Add copyright to manpages

[openssl.git] / doc / crypto / EVP_PKEY_sign.pod

diff --git a/doc/crypto/EVP_PKEY_sign.pod b/doc/crypto/EVP_PKEY_sign.pod
index 63d41c9b054c66d1617036b70a942e050a42217d..9b587e7c20574fd2f51d4365bb876f1c8c584824 100644 (file)
--- a/doc/crypto/EVP_PKEY_sign.pod
+++ b/doc/crypto/EVP_PKEY_sign.pod
@@ -2,7 +2,7 @@
 
 =head1 NAME
 
-EVP_PKEY_encrypt_init, EVP_PKEY_encrypt - encrypt using a public key algorithm
+EVP_PKEY_sign_init, EVP_PKEY_sign - sign using a public key algorithm
 
 =head1 SYNOPSIS
 
@@ -28,9 +28,14 @@ B<sig> and the amount of data written to B<siglen>.
 
 =head1 NOTES
 
+EVP_PKEY_sign() does not hash the data to be signed, and therefore is
+normally used to sign digests. For signing arbitrary messages, see the
+L<EVP_DigestSignInit(3)> and
+L<EVP_SignInit(3)> signing interfaces instead.
+
 After the call to EVP_PKEY_sign_init() algorithm specific control
 operations can be performed to set any appropriate parameters for the
-operation.
+operation (see L<EVP_PKEY_CTX_ctrl(3)>).
 
 The function EVP_PKEY_sign() can be called more than once on the same
 context if several operations are performed using the same parameters.
@@ -43,21 +48,70 @@ indicates the operation is not supported by the public key algorithm.
 
 =head1 EXAMPLE
 
-Sign data using PKCS#1 and SHA256 digest:
+Sign data using RSA with PKCS#1 padding and SHA256 digest:
+
+ #include <openssl/evp.h>
+ #include <openssl/rsa.h>
+
+ EVP_PKEY_CTX *ctx;
+ /* md is a SHA-256 digest in this example. */
+ unsigned char *md, *sig;
+ size_t mdlen = 32, siglen;
+ EVP_PKEY *signing_key;
+
+ /*
+  * NB: assumes signing_key and md are set up before the next
+  * step. signing_key must be an RSA private key and md must
+  * point to the SHA-256 digest to be signed.
+  */
+ ctx = EVP_PKEY_CTX_new(signing_key, NULL /* no engine */);
+ if (!ctx)
+       /* Error occurred */
+ if (EVP_PKEY_sign_init(ctx) <= 0)
+       /* Error */
+ if (EVP_PKEY_CTX_set_rsa_padding(ctx, RSA_PKCS1_PADDING) <= 0)
+       /* Error */
+ if (EVP_PKEY_CTX_set_signature_md(ctx, EVP_sha256()) <= 0)
+       /* Error */
+
+ /* Determine buffer length */
+ if (EVP_PKEY_sign(ctx, NULL, &siglen, md, mdlen) <= 0)
+       /* Error */
+
+ sig = OPENSSL_malloc(siglen);
+
+ if (!sig)
+       /* malloc failure */
+ 
+ if (EVP_PKEY_sign(ctx, sig, &siglen, md, mdlen) <= 0)
+       /* Error */
+
+ /* Signature is siglen bytes written to buffer sig */
 
-[to be added]
 
 =head1 SEE ALSO
 
-L<EVP_PKEY_CTX_new(3)|EVP_PKEY_CTX_new(3)>,
-L<EVP_PKEY_encrypt(3)|EVP_PKEY_encrypt(3)>,
-L<EVP_PKEY_decrypt(3)|EVP_PKEY_decrypt(3)>,
-L<EVP_PKEY_verify(3)|EVP_PKEY_verify(3)>,
-L<EVP_PKEY_verifyrecover(3)|EVP_PKEY_verifyrecover(3)>,
-L<EVP_PKEY_derive(3)|EVP_PKEY_derive(3)> 
+L<EVP_PKEY_CTX_new(3)>,
+L<EVP_PKEY_CTX_ctrl(3)>,
+L<EVP_PKEY_encrypt(3)>,
+L<EVP_PKEY_decrypt(3)>,
+L<EVP_PKEY_verify(3)>,
+L<EVP_PKEY_verify_recover(3)>,
+L<EVP_PKEY_derive(3)> 
 
 =head1 HISTORY
 
-These functions were first added to OpenSSL 0.9.9.
+These functions were first added to OpenSSL 1.0.0.
+
+=cut
+
+=head1 COPYRIGHT
+
+Copyright 2006-2016 The OpenSSL Project Authors. All Rights Reserved.
+
+Licensed under the OpenSSL license (the "License").  You may not use
+this file except in compliance with the License.  You can obtain a copy
+in the file LICENSE in the source distribution or at
+L<https://www.openssl.org/source/license.html>.
 
 =cut