I DNA-encode my encrypted database before writing it to disk - here's why (and why it's not "quantum" anything)

A developer built mdc-lite, a ~348KB embeddable encrypted key-value store in Rust that encodes ciphertext as DNA-like A/C/G/T strings before writing to disk. The design, part of the ModelDB repo, uses XChaCha20-Poly1305 encryption and BLAKE3-hashed filenames to prevent metadata leakage, aiming for secure storage on devices without server access.

Every value in my little embedded key-value store gets encrypted, then its ciphertext gets encoded as a string of A/C/G/T characters before it ever touches the filesystem. Open the file in a text editor and you'll see actual DNA-looking text - not because it's a gimmick, but because that's genuinely the storage format. This is mdc-lite , a ~348KB embeddable encrypted key-value store I built in Rust for places a server can't reach - a watch face, a phone app, a background service. It's part of a larger repo, ModelDB https://github.com/saji1970/ModelDB , that also includes MDC, a Python conversational data engine query AI models, databases, images, and documents in plain English, no SQL with its own DNA-inspired archival storage tier. Every put call does this, in order: key len key bytes value bytes into one plaintext buffer. nonce ciphertext tag blob: 2 bits per base, 00→A 01→C 10→G 11→T . Every byte maps to exactly 4 bases, so there's no padding ambiguity on decode.Filenames are keyed BLAKE3 hashes of the logical key, not the key name itself, so a directory listing alone leaks nothing - no key names, no values, no way to tell how many distinct keys exist versus how many files are on disk. php rust pub fn put &self, key: &str, value: & u8 - Result< , LiteStoreError { let mut plaintext = Vec::new ; plaintext.extend from slice & key.len as u16 .to le bytes ; plaintext.extend from slice key.as bytes ; plaintext.extend from slice value ; let nonce = XChaCha20Poly1305::generate nonce &mut OsRng ; let ciphertext = self.cipher .encrypt &nonce, plaintext.as ref ?; let mut record = nonce.to vec ; record.extend from slice &ciphertext ; let acgt text = dna::encode &record ; // <- the actual bytes on disk fs::write tmp path, &acgt text ?; fs::rename tmp path, final path ?; Ok }