[Resource Topic] 2001/097: An Efficient MAC for Short Messages

Welcome to the resource topic for 2001/097

Title:
An Efficient MAC for Short Messages

Authors: Sarvar Patel

Abstract:

HMAC is the internet standard for message authentication. What
distinguishes HMAC from other MAC algorithms is that it provides
proofs of security assuming that the underlying cryptographic hash
(e.g. SHA-1) has some reasonable properties. HMAC is efficient for
long messages, however, for short messages the nested construction
results in a significant inefficiency. For example to MAC a message
shorter than a block, HMAC requires at least two calls to the
compression function rather than one.

This inefficiency may be particularly high for some applications, like
message authentication of signaling messages, where the individual
messages may all fit within one or two blocks. Also for TCP/IP traffic
it is well known that large number of packets (e.g. acknowledgment)
have sizes around 40 bytes which fit within a block of most
cryptographic hashes. We propose an enhancement that allows both
short and long messages to be message authenticated more efficiently
than HMAC while also providing proofs of security. In particular, for
a message smaller than a block our MAC only requires one call to the
compression function.

ePrint: https://eprint.iacr.org/2001/097

See all topics related to this paper.

Feel free to post resources that are related to this paper below.

Example resources include: implementations, explanation materials, talks, slides, links to previous discussions on other websites.

For more information, see the rules for Resource Topics .