dig64

dig + base64.

Store images in DNS. Base64-encodes an image, chunks it across numbered TXT records, and reconstructs it on the other side with a single command.

How it works

An image encoded with name cat under example.com produces records like:

_meta_cat.example.com.  IN  TXT  "chunks=3 filename=cat.webp mimetype=image/webp"
_0._meta_cat.example.com.  IN  TXT  "iVBORw0KGgo..."
_1._meta_cat.example.com.  IN  TXT  "AAAANSUHEU..."
_2._meta_cat.example.com.  IN  TXT  "gAAAABJRU5..."

The _meta_<name> record stores the chunk count, original filename, and MIME type. Each chunk is stored at _<n>._meta_<name>, where n is the zero-indexed sequence number. The decoder reads the meta record first, then fetches chunks 0 through N-1 in order.

Requirements

• bash
• base64
• dig (only needed when decoding from live DNS)

All are standard on macOS and most Linux distributions.

Usage

Encode

./dig64.sh encode <image_file> <name> <domain> [chunk_size]

Argument	Description
image_file	Path to the image file
name	Custom name for the TXT records
domain	The DNS domain to use
chunk_size	Characters per chunk (default: 250)

./dig64.sh encode cat.webp cat example.com

Outputs cat_dns_records.txt containing zone-file formatted TXT records.

Decode

Pass the meta record name. The decoder reads chunks, filename, and mimetype from it, fetches the chunks, and writes the file using the original filename.

./dig64.sh decode <record> [--file <zone_file>] [dns_server]

Argument	Description
record	The TXT record containing the metadata
--file	Read from a local zone file instead of DNS
dns_server	Optional DNS server to query

From live DNS:

./dig64.sh decode _meta_cat.example.com
./dig64.sh decode _meta_cat.example.com 8.8.8.8

From a local file (for testing):

./dig64.sh decode _meta_cat.example.com --file cat_dns_records.txt

Limits

• DNS TXT records have a 255-byte string limit. The default chunk size of 250 stays safely under this.
• A 100KB image produces ~137KB of base64, which is ~548 TXT records.
• Some DNS providers impose limits on the number of records per zone. Check your provider's limits for large images.