20-11-2012, 03:15 PM
Public Key Cryptography and PGP
Public Key Cryptography.ppt (Size: 558.5 KB / Downloads: 29)
Overview of Cryptography
Cryptography is an often misunderstood and misused security tool. Today more than ever, privacy is a necessary part of business communications. The following is an overview of public key cryptography and one of its more widely-used implementations, Pretty Good Privacy (PGP).
Types of Cryptographic Systems
The simplest and oldest way to send a secret message to someone. The code must be known to the sender or recipient.
Types of Cryptographic Systems
Substitution ciphers are the simplest type of cipher system.
Each letter of the alphabet is assigned to a number or different letter.
ROT13 is a commonly used cipher.
Crypto Keys and Algorithms
As a password is used to access a computer system, a cryptographic key is a password or passphrase that is used to unlock an encrypted message.
Different encryption systems offer different key lengths - Just as a longer password provides more security (WindowsNT excluded) the longer and more complex the key is, the more security an encryption system provides.
A cryptographic algorithm is a mathematical function used for encryption and decryption. Most algorithms contain a certain number of “rounds.” This determines how many times the text will be run through the algorithm
Pretty Good Privacy
PGP is a personal high-security cryptographic software application that allows people to exchange messages or files with privacy, authentication, and convenience. PGP can be used to encrypt and digitally sign files and e-mail.
Developed by Phil Zimmerman in the mid ‘80s.
First version released on the Internet in 1991; got immediate NSA attention and encountered legal issues on its use of RSA and Merkle-Hellman cryptography patents.
Purchased by ViaCrypt in 1993 (they had RSA license). Re-released in 1994 with RSAREF toolkit license.
Purchased by Network Associates in 1998.