Fuzzy Evaluation Scheme for KDF Based on Stream Ciphers

Cryptography is a practice of technique to ensure security by using the cryptography keys. Key derivation function (KDF) is a standard algorithm to generate these cryptographic keys. Stream ciphers are one of the cryptographic primitives that are used to construct the key derivation function namely key derivation function based on stream ciphers. Though the key derivation function based on stream ciphers have a great role in security, it is necessary to have a framework which can evaluate the security level of the different types of key derivation function based on stream ciphers. Random oracle model (ROM) is the current procedure to proofs the security of KDF. However, the security evaluation of ROM did not evaluate the degree of secureness of KDF as it can only proof either the KDF is theoretically secure or insecure. Hence, this research applies fuzzy evaluation method to form a framework to evaluate the degree of secureness of the KDF for different types of key derivation function based on stream ciphers. Key sizes and complexity attacks are two main variables which are considered in the design of fuzzy rule. The proposed method introduces the information extraction to construct fuzzy membership function and rules. The result from this proposal is effective to approximate the security aspect in the computer system as well as network system.