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RSA_private_encrypt(3)
NAME
  RSA_private_encrypt, RSA_public_decrypt - Low level signature operations

SYNOPSIS
  #include <openssl/rsa.h>

  int RSA_private_encrypt(
	  int flen, unsigned char *from, unsigned char *to, RSA *rsa, int
  padding );

  int RSA_public_decrypt(
	  int flen, unsigned char *from, unsigned char *to, RSA *rsa, int
  padding );

DESCRIPTION
  These functions handle RSA signatures at a low level.

  The RSA_private_encrypt() function signs the flen bytes at from (usually a
  message digest with an algorithm identifier) using the private key rsa and
  stores the signature in to. The to must point to RSA_size(rsa) bytes of
  memory.

  The padding denotes one of the following modes:

  RSA_PKCS1_PADDING
	  PKCS #1 v1.5 padding. This function does not handle the
	  algorithmIdentifier specified in PKCS #1. When generating or
	  verifying PKCS #1 signatures, the RSA_sign() and RSA_verify()
	  functions should be used.

  RSA_NO_PADDING
	  Raw RSA signature. This mode should only be used to implement
	  cryptographically sound padding modes in the application code.
	  Signing user data directly with RSA is insecure.

  The RSA_public_decrypt() function recovers the message digest from the flen
  bytes long signature at from using the signer's public key rsa. The to must
  point to a memory section large enough to hold the message digest (which is
  smaller than RSA_size(rsa) - 11). The padding is the padding mode that was
  used to sign the data.

RETURN VALUES
  The RSA_private_encrypt() function returns the size of the signature (i.e.,
  RSA_size(rsa)). The RSA_public_decrypt() function returns the size of the
  recovered message digest.

  On error, -1 is returned; the error codes can be obtained by using the
  ERR_get_error() function.

HISTORY
  The padding argument was added in SSLeay 0.8. RSA_NO_PADDING is available
  since SSLeay 0.9.0.

SEE ALSO
  Functions: err(3), rsa(3), RSA_sign(3), RSA_verify(3)

Index for Section 3

Alphabetical listing for R

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