密码学是信息安全技术的核心，它的发展关系到国家安全、社会稳定和经济发展等多个方面。DNA密码的出现为信息安全领域的发展提供了新契机，它以DNA为信息载体，以分子生物学技术为实现工具，可实现数据加密、信息隐藏、安全认证等密码学功能。不同与以往的基于DNA序列的信息隐藏方法（一维代换），本研究基于DNA的构象多态性，通过荧光分子或者纳米材料调控其二级结构（单链、双链、三链、发卡、四链等）与发光变化，构建全系列16种基础逻辑门，并将基础逻辑门复合或将上游逻辑门的输出作为下游逻辑门的输入，实现基础逻辑门的网络化级联整合和重置。最后，我们利用进制转换探索分子逻辑门的密码学功能（加密技术、隐写技术和解密技术）。本研究是分子逻辑门和现代密码学的融合，是一种综合了数字密码、化学密码和生物密码优势的分子密码系统，可为信息加密或信息存储及隐藏提供新的研究方法，为现代密码学研究提供理论借鉴和实验基础。

Cryptography is the core of information security technology, whose development is related to several aspects, such as national safety, social stability and economic development et.al. DNA Cryptography provides a novel approach for the development of the information security, which is featured with using DNA as the information carrier and modern molecular biology biologic technique as the implementation tool．And it can realize many cryptographic functions such as encryption, authentication，and signature．Different from the former data hiding scheme depended on DNA sequences (one-dimensional substitution), we constructed a series of molecular logic gates based on the integration of DNA and nanomaterials by adjusting secondary structures of DNA (ssDNA, dsDNA,triplex, hairpin, G-quadruplex, I-motif) and employing nanomaterials or fluorescent dyes as outputs. In the first set of experiments, we fabricated a complete set of 16 elementary logic gate operations, then some gates will be connected and repeated in series where the output of the previous gate is the input for the next gate, our designed system will yield a library of logic operations subsequently. Finally, we will explore the cryptography function (encryption, steganography and decryption) of molecular logic gates by virtue of the binary/ decimal conversion.This molecular cryptography system is the fusion between molecular logic gates and of modern cryptography, by taking advantage of mathematics code, chemical code and biological code, which provides a new research method for the study of information disposal, storage and hide method and contribute to the theoretical reference and experimental basis of modern encryption system.