>>11205026first you find out your DNA sequence, then you encode the sequence digitally. say 00 = A, 01 = T, 10 = G, 11 = C. you get a stream of binary numbers. now you use modern encryption methods to encrypt the binary stream. you end up with an encrypted stream of 1 and 0. you convert it back into Nucleobases with the same algorithm and crate a DNA sequence equivalent to your encrypted stream. BAM you got yourself an encrypted stream of dna.
to ensure the safety of the encryption, you should hire a cryptographer who regularly gives you advice on how safe your digital encryption is. with that you have to encrypt it in new ways every time the enrcyption becomes unsafe. that way you can pretty much ensure the safety of your encryption for all eternity.
