Abstract: Based on the analysis of related concepts of the classical Vigenere cipher and Vigenere square，a 3-dimensional Vigenere cube model is proposed in this paper．The model uses dual key to encrypt the plaintext twice，thus weakens the characteristic statistical frequency of the ciphertext．The theoretical analysis indicates that the algorithm gains a good encryption effect of a long key by using two short keys，and it can carry on one-time pad to the plaintext，thus greatly enhances the decryption difficulty.

Key words: Vigenere cipher, One-Time Pad（OTP）, Vigenere square, Vigenere cube

摘要： 分析了经典维吉尼亚密码及维吉尼亚方阵的相关概念，在此基础上提出了一个三维维吉尼亚立方体模型。该模型使用双密钥对明文进行二次加密，削弱了密文的统计频率特征。理论分析表明，该算法在两个短密钥控制下达到了单个长密钥的加密效果，可以对明文进行一次一密加密，极大地提高了解密难度。

关键词: 维吉尼亚密码, 一次一密, 维吉尼亚方阵, 维吉尼亚立方体