A scheme for self-embedding an image into itself is proposed as a means for detecting and locating tamper

and self-recovering.The image is divided into small 8×8 blocks and each block is DCT transformed.A specified number of the lower frequency DCT coefficients are quantized and encoded using a fixed number of bits.The number of coefficients and their bit lengths are carefully chosen

according to the statistical property of these coefficients

the resulting bit-string for each block satisfies the payload of each block and has good self-recovering capability.The information about one block B (the bit string) is inserted into the LSB of another distant block

which is separated from B with an offset.We analyzed the method for choosing the offset.The proposed scheme is an one way watermarking and secure algorithm

and can well resist possible forged attack.