Chaos-based selective key (CSK) Cryptosystem: A new direction to secure VPN

VPNs todays are expected to be more secure and support higher throughput for their new applications, such as Inter-Cloud VPN and Virtual Private Cloud. Blockcipher is an important security component employed in most VPNs. On the other hand, most blockciphers have mathematical weaknesses in their structures, so the attacker can use these weaknesses to break them faster than brute-force attacks. This paper proposes a new method for increasing the security of blockciphers in a much more efficient method than the cascading encryption which is another manner of having a more secure blockcipher. Our method overcomes the weaknesses of blockcipher algorithms against the cryptanalysis which uses some ciphertext/plaintext pairs to obtain the key. The method makes it hard to collect the needed pairs. Our focus in this paper is using of the proposed method in building VPNs which provide higher security and acceptable throughput. Additionally, such VPNs do not need synchronization when the underlying transport protocol is unreliable. Our analytical and practical evaluations demonstrate the satisfaction of the claims.