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codeon
CodeOn Core
PLUGIN INTERNALS

License key format

CodeOn keys are designed to be copyable by humans and cheap to reject before a database lookup. Format validation catches most paste mistakes immediately.

Shape

SMS-A1B2-C3D4-E5F6-G7H8
Prefix
2-4 uppercase letters. The default generated prefix is SMS.
Body
Four blocks of four characters.
Alphabet
A-Z and 2-9. The generator avoids visually confusing 0/O and 1/I.
Checksum
The final block is derived from SHA-256 of the prefix plus the first three blocks.
Regex
^([A-Z]{2,4})-([A-Z2-9]{4})-([A-Z2-9]{4})-([A-Z2-9]{4})-([A-Z2-9]{4})$

Validation algorithm

  • Split the key into prefix and four 4-character blocks.
  • Reject if the regex does not match.
  • Compute SHA-256 over prefix-block1-block2-block3.
  • Map the first four hash bytes into the key alphabet.
  • Accept only when that generated checksum equals block 4.