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Is it possible to use RSA all the way through a PGP encrypted message (do not use IDEA)? If so, how? I know it would take a LONG time, but it would make for a nice option. If not, why? Although, it might take "forever", why not make it an option for those willing to wait? Am I mistaken in believing RSA is more secure than the present hybrid? Thanx, --demon
This was discussed about a year ago! It is a bad idea to do this for a couple reasons. First of all, RSA can only encrypt a block of data the same size as the key. So, for example, if you encrypt a message to me using my key, it RSA-encrypts in blocks of 709 bits! Second, there is no cypher-chaining, so the encryption from one block doesn't affect the encryption of the next. It is possible to do something like this, but I sure wouldn't want to do it. As for the time, lets say you have a 10K message (not unreasonable, although thats a fairly long email message ;-), and you are encrypting it in a 512-bit key. Well, 512 bits is 64 bytes, so you are encrypting 10K bytes 64 bytes at a time (or 160 blocks). Each 64-byte block takes a few seconds, lets just say one second (its a little faster on some system, and a lot slower on others!) This means you are spending 160 seconds, or almost THREE MINUTES, to encrypt this 10K file! Personally, I don't think that the extra security that you may (or may not: you now have a massive plain-text attack, although I don't know how you can really use it) get is worth the 2 extra orders of magnitude of time it takes to encrypt the data! As for adding this as a feature to PGP. It's *not* going to happen. -derek