Where can I find DNA decryption research?
I can think of several possible terms for what you could mean (with my interpretation of what people in those fields do):


Computational biology (the study of biological topics using computation)
Bioinformatics (the study of biological topics using computation)
Mathematical biology (the study of biological topics using mathematics)
Sequence analysis (the study of patterns in nucleotide [DNA] and protein sequences)
Genomics (the study of genomes or more generally large quantities of nucleotide sequence)


These all bleed into each other and doubtless other people have different interpretations.

There has been a ton of work in these areas, so they probably cover what you mean, but without some more concrete examples it's a little hard to say which is most appropriate.

As an aside, "DNA decryption" will be interpreted by most people in light of attempts to encode non-biological data in DNA and then decode it (see e.g. george church's stunts). However, based on what you say I think this is not really what you are interested in.

If you are looking for the technical literature for such fields, you could see the following journals, which are some of the better-known peer-reviewed journals focusing on these areas:


Bioinformatics
PLOS Computational Biology
Genome Research
BMC Bioinformatics
Molecular Biology and Evolution