Cryptology ePrint Archive: Report 2021/298

On extensions of the one-time-pad

Bhupendra Singh and G. Athithan and Rajesh Pillai

Abstract: The one-time-pad (OTP) is a classical yet the strongest cipher. Although the OTP offers perfect secrecy and is quantum-safe, it has cryptographic as well as operational weaknesses. Cryptographically its encryption is malleable. Operationally a key used more than once by mistake can lead to successful breaking of the OTP. Hence, there is a need for extensions of OTP to address these two weaknesses simultaneously keeping all the strength of OTP intact. To address this need, we propose two extensions of OTP. In the process we also prove a relation between block ciphers and Latin rectangles.

Category / Keywords: secret-key cryptography / Latin square, Malleable encryption, One-time-pad, Prefect secrecy, Quantum- safe

Date: received 6 Mar 2021

Contact author: bhupendra at cair drdo in,ga drdochair@cair drdo in,rpillai@sag drdo in