/xlv3/openssl/0.9.7e-sgipl1/work/0.9.7e-sgipl1/openssl-
0.9.7e/doc/crypto
Page 1 (printed 10/20/05)
RSA_private_encrypt(3)25/Sep/2002 (0.9.7e) 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.
RSA_private_encrypt() 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. to must
point to RSA_size(rsa) bytes of memory.
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, RSA_sign(3)
and RSA_verify(3) 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.
RSA_public_decrypt() recovers the message digest from the
flen bytes long signature at from using the signer's public
key rsa. to must point to a memory section large enough to
hold the message digest (which is smaller than RSA_size(rsa)
- 11). padding is the padding mode that was used to sign the
data.
RETURN VALUES
RSA_private_encrypt() returns the size of the signature
(i.e., RSA_size(rsa)). RSA_public_decrypt() returns the size
of the recovered message digest.
On error, -1 is returned; the error codes can be obtained by
ERR_get_error(3).
SEE ALSO
Page 1 (printed 10/20/05)
RSA_private_encrypt(3)25/Sep/2002 (0.9.7e) RSA_private_encrypt(3)ERR_get_error(3), rsa(3), RSA_sign(3), RSA_verify(3)
HISTORY
The padding argument was added in SSLeay 0.8. RSA_NO_PADDING
is available since SSLeay 0.9.0.
Page 2 (printed 10/20/05)
