CRYPTOGRAPHIC KEY IMPROVED PRIVACY UNDER THE CONDITIONS OF SOME OF CRYPTOGRAPHIC KEY VALUE DATA LEAK

• Main Authors: U. F. Holikau, V. L. Pivovarov
• Format: Article
• Language: English
• Published: Belarusian National Technical University 2016-07-01
• Series: Sistemnyj Analiz i Prikladnaâ Informatika
• Subjects: cryptographic key; dataleak; secret conversion; increased uncertainty
• Online Access: https://sapi.bntu.by/jour/article/view/108
• ISSN: 2309-4923; 2414-0481

The article outlines the possibility of increasing the privacy of cryptographic key generated in the conditions of data leakage of some of its values. Such a situation can occur in the formation of a common cryptographic key of a symmetric cryptosystem employing a quantum channel, listened by a cryptanalyst, or other methods that do not make use of one-way functions. A method with the conversion parameters to increase the entropy of a generated secret random key sequences suggested. The essence of the procedure developed is that the subscribers A and B (secretly to a cryptanalyst), but in agreement with each other, choose some of the bits in the generated key sequence (further referred to as «tagged») and produce a pre-announced conversion of this sequence, using the data about the tagged bits.Since the amount and serial numbers of tagged bits are unknown to a cryptanalyst, the layout of the bits known to a cryptanalyst before randomly changes and becomes uncertain. The fundamental point of this method is to obtain tagged bits, the positions of which are known only to subscribers A and B without using the secure communication channel. One of the possible methods of obtaining tagged bits based on a random and independent inversion of a generated key sequence by the subscribers A and B and followed by the analysis of parities pairs of bits is analyzed. The efficiency of the method is evaluated.