NetBSD/lib/libcrypto/man/RSA_public_encrypt.3

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.\" $NetBSD: RSA_public_encrypt.3,v 1.12 2003/07/24 14:16:42 itojun Exp $
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.\" ======================================================================
.\"
.IX Title "RSA_public_encrypt 3"
.TH RSA_public_encrypt 3 "0.9.7b" "2002-09-25" "OpenSSL"
.UC
.SH "NAME"
RSA_public_encrypt, RSA_private_decrypt \- \s-1RSA\s0 public key cryptography
.SH "LIBRARY"
libcrypto, -lcrypto
.SH "SYNOPSIS"
.IX Header "SYNOPSIS"
.Vb 1
\& #include <openssl/rsa.h>
.Ve
.Vb 2
\& int RSA_public_encrypt(int flen, unsigned char *from,
\& unsigned char *to, RSA *rsa, int padding);
.Ve
.Vb 2
\& int RSA_private_decrypt(int flen, unsigned char *from,
\& unsigned char *to, RSA *rsa, int padding);
.Ve
.SH "DESCRIPTION"
.IX Header "DESCRIPTION"
\&\fIRSA_public_encrypt()\fR encrypts the \fBflen\fR bytes at \fBfrom\fR (usually a
session key) using the public key \fBrsa\fR and stores the ciphertext in
\&\fBto\fR. \fBto\fR must point to RSA_size(\fBrsa\fR) bytes of memory.
.PP
\&\fBpadding\fR denotes one of the following modes:
.Ip "\s-1RSA_PKCS1_PADDING\s0" 4
.IX Item "RSA_PKCS1_PADDING"
\&\s-1PKCS\s0 #1 v1.5 padding. This currently is the most widely used mode.
.Ip "\s-1RSA_PKCS1_OAEP_PADDING\s0" 4
.IX Item "RSA_PKCS1_OAEP_PADDING"
\&\s-1EME-OAEP\s0 as defined in \s-1PKCS\s0 #1 v2.0 with \s-1SHA-1\s0, \s-1MGF1\s0 and an empty
encoding parameter. This mode is recommended for all new applications.
.Ip "\s-1RSA_SSLV23_PADDING\s0" 4
.IX Item "RSA_SSLV23_PADDING"
\&\s-1PKCS\s0 #1 v1.5 padding with an SSL-specific modification that denotes
that the server is \s-1SSL3\s0 capable.
.Ip "\s-1RSA_NO_PADDING\s0" 4
.IX Item "RSA_NO_PADDING"
Raw \s-1RSA\s0 encryption. This mode should \fIonly\fR be used to implement
cryptographically sound padding modes in the application code.
Encrypting user data directly with \s-1RSA\s0 is insecure.
.PP
\&\fBflen\fR must be less than RSA_size(\fBrsa\fR) \- 11 for the \s-1PKCS\s0 #1 v1.5
based padding modes, and less than RSA_size(\fBrsa\fR) \- 41 for
\&\s-1RSA_PKCS1_OAEP_PADDING\s0. The random number generator must be seeded
prior to calling \fIRSA_public_encrypt()\fR.
.PP
\&\fIRSA_private_decrypt()\fR decrypts the \fBflen\fR bytes at \fBfrom\fR using the
private key \fBrsa\fR and stores the plaintext in \fBto\fR. \fBto\fR must point
to a memory section large enough to hold the decrypted data (which is
smaller than RSA_size(\fBrsa\fR)). \fBpadding\fR is the padding mode that
was used to encrypt the data.
.SH "RETURN VALUES"
.IX Header "RETURN VALUES"
\&\fIRSA_public_encrypt()\fR returns the size of the encrypted data (i.e.,
RSA_size(\fBrsa\fR)). \fIRSA_private_decrypt()\fR returns the size of the
recovered plaintext.
.PP
On error, \-1 is returned; the error codes can be
obtained by ERR_get_error(3).
.SH "CONFORMING TO"
.IX Header "CONFORMING TO"
\&\s-1SSL\s0, \s-1PKCS\s0 #1 v2.0
.SH "SEE ALSO"
.IX Header "SEE ALSO"
ERR_get_error(3), openssl_rand(3), openssl_rsa(3),
RSA_size(3)
.SH "HISTORY"
.IX Header "HISTORY"
The \fBpadding\fR argument was added in SSLeay 0.8. \s-1RSA_NO_PADDING\s0 is
available since SSLeay 0.9.0, \s-1OAEP\s0 was added in OpenSSL 0.9.2b.