RSA_private_encrypt(3) OpenSSL 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 VALUESRSA_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 ALSOerr(3), rsa(3), RSA_sign(3), RSA_verify(3)16/Aug/2000 0.9.6 1
RSA_private_encrypt(3) OpenSSL RSA_private_encrypt(3)HISTORY
The padding argument was added in SSLeay 0.8.
RSA_NO_PADDING is available since SSLeay 0.9.0.
16/Aug/2000 0.9.6 2
