A novel general multiple-base data embedding algorithm

• Presenting a GMB algorithm to conceal secret bits in n pixels with least distortion.
• GMB offers greater flexibility providing large payloads or high image quality.
• Introducing four binary conversion schemes to carry an extra bit for concealment.
• Deriving mathematical expressions to predict expected payloads and image quality.
• GMB scheme outperforms ten current state-of-the-art competitors.

This paper presents a general multiple-base (GMB) data embedding algorithm to conceal a serial secret bit stream equivalent to an M-ary secret digit in a pixel-cluster consisting of n pixels, where M is automatically determined by the initial input (n, F) given by the end user. Through the change of two parameters, n and M, the proposed algorithm offers a multiple-purpose message embedding style to produce a high quality embedded image or provide a large embedding payload. Inspired by a single base (SB) data embedding approach, this study first introduces a multiple-base (MB) scheme which adopts an n-tuple optimal base vector (OBV) to conceal a secret M-ary digit with minimal pixel distortion, where M is the product of all vector components in the OBV. This study extends the MB scheme to develop the GMB algorithm, which supports a serial secret bit stream as a secret message. Four binary to M-ary conversion schemes are introduced, allowing the GMB algorithm to carry an extra secret bit per pixel-cluster, offering a larger payload without increasing the pixel distortion caused by data embedding. The proposed algorithm is analyzed, and mathematical expressions are derived so that prior to a real message embedding, it is possible to predict the expected payloads and the corresponding image quality. Finally, we extend the GMB algorithm to support content-adaptive data embedding. To the best of the authors' knowledge, the proposed algorithm is the first multiple-purpose data embedding technique, providing greater flexibility and offering large payloads or high image quality. Experimental results demonstrate that the proposed scheme outperforms current state-of-the-art competitors.