Introduced CPT scheme as a block-based hiding scheme based on the ring of the integers modulo 2r, which permits to embed r = âlog2(k+1)â secret bits in F by changing at most two entries, while the highest number of secret bits in any CPT-based schemes is MSDR2 = âlog2(1+k (k+1)/2)â, approximately 2r-1. This ratio can be reached approximately in our proposed CPTE1 scheme by using modules on the ring Z2 of integers modulo 2, as an instance of application of modules over rings of small characteristics. As a consequence, a new modified scheme-CPTE2 is to control the quality of stego-images. The CPTE2 scheme gives 2r-2 embedded bits approximately, more than r-2 bits by Tseng-Panâs scheme, while the quality is the same