**Author details**

each Mi is XOR-ed with all of the possible subkeys and only one of four possible 4 4 matrices is chosen for further processing. However, during decryption in the transformation step, only one 4 4 matrix is directly generated depending upon selected quadrant value. So, the generation of all of the possible intermediate values is one of the reasons for variation of encryption and decryption times in HGEA.

The DNA cryptosystem containing DNA hybridization technique and secure key generation technique OTP are studied, explained and implemented by taking input from the DES algorithm output. The output of DES-based DNA cryptography algorithm has encrypted message in the form of DNA sequences and the decrypted

The DDHO algorithm is tested on different types of plaintext; the encryption and decryption times are calculated; the analysis of length of plaintext, length of ciphertext and size of key is done and found that the length of ciphertext is proportional to the corresponding plaintext length. The encryption and decryption

From the process of analyzing various cryptographic algorithms, a unique encryption algorithm "hybrid graphical encryption algorithm" has been proposed. The algorithm was based on hybrid cubes encryption algorithm (HiSea). The features like graphical interpretation and computation of selected quadrant value are the unique features of this algorithm, which is different from existing standard

times increase slower with the changes in the length of plaintext.

**4. Conclusion**

**158**

**Figure 5.**

message is the original plaintext.

*File size vs. execution time of DES and HGEA.*

*Computer and Network Security*

Roshan Chitrakar1,2\*, Roshan Bhusal2 and Prajwol Maharjan<sup>2</sup>


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