Multi-Ciphersuite Security of the Secure Shell (SSH) Protocol
- 3 November 2014
- proceedings article
- Published by Association for Computing Machinery (ACM)
- p. 369-381
- https://doi.org/10.1145/2660267.2660286
Abstract
The Secure Shell (SSH) protocol is widely used to provide secure remote access to servers, making it among the most important security protocols on the Internet. We show that the signed-Diffie--Hellman SSH ciphersuites of the SSH protocol are secure: each is a secure authenticated and confidential channel establishment (ACCE) protocol, the same security definition now used to describe the security of Transport Layer Security (TLS) ciphersuites. While the ACCE definition suffices to describe the security of individual ciphersuites, it does not cover the case where parties use the same long-term key with many different ciphersuites: it is common in practice for the server to use the same signing key with both finite field and elliptic curve Diffie--Hellman, for example. While TLS is vulnerable to attack in this case, we show that SSH is secure even when the same signing key is used across multiple ciphersuites. We introduce a new generic multi-ciphersuite composition framework to achieve this result in a black-box way.Keywords
Funding Information
- Australian Research Council (DP130104304)
- German Academic Exchange Service
- Seventh Framework Programme (ICT-2007-216646)
This publication has 33 references indexed in Scilit:
- Multi-Ciphersuite Security of the Secure Shell (SSH) ProtocolPublished by Association for Computing Machinery (ACM) ,2014
- Proving the TLS Handshake Secure (As It Is)Published by Springer Nature ,2014
- Implementing TLS with Verified Cryptographic SecurityPublished by Institute of Electrical and Electronics Engineers (IEEE) ,2013
- Less is more: relaxed yet composable security notions for key exchangeInternational Journal of Information Security, 2013
- Plaintext Recovery Attacks against SSHPublished by Institute of Electrical and Electronics Engineers (IEEE) ,2009
- A framework for compositional verification of security protocolsInformation and Computation, 2007
- Verifying the Independence of Security ProtocolsPublished by Institute of Electrical and Electronics Engineers (IEEE) ,2007
- Breaking and provably repairing the SSH authenticated encryption schemeACM Transactions on Information and System Security, 2004
- Entity Authentication and Key DistributionPublished by Springer Nature ,2001
- Robustness Principles for Public Key ProtocolsPublished by Springer Nature ,1995