Vigenere cipher algorithm modification by adopting RC6 key expansion and double encryption process

2nd Nommensen International Conference on Technology and Engineering

Subandi, A.^1 ; Lydia, M.S.^2 ; Sembiring, R.W.^3 ; Zarlis, M.^2 ; Efendi, S.^2

Stud. of Computer Science, Universitas Sumatera Utara, Medan, Indonesia^1

Departement of Computer Science, Universitas Sumatera Utara, Medan, Indonesia^2

Politeknik Negeri Medan, Medan, Indonesia^3

关键词: Avalanche effects;    Cryptographic algorithms;    Key expansion;    Plaintext;    Vigenere ciphers;   

Others  :  https://iopscience.iop.org/article/10.1088/1757-899X/420/1/012119/pdf
DOI  :  10.1088/1757-899X/420/1/012119

来源: IOP

【 摘 要 】

Modifications to Vigenere cipher are possible to make in order to be effective and efficient of this algorithm. In this study, we tried to modify Vigenere by exploiting RC6 key expansion to generate new keys used for encryption process, RC6 is a well-known as a modern cryptographic algorithm. If the RC6 Key expansion process will generate the S key as much as 2r+4, in this research will produce S Key as long as the plaintext length. Then for the encryption process done twice. The results show that the method proposed producing completely different key sequences (not repetitions like Vigenere cipher) can also produce an average avalanche effect of 17 bitsof the total 64 bits or about 26,56 %, better than the standard Vigenere which only reached 7.81%, but unfortunately no better than Vigenere with the RC6 key expansion without twice encryption process that reaches31.25% and of RC6-8/5/b with 35.94%.