gcrypt mpi based Diffie-Hellman implementation

4 files changed, 634 insertions, 0 deletions

diff --git a/src/libstrongswan/plugins/gcrypt/Makefile.am b/src/libstrongswan/plugins/gcrypt/Makefile.am
index eae3bafce..2872fee08 100644
--- a/src/libstrongswan/plugins/gcrypt/Makefile.am
+++ b/src/libstrongswan/plugins/gcrypt/Makefile.am
@@ -6,6 +6,7 @@ AM_CFLAGS = -rdynamic
 plugin_LTLIBRARIES = libstrongswan-gcrypt.la
 
 libstrongswan_gcrypt_la_SOURCES = gcrypt_plugin.h gcrypt_plugin.c \
+	gcrypt_dh.h gcrypt_dh.c \
 	gcrypt_rng.h gcrypt_rng.c \
 	gcrypt_crypter.h gcrypt_crypter.c \
 	gcrypt_hasher.h gcrypt_hasher.c
diff --git a/src/libstrongswan/plugins/gcrypt/gcrypt_dh.c b/src/libstrongswan/plugins/gcrypt/gcrypt_dh.c
new file mode 100644
index 000000000..89d9f2348
--- /dev/null
+++ b/src/libstrongswan/plugins/gcrypt/gcrypt_dh.c
@@ -0,0 +1,564 @@
+/*
+ * Copyright (C) 2009 Martin Willi
+ * Hochschule fuer Technik Rapperswil
+ *
+ * This program is free software; you can redistribute it and/or modify it
+ * under the terms of the GNU General Public License as published by the
+ * Free Software Foundation; either version 2 of the License, or (at your
+ * option) any later version.  See <http://www.fsf.org/copyleft/gpl.txt>.
+ *
+ * This program is distributed in the hope that it will be useful, but
+ * WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY
+ * or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
+ * for more details.
+ */
+
+#include <gcrypt.h>
+
+#include "gcrypt_dh.h"
+
+#include <debug.h>
+
+/**
+ * Modulus of Group 1 (MODP_768_BIT).
+ */
+static u_int8_t group1_modulus[] = {
+	0xFF,0xFF,0xFF,0xFF,0xFF,0xFF,0xFF,0xFF,0xC9,0x0F,0xDA,0xA2,0x21,0x68,0xC2,0x34,
+	0xC4,0xC6,0x62,0x8B,0x80,0xDC,0x1C,0xD1,0x29,0x02,0x4E,0x08,0x8A,0x67,0xCC,0x74,
+	0x02,0x0B,0xBE,0xA6,0x3B,0x13,0x9B,0x22,0x51,0x4A,0x08,0x79,0x8E,0x34,0x04,0xDD,
+	0xEF,0x95,0x19,0xB3,0xCD,0x3A,0x43,0x1B,0x30,0x2B,0x0A,0x6D,0xF2,0x5F,0x14,0x37,
+	0x4F,0xE1,0x35,0x6D,0x6D,0x51,0xC2,0x45,0xE4,0x85,0xB5,0x76,0x62,0x5E,0x7E,0xC6,
+	0xF4,0x4C,0x42,0xE9,0xA6,0x3A,0x36,0x20,0xFF,0xFF,0xFF,0xFF,0xFF,0xFF,0xFF,0xFF
+};
+
+/**
+ * Modulus of Group 2 (MODP_1024_BIT).
+ */
+static u_int8_t group2_modulus[] = {
+	0xFF,0xFF,0xFF,0xFF,0xFF,0xFF,0xFF,0xFF,0xC9,0x0F,0xDA,0xA2,0x21,0x68,0xC2,0x34,
+	0xC4,0xC6,0x62,0x8B,0x80,0xDC,0x1C,0xD1,0x29,0x02,0x4E,0x08,0x8A,0x67,0xCC,0x74,
+	0x02,0x0B,0xBE,0xA6,0x3B,0x13,0x9B,0x22,0x51,0x4A,0x08,0x79,0x8E,0x34,0x04,0xDD,
+	0xEF,0x95,0x19,0xB3,0xCD,0x3A,0x43,0x1B,0x30,0x2B,0x0A,0x6D,0xF2,0x5F,0x14,0x37,
+	0x4F,0xE1,0x35,0x6D,0x6D,0x51,0xC2,0x45,0xE4,0x85,0xB5,0x76,0x62,0x5E,0x7E,0xC6,
+	0xF4,0x4C,0x42,0xE9,0xA6,0x37,0xED,0x6B,0x0B,0xFF,0x5C,0xB6,0xF4,0x06,0xB7,0xED,
+	0xEE,0x38,0x6B,0xFB,0x5A,0x89,0x9F,0xA5,0xAE,0x9F,0x24,0x11,0x7C,0x4B,0x1F,0xE6,
+	0x49,0x28,0x66,0x51,0xEC,0xE6,0x53,0x81,0xFF,0xFF,0xFF,0xFF,0xFF,0xFF,0xFF,0xFF
+};
+
+/**
+ * Modulus of Group 5 (MODP_1536_BIT).
+ */
+static u_int8_t group5_modulus[] = {
+	0xFF,0xFF,0xFF,0xFF,0xFF,0xFF,0xFF,0xFF,0xC9,0x0F,0xDA,0xA2,0x21,0x68,0xC2,0x34,
+	0xC4,0xC6,0x62,0x8B,0x80,0xDC,0x1C,0xD1,0x29,0x02,0x4E,0x08,0x8A,0x67,0xCC,0x74,
+	0x02,0x0B,0xBE,0xA6,0x3B,0x13,0x9B,0x22,0x51,0x4A,0x08,0x79,0x8E,0x34,0x04,0xDD,
+	0xEF,0x95,0x19,0xB3,0xCD,0x3A,0x43,0x1B,0x30,0x2B,0x0A,0x6D,0xF2,0x5F,0x14,0x37,
+	0x4F,0xE1,0x35,0x6D,0x6D,0x51,0xC2,0x45,0xE4,0x85,0xB5,0x76,0x62,0x5E,0x7E,0xC6,
+	0xF4,0x4C,0x42,0xE9,0xA6,0x37,0xED,0x6B,0x0B,0xFF,0x5C,0xB6,0xF4,0x06,0xB7,0xED,
+	0xEE,0x38,0x6B,0xFB,0x5A,0x89,0x9F,0xA5,0xAE,0x9F,0x24,0x11,0x7C,0x4B,0x1F,0xE6,
+	0x49,0x28,0x66,0x51,0xEC,0xE4,0x5B,0x3D,0xC2,0x00,0x7C,0xB8,0xA1,0x63,0xBF,0x05,
+	0x98,0xDA,0x48,0x36,0x1C,0x55,0xD3,0x9A,0x69,0x16,0x3F,0xA8,0xFD,0x24,0xCF,0x5F,
+	0x83,0x65,0x5D,0x23,0xDC,0xA3,0xAD,0x96,0x1C,0x62,0xF3,0x56,0x20,0x85,0x52,0xBB,
+	0x9E,0xD5,0x29,0x07,0x70,0x96,0x96,0x6D,0x67,0x0C,0x35,0x4E,0x4A,0xBC,0x98,0x04,
+	0xF1,0x74,0x6C,0x08,0xCA,0x23,0x73,0x27,0xFF,0xFF,0xFF,0xFF,0xFF,0xFF,0xFF,0xFF
+};
+/**
+ * Modulus of Group 14 (MODP_2048_BIT).
+ */
+static u_int8_t group14_modulus[] = {
+	0xFF,0xFF,0xFF,0xFF,0xFF,0xFF,0xFF,0xFF,0xC9,0x0F,0xDA,0xA2,0x21,0x68,0xC2,0x34,
+	0xC4,0xC6,0x62,0x8B,0x80,0xDC,0x1C,0xD1,0x29,0x02,0x4E,0x08,0x8A,0x67,0xCC,0x74,
+	0x02,0x0B,0xBE,0xA6,0x3B,0x13,0x9B,0x22,0x51,0x4A,0x08,0x79,0x8E,0x34,0x04,0xDD,
+	0xEF,0x95,0x19,0xB3,0xCD,0x3A,0x43,0x1B,0x30,0x2B,0x0A,0x6D,0xF2,0x5F,0x14,0x37,
+	0x4F,0xE1,0x35,0x6D,0x6D,0x51,0xC2,0x45,0xE4,0x85,0xB5,0x76,0x62,0x5E,0x7E,0xC6,
+	0xF4,0x4C,0x42,0xE9,0xA6,0x37,0xED,0x6B,0x0B,0xFF,0x5C,0xB6,0xF4,0x06,0xB7,0xED,
+	0xEE,0x38,0x6B,0xFB,0x5A,0x89,0x9F,0xA5,0xAE,0x9F,0x24,0x11,0x7C,0x4B,0x1F,0xE6,
+	0x49,0x28,0x66,0x51,0xEC,0xE4,0x5B,0x3D,0xC2,0x00,0x7C,0xB8,0xA1,0x63,0xBF,0x05,
+	0x98,0xDA,0x48,0x36,0x1C,0x55,0xD3,0x9A,0x69,0x16,0x3F,0xA8,0xFD,0x24,0xCF,0x5F,
+	0x83,0x65,0x5D,0x23,0xDC,0xA3,0xAD,0x96,0x1C,0x62,0xF3,0x56,0x20,0x85,0x52,0xBB,
+	0x9E,0xD5,0x29,0x07,0x70,0x96,0x96,0x6D,0x67,0x0C,0x35,0x4E,0x4A,0xBC,0x98,0x04,
+	0xF1,0x74,0x6C,0x08,0xCA,0x18,0x21,0x7C,0x32,0x90,0x5E,0x46,0x2E,0x36,0xCE,0x3B,
+	0xE3,0x9E,0x77,0x2C,0x18,0x0E,0x86,0x03,0x9B,0x27,0x83,0xA2,0xEC,0x07,0xA2,0x8F,
+	0xB5,0xC5,0x5D,0xF0,0x6F,0x4C,0x52,0xC9,0xDE,0x2B,0xCB,0xF6,0x95,0x58,0x17,0x18,
+	0x39,0x95,0x49,0x7C,0xEA,0x95,0x6A,0xE5,0x15,0xD2,0x26,0x18,0x98,0xFA,0x05,0x10,
+	0x15,0x72,0x8E,0x5A,0x8A,0xAC,0xAA,0x68,0xFF,0xFF,0xFF,0xFF,0xFF,0xFF,0xFF,0xFF
+};
+
+/**
+ * Modulus of Group 15 (MODP_3072_BIT).
+ */
+static u_int8_t group15_modulus[] = {
+	0xFF,0xFF,0xFF,0xFF,0xFF,0xFF,0xFF,0xFF,0xC9,0x0F,0xDA,0xA2,0x21,0x68,0xC2,0x34,
+	0xC4,0xC6,0x62,0x8B,0x80,0xDC,0x1C,0xD1,0x29,0x02,0x4E,0x08,0x8A,0x67,0xCC,0x74,
+	0x02,0x0B,0xBE,0xA6,0x3B,0x13,0x9B,0x22,0x51,0x4A,0x08,0x79,0x8E,0x34,0x04,0xDD,
+	0xEF,0x95,0x19,0xB3,0xCD,0x3A,0x43,0x1B,0x30,0x2B,0x0A,0x6D,0xF2,0x5F,0x14,0x37,
+	0x4F,0xE1,0x35,0x6D,0x6D,0x51,0xC2,0x45,0xE4,0x85,0xB5,0x76,0x62,0x5E,0x7E,0xC6,
+	0xF4,0x4C,0x42,0xE9,0xA6,0x37,0xED,0x6B,0x0B,0xFF,0x5C,0xB6,0xF4,0x06,0xB7,0xED,
+	0xEE,0x38,0x6B,0xFB,0x5A,0x89,0x9F,0xA5,0xAE,0x9F,0x24,0x11,0x7C,0x4B,0x1F,0xE6,
+	0x49,0x28,0x66,0x51,0xEC,0xE4,0x5B,0x3D,0xC2,0x00,0x7C,0xB8,0xA1,0x63,0xBF,0x05,
+	0x98,0xDA,0x48,0x36,0x1C,0x55,0xD3,0x9A,0x69,0x16,0x3F,0xA8,0xFD,0x24,0xCF,0x5F,
+	0x83,0x65,0x5D,0x23,0xDC,0xA3,0xAD,0x96,0x1C,0x62,0xF3,0x56,0x20,0x85,0x52,0xBB,
+	0x9E,0xD5,0x29,0x07,0x70,0x96,0x96,0x6D,0x67,0x0C,0x35,0x4E,0x4A,0xBC,0x98,0x04,
+	0xF1,0x74,0x6C,0x08,0xCA,0x18,0x21,0x7C,0x32,0x90,0x5E,0x46,0x2E,0x36,0xCE,0x3B,
+	0xE3,0x9E,0x77,0x2C,0x18,0x0E,0x86,0x03,0x9B,0x27,0x83,0xA2,0xEC,0x07,0xA2,0x8F,
+	0xB5,0xC5,0x5D,0xF0,0x6F,0x4C,0x52,0xC9,0xDE,0x2B,0xCB,0xF6,0x95,0x58,0x17,0x18,
+	0x39,0x95,0x49,0x7C,0xEA,0x95,0x6A,0xE5,0x15,0xD2,0x26,0x18,0x98,0xFA,0x05,0x10,
+	0x15,0x72,0x8E,0x5A,0x8A,0xAA,0xC4,0x2D,0xAD,0x33,0x17,0x0D,0x04,0x50,0x7A,0x33,
+	0xA8,0x55,0x21,0xAB,0xDF,0x1C,0xBA,0x64,0xEC,0xFB,0x85,0x04,0x58,0xDB,0xEF,0x0A,
+	0x8A,0xEA,0x71,0x57,0x5D,0x06,0x0C,0x7D,0xB3,0x97,0x0F,0x85,0xA6,0xE1,0xE4,0xC7,
+	0xAB,0xF5,0xAE,0x8C,0xDB,0x09,0x33,0xD7,0x1E,0x8C,0x94,0xE0,0x4A,0x25,0x61,0x9D,
+	0xCE,0xE3,0xD2,0x26,0x1A,0xD2,0xEE,0x6B,0xF1,0x2F,0xFA,0x06,0xD9,0x8A,0x08,0x64,
+	0xD8,0x76,0x02,0x73,0x3E,0xC8,0x6A,0x64,0x52,0x1F,0x2B,0x18,0x17,0x7B,0x20,0x0C,
+	0xBB,0xE1,0x17,0x57,0x7A,0x61,0x5D,0x6C,0x77,0x09,0x88,0xC0,0xBA,0xD9,0x46,0xE2,
+	0x08,0xE2,0x4F,0xA0,0x74,0xE5,0xAB,0x31,0x43,0xDB,0x5B,0xFC,0xE0,0xFD,0x10,0x8E,
+	0x4B,0x82,0xD1,0x20,0xA9,0x3A,0xD2,0xCA,0xFF,0xFF,0xFF,0xFF,0xFF,0xFF,0xFF,0xFF
+};
+
+/**
+ * Modulus of Group 16 (MODP_4096_BIT).
+ */
+static u_int8_t group16_modulus[] = {
+	0xFF,0xFF,0xFF,0xFF,0xFF,0xFF,0xFF,0xFF,0xC9,0x0F,0xDA,0xA2,0x21,0x68,0xC2,0x34,
+	0xC4,0xC6,0x62,0x8B,0x80,0xDC,0x1C,0xD1,0x29,0x02,0x4E,0x08,0x8A,0x67,0xCC,0x74,
+	0x02,0x0B,0xBE,0xA6,0x3B,0x13,0x9B,0x22,0x51,0x4A,0x08,0x79,0x8E,0x34,0x04,0xDD,
+	0xEF,0x95,0x19,0xB3,0xCD,0x3A,0x43,0x1B,0x30,0x2B,0x0A,0x6D,0xF2,0x5F,0x14,0x37,
+	0x4F,0xE1,0x35,0x6D,0x6D,0x51,0xC2,0x45,0xE4,0x85,0xB5,0x76,0x62,0x5E,0x7E,0xC6,
+	0xF4,0x4C,0x42,0xE9,0xA6,0x37,0xED,0x6B,0x0B,0xFF,0x5C,0xB6,0xF4,0x06,0xB7,0xED,
+	0xEE,0x38,0x6B,0xFB,0x5A,0x89,0x9F,0xA5,0xAE,0x9F,0x24,0x11,0x7C,0x4B,0x1F,0xE6,
+	0x49,0x28,0x66,0x51,0xEC,0xE4,0x5B,0x3D,0xC2,0x00,0x7C,0xB8,0xA1,0x63,0xBF,0x05,
+	0x98,0xDA,0x48,0x36,0x1C,0x55,0xD3,0x9A,0x69,0x16,0x3F,0xA8,0xFD,0x24,0xCF,0x5F,
+	0x83,0x65,0x5D,0x23,0xDC,0xA3,0xAD,0x96,0x1C,0x62,0xF3,0x56,0x20,0x85,0x52,0xBB,
+	0x9E,0xD5,0x29,0x07,0x70,0x96,0x96,0x6D,0x67,0x0C,0x35,0x4E,0x4A,0xBC,0x98,0x04,
+	0xF1,0x74,0x6C,0x08,0xCA,0x18,0x21,0x7C,0x32,0x90,0x5E,0x46,0x2E,0x36,0xCE,0x3B,
+	0xE3,0x9E,0x77,0x2C,0x18,0x0E,0x86,0x03,0x9B,0x27,0x83,0xA2,0xEC,0x07,0xA2,0x8F,
+	0xB5,0xC5,0x5D,0xF0,0x6F,0x4C,0x52,0xC9,0xDE,0x2B,0xCB,0xF6,0x95,0x58,0x17,0x18,
+	0x39,0x95,0x49,0x7C,0xEA,0x95,0x6A,0xE5,0x15,0xD2,0x26,0x18,0x98,0xFA,0x05,0x10,
+	0x15,0x72,0x8E,0x5A,0x8A,0xAA,0xC4,0x2D,0xAD,0x33,0x17,0x0D,0x04,0x50,0x7A,0x33,
+	0xA8,0x55,0x21,0xAB,0xDF,0x1C,0xBA,0x64,0xEC,0xFB,0x85,0x04,0x58,0xDB,0xEF,0x0A,
+	0x8A,0xEA,0x71,0x57,0x5D,0x06,0x0C,0x7D,0xB3,0x97,0x0F,0x85,0xA6,0xE1,0xE4,0xC7,
+	0xAB,0xF5,0xAE,0x8C,0xDB,0x09,0x33,0xD7,0x1E,0x8C,0x94,0xE0,0x4A,0x25,0x61,0x9D,
+	0xCE,0xE3,0xD2,0x26,0x1A,0xD2,0xEE,0x6B,0xF1,0x2F,0xFA,0x06,0xD9,0x8A,0x08,0x64,
+	0xD8,0x76,0x02,0x73,0x3E,0xC8,0x6A,0x64,0x52,0x1F,0x2B,0x18,0x17,0x7B,0x20,0x0C,
+	0xBB,0xE1,0x17,0x57,0x7A,0x61,0x5D,0x6C,0x77,0x09,0x88,0xC0,0xBA,0xD9,0x46,0xE2,
+	0x08,0xE2,0x4F,0xA0,0x74,0xE5,0xAB,0x31,0x43,0xDB,0x5B,0xFC,0xE0,0xFD,0x10,0x8E,
+	0x4B,0x82,0xD1,0x20,0xA9,0x21,0x08,0x01,0x1A,0x72,0x3C,0x12,0xA7,0x87,0xE6,0xD7,
+	0x88,0x71,0x9A,0x10,0xBD,0xBA,0x5B,0x26,0x99,0xC3,0x27,0x18,0x6A,0xF4,0xE2,0x3C,
+	0x1A,0x94,0x68,0x34,0xB6,0x15,0x0B,0xDA,0x25,0x83,0xE9,0xCA,0x2A,0xD4,0x4C,0xE8,
+	0xDB,0xBB,0xC2,0xDB,0x04,0xDE,0x8E,0xF9,0x2E,0x8E,0xFC,0x14,0x1F,0xBE,0xCA,0xA6,
+	0x28,0x7C,0x59,0x47,0x4E,0x6B,0xC0,0x5D,0x99,0xB2,0x96,0x4F,0xA0,0x90,0xC3,0xA2,
+	0x23,0x3B,0xA1,0x86,0x51,0x5B,0xE7,0xED,0x1F,0x61,0x29,0x70,0xCE,0xE2,0xD7,0xAF,
+	0xB8,0x1B,0xDD,0x76,0x21,0x70,0x48,0x1C,0xD0,0x06,0x91,0x27,0xD5,0xB0,0x5A,0xA9,
+	0x93,0xB4,0xEA,0x98,0x8D,0x8F,0xDD,0xC1,0x86,0xFF,0xB7,0xDC,0x90,0xA6,0xC0,0x8F,
+	0x4D,0xF4,0x35,0xC9,0x34,0x06,0x31,0x99,0xFF,0xFF,0xFF,0xFF,0xFF,0xFF,0xFF,0xFF
+};
+
+/**
+ * Modulus of Group 17 (MODP_6144_BIT).
+ */
+static u_int8_t group17_modulus[] = {
+	0xFF,0xFF,0xFF,0xFF,0xFF,0xFF,0xFF,0xFF,0xC9,0x0F,0xDA,0xA2,0x21,0x68,0xC2,0x34,
+	0xC4,0xC6,0x62,0x8B,0x80,0xDC,0x1C,0xD1,0x29,0x02,0x4E,0x08,0x8A,0x67,0xCC,0x74,
+	0x02,0x0B,0xBE,0xA6,0x3B,0x13,0x9B,0x22,0x51,0x4A,0x08,0x79,0x8E,0x34,0x04,0xDD,
+	0xEF,0x95,0x19,0xB3,0xCD,0x3A,0x43,0x1B,0x30,0x2B,0x0A,0x6D,0xF2,0x5F,0x14,0x37,
+	0x4F,0xE1,0x35,0x6D,0x6D,0x51,0xC2,0x45,0xE4,0x85,0xB5,0x76,0x62,0x5E,0x7E,0xC6,
+	0xF4,0x4C,0x42,0xE9,0xA6,0x37,0xED,0x6B,0x0B,0xFF,0x5C,0xB6,0xF4,0x06,0xB7,0xED,
+	0xEE,0x38,0x6B,0xFB,0x5A,0x89,0x9F,0xA5,0xAE,0x9F,0x24,0x11,0x7C,0x4B,0x1F,0xE6,
+	0x49,0x28,0x66,0x51,0xEC,0xE4,0x5B,0x3D,0xC2,0x00,0x7C,0xB8,0xA1,0x63,0xBF,0x05,
+	0x98,0xDA,0x48,0x36,0x1C,0x55,0xD3,0x9A,0x69,0x16,0x3F,0xA8,0xFD,0x24,0xCF,0x5F,
+	0x83,0x65,0x5D,0x23,0xDC,0xA3,0xAD,0x96,0x1C,0x62,0xF3,0x56,0x20,0x85,0x52,0xBB,
+	0x9E,0xD5,0x29,0x07,0x70,0x96,0x96,0x6D,0x67,0x0C,0x35,0x4E,0x4A,0xBC,0x98,0x04,
+	0xF1,0x74,0x6C,0x08,0xCA,0x18,0x21,0x7C,0x32,0x90,0x5E,0x46,0x2E,0x36,0xCE,0x3B,
+	0xE3,0x9E,0x77,0x2C,0x18,0x0E,0x86,0x03,0x9B,0x27,0x83,0xA2,0xEC,0x07,0xA2,0x8F,
+	0xB5,0xC5,0x5D,0xF0,0x6F,0x4C,0x52,0xC9,0xDE,0x2B,0xCB,0xF6,0x95,0x58,0x17,0x18,
+	0x39,0x95,0x49,0x7C,0xEA,0x95,0x6A,0xE5,0x15,0xD2,0x26,0x18,0x98,0xFA,0x05,0x10,
+	0x15,0x72,0x8E,0x5A,0x8A,0xAA,0xC4,0x2D,0xAD,0x33,0x17,0x0D,0x04,0x50,0x7A,0x33,
+	0xA8,0x55,0x21,0xAB,0xDF,0x1C,0xBA,0x64,0xEC,0xFB,0x85,0x04,0x58,0xDB,0xEF,0x0A,
+	0x8A,0xEA,0x71,0x57,0x5D,0x06,0x0C,0x7D,0xB3,0x97,0x0F,0x85,0xA6,0xE1,0xE4,0xC7,
+	0xAB,0xF5,0xAE,0x8C,0xDB,0x09,0x33,0xD7,0x1E,0x8C,0x94,0xE0,0x4A,0x25,0x61,0x9D,
+	0xCE,0xE3,0xD2,0x26,0x1A,0xD2,0xEE,0x6B,0xF1,0x2F,0xFA,0x06,0xD9,0x8A,0x08,0x64,
+	0xD8,0x76,0x02,0x73,0x3E,0xC8,0x6A,0x64,0x52,0x1F,0x2B,0x18,0x17,0x7B,0x20,0x0C,
+	0xBB,0xE1,0x17,0x57,0x7A,0x61,0x5D,0x6C,0x77,0x09,0x88,0xC0,0xBA,0xD9,0x46,0xE2,
+	0x08,0xE2,0x4F,0xA0,0x74,0xE5,0xAB,0x31,0x43,0xDB,0x5B,0xFC,0xE0,0xFD,0x10,0x8E,
+	0x4B,0x82,0xD1,0x20,0xA9,0x21,0x08,0x01,0x1A,0x72,0x3C,0x12,0xA7,0x87,0xE6,0xD7,
+	0x88,0x71,0x9A,0x10,0xBD,0xBA,0x5B,0x26,0x99,0xC3,0x27,0x18,0x6A,0xF4,0xE2,0x3C,
+	0x1A,0x94,0x68,0x34,0xB6,0x15,0x0B,0xDA,0x25,0x83,0xE9,0xCA,0x2A,0xD4,0x4C,0xE8,
+	0xDB,0xBB,0xC2,0xDB,0x04,0xDE,0x8E,0xF9,0x2E,0x8E,0xFC,0x14,0x1F,0xBE,0xCA,0xA6,
+	0x28,0x7C,0x59,0x47,0x4E,0x6B,0xC0,0x5D,0x99,0xB2,0x96,0x4F,0xA0,0x90,0xC3,0xA2,
+	0x23,0x3B,0xA1,0x86,0x51,0x5B,0xE7,0xED,0x1F,0x61,0x29,0x70,0xCE,0xE2,0xD7,0xAF,
+	0xB8,0x1B,0xDD,0x76,0x21,0x70,0x48,0x1C,0xD0,0x06,0x91,0x27,0xD5,0xB0,0x5A,0xA9,
+	0x93,0xB4,0xEA,0x98,0x8D,0x8F,0xDD,0xC1,0x86,0xFF,0xB7,0xDC,0x90,0xA6,0xC0,0x8F,
+	0x4D,0xF4,0x35,0xC9,0x34,0x02,0x84,0x92,0x36,0xC3,0xFA,0xB4,0xD2,0x7C,0x70,0x26,
+	0xC1,0xD4,0xDC,0xB2,0x60,0x26,0x46,0xDE,0xC9,0x75,0x1E,0x76,0x3D,0xBA,0x37,0xBD,
+	0xF8,0xFF,0x94,0x06,0xAD,0x9E,0x53,0x0E,0xE5,0xDB,0x38,0x2F,0x41,0x30,0x01,0xAE,
+	0xB0,0x6A,0x53,0xED,0x90,0x27,0xD8,0x31,0x17,0x97,0x27,0xB0,0x86,0x5A,0x89,0x18,
+	0xDA,0x3E,0xDB,0xEB,0xCF,0x9B,0x14,0xED,0x44,0xCE,0x6C,0xBA,0xCE,0xD4,0xBB,0x1B,
+	0xDB,0x7F,0x14,0x47,0xE6,0xCC,0x25,0x4B,0x33,0x20,0x51,0x51,0x2B,0xD7,0xAF,0x42,
+	0x6F,0xB8,0xF4,0x01,0x37,0x8C,0xD2,0xBF,0x59,0x83,0xCA,0x01,0xC6,0x4B,0x92,0xEC,
+	0xF0,0x32,0xEA,0x15,0xD1,0x72,0x1D,0x03,0xF4,0x82,0xD7,0xCE,0x6E,0x74,0xFE,0xF6,
+	0xD5,0x5E,0x70,0x2F,0x46,0x98,0x0C,0x82,0xB5,0xA8,0x40,0x31,0x90,0x0B,0x1C,0x9E,
+	0x59,0xE7,0xC9,0x7F,0xBE,0xC7,0xE8,0xF3,0x23,0xA9,0x7A,0x7E,0x36,0xCC,0x88,0xBE,
+	0x0F,0x1D,0x45,0xB7,0xFF,0x58,0x5A,0xC5,0x4B,0xD4,0x07,0xB2,0x2B,0x41,0x54,0xAA,
+	0xCC,0x8F,0x6D,0x7E,0xBF,0x48,0xE1,0xD8,0x14,0xCC,0x5E,0xD2,0x0F,0x80,0x37,0xE0,
+	0xA7,0x97,0x15,0xEE,0xF2,0x9B,0xE3,0x28,0x06,0xA1,0xD5,0x8B,0xB7,0xC5,0xDA,0x76,
+	0xF5,0x50,0xAA,0x3D,0x8A,0x1F,0xBF,0xF0,0xEB,0x19,0xCC,0xB1,0xA3,0x13,0xD5,0x5C,
+	0xDA,0x56,0xC9,0xEC,0x2E,0xF2,0x96,0x32,0x38,0x7F,0xE8,0xD7,0x6E,0x3C,0x04,0x68,
+	0x04,0x3E,0x8F,0x66,0x3F,0x48,0x60,0xEE,0x12,0xBF,0x2D,0x5B,0x0B,0x74,0x74,0xD6,
+	0xE6,0x94,0xF9,0x1E,0x6D,0xCC,0x40,0x24,0xFF,0xFF,0xFF,0xFF,0xFF,0xFF,0xFF,0xFF
+};
+
+/**
+ * Modulus of Group 18 (MODP_8192_BIT).
+ */
+static u_int8_t group18_modulus[] = {
+	0xFF,0xFF,0xFF,0xFF,0xFF,0xFF,0xFF,0xFF,0xC9,0x0F,0xDA,0xA2,0x21,0x68,0xC2,0x34,
+	0xC4,0xC6,0x62,0x8B,0x80,0xDC,0x1C,0xD1,0x29,0x02,0x4E,0x08,0x8A,0x67,0xCC,0x74,
+	0x02,0x0B,0xBE,0xA6,0x3B,0x13,0x9B,0x22,0x51,0x4A,0x08,0x79,0x8E,0x34,0x04,0xDD,
+	0xEF,0x95,0x19,0xB3,0xCD,0x3A,0x43,0x1B,0x30,0x2B,0x0A,0x6D,0xF2,0x5F,0x14,0x37,
+	0x4F,0xE1,0x35,0x6D,0x6D,0x51,0xC2,0x45,0xE4,0x85,0xB5,0x76,0x62,0x5E,0x7E,0xC6,
+	0xF4,0x4C,0x42,0xE9,0xA6,0x37,0xED,0x6B,0x0B,0xFF,0x5C,0xB6,0xF4,0x06,0xB7,0xED,
+	0xEE,0x38,0x6B,0xFB,0x5A,0x89,0x9F,0xA5,0xAE,0x9F,0x24,0x11,0x7C,0x4B,0x1F,0xE6,
+	0x49,0x28,0x66,0x51,0xEC,0xE4,0x5B,0x3D,0xC2,0x00,0x7C,0xB8,0xA1,0x63,0xBF,0x05,
+	0x98,0xDA,0x48,0x36,0x1C,0x55,0xD3,0x9A,0x69,0x16,0x3F,0xA8,0xFD,0x24,0xCF,0x5F,
+	0x83,0x65,0x5D,0x23,0xDC,0xA3,0xAD,0x96,0x1C,0x62,0xF3,0x56,0x20,0x85,0x52,0xBB,
+	0x9E,0xD5,0x29,0x07,0x70,0x96,0x96,0x6D,0x67,0x0C,0x35,0x4E,0x4A,0xBC,0x98,0x04,
+	0xF1,0x74,0x6C,0x08,0xCA,0x18,0x21,0x7C,0x32,0x90,0x5E,0x46,0x2E,0x36,0xCE,0x3B,
+	0xE3,0x9E,0x77,0x2C,0x18,0x0E,0x86,0x03,0x9B,0x27,0x83,0xA2,0xEC,0x07,0xA2,0x8F,
+	0xB5,0xC5,0x5D,0xF0,0x6F,0x4C,0x52,0xC9,0xDE,0x2B,0xCB,0xF6,0x95,0x58,0x17,0x18,
+	0x39,0x95,0x49,0x7C,0xEA,0x95,0x6A,0xE5,0x15,0xD2,0x26,0x18,0x98,0xFA,0x05,0x10,
+	0x15,0x72,0x8E,0x5A,0x8A,0xAA,0xC4,0x2D,0xAD,0x33,0x17,0x0D,0x04,0x50,0x7A,0x33,
+	0xA8,0x55,0x21,0xAB,0xDF,0x1C,0xBA,0x64,0xEC,0xFB,0x85,0x04,0x58,0xDB,0xEF,0x0A,
+	0x8A,0xEA,0x71,0x57,0x5D,0x06,0x0C,0x7D,0xB3,0x97,0x0F,0x85,0xA6,0xE1,0xE4,0xC7,
+	0xAB,0xF5,0xAE,0x8C,0xDB,0x09,0x33,0xD7,0x1E,0x8C,0x94,0xE0,0x4A,0x25,0x61,0x9D,
+	0xCE,0xE3,0xD2,0x26,0x1A,0xD2,0xEE,0x6B,0xF1,0x2F,0xFA,0x06,0xD9,0x8A,0x08,0x64,
+	0xD8,0x76,0x02,0x73,0x3E,0xC8,0x6A,0x64,0x52,0x1F,0x2B,0x18,0x17,0x7B,0x20,0x0C,
+	0xBB,0xE1,0x17,0x57,0x7A,0x61,0x5D,0x6C,0x77,0x09,0x88,0xC0,0xBA,0xD9,0x46,0xE2,
+	0x08,0xE2,0x4F,0xA0,0x74,0xE5,0xAB,0x31,0x43,0xDB,0x5B,0xFC,0xE0,0xFD,0x10,0x8E,
+	0x4B,0x82,0xD1,0x20,0xA9,0x21,0x08,0x01,0x1A,0x72,0x3C,0x12,0xA7,0x87,0xE6,0xD7,
+	0x88,0x71,0x9A,0x10,0xBD,0xBA,0x5B,0x26,0x99,0xC3,0x27,0x18,0x6A,0xF4,0xE2,0x3C,
+	0x1A,0x94,0x68,0x34,0xB6,0x15,0x0B,0xDA,0x25,0x83,0xE9,0xCA,0x2A,0xD4,0x4C,0xE8,
+	0xDB,0xBB,0xC2,0xDB,0x04,0xDE,0x8E,0xF9,0x2E,0x8E,0xFC,0x14,0x1F,0xBE,0xCA,0xA6,
+	0x28,0x7C,0x59,0x47,0x4E,0x6B,0xC0,0x5D,0x99,0xB2,0x96,0x4F,0xA0,0x90,0xC3,0xA2,
+	0x23,0x3B,0xA1,0x86,0x51,0x5B,0xE7,0xED,0x1F,0x61,0x29,0x70,0xCE,0xE2,0xD7,0xAF,
+	0xB8,0x1B,0xDD,0x76,0x21,0x70,0x48,0x1C,0xD0,0x06,0x91,0x27,0xD5,0xB0,0x5A,0xA9,
+	0x93,0xB4,0xEA,0x98,0x8D,0x8F,0xDD,0xC1,0x86,0xFF,0xB7,0xDC,0x90,0xA6,0xC0,0x8F,
+	0x4D,0xF4,0x35,0xC9,0x34,0x02,0x84,0x92,0x36,0xC3,0xFA,0xB4,0xD2,0x7C,0x70,0x26,
+	0xC1,0xD4,0xDC,0xB2,0x60,0x26,0x46,0xDE,0xC9,0x75,0x1E,0x76,0x3D,0xBA,0x37,0xBD,
+	0xF8,0xFF,0x94,0x06,0xAD,0x9E,0x53,0x0E,0xE5,0xDB,0x38,0x2F,0x41,0x30,0x01,0xAE,
+	0xB0,0x6A,0x53,0xED,0x90,0x27,0xD8,0x31,0x17,0x97,0x27,0xB0,0x86,0x5A,0x89,0x18,
+	0xDA,0x3E,0xDB,0xEB,0xCF,0x9B,0x14,0xED,0x44,0xCE,0x6C,0xBA,0xCE,0xD4,0xBB,0x1B,
+	0xDB,0x7F,0x14,0x47,0xE6,0xCC,0x25,0x4B,0x33,0x20,0x51,0x51,0x2B,0xD7,0xAF,0x42,
+	0x6F,0xB8,0xF4,0x01,0x37,0x8C,0xD2,0xBF,0x59,0x83,0xCA,0x01,0xC6,0x4B,0x92,0xEC,
+	0xF0,0x32,0xEA,0x15,0xD1,0x72,0x1D,0x03,0xF4,0x82,0xD7,0xCE,0x6E,0x74,0xFE,0xF6,
+	0xD5,0x5E,0x70,0x2F,0x46,0x98,0x0C,0x82,0xB5,0xA8,0x40,0x31,0x90,0x0B,0x1C,0x9E,
+	0x59,0xE7,0xC9,0x7F,0xBE,0xC7,0xE8,0xF3,0x23,0xA9,0x7A,0x7E,0x36,0xCC,0x88,0xBE,
+	0x0F,0x1D,0x45,0xB7,0xFF,0x58,0x5A,0xC5,0x4B,0xD4,0x07,0xB2,0x2B,0x41,0x54,0xAA,
+	0xCC,0x8F,0x6D,0x7E,0xBF,0x48,0xE1,0xD8,0x14,0xCC,0x5E,0xD2,0x0F,0x80,0x37,0xE0,
+	0xA7,0x97,0x15,0xEE,0xF2,0x9B,0xE3,0x28,0x06,0xA1,0xD5,0x8B,0xB7,0xC5,0xDA,0x76,
+	0xF5,0x50,0xAA,0x3D,0x8A,0x1F,0xBF,0xF0,0xEB,0x19,0xCC,0xB1,0xA3,0x13,0xD5,0x5C,
+	0xDA,0x56,0xC9,0xEC,0x2E,0xF2,0x96,0x32,0x38,0x7F,0xE8,0xD7,0x6E,0x3C,0x04,0x68,
+	0x04,0x3E,0x8F,0x66,0x3F,0x48,0x60,0xEE,0x12,0xBF,0x2D,0x5B,0x0B,0x74,0x74,0xD6,
+	0xE6,0x94,0xF9,0x1E,0x6D,0xBE,0x11,0x59,0x74,0xA3,0x92,0x6F,0x12,0xFE,0xE5,0xE4,
+	0x38,0x77,0x7C,0xB6,0xA9,0x32,0xDF,0x8C,0xD8,0xBE,0xC4,0xD0,0x73,0xB9,0x31,0xBA,
+	0x3B,0xC8,0x32,0xB6,0x8D,0x9D,0xD3,0x00,0x74,0x1F,0xA7,0xBF,0x8A,0xFC,0x47,0xED,
+	0x25,0x76,0xF6,0x93,0x6B,0xA4,0x24,0x66,0x3A,0xAB,0x63,0x9C,0x5A,0xE4,0xF5,0x68,
+	0x34,0x23,0xB4,0x74,0x2B,0xF1,0xC9,0x78,0x23,0x8F,0x16,0xCB,0xE3,0x9D,0x65,0x2D,
+	0xE3,0xFD,0xB8,0xBE,0xFC,0x84,0x8A,0xD9,0x22,0x22,0x2E,0x04,0xA4,0x03,0x7C,0x07,
+	0x13,0xEB,0x57,0xA8,0x1A,0x23,0xF0,0xC7,0x34,0x73,0xFC,0x64,0x6C,0xEA,0x30,0x6B,
+	0x4B,0xCB,0xC8,0x86,0x2F,0x83,0x85,0xDD,0xFA,0x9D,0x4B,0x7F,0xA2,0xC0,0x87,0xE8,
+	0x79,0x68,0x33,0x03,0xED,0x5B,0xDD,0x3A,0x06,0x2B,0x3C,0xF5,0xB3,0xA2,0x78,0xA6,
+	0x6D,0x2A,0x13,0xF8,0x3F,0x44,0xF8,0x2D,0xDF,0x31,0x0E,0xE0,0x74,0xAB,0x6A,0x36,
+	0x45,0x97,0xE8,0x99,0xA0,0x25,0x5D,0xC1,0x64,0xF3,0x1C,0xC5,0x08,0x46,0x85,0x1D,
+	0xF9,0xAB,0x48,0x19,0x5D,0xED,0x7E,0xA1,0xB1,0xD5,0x10,0xBD,0x7E,0xE7,0x4D,0x73,
+	0xFA,0xF3,0x6B,0xC3,0x1E,0xCF,0xA2,0x68,0x35,0x90,0x46,0xF4,0xEB,0x87,0x9F,0x92,
+	0x40,0x09,0x43,0x8B,0x48,0x1C,0x6C,0xD7,0x88,0x9A,0x00,0x2E,0xD5,0xEE,0x38,0x2B,
+	0xC9,0x19,0x0D,0xA6,0xFC,0x02,0x6E,0x47,0x95,0x58,0xE4,0x47,0x56,0x77,0xE9,0xAA,
+	0x9E,0x30,0x50,0xE2,0x76,0x56,0x94,0xDF,0xC8,0x1F,0x56,0xE8,0x80,0xB9,0x6E,0x71,
+	0x60,0xC9,0x80,0xDD,0x98,0xED,0xD3,0xDF,0xFF,0xFF,0xFF,0xFF,0xFF,0xFF,0xFF,0xFF,
+};
+
+typedef struct modulus_entry_t modulus_entry_t;
+
+/** 
+ * Entry of the modulus list.
+ */
+struct modulus_entry_t {
+	/** IKEv2 DH group */
+	diffie_hellman_group_t group;
+	/** modulus */
+	chunk_t modulus;
+	/** optimum length of exponent in bytes */
+	size_t opt_len;
+	/** generator */
+	u_int16_t g;
+};
+
+/**
+ * All supported modulus values - optimum exponent size according to RFC 3526.
+ */
+static modulus_entry_t modulus_entries[] = {
+	{MODP_768_BIT,  {group1_modulus,  sizeof(group1_modulus)},  32, 2},
+	{MODP_1024_BIT, {group2_modulus,  sizeof(group2_modulus)},  32, 2},
+	{MODP_1536_BIT, {group5_modulus,  sizeof(group5_modulus)},  32, 2},
+	{MODP_2048_BIT, {group14_modulus, sizeof(group14_modulus)}, 48, 2},
+	{MODP_3072_BIT, {group15_modulus, sizeof(group15_modulus)}, 48, 2},
+	{MODP_4096_BIT, {group16_modulus, sizeof(group16_modulus)}, 64, 2},
+	{MODP_6144_BIT, {group17_modulus, sizeof(group17_modulus)}, 64, 2},
+	{MODP_8192_BIT, {group18_modulus, sizeof(group18_modulus)}, 64, 2},
+};
+
+/**
+ * Lookup the modulus in modulo table
+ */
+static modulus_entry_t *find_entry(diffie_hellman_group_t group)
+{
+	int i;
+	
+	for (i = 0; i < countof(modulus_entries); i++)
+	{
+		if (modulus_entries[i].group == group)
+		{
+			return &modulus_entries[i];
+		}
+	}
+	return NULL;
+}
+
+typedef struct private_gcrypt_dh_t private_gcrypt_dh_t;
+
+/**
+ * Private data of an gcrypt_dh_t object.
+ */
+struct private_gcrypt_dh_t {
+	
+	/**
+	 * Public gcrypt_dh_t interface
+	 */
+	gcrypt_dh_t public;
+	
+	/**
+	 * Diffie Hellman group number
+	 */
+	u_int16_t group;
+	
+	/* 
+	 * Generator value
+	 */	
+	gcry_mpi_t g;
+	
+	/**
+	 * Own private value
+	 */
+	gcry_mpi_t xa;
+	
+	/**
+	 * Own public value
+	 */
+	gcry_mpi_t ya;
+	
+	/**
+	 * Other public value
+	 */
+	gcry_mpi_t yb;
+	
+	/**
+	 * Shared secret
+	 */
+	gcry_mpi_t zz;
+	
+	/**
+	 * Modulus
+	 */
+	gcry_mpi_t p;
+	
+	/**
+	 * Modulus length.
+	 */
+	size_t p_len;
+};
+
+/**
+ * Implementation of gcrypt_dh_t.set_other_public_value.
+ */
+static void set_other_public_value(private_gcrypt_dh_t *this, chunk_t value)
+{
+	gcry_mpi_t p_min_1;
+	gcry_error_t err;
+	
+	if (this->yb)
+	{
+		gcry_mpi_release(this->yb);
+		this->yb = NULL;
+	}
+	err = gcry_mpi_scan(&this->yb, GCRYMPI_FMT_USG, value.ptr, value.len, NULL);
+	if (err)
+	{
+		DBG1("importing mpi yb failed: %s", gpg_strerror(err));
+		return;
+	}
+	
+	p_min_1 = gcry_mpi_new(this->p_len * 8);
+	gcry_mpi_sub_ui(p_min_1, this->p, 1);
+	
+	/* check public value: 
+	 * 1. 0 or 1 is invalid as 0^a = 0 and 1^a = 1
+	 * 2. a public value larger or equal the modulus is invalid */
+	if (gcry_mpi_cmp_ui(this->yb, 1) > 0 &&
+		gcry_mpi_cmp(this->yb, p_min_1) < 0)
+	{
+		if (!this->zz)
+		{
+			this->zz = gcry_mpi_new(this->p_len * 8);
+		}
+		gcry_mpi_powm(this->zz, this->yb, this->xa, this->p);
+	}
+	else
+	{
+		DBG1("public DH value verification failed: y < 2 || y > p - 1 ");
+	}
+	gcry_mpi_release(p_min_1);
+}
+
+/**
+ * export a gcry_mpi to an allocated chunk of len bytes
+ */
+static chunk_t export_mpi(gcry_mpi_t value, size_t len)
+{
+	chunk_t chunk;
+	size_t written;
+	
+	chunk = chunk_alloc(len);
+	gcry_mpi_print(GCRYMPI_FMT_USG, chunk.ptr, chunk.len, &written, value);
+	if (written < len)
+	{	/* right-align number of written bytes in chunk */
+		memmove(chunk.ptr + (len - written), chunk.ptr, written);
+		memset(chunk.ptr, 0, len - written);
+	}
+	return chunk;
+}
+
+/**
+ * Implementation of gcrypt_dh_t.get_my_public_value.
+ */
+static void get_my_public_value(private_gcrypt_dh_t *this, chunk_t *value)
+{
+	*value = export_mpi(this->ya, this->p_len);
+}
+
+/**
+ * Implementation of gcrypt_dh_t.get_shared_secret.
+ */
+static status_t get_shared_secret(private_gcrypt_dh_t *this, chunk_t *secret)
+{
+	if (!this->zz)
+	{
+		return FAILED;
+	}
+	*secret = export_mpi(this->zz, this->p_len);
+	return SUCCESS;
+}
+
+/**
+ * Implementation of gcrypt_dh_t.get_dh_group.
+ */
+static diffie_hellman_group_t get_dh_group(private_gcrypt_dh_t *this)
+{
+	return this->group;
+}
+
+/**
+ * Implementation of gcrypt_dh_t.destroy.
+ */
+static void destroy(private_gcrypt_dh_t *this)
+{
+	gcry_mpi_release(this->p);
+	gcry_mpi_release(this->xa);
+	gcry_mpi_release(this->ya);
+	gcry_mpi_release(this->g);
+	gcry_mpi_release(this->yb);
+	gcry_mpi_release(this->zz);
+	free(this);
+}
+
+/*
+ * Described in header.
+ */
+gcrypt_dh_t *gcrypt_dh_create(diffie_hellman_group_t group)
+{
+	private_gcrypt_dh_t *this;
+	modulus_entry_t *entry;
+	gcry_error_t err;
+	chunk_t random;
+	rng_t *rng;
+	size_t len;
+	
+	entry = find_entry(group);
+	if (!entry)
+	{
+		return NULL;
+	}
+	
+	this = malloc_thing(private_gcrypt_dh_t);
+	
+	this->public.dh.get_shared_secret = (status_t (*)(diffie_hellman_t *, chunk_t *)) get_shared_secret;
+	this->public.dh.set_other_public_value = (void (*)(diffie_hellman_t *, chunk_t )) set_other_public_value;
+	this->public.dh.get_my_public_value = (void (*)(diffie_hellman_t *, chunk_t *)) get_my_public_value;
+	this->public.dh.get_dh_group = (diffie_hellman_group_t (*)(diffie_hellman_t *)) get_dh_group;
+	this->public.dh.destroy = (void (*)(diffie_hellman_t *)) destroy;
+	
+	this->group = group;
+	this->p_len = entry->modulus.len;
+	err = gcry_mpi_scan(&this->p, GCRYMPI_FMT_USG,
+						entry->modulus.ptr, entry->modulus.len, NULL);
+	if (err)
+	{
+		DBG1("importing mpi modulus failed: %s", gpg_strerror(err));
+		free(this);
+		return NULL;
+	}
+	if (lib->settings->get_int(lib->settings,
+								"libstrongswan.dh_exponent_ansi_x9_42", TRUE))
+	{
+		len = this->p_len;
+	}
+	else
+	{
+		len = entry->opt_len;
+	}
+	
+	rng = lib->crypto->create_rng(lib->crypto, RNG_STRONG);
+	if (rng)
+	{	/* prefer external randomizer */
+		rng->allocate_bytes(rng, len, &random);
+		rng->destroy(rng);
+		err = gcry_mpi_scan(&this->xa, GCRYMPI_FMT_USG,
+							random.ptr, random.len, NULL);
+		chunk_clear(&random);
+		if (err)
+		{
+			DBG1("importing mpi xa failed: %s", gpg_strerror(err));
+			gcry_mpi_release(this->p);
+			free(this);
+			return NULL;
+		}
+	}
+	else
+	{	/* fallback to gcrypt internal randomizer, shouldn't ever happen */
+		this->xa = gcry_mpi_new(len * 8);
+		gcry_mpi_randomize(this->xa, len * 8, GCRY_STRONG_RANDOM);
+	}
+	if (len == this->p_len)
+	{
+		/* achieve bitsof(p)-1 by setting MSB to 0 */
+		gcry_mpi_clear_bit(this->xa, len * 8 - 1);
+	}
+	
+	this->g = gcry_mpi_set_ui(NULL, entry->g);
+	this->ya = gcry_mpi_new(this->p_len * 8);
+	this->yb = NULL;
+	this->zz = NULL;
+	
+	gcry_mpi_powm(this->ya, this->g, this->xa, this->p);
+	
+	return &this->public;
+}
+
diff --git a/src/libstrongswan/plugins/gcrypt/gcrypt_dh.h b/src/libstrongswan/plugins/gcrypt/gcrypt_dh.h
new file mode 100644
index 000000000..dbef96ca7
--- /dev/null
+++ b/src/libstrongswan/plugins/gcrypt/gcrypt_dh.h
@@ -0,0 +1,48 @@
+/*
+ * Copyright (C) 2009 Martin Willi
+ * Hochschule fuer Technik Rapperswil
+ *
+ * This program is free software; you can redistribute it and/or modify it
+ * under the terms of the GNU General Public License as published by the
+ * Free Software Foundation; either version 2 of the License, or (at your
+ * option) any later version.  See <http://www.fsf.org/copyleft/gpl.txt>.
+ *
+ * This program is distributed in the hope that it will be useful, but
+ * WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY
+ * or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
+ * for more details.
+ */
+
+/**
+ * @defgroup gcrypt_dh gcrypt_dh
+ * @{ @ingroup gcrypt_p
+ */
+
+#ifndef GCRYPT_DH_H_
+#define GCRYPT_DH_H_
+
+typedef struct gcrypt_dh_t gcrypt_dh_t;
+
+#include <library.h>
+
+/**
+ * Implementation of the Diffie-Hellman algorithm using libgcrypt mpi.
+ */
+struct gcrypt_dh_t {
+	
+	/**
+	 * Implements diffie_hellman_t interface.
+	 */
+	diffie_hellman_t dh;
+};
+
+/**
+ * Creates a new gcrypt_dh_t object.
+ * 
+ * @param group			Diffie Hellman group number to use
+ * @return				gcrypt_dh_t object, NULL if not supported
+ */
+gcrypt_dh_t *gcrypt_dh_create(diffie_hellman_group_t group);
+
+#endif /** GCRYPT_DH_H_ @}*/
+
diff --git a/src/libstrongswan/plugins/gcrypt/gcrypt_plugin.c b/src/libstrongswan/plugins/gcrypt/gcrypt_plugin.c
index 4d1137d44..04eb512d3 100644
--- a/src/libstrongswan/plugins/gcrypt/gcrypt_plugin.c
+++ b/src/libstrongswan/plugins/gcrypt/gcrypt_plugin.c
@@ -18,6 +18,7 @@
 #include "gcrypt_hasher.h"
 #include "gcrypt_crypter.h"
 #include "gcrypt_rng.h"
+#include "gcrypt_dh.h"
 
 #include <library.h>
 #include <debug.h>
@@ -101,6 +102,8 @@ static void destroy(private_gcrypt_plugin_t *this)
 					(crypter_constructor_t)gcrypt_crypter_create);
 	lib->crypto->remove_rng(lib->crypto,
 					(rng_constructor_t)gcrypt_rng_create);
+	lib->crypto->remove_dh(lib->crypto,
+					(dh_constructor_t)gcrypt_dh_create);
 	free(this);
 }
 
@@ -173,6 +176,24 @@ plugin_t *plugin_create()
 	lib->crypto->add_rng(lib->crypto, RNG_TRUE, 
 						 (rng_constructor_t)gcrypt_rng_create);
 	
+	/* diffie hellman groups, using modp */
+	lib->crypto->add_dh(lib->crypto, MODP_2048_BIT, 
+					(dh_constructor_t)gcrypt_dh_create);
+	lib->crypto->add_dh(lib->crypto, MODP_1536_BIT, 
+					(dh_constructor_t)gcrypt_dh_create);
+	lib->crypto->add_dh(lib->crypto, MODP_3072_BIT, 
+					(dh_constructor_t)gcrypt_dh_create);
+	lib->crypto->add_dh(lib->crypto, MODP_4096_BIT, 
+					(dh_constructor_t)gcrypt_dh_create);
+	lib->crypto->add_dh(lib->crypto, MODP_6144_BIT, 
+					(dh_constructor_t)gcrypt_dh_create);
+	lib->crypto->add_dh(lib->crypto, MODP_8192_BIT, 
+					(dh_constructor_t)gcrypt_dh_create);
+	lib->crypto->add_dh(lib->crypto, MODP_1024_BIT,
+					(dh_constructor_t)gcrypt_dh_create);
+	lib->crypto->add_dh(lib->crypto, MODP_768_BIT, 
+					(dh_constructor_t)gcrypt_dh_create);
+	
 	return &this->public.plugin;
 }