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

> Source: <https://dev.to/saji1970/i-dna-encode-my-encrypted-database-before-writing-it-to-disk-heres-why-and-why-its-not-3fa3>
> Published: 2026-08-30 12:18:59+00:00

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(())
}
```