A common method to transfer a secret information is encrypting the secret information before transmission. However, most cipher texts are incomprehensible which attracts more attackers. A better scheme is to hide the secret information in a common document and to transfer it in common channel. The sender encrypts the secret information before the cipher text is embedded into a text file based on the characteristics of line and diagonal profile of the text documents. Then, the sender embeds the factors to encrypt the cipher text as a double-watermark into the seal image based on DCT and LSB algorithms. The receiver extracts and recovers the secret information from the text file and the seal image. The system of the Identity based on Encryption is the basis of the communication between the sender and the receiver.