International Association for Cryptologic Research

International Association
for Cryptologic Research

CryptoDB

Bartosz Zoltak

Publications

Year
Venue
Title
2014
EPRINT
2004
FSE
2004
EPRINT
Tail-MAC: A Message Authentication Scheme for Stream Ciphers
Bartosz Zoltak
Tail-MAC, A predecessor to the VMPC-MAC, algorithm for computing Message Authentication Codes for stream ciphers is described along with the analysis of its security. The proposed algorithm was designed to employ some of the data already computed by the underlying stream cipher in the purpose of minimizing the computational cost of the operations required by the MAC algorithm. The performed analyses indicate several problems with the security of the scheme and lead to a new design which described in a paper "VMPC-MAC: A Stream Cipher Based Authenticated Encryption Scheme". The new scheme solves all the problems found at a cost of some compromise in the performance.
2004
EPRINT
Security of Symmetric Encryption Schemes with One-Way IND-CNA Key Setup
Bartosz Zoltak
We analyse the consequences of specific properties of the key-setup phase in symmetric encryption schemes for their security. We find that key-setup routines satisfying IND-CNA and one-wayness allow to construct schemes which are provably secure against key-recovery attacks. We propose a specific cryptosystem based on a stream cipher with a one-way IND-CNA key-setup, for which we present a proof, based on a set of scheme-specific assumptions, that it remains secure even if a successful key-recovery attack against the underlying cipher is found.
2004
EPRINT
VMPC-MAC: A Stream Cipher Based Authenticated Encryption Scheme
Bartosz Zoltak
A stream cipher based algorithm for computing Message Authentication Codes is described. The algorithm employs the internal state of the underlying cipher to minimize the required additional-to-encryption computational effort and maintain general simplicity of the design. The scheme appears to provide proper statistical properties, a comfortable level of resistance against forgery attacks in a chosen ciphertext attack model and high efficiency in software implementations.
2003
EPRINT
VMPC One-Way Function
Bartosz Zoltak
The VMPC function is a combination of two basic operations: permutation composition and integer addition. The function resulting from this combination shows to have very high resistance to inverting. Computational effort of about 2^260 operations is estimated to be required to invert the VMPC function. The value of the function can be computed with 3 elementary computer processor instructions per byte. An open question is whether the function's simplicity raises a realistic chance that the lower bound on the complexity of inverting it might be proved.
2003
EPRINT
VMPC Stream Cipher
Bartosz Zoltak
The VMPC Stream Cipher is a simple encryption algorithm, designed as a proposed practical application of the VMPC one-way function. The general structure of the Cipher is based on an internal 256-element permutation. The VMPC Cipher, together with its Key Scheduling Algorithm, were designed in particular to eliminate some of the known weaknesses characteristic of the alleged RC4 keystream generator.