RSA_PRIVATE_ENCRYPT(3) OpenSSL RSA_PRIVATE_ENCRYPT(3)

## NAME

RSA_private_encrypt, RSA_public_decrypt - low level signa-
ture 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 generat-
ing 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

*ERR_get_error*(3), *rsa*(3), *RSA_sign*(3), *RSA_verify*(3)
MirOS BSD #10-current 2005-02-05 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.
MirOS BSD #10-current 2005-02-05 2

Generated on 2017-04-03 16:26:17 by `$MirOS: src/scripts/roff2htm,v 1.88 2017/01/29 00:51:06 tg Exp $`

These manual pages and other documentation are copyrighted by their respective writers;
their source is available at our CVSweb,
AnonCVS, and other mirrors. The rest is Copyright © 2002–2017 The MirOS Project, Germany.

This product includes material
provided by **mirabilos**.

This manual page’s HTML representation
is supposed to be valid
XHTML/1.1; if not, please send a bug report — diffs preferred.