Manual Pages for UNIX Operating System command usage for man EVP_VerifyInit

OpenSSL                                  EVP_VerifyInit(3openssl)



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     EVP_VerifyInit, EVP_VerifyUpdate, EVP_VerifyFinal - EVP
     signature verification functions

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      #include 

      int EVP_VerifyInit_ex(EVP_MD_CTX *ctx, const EVP_MD *type, ENGINE *impl);
      int EVP_VerifyUpdate(EVP_MD_CTX *ctx, const void *d, unsigned int cnt);
      int EVP_VerifyFinal(EVP_MD_CTX *ctx,unsigned char *sigbuf, unsigned int siglen,EVP_PKEY *pkey);

      int EVP_VerifyInit(EVP_MD_CTX *ctx, const EVP_MD *type);


DDDDEEEESSSSCCCCRRRRIIIIPPPPTTTTIIIIOOOONNNN
     The EVP signature verification routines are a high level
     interface to digital signatures.

     EVP_VerifyInit_ex() sets up verification context ccccttttxxxx to use
     digest ttttyyyyppppeeee from ENGINE iiiimmmmppppllll. ccccttttxxxx must be initialized by
     calling EVP_MD_CTX_init() before calling this function.

     EVP_VerifyUpdate() hashes ccccnnnntttt bytes of data at dddd into the
     verification context ccccttttxxxx. This function can be called
     several times on the same ccccttttxxxx to include additional data.

     EVP_VerifyFinal() verifies the data in ccccttttxxxx using the public
     key ppppkkkkeeeeyyyy and against the ssssiiiigggglllleeeennnn bytes at ssssiiiiggggbbbbuuuuffff.

     EVP_VerifyInit() initializes verification context ccccttttxxxx to use
     the default implementation of digest ttttyyyyppppeeee.

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     EVP_VerifyInit_ex() and EVP_VerifyUpdate() return 1 for
     success and 0 for failure.

     EVP_VerifyFinal() returns 1 for a correct signature, 0 for
     failure and -1 if some other error occurred.

     The error codes can be obtained by ERR_get_error(3).

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     The EEEEVVVVPPPP interface to digital signatures should almost always
     be used in preference to the low level interfaces. This is
     because the code then becomes transparent to the algorithm
     used and much more flexible.

     Due to the link between message digests and public key
     algorithms the correct digest algorithm must be used with
     the correct public key type. A list of algorithms and
     associated public key algorithms appears in
     EVP_DigestInit(3).



10/Jul/2002            Last change: 0.9.8o                      1






OpenSSL                                  EVP_VerifyInit(3openssl)



     The call to EVP_VerifyFinal() internally finalizes a copy of
     the digest context.  This means that calls to
     EVP_VerifyUpdate() and EVP_VerifyFinal() can be called later
     to digest and verify additional data.

     Since only a copy of the digest context is ever finalized
     the context must be cleaned up after use by calling
     EVP_MD_CTX_cleanup() or a memory leak will occur.

BBBBUUUUGGGGSSSS
     Older versions of this documentation wrongly stated that
     calls to EVP_VerifyUpdate() could not be made after calling
     EVP_VerifyFinal().

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     evp(3), EVP_SignInit(3), EVP_DigestInit(3), err(3), evp(3),
     hmac(3), md2(3), md5(3), mdc2(3), ripemd(3), sha(3), dgst(1)

HHHHIIIISSSSTTTTOOOORRRRYYYY
     EVP_VerifyInit(), EVP_VerifyUpdate() and EVP_VerifyFinal()
     are available in all versions of SSLeay and OpenSSL.

     EVP_VerifyInit_ex() was added in OpenSSL 0.9.7
































10/Jul/2002            Last change: 0.9.8o                      2