--- /dev/null
+.\" $OpenBSD: X25519.3,v 1.1 2017/04/10 17:45:06 schwarze Exp $
+.\" OpenSSL X25519.pod 69687aa8 Mar 28 23:57:28 2017 +0200
+.\"
+.\" This file was written by Dr. Stephen Henson <steve@openssl.org>.
+.\" Copyright (c) 2017 The OpenSSL Project. All rights reserved.
+.\"
+.\" Redistribution and use in source and binary forms, with or without
+.\" modification, are permitted provided that the following conditions
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+.\"
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+.\" notice, this list of conditions and the following disclaimer.
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+.\" software must display the following acknowledgment:
+.\" "This product includes software developed by the OpenSSL Project
+.\" for use in the OpenSSL Toolkit. (http://www.openssl.org/)"
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+.\" 4. The names "OpenSSL Toolkit" and "OpenSSL Project" must not be used to
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+.Dd $Mdocdate: April 10 2017 $
+.Dt X25519 3
+.Os
+.Sh NAME
+.Nm X25519
+.Nd EVP_PKEY X25519 support
+.Sh DESCRIPTION
+The
+.Nm
+.Vt EVP_PKEY
+implementation supports key generation and key derivation using X25519.
+It has associated private and public key formats compatible with
+draft-ietf-curdle-pkix-03.
+.Pp
+No additional parameters can be set during key generation.
+.Pp
+The peer public key must be set using
+.Xr EVP_PKEY_derive_set_peer 3
+when performing key derivation.
+.Pp
+A context for the
+.Nm
+algorithm can be obtained by calling:
+.Pp
+.Dl EVP_PKEY_CTX *pctx = EVP_PKEY_CTX_new_id(NID_X25519, NULL);
+.Sh EXAMPLES
+Generate an
+.Nm
+private key and write it to standard output in PEM format:
+.Bd -literal
+#include <openssl/evp.h>
+#include <openssl/pem.h>
+
+EVP_PKEY *pkey = NULL;
+EVP_PKEY_CTX *pctx = EVP_PKEY_CTX_new_id(NID_X25519, NULL);
+EVP_PKEY_keygen_init(pctx);
+EVP_PKEY_keygen(pctx, &pkey);
+EVP_PKEY_CTX_free(pctx);
+PEM_write_PrivateKey(stdout, pkey, NULL, NULL, 0, NULL, NULL);
+.Ed
+.Pp
+The key derivation example in
+.Xr EVP_PKEY_derive 3
+can be used with
+.Nm .
+.Sh SEE ALSO
+.Xr EVP_PKEY_CTX_new 3 ,
+.Xr EVP_PKEY_derive 3 ,
+.Xr EVP_PKEY_keygen 3