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Diffstat (limited to 'doc/crypto/EVP_DigestInit.pod')
| -rw-r--r-- | doc/crypto/EVP_DigestInit.pod | 202 |
1 files changed, 0 insertions, 202 deletions
diff --git a/doc/crypto/EVP_DigestInit.pod b/doc/crypto/EVP_DigestInit.pod deleted file mode 100644 index b8a231c642d..00000000000 --- a/doc/crypto/EVP_DigestInit.pod +++ /dev/null @@ -1,202 +0,0 @@ -=pod - -=head1 NAME - -EVP_DigestInit, EVP_DigestUpdate, EVP_DigestFinal, EVP_MAX_MD_SIZE, -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 - -=head1 SYNOPSIS - - #include <openssl/evp.h> - - void EVP_DigestInit(EVP_MD_CTX *ctx, const EVP_MD *type); - void EVP_DigestUpdate(EVP_MD_CTX *ctx, const void *d, unsigned int cnt); - void EVP_DigestFinal(EVP_MD_CTX *ctx, unsigned char *md, - unsigned int *s); - - #define EVP_MAX_MD_SIZE (16+20) /* The SSLv3 md5+sha1 type */ - - int EVP_MD_CTX_copy(EVP_MD_CTX *out,EVP_MD_CTX *in); - - #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) - - EVP_MD *EVP_md_null(void); - EVP_MD *EVP_md2(void); - EVP_MD *EVP_md5(void); - EVP_MD *EVP_sha(void); - EVP_MD *EVP_sha1(void); - EVP_MD *EVP_dss(void); - EVP_MD *EVP_dss1(void); - EVP_MD *EVP_mdc2(void); - 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)) - -=head1 DESCRIPTION - -The EVP digest routines are a high level interface to message digests. - -EVP_DigestInit() initializes a digest context B<ctx> to use a digest -B<type>: this will typically be supplied by a function such as -EVP_sha1(). - -EVP_DigestUpdate() hashes B<cnt> bytes of data at B<d> into the -digest context B<ctx>. This function can be called several times on the -same B<ctx> to hash additional data. - -EVP_DigestFinal() retrieves the digest value from B<ctx> and places -it in B<md>. If the B<s> 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 B<s>, at most B<EVP_MAX_MD_SIZE> bytes will be written. -After calling EVP_DigestFinal() no additional calls to EVP_DigestUpdate() -can be made, but EVP_DigestInit() can be called to initialize a new -digest operation. - -EVP_MD_CTX_copy() can be used to copy the message digest state from -B<in> to B<out>. This is useful if large amounts of data are to be -hashed which only differ in the last few bytes. - -EVP_MD_size() and EVP_MD_CTX_size() return the size of the message digest -when passed an B<EVP_MD> or an B<EVP_MD_CTX> 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 B<EVP_MD> or an B<EVP_MD_CTX> structure. - -EVP_MD_type() and EVP_MD_CTX_type() return the NID of the OBJECT IDENTIFIER -representing the given message digest when passed an B<EVP_MD> structure. -For example EVP_MD_type(EVP_sha1()) returns B<NID_sha1>. This function is -normally used when setting ASN1 OIDs. - -EVP_MD_CTX_md() returns the B<EVP_MD> structure corresponding to the passed -B<EVP_MD_CTX>. - -EVP_MD_pkey_type() returns the NID of the public key signing algorithm associated -with this digest. For example EVP_sha1() is associated with RSA so this will -return B<NID_sha1WithRSAEncryption>. 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 B<EVP_MD> 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 B<EVP_MD> 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. - -EVP_get_digestbyname(), EVP_get_digestbynid() and EVP_get_digestbyobj() -return an B<EVP_MD> 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. - -=head1 RETURN VALUES - -EVP_DigestInit(), EVP_DigestUpdate() and EVP_DigestFinal() do not return values. - -EVP_MD_CTX_copy() 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 B<EVP_MD> structure or NULL if an error occurs. - -=head1 NOTES - -The B<EVP> 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. - -=head1 EXAMPLE - -This example digests the data "Test Message\n" and "Hello World\n", using the -digest name passed on the command line. - - #include <stdio.h> - #include <openssl/evp.h> - - 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_DigestInit(&mdctx, md); - EVP_DigestUpdate(&mdctx, mess1, strlen(mess1)); - EVP_DigestUpdate(&mdctx, mess2, strlen(mess2)); - EVP_DigestFinal(&mdctx, md_value, &md_len); - - printf("Digest is: "); - for(i = 0; i < md_len; i++) printf("%02x", md_value[i]); - printf("\n"); - } - -=head1 BUGS - -Several of the functions do not return values: maybe they should. Although the -internal digest operations will never fail some future hardware based operations -might. - -The link between digests and signing algorithms results in a situation where -EVP_sha1() must be used with RSA and EVP_dss1() must be used with DSS -even though they are identical digests. - -The size of an B<EVP_MD_CTX> structure is determined at compile time: this results -in code that must be recompiled if the size of B<EVP_MD_CTX> increases. - -=head1 SEE ALSO - -L<evp(3)|evp(3)>, L<hmac(3)|hmac(3)>, L<md2(3)|md2(3)>, -L<md5(3)|md5(3)>, L<mdc2(3)|mdc2(3)>, L<ripemd(3)|ripemd(3)>, -L<sha(3)|sha(3)>, L<digest(1)|digest(1)> - -=head1 HISTORY - -EVP_DigestInit(), EVP_DigestUpdate() and EVP_DigestFinal() are -available in all versions of SSLeay and OpenSSL. - -=cut |