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EVP_VerifyInit(3)
NAME
  EVP_VerifyInit, EVP_VerifyUpdate, EVP_VerifyFinal - EVP signature
  verification functions

SYNOPSIS
  #include <openssl/evp.h>

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

  void 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 );

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

  The EVP_VerifyInit() function initializes a verification context ctx to
  using digest type. This will typically be supplied by a function such as
  EVP_sha1().

  The EVP_VerifyUpdate() function hashes cnt bytes of data at d into the
  verification context ctx. This function can be called several times on the
  same ctx to include additional data.

  The EVP_VerifyFinal() function verifies the data in ctx using the public
  key pkey and against the siglen bytes at sigbuf.  After calling the
  EVP_VerifyFinal() function no additional calls to the EVP_VerifyUpdate()
  function can be made, but the EVP_VerifyInit() function can be called to
  initialize a new verification operation.

NOTES
  The EVP interface to digital signatures should 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).

RESTRICTIONS
  Several of the functions do not return values. Although the internal digest
  operations will never fail some future hardware based operations might.

RETURN VALUES
  The EVP_VerifyInit() and EVP_VerifyUpdate() functions do not return values.

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

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

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

SEE ALSO
  Commands: dgst(1)

  Functions: evp(3), EVP_SignInit(3), EVP_DigestInit(3), err(3), evp(3),
  hmac(3), md2(3), md5(3), mdc2(3), ripemd(3), sha(3)

Index for Section 3

Alphabetical listing for E

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