diff options
Diffstat (limited to 'src/lib/libcrypto/doc/EVP_VerifyInit.pod')
-rw-r--r-- | src/lib/libcrypto/doc/EVP_VerifyInit.pod | 86 |
1 files changed, 86 insertions, 0 deletions
diff --git a/src/lib/libcrypto/doc/EVP_VerifyInit.pod b/src/lib/libcrypto/doc/EVP_VerifyInit.pod new file mode 100644 index 0000000000..b6afaedee5 --- /dev/null +++ b/src/lib/libcrypto/doc/EVP_VerifyInit.pod | |||
@@ -0,0 +1,86 @@ | |||
1 | =pod | ||
2 | |||
3 | =head1 NAME | ||
4 | |||
5 | EVP_VerifyInit, EVP_VerifyUpdate, EVP_VerifyFinal - EVP signature verification functions | ||
6 | |||
7 | =head1 SYNOPSIS | ||
8 | |||
9 | #include <openssl/evp.h> | ||
10 | |||
11 | int EVP_VerifyInit_ex(EVP_MD_CTX *ctx, const EVP_MD *type, ENGINE *impl); | ||
12 | int EVP_VerifyUpdate(EVP_MD_CTX *ctx, const void *d, unsigned int cnt); | ||
13 | int EVP_VerifyFinal(EVP_MD_CTX *ctx,unsigned char *sigbuf, unsigned int siglen,EVP_PKEY *pkey); | ||
14 | |||
15 | int EVP_VerifyInit(EVP_MD_CTX *ctx, const EVP_MD *type); | ||
16 | |||
17 | =head1 DESCRIPTION | ||
18 | |||
19 | The EVP signature verification routines are a high level interface to digital | ||
20 | signatures. | ||
21 | |||
22 | EVP_VerifyInit_ex() sets up verification context B<ctx> to use digest | ||
23 | B<type> from ENGINE B<impl>. B<ctx> must be initialized by calling | ||
24 | EVP_MD_CTX_init() before calling this function. | ||
25 | |||
26 | EVP_VerifyUpdate() hashes B<cnt> bytes of data at B<d> into the | ||
27 | verification context B<ctx>. This function can be called several times on the | ||
28 | same B<ctx> to include additional data. | ||
29 | |||
30 | EVP_VerifyFinal() verifies the data in B<ctx> using the public key B<pkey> | ||
31 | and against the B<siglen> bytes at B<sigbuf>. | ||
32 | |||
33 | EVP_VerifyInit() initializes verification context B<ctx> to use the default | ||
34 | implementation of digest B<type>. | ||
35 | |||
36 | =head1 RETURN VALUES | ||
37 | |||
38 | EVP_VerifyInit_ex() and EVP_VerifyUpdate() return 1 for success and 0 for | ||
39 | failure. | ||
40 | |||
41 | EVP_VerifyFinal() returns 1 for a correct signature, 0 for failure and -1 if some | ||
42 | other error occurred. | ||
43 | |||
44 | The error codes can be obtained by L<ERR_get_error(3)|ERR_get_error(3)>. | ||
45 | |||
46 | =head1 NOTES | ||
47 | |||
48 | The B<EVP> interface to digital signatures should almost always be used in | ||
49 | preference to the low level interfaces. This is because the code then becomes | ||
50 | transparent to the algorithm used and much more flexible. | ||
51 | |||
52 | Due to the link between message digests and public key algorithms the correct | ||
53 | digest algorithm must be used with the correct public key type. A list of | ||
54 | algorithms and associated public key algorithms appears in | ||
55 | L<EVP_DigestInit(3)|EVP_DigestInit(3)>. | ||
56 | |||
57 | The call to EVP_VerifyFinal() internally finalizes a copy of the digest context. | ||
58 | This means that calls to EVP_VerifyUpdate() and EVP_VerifyFinal() can be called | ||
59 | later to digest and verify additional data. | ||
60 | |||
61 | Since only a copy of the digest context is ever finalized the context must | ||
62 | be cleaned up after use by calling EVP_MD_CTX_cleanup() or a memory leak | ||
63 | will occur. | ||
64 | |||
65 | =head1 BUGS | ||
66 | |||
67 | Older versions of this documentation wrongly stated that calls to | ||
68 | EVP_VerifyUpdate() could not be made after calling EVP_VerifyFinal(). | ||
69 | |||
70 | =head1 SEE ALSO | ||
71 | |||
72 | L<evp(3)|evp(3)>, | ||
73 | L<EVP_SignInit(3)|EVP_SignInit(3)>, | ||
74 | L<EVP_DigestInit(3)|EVP_DigestInit(3)>, L<err(3)|err(3)>, | ||
75 | L<evp(3)|evp(3)>, L<hmac(3)|hmac(3)>, L<md2(3)|md2(3)>, | ||
76 | L<md5(3)|md5(3)>, L<mdc2(3)|mdc2(3)>, L<ripemd(3)|ripemd(3)>, | ||
77 | L<sha(3)|sha(3)>, L<dgst(1)|dgst(1)> | ||
78 | |||
79 | =head1 HISTORY | ||
80 | |||
81 | EVP_VerifyInit(), EVP_VerifyUpdate() and EVP_VerifyFinal() are | ||
82 | available in all versions of SSLeay and OpenSSL. | ||
83 | |||
84 | EVP_VerifyInit_ex() was added in OpenSSL 0.9.7 | ||
85 | |||
86 | =cut | ||