Visible to the public Finding State Collisions in the Authenticated Encryption Stream Cipher ACORN

TitleFinding State Collisions in the Authenticated Encryption Stream Cipher ACORN
Publication TypeConference Paper
Year of Publication2016
AuthorsSalam, Md Iftekhar, Wong, Kenneth Koon-Ho, Bartlett, Harry, Simpson, Leonie, Dawson, Ed, Pieprzyk, Josef
Conference NameProceedings of the Australasian Computer Science Week Multiconference
Conference LocationNew York, NY, USA
ISBN Number978-1-4503-4042-7
KeywordsACORN, AEAD, authenticated encryption, Caesar, collision, integrity, Lightweight Ciphers, MAC, pubcrawl, Resiliency, stream cipher, symmetric encryption

This paper analyzes the authenticated encryption algorithm ACORN, a candidate in the CAESAR cryptographic competition. We identify weaknesses in the state update function of ACORN which result in collisions in the internal state of ACORN. This paper shows that for a given set of key and initialization vector values we can construct two distinct input messages which result in a collision in the ACORN internal state. Using a standard PC the collision can be found almost instantly when the secret key is known. This flaw can be used by a message sender to create a forged message which will be accepted as legitimate.

Citation Keysalam_finding_2016