PGP EncryptionJustin Shelby

Encryption Methods There are two basic key types for

cryptography Symmetric Asymmetric

Symmetric Key Cryptosystems One key is used to both encrypt and decrypt

messages Much more widely used than asymmetric. Must use an alternate transfer method to

spread the key.

Asymmetric Key Cryptography Also called public key encryption. Uses two keys, one public, the other private. Can freely transmit the public key. VERY slow.

Approximately10,000 times slower than symmetric.

Why bother? Financial information Medical information Military secrets Privacy

Background of PGP Pretty Good Privacy Created by Phil Zimmerman in 1991 No license required for non-commercial use Rapidly spread across the internet

Background Continued Criminal investigation started for export of

munitions due to using a key larger than 40 bits.

Eventually dropped and regulations relaxed. Created the OpenPGP standard for

interoperability. Free Software Foundation created GPG

GNU Privacy Guard

How PGP Works Compresses the message or file Generates a symmetric key Encrypts the compressed message Encrypts the symmetric key with the

recipients public key Signs the compressed and encrypted file with

one of PGP’s hash functions

Program functions Encrypted emails and instant messages Creation of an encrypted virtual partition Encrypt the hard drive

Must enter passphrase to access it, even to boot up the machine.

Secure shared folder File shredder

Algorithms Asymmetric

RSA DSS/DH

Symmetric AES CAST TripleDES IDEA Twofish

Hashes SHA-2

256, 384, and 512 bits

RIPEMD-160 SHA-1 MD-5

PGP Setup Download the software from the website

www.pgp.com Current version 9.61

Run the setup program and reboot Enter your information

PGP Setup Continued

Select your preferred key type

Enter your passphrase and generate your key

Is it Secure? “If all the personal computers in the world –

260 million – were put to work on a single PGP-encrypted message, it would still take an estimated 12 million times the age of the universe, on average, to break a single message William Crowell, Deputy Director of the NSA

March 20, 1997

Questions?

Sources http://www.wikipedia.org PGP Desktop 9.6 help pages http://cpsc420.cs.clemson.edu http://www.mccune.cc