diff options
Diffstat (limited to 'src/lib/libcrypto/doc/EVP_PKEY_verify.pod')
-rw-r--r-- | src/lib/libcrypto/doc/EVP_PKEY_verify.pod | 91 |
1 files changed, 91 insertions, 0 deletions
diff --git a/src/lib/libcrypto/doc/EVP_PKEY_verify.pod b/src/lib/libcrypto/doc/EVP_PKEY_verify.pod new file mode 100644 index 0000000000..10633da3f2 --- /dev/null +++ b/src/lib/libcrypto/doc/EVP_PKEY_verify.pod | |||
@@ -0,0 +1,91 @@ | |||
1 | =pod | ||
2 | |||
3 | =head1 NAME | ||
4 | |||
5 | EVP_PKEY_verify_init, EVP_PKEY_verify - signature verification using a public key algorithm | ||
6 | |||
7 | =head1 SYNOPSIS | ||
8 | |||
9 | #include <openssl/evp.h> | ||
10 | |||
11 | int EVP_PKEY_verify_init(EVP_PKEY_CTX *ctx); | ||
12 | int EVP_PKEY_verify(EVP_PKEY_CTX *ctx, | ||
13 | const unsigned char *sig, size_t siglen, | ||
14 | const unsigned char *tbs, size_t tbslen); | ||
15 | |||
16 | =head1 DESCRIPTION | ||
17 | |||
18 | The EVP_PKEY_verify_init() function initializes a public key algorithm | ||
19 | context using key B<pkey> for a signature verification operation. | ||
20 | |||
21 | The EVP_PKEY_verify() function performs a public key verification operation | ||
22 | using B<ctx>. The signature is specified using the B<sig> and | ||
23 | B<siglen> parameters. The verified data (i.e. the data believed originally | ||
24 | signed) is specified using the B<tbs> and B<tbslen> parameters. | ||
25 | |||
26 | =head1 NOTES | ||
27 | |||
28 | After the call to EVP_PKEY_verify_init() algorithm specific control | ||
29 | operations can be performed to set any appropriate parameters for the | ||
30 | operation. | ||
31 | |||
32 | The function EVP_PKEY_verify() can be called more than once on the same | ||
33 | context if several operations are performed using the same parameters. | ||
34 | |||
35 | =head1 RETURN VALUES | ||
36 | |||
37 | EVP_PKEY_verify_init() and EVP_PKEY_verify() return 1 if the verification was | ||
38 | successful and 0 if it failed. Unlike other functions the return value 0 from | ||
39 | EVP_PKEY_verify() only indicates that the signature did not not verify | ||
40 | successfully (that is tbs did not match the original data or the signature was | ||
41 | of invalid form) it is not an indication of a more serious error. | ||
42 | |||
43 | A negative value indicates an error other that signature verification failure. | ||
44 | In particular a return value of -2 indicates the operation is not supported by | ||
45 | the public key algorithm. | ||
46 | |||
47 | =head1 EXAMPLE | ||
48 | |||
49 | Verify signature using PKCS#1 and SHA256 digest: | ||
50 | |||
51 | #include <openssl/evp.h> | ||
52 | #include <openssl/rsa.h> | ||
53 | |||
54 | EVP_PKEY_CTX *ctx; | ||
55 | unsigned char *md, *sig; | ||
56 | size_t mdlen, siglen; | ||
57 | EVP_PKEY *verify_key; | ||
58 | /* NB: assumes verify_key, sig, siglen md and mdlen are already set up | ||
59 | * and that verify_key is an RSA public key | ||
60 | */ | ||
61 | ctx = EVP_PKEY_CTX_new(verify_key); | ||
62 | if (!ctx) | ||
63 | /* Error occurred */ | ||
64 | if (EVP_PKEY_verify_init(ctx) <= 0) | ||
65 | /* Error */ | ||
66 | if (EVP_PKEY_CTX_set_rsa_padding(ctx, RSA_PKCS1_PADDING) <= 0) | ||
67 | /* Error */ | ||
68 | if (EVP_PKEY_CTX_set_signature_md(ctx, EVP_sha256()) <= 0) | ||
69 | /* Error */ | ||
70 | |||
71 | /* Perform operation */ | ||
72 | ret = EVP_PKEY_verify(ctx, md, mdlen, sig, siglen); | ||
73 | |||
74 | /* ret == 1 indicates success, 0 verify failure and < 0 for some | ||
75 | * other error. | ||
76 | */ | ||
77 | |||
78 | =head1 SEE ALSO | ||
79 | |||
80 | L<EVP_PKEY_CTX_new(3)|EVP_PKEY_CTX_new(3)>, | ||
81 | L<EVP_PKEY_encrypt(3)|EVP_PKEY_encrypt(3)>, | ||
82 | L<EVP_PKEY_decrypt(3)|EVP_PKEY_decrypt(3)>, | ||
83 | L<EVP_PKEY_sign(3)|EVP_PKEY_sign(3)>, | ||
84 | L<EVP_PKEY_verifyrecover(3)|EVP_PKEY_verifyrecover(3)>, | ||
85 | L<EVP_PKEY_derive(3)|EVP_PKEY_derive(3)> | ||
86 | |||
87 | =head1 HISTORY | ||
88 | |||
89 | These functions were first added to OpenSSL 1.0.0. | ||
90 | |||
91 | =cut | ||