Multimedia Encryption Schemes for Cryptanalysis

Abstract

Nowadays, digital rights management is becoming more and more important aspect of multimedia content. This is due to
the copyrights infringement that can be found widely in the internet. To overcome this problem, multimedia contents must
be encrypted. Until now, a number of encryption schemes have been proposed. In this report, we are going to introduced
three multimedia encryption schemes, respectively, Multiple Huffman Tables (MHT, randomized arithmetic coding (RAC),
and arithmetic coding with key-based interval splitting (KSAC). The MHT encryption scheme and its cryptanalysis is
addressed by Mardianto. I think that future works for cryptanalysis part is left for the ciphertext-only attack and to improve
the efficiency of the already possible attacks. The RAC encryption scheme is addressed by David Hermawan. Randomized
Arithmetic Coding (RAC) is developed particularly by leveraging poor synchronization property of Arithmetic Coding
(AC). In, Jakimoski and Subbalakshmi gave an overview of the RAC encryption scheme. They compare RAC with
standard approach and commented that RAC is less efficient than standard approach. Another disadvantages of RAC
suggested is the vulnerability of Pseudorandom Bit Generator (PRBG). Their discussion however is not comprehensive.
RAC is merely overviewed and cryptanalysis of RAC is not given. Resynchronization attack on RAC is also discussed with
example, complementing the known-plaintext attack commented. The contributions of the report are: cryptanalysis and
resynchronization attack on RAC, PRBGs vulnerabilities and design guidelines toward more robust PRBGs. the importance
of Random Number Generation in relation with robustness of encryption schemes pearly studied. The KSAC encryption
scheme and its cryptanalysis will be discussed by Robby Tendean. As an analysis to arithmetic coding with key-based
interval splitting (KSAC), a known-plaintext attack is discussed. From the analysis result, it is shown that KSAC is
vulnerable to low complexity known plaintext attack.