Stephen M. Matyas

Learn More
We describe MARS, a shared-key (symmetric) block cipher supporting 128-bit blocks and variable key size. MARS is designed to take advantage of the powerful operations supported in today’s computers, resulting in a much improved security/performance tradeoff over existing ciphers. As a result, MARS offers better security than triple DES while running(More)
We propose a new mode of multiple encryption-triple-DES external feedback cipher block chaining with output feedback masking. The aim is to provide increased protection against certain attacks (dictionary attacks and matching ciphertext attacks) which exploit the short message-block size of DES. The new mode obtains this protection through the introduction(More)
In many applications of cryptography, assuring the authenticity of communications is as important as protecting their secrecy. A well known and secure method of providing message authentication is to compute a Message Authentication Code (MAC) by encrypting the message. If only one key is used to both encrypt and authenticate a message, however, the system(More)
Cryptography Is considered by many users to be a complicated sUbject. An architecture for a cryptographic application programming Interface simplifies customer use of cryptographic services by helping to ensure compliance with national and International standards and by providing Intuitive high-level services that may be Implemented on a broad range of(More)
LIMITED DISTRIBUTION NOTICE This report has been submitted for publication outside of IBM and will probably be copyrighted if accepted for publication. It has been issued as a Research Report for early dissemination of its contents. In view of the transfer of copyright to the outside publisher, its distribution outside of IBM prior to publication should be(More)
A method is presented for controlling cryptographic key usage based on control vectors. Each cryptographic key has an associated control vector that defines the permitted uses of the key within the cryptographic system. At key generation, the control vector is cryptographically coupled to the key by way of a special encryption process. Each encrypted key(More)