1 files changed, 93 insertions, 0 deletions
diff --git a/openssl/doc/crypto/EVP_PKEY_decrypt.pod b/openssl/doc/crypto/EVP_PKEY_decrypt.pod
new file mode 100644
index 000000000..42b2a8c44
--- /dev/null
+++ b/openssl/doc/crypto/EVP_PKEY_decrypt.pod
@@ -0,0 +1,93 @@
+=pod
+
+=head1 NAME
+
+EVP_PKEY_decrypt_init, EVP_PKEY_decrypt - decrypt using a public key algorithm
+
+=head1 SYNOPSIS
+
+ #include <openssl/evp.h>
+
+ int EVP_PKEY_decrypt_init(EVP_PKEY_CTX *ctx);
+ int EVP_PKEY_decrypt(EVP_PKEY_CTX *ctx,
+			unsigned char *out, size_t *outlen,
+			const unsigned char *in, size_t inlen);
+
+=head1 DESCRIPTION
+
+The EVP_PKEY_decrypt_init() function initializes a public key algorithm
+context using key B<pkey> for a decryption operation.
+
+The EVP_PKEY_decrypt() function performs a public key decryption operation
+using B<ctx>. The data to be decrypted is specified using the B<in> and
+B<inlen> parameters. If B<out> is B<NULL> then the maximum size of the output
+buffer is written to the B<outlen> parameter. If B<out> is not B<NULL> then
+before the call the B<outlen> parameter should contain the length of the
+B<out> buffer, if the call is successful the decrypted data is written to
+B<out> and the amount of data written to B<outlen>.
+
+=head1 NOTES
+
+After the call to EVP_PKEY_decrypt_init() algorithm specific control
+operations can be performed to set any appropriate parameters for the
+operation.
+
+The function EVP_PKEY_decrypt() can be called more than once on the same
+context if several operations are performed using the same parameters.
+
+=head1 RETURN VALUES
+
+EVP_PKEY_decrypt_init() and EVP_PKEY_decrypt() return 1 for success and 0
+or a negative value for failure. In particular a return value of -2
+indicates the operation is not supported by the public key algorithm.
+
+=head1 EXAMPLE
+
+Decrypt data using OAEP (for RSA keys):
+
+ #include <openssl/evp.h>
+ #include <openssl/rsa.h>
+
+ EVP_PKEY_CTX *ctx;
+ unsigned char *out, *in;
+ size_t outlen, inlen; 
+ EVP_PKEY *key;
+ /* NB: assumes key in, inlen are already set up
+  * and that key is an RSA private key
+  */
+ ctx = EVP_PKEY_CTX_new(key);
+ if (!ctx)
+	/* Error occurred */
+ if (EVP_PKEY_decrypt_init(ctx) <= 0)
+	/* Error */
+ if (EVP_PKEY_CTX_set_rsa_padding(ctx, RSA_OAEP_PADDING) <= 0)
+	/* Error */
+
+ /* Determine buffer length */
+ if (EVP_PKEY_decrypt(ctx, NULL, &outlen, in, inlen) <= 0)
+	/* Error */
+
+ out = OPENSSL_malloc(outlen);
+
+ if (!out)
+	/* malloc failure */
+ 
+ if (EVP_PKEY_decrypt(ctx, out, &outlen, in, inlen) <= 0)
+	/* Error */
+
+ /* Decrypted data is outlen bytes written to buffer out */
+
+=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_sign(3)|EVP_PKEY_sign(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)> 
+
+=head1 HISTORY
+
+These functions were first added to OpenSSL 1.0.0.
+
+=cut