An Affine Based Homomorphic Encryption Scheme

Abstract

Standard encryption protocols do not allow for native searching or modification of data, without decryption. In this scenario, whoever is performing the operations on this file must also have the encryption key. Homomorphic encryption aims to solve this problem. Using homomorphic encryption, an encrypted file could be searched or modified without having to decrypt it, while still preserving the privacy of the file. This feature would allow users to outsource their processing needs to third parties, while still retaining information secrecy. These third parties would be able to perform operations on behalf of the user without attributing meaning to the user’s input and output values. The homomorphic encryption model proposed in this paper works with plain text files by representing characters using the ASCII encoding scheme. These characters will be encrypted using an affine cipher. This scheme supports string search and concatenation, and integer addition and subtraction operations.