ABSTRACT

Random Number Generators (RNGs) are an important building block for algorithms and protocols in cryptography. Random number generation is used in a wide variety of cryptographic operations, such as key generation and challenge/response protocols. A random number generator outputs a sequence of 0s and 1s such that at any position, the next bit cannot be expected on the previous bits. However, true random number produces non- deterministic output since if the same random generator is run twice, identical results are not received. Thus we go for pseudo random number generator that is deterministic device because if this random number generator is run twice or more, it gives same results. Our paper presents new crypto based pseudo random number generator. It uses BLOW FISH ciphers and the Cipher-Block chaining (CBC) mode that uses three stages of the block chaining. The plain text for each stage comes from the output of the first BLOW FISH, which uses the 64-Bit date and time as the plain text. CBPRNG creates three 64-bit random numbers, the first and the second are concatenated to create a 128-random number and the third is used as next initial vector (IV) for CBPRNG. Our Crypto-Based Pseudo-random Number Generator produces a sequence of bits that has a random looking distribution. This new generator helps to develop huge range cryptographic applications to increase the system security. A number of applications such as financial security applications and Pretty Good Privacy (PGP) use this technique.