diff --git a/extensions/Kbuild b/extensions/Kbuild
index 81a8b30..4c2b91d 100644
--- a/extensions/Kbuild
+++ b/extensions/Kbuild
@@ -35,6 +35,7 @@
 obj-${build_pknock}      += pknock/
 obj-${build_psd}         += xt_psd.o
 obj-${build_quota2}      += xt_quota2.o
+obj-${build_OBSF} += xt_OBSF.o
 
 -include ${M}/*.Kbuild
 -include ${M}/Kbuild.*
diff --git a/extensions/xt_OBSF.c b/extensions/xt_OBSF.c
new file mode 100644
index 0000000..a1060a9
--- /dev/null
+++ b/extensions/xt_OBSF.c
@@ -0,0 +1,148 @@
+#include <linux/module.h>
+#include <linux/skbuff.h>
+
+#include <linux/ip.h>
+#include <linux/ipv6.h>
+#include <linux/udp.h>
+
+#include <linux/netfilter.h>
+#include <linux/netfilter/x_tables.h>
+#include <linux/netfilter/xt_OBSF.h>
+#include <linux/crypto.h>
+#include <linux/scatterlist.h>
+
+MODULE_AUTHOR("Arif Hossain <aftnix@gmail.com>");
+MODULE_DESCRIPTION("Xtables: obsfuscation of UDP traffic");
+MODULE_LICENSE("GPL");
+MODULE_ALIAS("ipt_OBSF");
+MODULE_ALIAS("ip6t_OBSF");
+
+struct xt_obsf_priv {
+	__u8 iv;
+	struct crypto_blkcipher *tfm;
+};
+
+static unsigned int obsf_tg(struct sk_buff *skb, const struct xt_action_param *par)
+{
+	struct udphdr *udh, *udh_buf;
+	unsigned int data_len;
+	void *payload;
+
+ 	struct scatterlist sg;
+	struct blkcipher_desc desc;
+
+	const struct xt_OBSF_tginfo *info = (const void *)par->targinfo;
+
+	if (skb_linearize (skb) < 0)
+		return NF_DROP;
+	
+	udh = skb_header_pointer(skb, par->thoff, sizeof(struct udphdr), &udh_buf);
+	if (udh == NULL)
+		return NF_DROP;
+	if (ntohs(udh->len) <= sizeof(struct udphdr)) /* malformed packet */
+		return NF_DROP;
+	
+	/* data len of udp payload */
+	data_len = htons(udh->len) - sizeof(*udh);
+	payload = skb_header_pointer(skb, par->thoff + sizeof(*udh), data_len, NULL); 
+
+	if (info->flags & XT_OBSF_ENC_ARC4) {
+		/* crypto */
+
+		desc.tfm = info->priv->tfm;
+		desc.flags = 0;
+
+		crypto_blkcipher_set_iv(info->priv->tfm, &info->priv->iv, 4);
+		crypto_blkcipher_setkey(info->priv->tfm, info->key, info->key_len);
+
+		sg_init_one(&sg, payload, data_len);
+
+		if (info->flags & XT_OBSF_ENC_ENC)
+			crypto_blkcipher_encrypt(&desc, &sg, &sg, data_len);
+
+		if (info->flags & XT_OBSF_ENC_DEC)
+			crypto_blkcipher_decrypt(&desc, &sg, &sg, data_len);
+	}	
+	return NF_ACCEPT;
+}
+
+static unsigned int obsf_tg_v1(struct sk_buff *skb, const struct xt_action_param *par)
+{
+	printk("inside obsf_tg_v1");
+	return NF_ACCEPT;
+}
+
+static int obsf_tg_check(const struct xt_tgchk_param *par)
+{
+	struct xt_OBSF_tginfo *info = par->targinfo;
+	/* Allocate and initialize private data structure */
+	struct xt_obsf_priv *priv = kzalloc(sizeof(*priv), GFP_KERNEL);
+	if (priv == NULL)
+		goto fail;
+
+	if (info->flags & XT_OBSF_ENC_ARC4) {
+		priv->tfm = crypto_alloc_blkcipher("ecb(arc4)", 0, CRYPTO_ALG_ASYNC);
+			if (IS_ERR(priv->tfm)) {
+				priv->tfm = NULL;
+				goto fail;
+			}
+
+			get_random_bytes(&priv->iv, 4);
+
+			info->priv = priv;
+			/* flag consistency check */
+
+			return 0;
+	}
+
+	/* failover */
+	fail:
+	if (priv) {
+		if (priv->tfm)
+			crypto_free_blkcipher(priv->tfm);
+		kfree(priv);
+	}
+	info->priv = NULL;
+	return -ENOMEM;
+
+}
+
+static int obsf_tg_check_v1(const struct xt_tgchk_param *par)
+{
+	printk("inside obsf_tg_check_v1");
+	return 0;
+}
+
+static struct xt_target obsf_tg_reg[] __read_mostly = {
+	{
+		.name = "OBSF",
+		.family = NFPROTO_UNSPEC,
+		.target = obsf_tg,
+		.checkentry = obsf_tg_check,
+		.targetsize = sizeof(struct xt_OBSF_tginfo),
+		.me = THIS_MODULE,
+	},
+	{
+		.name = "OBSF",
+		.revision = 1,
+		.family = NFPROTO_UNSPEC,
+		.target = obsf_tg_v1,
+		.targetsize = sizeof(struct xt_OBSF_tginfo_v1),
+		.checkentry = obsf_tg_check_v1,
+		.me = THIS_MODULE,
+	},
+};
+
+static int __init obsf_tg_init(void)
+{
+	return xt_register_targets(obsf_tg_reg, ARRAY_SIZE(obsf_tg_reg));
+}
+
+static void __exit obsf_tg_exit(void)
+{
+	xt_unregister_targets(obsf_tg_reg, ARRAY_SIZE(obsf_tg_reg));
+}
+
+module_init(obsf_tg_init);
+module_exit(obsf_tg_exit);
+
diff --git a/extensions/xt_OBSF.h b/extensions/xt_OBSF.h
new file mode 100644
index 0000000..cef781f
--- /dev/null
+++ b/extensions/xt_OBSF.h
@@ -0,0 +1,32 @@
+#ifndef _LINUX_NETFILTER_XT_OBSF_H
+#define _LINUX_NETFILTER_XT_OBSF_H 1
+
+#define XT_OBSF_MAX_KEY_LEN 32
+enum {
+	XT_OBSF_ENC_ARC4 = 1 << 0,
+	XT_OBSF_ENC_AES = 1 << 1,
+	XT_OBSF_PAD_STATIC = 1 << 2,
+	XT_OBSF_PAD_RANDOM = 1 << 3,
+	XT_OBSF_ENC_ENC = 1 << 4,
+	XT_OBSF_ENC_DEC = 1 << 5,
+	XT_OBSF_PAD_ADD = 1 << 6,
+	XT_OBSF_PAD_REM = 1 << 7
+};
+
+struct xt_OBSF_tginfo {
+	__u8 flags;
+	__u8 key[XT_OBSF_MAX_KEY_LEN];
+	__u8 key_len;
+	struct xt_obsf_priv *priv;
+};
+
+struct xt_OBSF_tginfo_v1 {
+	__u8 flags;
+	__u8 key[XT_OBSF_MAX_KEY_LEN];
+	__u8 key_len;
+	__u8 start;
+	__u8 end;
+	struct xt_obsf_priv *priv;
+};
+
+#endif /* _LINUX_NETFILTER_XT_OBSF_H */
diff --git a/mconfig b/mconfig
index 4fc664a..6c66d43 100644
--- a/mconfig
+++ b/mconfig
@@ -26,3 +26,4 @@
 build_pknock=m
 build_psd=m
 build_quota2=m
+build_OBSF=m