Abstract: A general chaotic stream encryption scheme is proposed by using two chaotic systems which topologically conjugate with Tent map and a method to generate independent and identically distributed chaotic streams. The stream encryption scheme is similar to the digital envelop, but the difference is that we only transport the initial values of Tent map and the parameters of the two chaotic sys-tems as the initial key. According to the conjugate relation, the initial values of the chaotic systems are obtained to achieve the purpose of masking these initial values. We calculate two independent and identically distributed chaotic key streams based on the two chaotic systems to encrypt the plaintext through twice feedback XOR. An application result of image cryptograph illustrates that the stream en-cryption scheme is effective and secure.