Cryptography has been extensively employed in the information security field for the purpose of providing security for confidential data. The field of cryptography has recently considered a hybrid cryptographic implementation that combines conventional cryptographic techniques with the knowledge of DNA technologies to formulate what is known as DNA cryptography. DNA based cryptography is considered a branch of sustainability science as it combines transdisciplinary structures from natural sciences (biology) and technological sciences (information security). This paper discusses the various biological DNA techniques that have been implemented in recent DNA cryptographic algorithms. Among them are the Watson-Crick Complementary Rules, DNA Encoding/Decoding Rules, DNA Operation Rules, the Triplet Codon DNA Code, DNA Segmentation, DNA Hybridisation (DNA Annealing) and DNA Transcription and DNA Replication from the Central Dogma Molecular Biology process. A description of the algorithms and a theoretical comparative analysis of these DNA cryptographic algorithms is also presented in this research paper. Comparisons have also been made based on the following parameters: Conventional cryptographic techniques vis-a-vis the techniques used by DNA cryptographic algorithms, the application of these algorithms, their limitations and a security analysis to see how well DNA cryptography perform as against current conventional cryptography.