信息隐藏中伪随机序列碰撞问题的算法改进

Algorithm Improvement of Pseudo-random Sequence Collision in Information Hiding

将秘密信息嵌入到有限大的载体图片的过程中,一般利用伪随机序列来选取要嵌入信息的像素点的位置。当秘密信息足够大时,伪随机数发生器产生的伪随机序列会重复出现,从而产生碰撞。如果选择跳过重复的位置,嵌入到有限大的载体图片中的秘密信息量将受限。因此,提出了一种改进算法,当伪随机数发生器产生的序列重复出现时,不跳过重复位置,正常进行嵌入操作,并将该重复位置上的操作过程以某种形式记录并保存;逆向提取时,通过密钥和该操作记录提取密文。该改进算法结合了密码学与信息隐藏技术,极大地扩展了嵌入到有限大的载体图片中的秘密信息的隐藏量,提高了信息隐藏过程的安全性。

In the process of embedding secret information into a limited large vector image,a pseudo-random sequence is generally used to select the position of the pixel to be embedded in the information.When the secret information is large enough,the pseudo-random number generated by the pseudo-random number generator would be repeated,thus resulting in collision.If we choose to skip all the duplicate locations,the amount of confidential information which had been embedded in a limited large vector image would be limited.Therefore,this paper proposed an improved algorithm.When the sequence generated by the pseudo-random number generator reoccurs,the repeated position will not be skipped and the embedded operation will be performed normally,and the operation process at the repeated position will be recorded and saved in some form.In reverse extraction,the key and this action record are used to extract the ciphertext.The improved algorithm,combined with cryptography and information hiding,greatly expands the amount of secret information hidden in a limited number of pictures and improves the security of information hiding.