From: Diagonal queue medical image steganography with Rabin cryptosystem
1. Suppose we have the following data |
     a. N blocks of cipher text: 1 × 16 |
                  (a) Cipher text blocks |
     b. 4 sub-blocks of each N block of cipher text: 1 × 4 |
                  (b) Cipher text sub-blocks |
      c. M block of 8 pixels each, from Brain disease cover image: 1 × 8 |
                  (c) Brain disease cover image blocks |
      d. M block of 64 bits each. We can obtain this by converting the above block into bits: 8 × 8 |
                  (d) Cover image block into bits |
2. From the above matrix, we have 15 diagonal queues from right to left inserted bits, and among the 5th–15th diagonal queues are eligible for secret cipher data embedding |
                  (e) Diagonal queues |
3. The above-shown bold bits are the diagonal queue LSB bits (i.e., 8th to 5th), which can be swapped with the cipher text bits using FIFO property of queue |
4. Now, we will select one of these eligible diagonal queues, dynamically |
5. We will also select one block from the N blocks and sub-blocks dynamically |
6. We will then put the selected ciphertext bits in selected diagonal queue at 8th to 5th bit LSB position sequentially |