Coding for Cryptographic Security Enhancement using Stopping Sets

• Type: Article in International Scientific Journal
• Date: 2011

Authors

W. K. Harrison (Author) Other; João Almeida (Author) FEUP; S. W. McLaughlin (Author) Other; João Barros (Author) FEUP

Journal

Title: IEEE Transactions on Information Forensics and Security

Vol. 6 No. 3

Pages: 575-584

ISSN: 1556-6013

Publisher: IEEE

Indexing

ISI Web of Science

Scientific classification

FOS: Engineering and technology > Other engineering and technologies

Other information

DOI: 10.1109/TIFS.2011.2145371

Abstract (EN): In this paper, we discuss the ability of channel codes to enhance cryptographic secrecy. Toward that end, we present the secrecy metric of degrees of freedom in an attacker's knowledge of the cryptogram, which is similar to equivocation. Using this notion of secrecy, we show how a specific practical channel coding system can be used to hide information about the ciphertext, thus increasing the difficulty of cryptographic attacks. The system setup is the wiretap channel model where transmitted data traverse through independent packet erasure channels (PECs) with public feedback for authenticated automatic repeat-request (ARQ). The code design relies on puncturing nonsystematic low-density parity-check (LDPC) codes with the intent of inflicting an eavesdropper with stopping sets in the decoder. The design amplifies errors when stopping sets occur such that a receiver must guess all the channel-erased bits correctly to avoid an error rate of one half in the ciphertext. We extend previous results on the coding scheme by giving design criteria that reduce the effectiveness of a maximum-likelihood (ML) attack to that of a message-passing (MP) attack. We further extend security analysis to models with multiple receivers and collaborative attackers. Cryptographic security is even enhanced by the system when eavesdroppers have better channel quality than legitimate receivers.

Language: English

Type (Professor's evaluation): Scientific