMDDDD structures for the MD2, MD5,
SHA, SHA1, MDC2 and RIPEMD160 digest algorithms respectively. The associated signature algorithm is RSA in each case.EVP_dss() and EVP_dss1() return EEEEVVVVPPPP_MMMMDDDD structures for SHA
and SHA1 digest algorithms but using DSS (DSA) for the signature algorithm.EVP_md_null() is a "null" message digest that does nothing:
i.e. the hash it returns is of zero length.16/Oct/2009 Last change: 0.9.8o 3
OpenSSL EVP_DigestInit(3openssl)
EVP_get_digestbyname(), EVP_get_digestbynid() and
EVP_get_digestbyobj() return an EEEEVVVVPPPP_MMMMDDDD structure when passed
a digest name, a digest NID or an ASN1_OBJECT structure
respectively. The digest table must be initialized using,for example, OpenSSL_add_all_digests() for these functions
to work. RRRREEEETTTTUUUURRRRNNNN VVVVAAAALLLLUUUUEEEESSSSEVP_DigestInit_ex(), EVP_DigestUpdate() and
EVP_DigestFinal_ex() return 1 for success and 0 for failure.
EVP_MD_CTX_copy_ex() returns 1 if successful or 0 for
failure.EVP_MD_type(), EVP_MD_pkey_type() and EVP_MD_type() return
the NID of the corresponding OBJECT IDENTIFIER or NID_undef
if none exists.EVP_MD_size(), EVP_MD_block_size(), EVP_MD_CTX_size(e),
EVP_MD_size(), EVP_MD_CTX_block_size() and
EVP_MD_block_size() return the digest or block size in
bytes.EVP_md_null(), EVP_md2(), EVP_md5(), EVP_sha(), EVP_sha1(),
EVP_dss(), EVP_dss1(), EVP_mdc2() and EVP_ripemd160() return
pointers to the corresponding EVP_MD structures.
EVP_get_digestbyname(), EVP_get_digestbynid() and
EVP_get_digestbyobj() return either an EEEEVVVVPPPP_MMMMDDDD structure or
NULL if an error occurs. NNNNOOOOTTTTEEEESSSS The EEEEVVVVPPPP interface to message digests should almost always be used in preference to the low level interfaces. This is because the code then becomes transparent to the digest used and much more flexible. SHA1 is the digest of choice for new applications. The other digest algorithms are still in common use. For most applications the iiiimmmmppppllll parameter toEVP_DigestInit_ex() will be set to NULL to use the default
digest implementation.The functions EVP_DigestInit(), EVP_DigestFinal() and
EVP_MD_CTX_copy() are obsolete but are retained to maintain
compatibility with existing code. New applications shoulduse EVP_DigestInit_ex(), EVP_DigestFinal_ex() and
EVP_MD_CTX_copy_ex() because they can efficiently reuse a
digest context instead of initializing and cleaning it up on each call and allow non default implementations of digests to be specified.16/Oct/2009 Last change: 0.9.8o 4
OpenSSL EVP_DigestInit(3openssl)
In OpenSSL 0.9.7 and later if digest contexts are not cleaned up after use memory leaks will occur. EEEEXXXXAAAAMMMMPPPPLLLLEEEE This example digests the data "Test Message\n" and "Hello World\n", using the digest name passed on the command line.#include
#include
main(int argc, char *argv[]) {EVP_MD_CTX mdctx;
const EVP_MD *md;
char mess1[] = "Test Message\n"; char mess2[] = "Hello World\n";unsigned char md_value[EVP_MAX_MD_SIZE];
int md_len, i;
OpenSSL_add_all_digests();
if(!argv[1]) { printf("Usage: mdtest digestname\n"); exit(1); }md = EVP_get_digestbyname(argv[1]);
if(!md) {printf("Unknown message digest %s\n", argv[1]);
exit(1); }EVP_MD_CTX_init(&mdctx);
EVP_DigestInit_ex(&mdctx, md, NULL);
EVP_DigestUpdate(&mdctx, mess1, strlen(mess1));
EVP_DigestUpdate(&mdctx, mess2, strlen(mess2));
EVP_DigestFinal_ex(&mdctx, md_value, &md_len);
EVP_MD_CTX_cleanup(&mdctx);
printf("Digest is: ");for(i = 0; i < md_len; i++) printf("%02x", md_value[i]);
printf("\n"); } BBBBUUUUGGGGSSSS The link between digests and signing algorithms results in asituation where EVP_sha1() must be used with RSA and
EVP_dss1() must be used with DSS even though they are
identical digests.16/Oct/2009 Last change: 0.9.8o 5
OpenSSL EVP_DigestInit(3openssl)
SSSSEEEEEEEE AAAALLLLSSSSOOOO evp(3), hmac(3), md2(3), md5(3), mdc2(3), ripemd(3), sha(3), dgst(1) HHHHIIIISSSSTTTTOOOORRRRYYYYEVP_DigestInit(), EVP_DigestUpdate() and EVP_DigestFinal()
are available in all versions of SSLeay and OpenSSL.EVP_MD_CTX_init(), EVP_MD_CTX_create(),
EVP_MD_CTX_copy_ex(), EVP_MD_CTX_cleanup(),
EVP_MD_CTX_destroy(), EVP_DigestInit_ex() and
EVP_DigestFinal_ex() were added in OpenSSL 0.9.7.
EVP_md_null(), EVP_md2(), EVP_md5(), EVP_sha(), EVP_sha1(),
EVP_dss(), EVP_dss1(), EVP_mdc2() and EVP_ripemd160() were
changed to return truely const EVP_MD * in OpenSSL 0.9.7.
16/Oct/2009 Last change: 0.9.8o 6