THE WORKING PRINCIPLE OF PGP

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One of the earliest pieces of widely used software to use public key cryptography is PGP. In order to attain a high level of security, it is a hybrid cryptosystem that uses both symmetric and asymmetric encryption.

Text encryption works by converting plaintext (data that can be understood clearly) into ciphertext (data that cannot be read). But most PGP systems first compress data before beginning the encryption process. PGP increases security while reducing disk space and transmission time by compressing plaintext files before sending them.

After file compression, the true encryption process starts. At this point, the compressed plaintext file is encrypted using a session key, a one-time use key. This key is created at random by symmetric cryptography, and a different session key is used for every PGP communication session.

Following that, asymmetric encryption is used to encrypt the session key (1) itself. To do this, the intended recipient (Bob) gives Alice, the message's sender, access to his public key (2). Through this procedure, Alice can securely send Bob the session key over the Internet without worrying about security restrictions.

The RSA algorithm is typically used to perform the asymmetric encryption of the session key. The Transport Layer Security (TLS) protocol, which secures a sizable section of the Internet, is one of many encryption methods that use RSA.

Bob can use his private key (3) to decode the session key after the message's ciphertext and encrypted session key have been delivered. The session key can then be used to restore the message's original plaintext after being encrypted.

PGP enables digital signatures in addition to the fundamental encryption and decryption processes. Digital signatures have at least three purposes.