The receiving software keeps a copy of the message signature. The receiving software generates a new hash code for the received message and verifies it using the message's signature. If the verification is successful, the message is accepted as authentic. Compression OpenPGP implementations MAY compress the message after applying the signature but before encryption. Conversion to Radix-64 OpenPGP's underlying native representation for encrypted messages, signature certificates, and keys is a stream of arbitrary octets.
Some systems only permit the use of blocks consisting of seven-bit, printable text.
For transporting OpenPGP's native raw binary octets through channels that are not safe to raw binary data, a printable encoding of these binary octets is needed. Note that many applications, particularly messaging applications, will want more advanced features as described in the OpenPGP-MIME document, RFC 2015. Although this specification requires both encryption and signatures, it is reasonable for there to be subset implementations that are non-comformant only in that they omit encryption. Werner Koch , Remscheider Str. D sseldorf, Germany.