Enhanced TSFS algorithm for secure database encryption

Security of databases has become increasingly crucial in all application areas. Database encryption is an important mechanism to secure databases from attacks and unauthorised access. The Transposition-Substitution-Folding-Shifting encryption algorithm (TSFS) is a symmetric database encryption algorithm that uses three keys with an expansion technique to provide high security: it improves the efficiency of query execution time by encrypting the sensitive data only. However, it applies merely for the alphanumeric characters. This paper extends the data set of the TSFS encryption algorithm to special characters as well, and corrects substitution and shifting processes by providing more than one modulo factor and four 16-arrays respectively in order to avoid the error that occurs in decryption steps. Experiment results show that enhanced TSFS encryption algorithm outperforms Data Encryption Standard algorithm (DES) and Advanced Encryption Standard algorithm (AES) in terms of query execution time and database added size.