Cryptography in Theory and Practice: The Case of Encryption in IPsec

Abstract. This paper studies the gaps that exist between cryptography as studied in theory, as defined in standards, as implemented by software engineers, and as actually consumed by users. Our focus is on IPsec, an important and widely-used suite of protocols providing security at the IP layer of network communications. Despite well-known results in theoretical cryptography highlighting the vulnerabilities of unauthenticated encryption, the IPsec standards currently mandate its support. We present evidence that such "encryption-only" configurations are in fact still often selected by users in practice, even with strong warnings advising against this in the IPsec standards. We then describe a variety of attacks against such configurations and report on their successful implementation in the case of the Linux kernel implementation of IPsec. Our attacks are realistic in their requirements, highly efficient, and recover the complete contents of IPsec-protected datagrams. Our att...

• Type: Conference
• Year: 2006
• Where: EUROCRYPT
• Authors: Kenneth G. Paterson, Arnold K. L. Yau
• Keywords: Cryptology, EUROCRYPT 2006, IPsec Standards, Linux Kernel Implementation, Protocols Providing Security