The security strength of the traditional one-time-pad encryption system depends on the randomness of the secret key. However, It can hardly to generatea truerandom key by using the existing technologies and methods, and it is also difficult to issue and store the random keywhich is at least as long as the plaintext. Therefore, we pay more attention to the logical operation used in the encryption and decryption but not to how to generate the random key. The calculator, a three-dimensional DNA self-assembly pyramid structure, is designed to construct four common logical operations (AND, OR, NOT, XOR) by programming DNA interactions. And two novel one-time-pad cryptography schemes, a single-bit one-time-pad algorithm and improved double-bit one-time-pad algorithm, are proposed based on the calculator. The security fragments, used to construct the three-dimensional DNA self-assembly pyramid structure, are intercepted from a reference chain which is selected from the DNA database. All of the interception parameters are transmitted to recipient by hiding in DNA sequences. Only the authorized user can get all secret parameters to reconstruct the structure. The secret random key sequences for the two one-time-pad cryptography algorithms are generated by using logistic map. It only needs to share two parameters and thresholding function in sender and recipient without code books. The simulation results and security analysis show that the encryption algorithms are effective and can provide higher computational complexity as well as a reduced cracking probability except for the difficult of biological experiments.
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