How to ASCII-armor my public key without installing GPG?

Solution 1:

OpenPGP's "Radix-64" ASCII armor, described in RFC 4880 § 6, is mostly just standard Base64 with PEM-like begin/end headers, and with a CRC24 checksum at the end. It can be implemented like this:

1. Write the Armor Header Line; optional Armor Headers; and a blank line:

   -----BEGIN PGP PUBLIC KEY BLOCK-----
   Version: conradpgp v1.0
   (leave this line empty)
   

2. Write the Base64-encoded message, wrapped to 76 characters per line.

3. Write the checksum line, consisting of a = followed by the Base64-encoded Armor Checksum:

   The checksum is a 24-bit Cyclic Redundancy Check (CRC) converted to
   four characters of radix-64 encoding by the same MIME base64
   transformation, preceded by an equal sign (=). The CRC is computed
   by using the generator 0x864CFB and an initialization of 0xB704CE.
   The accumulation is done on the data before it is converted to
   radix-64, rather than on the converted data. A sample implementation
   of this algorithm is in the next section.

   (See section 6.1 for the example CRC24 code.)

4. Finally, write the Armor Tail:

   -----END PGP PUBLIC KEY BLOCK-----