PGP step by step

cobijones

Does anyone have a basic step by step guide of how to people would send an email ecrypted with PGP?

aidan_walsh

Step 1) Find PGP plugin for your preferred email application (which you failed to mention).
Step 2) Follow their instructions.

cobijones

aidan_walsh wrote:

Step 1) Find PGP plugin for your preferred email application (which you failed to mention).
Step 2) Follow their instructions.

Thanks for the reply but I was actually wondering about the steps involved in the process of PGP ie RSA, MD5 hash, Compression etc.

Does anyone know anthing about this?

Smellyirishman

Generate MD5 key -> Encrypt with your RSA -> Compress -> encrypt with IDEA -> key encrypted with public key of recipient.

I think that's how it goes. Can't fully remember.

cobijones

Smellyirishman wrote:

Generate MD5 key -> Encrypt with your RSA -> Compress -> encrypt with IDEA -> key encrypted with public key of recipient.

I think that's how it goes. Can't fully remember.

Thanks

cobijones

Just another thing on this. Can anyone tell me which would come first encryption or compression(in general not just PGP)?

Would I be correct in saying compression should come first as it narrows down the amount of patterns in the plaintext that a hacker could work out?

Smellyirishman

Compression first.

Compression uses patterns.
Encryption muddles things up, destroying patterns.

cobijones

Smellyirishman wrote:

Compression first.

Compression uses patterns.
Encryption muddles things up, destroying patterns.

Thank you but why then does PGP do compression after adding the MD5 hash and using the RSA keys?

Smellyirishman

It compresses the plain text (the majority of the document) along with the MD5 (which has been generated ftom the uncompressed plain text). The MD5 is only a small hash key, it does not jumble up the plain text.

cobijones

Smellyirishman wrote:

It compresses the plain text (the majority of the document) along with the MD5 (which has been generated ftom the uncompressed plain text). The MD5 is only a small hash key, it does not jumble up the plain text.

Thanks again

cobijones

Can anyone explain the role of IDEA in pgp. I understand the other parts but i'm having difficulty in finding any documents for IDEA

quinta

Just Google there are endless documents on IDEA, plus endless amounts of cryptanalysis has been done on it.

http://www.finecrypt.net/idea.html

Main problem with IDEA it is slower than other alternatives due to the fact that it uses Integer multiplication modulo 2^(16+1) which is not easy to implement in software and adds to the reduced performance of the cipher. But still makes it very strong.

cobijones

Thanks for the reply there - I was looking for how it works specifically with PGP.

I found a nice site about it if anyone else is looking for it. Thanks again for the help

http://www.byte.com/art/9407/sec12/art4.htm