5 EVP_VerifyInit, EVP_VerifyUpdate, EVP_VerifyFinal - EVP signature verification functions
9 #include <openssl/evp.h>
11 void EVP_VerifyInit(EVP_MD_CTX *ctx, const EVP_MD *type);
12 void 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);
17 The EVP signature verification routines are a high level interface to digital
20 EVP_VerifyInit() initializes a verification context B<ctx> to using digest
21 B<type>: this will typically be supplied by a function such as EVP_sha1().
23 EVP_VerifyUpdate() hashes B<cnt> bytes of data at B<d> into the
24 verification context B<ctx>. This function can be called several times on the
25 same B<ctx> to include additional data.
27 EVP_VerifyFinal() verifies the data in B<ctx> using the public key B<pkey>
28 and against the B<siglen> bytes at B<sigbuf>. After calling EVP_VerifyFinal()
29 no additional calls to EVP_VerifyUpdate() can be made, but EVP_VerifyInit()
30 can be called to initialize a new verification operation.
34 EVP_VerifyInit() and EVP_VerifyUpdate() do not return values.
36 EVP_VerifyFinal() returns 1 for a correct signature, 0 for failure and -1 if some
39 The error codes can be obtained by L<ERR_get_error(3)|ERR_get_error(3)>.
43 The B<EVP> interface to digital signatures should almost always be used in
44 preference to the low level interfaces. This is because the code then becomes
45 transparent to the algorithm used and much more flexible.
47 Due to the link between message digests and public key algorithms the correct
48 digest algorithm must be used with the correct public key type. A list of
49 algorithms and associated public key algorithms appears in
50 L<EVP_DigestInit(3)|EVP_DigestInit(3)>.
54 Several of the functions do not return values: maybe they should. Although the
55 internal digest operations will never fail some future hardware based operations
61 L<EVP_SignInit(3)|EVP_SignInit(3)>,
62 L<EVP_DigestInit(3)|EVP_DigestInit(3)>, L<err(3)|err(3)>,
63 L<evp(3)|evp(3)>, L<hmac(3)|hmac(3)>, L<md2(3)|md2(3)>,
64 L<md5(3)|md5(3)>, L<mdc2(3)|mdc2(3)>, L<ripemd(3)|ripemd(3)>,
65 L<sha(3)|sha(3)>, L<digest(1)|digest(1)>
69 EVP_VerifyInit(), EVP_VerifyUpdate() and EVP_VerifyFinal() are
70 available in all versions of SSLeay and OpenSSL.