Article ID | Journal | Published Year | Pages | File Type |
---|---|---|---|---|
428854 | Information Processing Letters | 2015 | 4 Pages |
Abstract
•A scheme to reduce the message overhead when authenticating short messages is cryptanalyzed.
MAC striping intermixes a payload with its authentication tag, placing the bits used for message authentication in positions derived from a secret key. The use of MAC striping has been suggested to authenticate encrypted payloads using short tags. For an idealized MAC scheme, the probability of a selective forgery has been estimated as (ℓ+mm)−1⋅2−m, when utilizing MAC striping with ℓ-bit payloads and m -bit tags. We show that this estimate is too optimistic. For m≤ℓm≤ℓ and any payload, we achieve a selective forgery with probability ≥(ℓ+mm)−1, and usually many orders of magnitude more than that.
Keywords
Related Topics
Physical Sciences and Engineering
Computer Science
Computational Theory and Mathematics
Authors
T. Eisenbarth, A. Meyerowitz, R. Steinwandt,