codegroup

About codegroup

From Debian's package description

codegroup encodes any file into five-letter code groups, allowing it to be transmitted through any medium, and decodes files containing codegroups into the original input. Encoded files contain a 16-bit cyclical redundancy check (CRC) and file size to verify, when decoded, that the message is complete and correct. Files being decoded may contain other information before and after the codegroups, allowing in-the-clear annotations to be included.

codegroup makes no attempt, on its own, to prevent your message from being read. Cryptographic security should be delegated to a package intended for that purpose, such as pgp. It can then be applied to the encrypted binary output, transforming it into easily transmitted text. Text created by it uses only upper case ASCII letters and spaces. Unlike files encoded with uuencode or pgp's "ASCII armour" facility, the output of codegroup can be easily (albeit tediously) read over the telephone, broadcast by shortwave radio to agents in the field, or sent by telegram, telex, or Morse code.

From Debian's description of the codegroup package, under that package's license.