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Diffstat (limited to 'secure/lib/libcrypto/man/EVP_DigestInit.3')
| -rw-r--r-- | secure/lib/libcrypto/man/EVP_DigestInit.3 | 349 |
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diff --git a/secure/lib/libcrypto/man/EVP_DigestInit.3 b/secure/lib/libcrypto/man/EVP_DigestInit.3 new file mode 100644 index 0000000..ee9f78b --- /dev/null +++ b/secure/lib/libcrypto/man/EVP_DigestInit.3 @@ -0,0 +1,349 @@ +.\" Automatically generated by Pod::Man version 1.15 +.\" Thu May 9 13:17:47 2002 +.\" +.\" Standard preamble: +.\" ====================================================================== +.de Sh \" Subsection heading +.br +.if t .Sp +.ne 5 +.PP +\fB\\$1\fR +.PP +.. +.de Sp \" Vertical space (when we can't use .PP) +.if t .sp .5v +.if n .sp +.. +.de Ip \" List item +.br +.ie \\n(.$>=3 .ne \\$3 +.el .ne 3 +.IP "\\$1" \\$2 +.. +.de Vb \" Begin verbatim text +.ft CW +.nf +.ne \\$1 +.. +.de Ve \" End verbatim text +.ft R + +.fi +.. +.\" Set up some character translations and predefined strings. \*(-- will +.\" give an unbreakable dash, \*(PI will give pi, \*(L" will give a left +.\" double quote, and \*(R" will give a right double quote. | will give a +.\" real vertical bar. \*(C+ will give a nicer C++. Capital omega is used +.\" to do unbreakable dashes and therefore won't be available. \*(C` and +.\" \*(C' expand to `' in nroff, nothing in troff, for use with C<> +.tr \(*W-|\(bv\*(Tr +.ds C+ C\v'-.1v'\h'-1p'\s-2+\h'-1p'+\s0\v'.1v'\h'-1p' +.ie n \{\ +. ds -- \(*W- +. ds PI pi +. if (\n(.H=4u)&(1m=24u) .ds -- \(*W\h'-12u'\(*W\h'-12u'-\" diablo 10 pitch +. if (\n(.H=4u)&(1m=20u) .ds -- \(*W\h'-12u'\(*W\h'-8u'-\" diablo 12 pitch +. ds L" "" +. ds R" "" +. ds C` "" +. ds C' "" +'br\} +.el\{\ +. ds -- \|\(em\| +. ds PI \(*p +. ds L" `` +. ds R" '' +'br\} +.\" +.\" If the F register is turned on, we'll generate index entries on stderr +.\" for titles (.TH), headers (.SH), subsections (.Sh), items (.Ip), and +.\" index entries marked with X<> in POD. Of course, you'll have to process +.\" the output yourself in some meaningful fashion. +.if \nF \{\ +. de IX +. tm Index:\\$1\t\\n%\t"\\$2" +.. +. nr % 0 +. rr F +.\} +.\" +.\" For nroff, turn off justification. 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This function can be called several times on the +same \fBctx\fR to hash additional data. +.PP +\&\fIEVP_DigestFinal()\fR retrieves the digest value from \fBctx\fR and places +it in \fBmd\fR. If the \fBs\fR parameter is not \s-1NULL\s0 then the number of +bytes of data written (i.e. the length of the digest) will be written +to the integer at \fBs\fR, at most \fB\s-1EVP_MAX_MD_SIZE\s0\fR bytes will be written. +After calling \fIEVP_DigestFinal()\fR no additional calls to \fIEVP_DigestUpdate()\fR +can be made, but \fIEVP_DigestInit()\fR can be called to initialize a new +digest operation. +.PP +\&\fIEVP_MD_CTX_copy()\fR can be used to copy the message digest state from +\&\fBin\fR to \fBout\fR. This is useful if large amounts of data are to be +hashed which only differ in the last few bytes. +.PP +\&\fIEVP_MD_size()\fR and \fIEVP_MD_CTX_size()\fR return the size of the message digest +when passed an \fB\s-1EVP_MD\s0\fR or an \fB\s-1EVP_MD_CTX\s0\fR structure, i.e. the size of the +hash. +.PP +\&\fIEVP_MD_block_size()\fR and \fIEVP_MD_CTX_block_size()\fR return the block size of the +message digest when passed an \fB\s-1EVP_MD\s0\fR or an \fB\s-1EVP_MD_CTX\s0\fR structure. +.PP +\&\fIEVP_MD_type()\fR and \fIEVP_MD_CTX_type()\fR return the \s-1NID\s0 of the \s-1OBJECT\s0 \s-1IDENTIFIER\s0 +representing the given message digest when passed an \fB\s-1EVP_MD\s0\fR structure. +For example EVP_MD_type(\fIEVP_sha1()\fR) returns \fBNID_sha1\fR. This function is +normally used when setting \s-1ASN1\s0 OIDs. +.PP +\&\fIEVP_MD_CTX_md()\fR returns the \fB\s-1EVP_MD\s0\fR structure corresponding to the passed +\&\fB\s-1EVP_MD_CTX\s0\fR. +.PP +\&\fIEVP_MD_pkey_type()\fR returns the \s-1NID\s0 of the public key signing algorithm associated +with this digest. For example \fIEVP_sha1()\fR is associated with \s-1RSA\s0 so this will +return \fBNID_sha1WithRSAEncryption\fR. This \*(L"link\*(R" between digests and signature +algorithms may not be retained in future versions of OpenSSL. +.PP +\&\fIEVP_md2()\fR, \fIEVP_md5()\fR, \fIEVP_sha()\fR, \fIEVP_sha1()\fR, \fIEVP_mdc2()\fR and \fIEVP_ripemd160()\fR +return \fB\s-1EVP_MD\s0\fR structures for the \s-1MD2\s0, \s-1MD5\s0, \s-1SHA\s0, \s-1SHA1\s0, \s-1MDC2\s0 and \s-1RIPEMD160\s0 digest +algorithms respectively. The associated signature algorithm is \s-1RSA\s0 in each case. +.PP +\&\fIEVP_dss()\fR and \fIEVP_dss1()\fR return \fB\s-1EVP_MD\s0\fR structures for \s-1SHA\s0 and \s-1SHA1\s0 digest +algorithms but using \s-1DSS\s0 (\s-1DSA\s0) for the signature algorithm. +.PP +\&\fIEVP_md_null()\fR is a \*(L"null\*(R" message digest that does nothing: i.e. the hash it +returns is of zero length. +.PP +\&\fIEVP_get_digestbyname()\fR, \fIEVP_get_digestbynid()\fR and \fIEVP_get_digestbyobj()\fR +return an \fB\s-1EVP_MD\s0\fR structure when passed a digest name, a digest \s-1NID\s0 or +an \s-1ASN1_OBJECT\s0 structure respectively. The digest table must be initialized +using, for example, \fIOpenSSL_add_all_digests()\fR for these functions to work. +.SH "RETURN VALUES" +.IX Header "RETURN VALUES" +\&\fIEVP_DigestInit()\fR, \fIEVP_DigestUpdate()\fR and \fIEVP_DigestFinal()\fR do not return values. +.PP +\&\fIEVP_MD_CTX_copy()\fR returns 1 if successful or 0 for failure. +.PP +\&\fIEVP_MD_type()\fR, \fIEVP_MD_pkey_type()\fR and \fIEVP_MD_type()\fR return the \s-1NID\s0 of the +corresponding \s-1OBJECT\s0 \s-1IDENTIFIER\s0 or NID_undef if none exists. +.PP +\&\fIEVP_MD_size()\fR, \fIEVP_MD_block_size()\fR, \fIEVP_MD_CTX_size\fR\|(e), \fIEVP_MD_size()\fR, +\&\fIEVP_MD_CTX_block_size()\fR and \fIEVP_MD_block_size()\fR return the digest or block +size in bytes. +.PP +\&\fIEVP_md_null()\fR, \fIEVP_md2()\fR, \fIEVP_md5()\fR, \fIEVP_sha()\fR, \fIEVP_sha1()\fR, \fIEVP_dss()\fR, +\&\fIEVP_dss1()\fR, \fIEVP_mdc2()\fR and \fIEVP_ripemd160()\fR return pointers to the +corresponding \s-1EVP_MD\s0 structures. +.PP +\&\fIEVP_get_digestbyname()\fR, \fIEVP_get_digestbynid()\fR and \fIEVP_get_digestbyobj()\fR +return either an \fB\s-1EVP_MD\s0\fR structure or \s-1NULL\s0 if an error occurs. +.SH "NOTES" +.IX Header "NOTES" +The \fB\s-1EVP\s0\fR 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. +.PP +\&\s-1SHA1\s0 is the digest of choice for new applications. The other digest algorithms +are still in common use. +.SH "EXAMPLE" +.IX Header "EXAMPLE" +This example digests the data \*(L"Test Message\en\*(R" and \*(L"Hello World\en\*(R", using the +digest name passed on the command line. +.PP +.Vb 2 +\& #include <stdio.h> +\& #include <openssl/evp.h> +.Ve +.Vb 8 +\& main(int argc, char *argv[]) +\& { +\& EVP_MD_CTX mdctx; +\& const EVP_MD *md; +\& char mess1[] = "Test Message\en"; +\& char mess2[] = "Hello World\en"; +\& unsigned char md_value[EVP_MAX_MD_SIZE]; +\& int md_len, i; +.Ve +.Vb 1 +\& OpenSSL_add_all_digests(); +.Ve +.Vb 4 +\& if(!argv[1]) { +\& printf("Usage: mdtest digestname\en"); +\& exit(1); +\& } +.Ve +.Vb 1 +\& md = EVP_get_digestbyname(argv[1]); +.Ve +.Vb 4 +\& if(!md) { +\& printf("Unknown message digest %s\en", argv[1]); +\& exit(1); +\& } +.Ve +.Vb 4 +\& EVP_DigestInit(&mdctx, md); +\& EVP_DigestUpdate(&mdctx, mess1, strlen(mess1)); +\& EVP_DigestUpdate(&mdctx, mess2, strlen(mess2)); +\& EVP_DigestFinal(&mdctx, md_value, &md_len); +.Ve +.Vb 4 +\& printf("Digest is: "); +\& for(i = 0; i < md_len; i++) printf("%02x", md_value[i]); +\& printf("\en"); +\& } +.Ve +.SH "BUGS" +.IX Header "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. +.PP +The link between digests and signing algorithms results in a situation where +\&\fIEVP_sha1()\fR must be used with \s-1RSA\s0 and \fIEVP_dss1()\fR must be used with \s-1DSS\s0 +even though they are identical digests. +.PP +The size of an \fB\s-1EVP_MD_CTX\s0\fR structure is determined at compile time: this results +in code that must be recompiled if the size of \fB\s-1EVP_MD_CTX\s0\fR increases. +.SH "SEE ALSO" +.IX Header "SEE ALSO" +evp(3), hmac(3), md2(3), +md5(3), mdc2(3), ripemd(3), +sha(3), digest(1) +.SH "HISTORY" +.IX Header "HISTORY" +\&\fIEVP_DigestInit()\fR, \fIEVP_DigestUpdate()\fR and \fIEVP_DigestFinal()\fR are +available in all versions of SSLeay and OpenSSL. |
