Fixed minor duplication in docs

[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 98daf91541cec7c7e0cbad4e479641348cfda73c..a044f2c13127fa3a6d71ec5db1a8869f7350c94e 100644 (file)
--- a/doc/crypto/EVP_PKEY_sign.pod
+++ b/doc/crypto/EVP_PKEY_sign.pod
@@ -43,9 +43,42 @@ 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;
+ unsigned char *md, *sig;
+ size_t mdlen, siglen; 
+ EVP_PKEY *signing_key;
+ /* NB: assumes signing_key, md and mdlen are already set up
+  * and that signing_key is an RSA private key
+  */
+ ctx = EVP_PKEY_CTX_new(signing_key);
+ 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
 
@@ -53,11 +86,11 @@ 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_verify_recover(3)|EVP_PKEY_verify_recover(3)>,
 L<EVP_PKEY_derive(3)|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