This problem was addressed only recently by the introduction of seekable sequential key generators (SSKG). Every instance of this cryptographic primitive produces a forward-secure sequence of symmetric (authentication) keys, but also offers an explicit fast-forward functionality. The only currently known SSKG construction replaces traditional hash chains by the iterated evaluation of a shortcut one-way permutation, a factoring-based and hence in practice not too efficient building block.
In this paper we revisit the challenge of marrying forward-secure key generation with seekability and show that symmetric primitives like PRGs, block ciphers, and hash functions suffice for obtaining secure SSKGs. Our scheme is not only considerably more efficient than the prior number-theoretic construction, but also extends the seeking functionality in a way that we believe is important in practice. Our construction is provably (forward-)secure in the standard model.Category / Keywords: secret-key cryptography / secured logging, forward security, seekability, pseudorandom generators Original Publication (with major differences): ESORICS 2014 Date: received 17 Jun 2014, last revised 16 Jan 2015 Contact author: giorgia marson at cased de Available format(s): PDF | BibTeX Citation Version: 20150116:214852 (All versions of this report) Discussion forum: Show discussion | Start new discussion