diff --git a/kex.h b/kex.h
index 9f1e1ad..0f67f59 100644
--- a/kex.h
+++ b/kex.h
@@ -1,4 +1,4 @@
-/* $OpenBSD: kex.h,v 1.56 2013/07/19 07:37:48 markus Exp $ */
+/* $OpenBSD: kex.h,v 1.57 2013/11/02 21:59:15 markus Exp $ */
 
 /*
  * Copyright (c) 2000, 2001 Markus Friedl.  All rights reserved.
@@ -43,6 +43,7 @@
 #define	KEX_ECDH_SHA2_NISTP256	"ecdh-sha2-nistp256"
 #define	KEX_ECDH_SHA2_NISTP384	"ecdh-sha2-nistp384"
 #define	KEX_ECDH_SHA2_NISTP521	"ecdh-sha2-nistp521"
+#define	KEX_CURVE25519_SHA256	"curve25519-sha256@libssh.org"
 
 #define COMP_NONE	0
 #define COMP_ZLIB	1
@@ -74,6 +75,7 @@
 	KEX_DH_GEX_SHA1,
 	KEX_DH_GEX_SHA256,
 	KEX_ECDH_SHA2,
+	KEX_C25519_SHA256,
 	KEX_MAX
 };
 
@@ -161,6 +163,8 @@
 void	 kexgex_server(Kex *);
 void	 kexecdh_client(Kex *);
 void	 kexecdh_server(Kex *);
+void	 kexc25519_client(Kex *);
+void	 kexc25519_server(Kex *);
 
 void
 kex_dh_hash(char *, char *, char *, int, char *, int, u_char *, int,
@@ -175,6 +179,19 @@
     char *, int, u_char *, int, const EC_POINT *, const EC_POINT *,
     const BIGNUM *, u_char **, u_int *);
 #endif
+void
+kex_c25519_hash(const EVP_MD *, char *, char *, char *, int,
+    char *, int, u_char *, int, const u_char *, const u_char *,
+    const BIGNUM *, u_char **, u_int *);
+
+#define CURVE25519_SIZE 32
+void	kexc25519_keygen(u_char[CURVE25519_SIZE], u_char[CURVE25519_SIZE])
+	__attribute__((__bounded__(__minbytes__, 1, CURVE25519_SIZE)))
+	__attribute__((__bounded__(__minbytes__, 2, CURVE25519_SIZE)));
+BIGNUM *kexc25519_shared_key(const u_char[CURVE25519_SIZE],
+    const u_char[CURVE25519_SIZE])
+	__attribute__((__bounded__(__minbytes__, 1, CURVE25519_SIZE)))
+	__attribute__((__bounded__(__minbytes__, 2, CURVE25519_SIZE)));
 
 void
 derive_ssh1_session_id(BIGNUM *, BIGNUM *, u_int8_t[8], u_int8_t[16]);