Secure image steganography using RRPBA-encrypted payload embedding

Abstract

Protecting both the content and the existence of transmitted data is a growing requirement in modern secure communication, and combining cryptography with steganography addresses both needs at once. However, most crypto-stego schemes rely on standard ciphers such as advanced encryption standard (AES), and the effect of a reduced-round, permutation-based AES variant on steganographic quality has not been established. This study evaluates an encrypt-then-hide scheme that pairs the round-reduced permutation-based advanced encryption standard (RRPBA) with single-plane least significant bit (LSB) image steganography. The payload is encrypted with RRPBA in cipher block chaining mode, embedded in the LSBs of a cover image, then extracted and decrypted. The scheme is tested on five standard USC-SIPI images at embedding rates from 25% to 100% of capacity, with robustness and efficiency comparisons against standard AES. The peak signal-to-noise ratio ranges from 57.16 to 51.14 dB, the structural similarity index stays above 0.994, and the bit error rate (BER) is 0% under lossless storage, while RRPBA encrypts about thirteen times faster than AES. The results show that RRPBA is a drop-in replacement for AES in encrypt-then-hide architectures without loss of steganographic quality.