Paper 2012/497
The low-call diet: Authenticated Encryption for call counting HSM users
Mike Bond and George French and Nigel P. Smart and Gaven J. Watson
Abstract
We present a new mode of operation for obtaining authenticated encryption suited for use in banking and government environments where cryptographic services are only available via a Hardware Security Module (HSM) which protects the keys but offers a limited API. The practical problem is that despite the existence of better modes of operation, modern HSMs still provide nothing but a basic (unauthenticated) CBC mode of encryption, and since they mediate all access to the key, solutions must work around this. Our mode of operation makes only a single call to the HSM, yet provides a secure authenticated encryption scheme; authentication is obtained by manipulation of the plaintext being passed to the HSM via a call to an unkeyed hash function. The scheme offers a considerable performance improvement compared to more traditional authenticated encryption techniques which must be implemented using multiple calls to the HSM. Our new mode of operation is provided with a proof of security, on the assumption that the underlying block cipher used in the CBC mode is a strong pseudorandom permutation, and that the hash function is modelled as a random oracle.
Metadata
- Available format(s)
- Category
- Secret-key cryptography
- Publication info
- Published elsewhere. CT-RSA 2013
- DOI
- 10.1007/978-3-642-36095-4_23
- Contact author(s)
- nigel @ cs bris ac uk,Mike Bond @ cryptomathic com,george french @ barclays com,gavenjwatson @ gmail com
- History
- 2013-08-12: revised
- 2012-09-03: received
- See all versions
- Short URL
- https://ia.cr/2012/497
- License
-
CC BY