1. INTRODUCTIONPretty Good Privacy, known as PGP, is a popular data encryption and decryption program, providing security services for email messages and data files. Created by Philip Zimmermann in 1991, this program has been widely used in the global computing community to protect the confidentiality and integrity of users' data, giving them the ability to forward messages and files only to the individual concerned or to the authorized person (Singh, 2012). Not only is it useful to individuals as a privacy-enhancing program, but it has also been used in many companies to prevent their company's data from falling into the wrong hands (Rouse, 2005). This program mainly uses the concept of cryptology. Cryptology is the study of secret communication between two parties, where there is the presence of a third party known as adversaries, and this party knows nothing about the content of the communication (Rivest, 1990). The security that PGP offers is basically based on the concept of encryption and decryption, addressing different types of keys such as public keys and conventional keys, hash function, digital signatures and sometimes a combination of a few methods to make even More secure sending data to authorized and authorized recipients. Additionally, following the Internet Standard Track, this program is currently one of the widely used trust programs (Stallings, 2011).2. CRYPTOGRAPHY IN THE PRETTY GOOD PRIVACY PROGRAM2.1 CryptologyIn general, the Pretty Good Privacy (PGP) program is entirely devoted to cryptography, the basis of which is encryption and decryption. Encryption is a process of encoding a message, to the extent that the meaning of the message is not obvious or cannot be read... middle of paper ... uh, so the more random the keystrokes , the better the data needed to generate the key (Senderek, 2003).2.2.4 Symmetric keys based on a passphraseThe passphrase is very similar to the password, except that it is a longer version of a password and is theoretically more secure than the password (Network Associates, Inc., 1999). It is a secure code created with one or a few small words chosen by the user for a security setting (Mitchell, n.d.). Normally for a passphrase it contains multiple words, where the words may or may not be found in a dictionary. A good passphrase is similar to a good password, and the characteristics of a good passphrase should be long and complex, containing upper and lower case letters, symbols and numbers. So, it is obviously more secure than password, in which the attacker tried all the words in order to understand the passphrase you used..