This is the previous, raw, version of the encoding & decoding machines. See the Software article for an explanation or the Encoding and Decoding pages for more user-friendly versions of this page. The sequences created by this page are fully compatible with the other pages.
Enter a message into the Message field to have it encoded, or enter an encoded message into the Encoded field to have it decoded. The Key field is used for encryption & decryption and the Formatted field shows more details about the message block.
To counter restriction enzymes a sequence of 'A'-bases is inserted whereever the sequence for a restriction-enzyme occurs. When decoding the message these sequences are removed. The length of the substitution sequence is the shortest sequence of 'A' that does not occur in the encoded message.
The encoding requires 4 bases per character.
The fully encoded message block is formatted as follows:
- The letters
'Spy': 3 × 4 bases.
- Padding: 4 'A' bases.
- The length of the restriction-substitutes: 8-bit number (4 bases).
- The length of the encoded message: 16-bit number (8 bases).
- The checksum of the encoded message: 16-bit number (8 bases).
- The message: 4 bases per character.
- The letters
'GEM': 3 × 4 bases.
The total overhead is 48 bases and the maximum message length is 65535 characters.
Encryption has an additional 8 characters (48 bases) overhead, regardless of key or message length.