Abstract: By analyzing the new standard SHA-3 and the traditional cryptographic algorithm, this paper proposes a novel key generation scheme, which combines SHA-3 algorithm with image. Firstly, image data are processed into the form of SHA-3 which can be absorbeal, and they are further conversed via three-dimensional matrix space of SHA-3 algorithm to generate secret key. Secondly, the secret key is displayed in the form of histogram distribution of the pixel in order to demonstrate that the generated key satisfies the security requirements of cryptographic algorithm in the initial key or key stream. Finally, the proposed scheme is realized by VS2013 and Quartus II tools. The experimental results show that the randomness of the generated key can reach 97.7% and the space can reach 2²²⁴ at least.