diff options
author | beck <> | 2000-04-15 06:18:51 +0000 |
---|---|---|
committer | beck <> | 2000-04-15 06:18:51 +0000 |
commit | b608c7f2b175e121f2c22d53341a317153afdc8e (patch) | |
tree | e94b160b3fcd8180df79e4251d68d24d665f0195 /src/lib/libcrypto/doc/EVP_SignInit.pod | |
parent | c8d6701c396cebdcd0d45eac73b762e9498f6b01 (diff) | |
download | openbsd-b608c7f2b175e121f2c22d53341a317153afdc8e.tar.gz openbsd-b608c7f2b175e121f2c22d53341a317153afdc8e.tar.bz2 openbsd-b608c7f2b175e121f2c22d53341a317153afdc8e.zip |
OpenSSL 0.9.5a merge
Diffstat (limited to 'src/lib/libcrypto/doc/EVP_SignInit.pod')
-rw-r--r-- | src/lib/libcrypto/doc/EVP_SignInit.pod | 85 |
1 files changed, 85 insertions, 0 deletions
diff --git a/src/lib/libcrypto/doc/EVP_SignInit.pod b/src/lib/libcrypto/doc/EVP_SignInit.pod new file mode 100644 index 0000000000..bbc9203c9c --- /dev/null +++ b/src/lib/libcrypto/doc/EVP_SignInit.pod | |||
@@ -0,0 +1,85 @@ | |||
1 | =pod | ||
2 | |||
3 | =head1 NAME | ||
4 | |||
5 | EVP_SignInit, EVP_SignUpdate, EVP_SignFinal - EVP signing functions | ||
6 | |||
7 | =head1 SYNOPSIS | ||
8 | |||
9 | #include <openssl/evp.h> | ||
10 | |||
11 | void EVP_SignInit(EVP_MD_CTX *ctx, const EVP_MD *type); | ||
12 | void EVP_SignUpdate(EVP_MD_CTX *ctx, const void *d, unsigned int cnt); | ||
13 | int EVP_SignFinal(EVP_MD_CTX *ctx,unsigned char *sig,unsigned int *s, EVP_PKEY *pkey); | ||
14 | |||
15 | int EVP_PKEY_size(EVP_PKEY *pkey); | ||
16 | |||
17 | =head1 DESCRIPTION | ||
18 | |||
19 | The EVP signature routines are a high level interface to digital | ||
20 | signatures. | ||
21 | |||
22 | EVP_SignInit() initialises a signing context B<ctx> to using digest | ||
23 | B<type>: this will typically be supplied by a function such as | ||
24 | EVP_sha1(). | ||
25 | |||
26 | EVP_SignUpdate() hashes B<cnt> bytes of data at B<d> into the | ||
27 | signature context B<ctx>. This funtion can be called several times on the | ||
28 | same B<ctx> to include additional data. | ||
29 | |||
30 | EVP_SignFinal() signs the data in B<ctx> using the private key B<pkey> | ||
31 | and places the signature in B<sig>. If the B<s> parameter is not NULL | ||
32 | then the number of bytes of data written (i.e. the length of the signature) | ||
33 | will be written to the integer at B<s>, at most EVP_PKEY_size(pkey) bytes | ||
34 | will be written. After calling EVP_SignFinal() no additional calls to | ||
35 | EVP_SignUpdate() can be made, but EVP_SignInit() can be called to initialiase | ||
36 | a new signature operation. | ||
37 | |||
38 | EVP_PKEY_size() returns the maximum size of a signature in bytes. The actual | ||
39 | signature returned by EVP_SignFinal() may be smaller. | ||
40 | |||
41 | =head1 RETURN VALUES | ||
42 | |||
43 | EVP_SignInit() and EVP_SignUpdate() do not return values. | ||
44 | |||
45 | EVP_SignFinal() returns 1 for success and 0 for failure. | ||
46 | |||
47 | EVP_PKEY_size() returns the maximum size of a signature in bytes. | ||
48 | |||
49 | The error codes can be obtained by L<ERR_get_error(3)|ERR_get_error(3)>. | ||
50 | |||
51 | =head1 NOTES | ||
52 | |||
53 | The B<EVP> interface to digital signatures should almost always be used in | ||
54 | preference to the low level interfaces. This is because the code then becomes | ||
55 | transparent to the algorithm used and much more flexible. | ||
56 | |||
57 | Due to the link between message digests and public key algorithms the correct | ||
58 | digest algorithm must be used with the correct public key type. A list of | ||
59 | algorithms and associated public key algorithms appears in | ||
60 | L<EVP_DigestInit(3)|EVP_DigestInit(3)>. | ||
61 | |||
62 | When signing with DSA private keys the random number generator must be seeded | ||
63 | or the operation will fail. The random number generator does not need to be | ||
64 | seeded for RSA signatures. | ||
65 | |||
66 | =head1 BUGS | ||
67 | |||
68 | Several of the functions do not return values: maybe they should. Although the | ||
69 | internal digest operations will never fail some future hardware based operations | ||
70 | might. | ||
71 | |||
72 | =head1 SEE ALSO | ||
73 | |||
74 | L<EVP_VerifyInit(3)|EVP_VerifyInit(3)>, | ||
75 | L<EVP_DigestInit(3)|EVP_DigestInit(3)>, L<err(3)|err(3)>, | ||
76 | L<evp(3)|evp(3)>, L<hmac(3)|hmac(3)>, L<md2(3)|md2(3)>, | ||
77 | L<md5(3)|md5(3)>, L<mdc2(3)|mdc2(3)>, L<ripemd(3)|ripemd(3)>, | ||
78 | L<sha(3)|sha(3)>, L<digest(1)|digest(1)> | ||
79 | |||
80 | =head1 HISTORY | ||
81 | |||
82 | EVP_SignInit(), EVP_SignUpdate() and EVP_SignFinal() are | ||
83 | available in all versions of SSLeay and OpenSSL. | ||
84 | |||
85 | =cut | ||