Hi! ~~~ On 02/17/2012 03:28 PM, Sean Colyer wrote: > I'm confused. Even with Tag's 18/19 which can verify modification, doesn't > the ascii armor still have to use a radix 64 (base64 data+crc24)? I looked > over the RFC again, and don't seem to see that the crc is optional for > armoring text? I could just be missing something though. >
RFC4880 section 6.2. "An OpenPGP implementation MAY use ASCII armor to protect raw binary data." So the whole ASCII armoring is optional. Still it is a good idea to store and retrieve data in base64 to prevent encoding issues. Tankred tries to write a dropbox replacement using this library to encrypt data on the client side so i suggested to remove the checksum from *his* code because the MDC system protects the encrypted data already. In general a crc24 checksum its not optional for having a valid radix encoded PGP message, but in this case of combining ASCII armor and MDC the crc24 only protects integrity of the surrounding packet such as the session key or a signature packet. > I was looking at the CRC24 method yesterday. So, I think the issue comes from > the fact that we're looping over lots of data, and looping 8 times for each > entry. I think what we need to do is build a lookup table for CRC24. I was > looking around to see if other CRC's had lookup tables or other optimizations > some of them do. http://wiki.osdev.org/CRC32 Describes one method for CRC32 > that could be adjusted for building a similar table for CRC24. > > Thoughts? Very good idea. This should speed up the calculation. regards, carsten _______________________________________________ http://openpgpjs.org
