Cryptography Encryption Technique Using Circular Bit Rotation in Binary Field

摘要

In the digital age when technology has advanced so much that communication between people is just a text away no matter where they are geographical. But with every advancement, the technology must be secure enough so that no eavesdropping can take place. That’s where cryptography comes into play, Cryptography is necessary when communicating over any untrusted medium. Cryptography is an important field in information security, and, in this modern age, cryptography is used everywhere from surfing the internet to phone calls. The requirement for a better cryptosystem keeps increasing as the advancement of modern computers outpaces the old cryptosystems. In cryptography, the plain text is the original text and ciphertext is the encrypted text. So, the proposed technique in this paper encrypts plain text into ciphertext that is unrecognizable that makes the ciphertext unidentifiable when compared to plain text. First, we generate a very large random number that is at least 1024 bits which will be the key. Encrypting the plaintext is based on the key, first the plain text is divided into blocks of 9 bytes then the key divided into array of ‘n/2’ number of pairs, the first digit of pair being position in the block and second digit being the number of bits to shift right, the shift is circular from the position of the selected character. In the decryption the left shift is performed to the blocks, the start of decryption begins from the end of the array of key pairs.