中文摘要：

Most of the existing image encryption schemes with the substitution-diffusion structure are not secure and efficient.In this letter,a chaos-based pseudo-random bit generator with good statistical properties is proposed,where a simple post-processing by compressing is employed.A new adaptive image encryption scheme with the substitution-diffusion architecture is designed using the new pseudo-random bit generator.In the scheme,the session key for the pseudo-random bit generator is dependent on the content of the image which ensures that the scheme can effectively resist knownplaintext and chosen-plaintext attacks.Theoretical analysis and computer simulation indicate that the proposed algorithm is efficient and highly secure.

英文摘要：

Most of the existing image encryption schemes with the substitutlon-chltuslon structure are not secure and efficient. In this letter, a chaos-based pseudo-random bit generator with good statistical properties is proposed, where a simple post-processing by compressing is employed. A new adaptive image encryption scheme with the substitution-diffusion architecture is designed using the new pseu- do-random bit generator. In the scheme, the session key for the pseudo-random bit generator is dependent on the content of the image which ensures that the scheme can effectively resist knownplaintext and chosen-plaintext attacks. Theoretical analysis and computer simulation indicate that the proposed algorithm is efficient and highly secure.