BAP: Broadcast authentication using cryptographic puzzles

Abstract

We present two broadcast authentication protocols based on delayed key disclosure. Our protocols rely on symmetric-key cryptographic primitives and use cryptographic puzzles to provide efficient broadcast authentication in different application scenarios, including those with resource-constrained wireless devices such as sensor nodes. The strong points of the protocols proposed are that one protocol allows instantaneous message origin authentication, whereas the other has low communication overhead. In addition to formalizing and analyzing these specific protocols, we carry out a general analysis of broadcast authentication protocols based on delayed key disclosure. This analysis uncovers fundamental limitations of this class of protocols in terms of the required accuracy of message propagation time estimations, if the protocols are to guarantee security and run efficiently. © Springer-Verlag Berlin Heidelberg 2007.