Ans 1:PGP combines some of the best features of both conventional and public key cryptography. PGP is a hybrid cryptosystem. When a user encrypts plaintext with PGP, PGP first compresses the plaintext. Data compression saves modem transmission time and disk space and, more importantly, strengthens cryptographic security. Most cryptanalysis techniques exploit patterns found in the plaintext to crack the cipher. Compression reduces these patterns in the plaintext, thereby greatly enhancing resistance to cryptanalysis. (Files that are too short to compress or which don't compress well aren't compressed.)
Philip Zimmerman
Pretty Good Privacy (PGP) is a data encryption and decryption computer program that provides cryptographic privacy and authentication for data communication. PGP is often used for signing, encrypting and decrypting texts, E-mails, files, directories and whole disk partitions to increase the security of e-mail communications. It was created by Phil Zimmermann in 1991.
When one key is used for encryption and a different key is used for decryption this is call asymmetric cryptography. A good example of this is PGP (pretty good privacy). PGP is used to secure email. It accomplishes this by generating a pair of keys for each user. After the keys have been generated each user shares one key their public key and keeps their privet key secret. When someone wants to email a person who is using PGP they encrypt their message with the recipient's public key. This ensures that the message cannot be snooped on during transit and that only the person who has the corresponding privet key can decrypt the message.
See the related link for more information. Hushmail offers secure and unreadable email to its users. It uses PGP encryption and a key management system to secure email for the sender and receiver.
The exact mathematics of the encryption differ depending on the algorithm used, but in principle, this is how it works. An algorithm is used to generate a pair of keys that are related mathematically. In many cases they are factors of a very large number. One of the keys is the Public key, which is published to a key registry. The other is the Private key which is held by the owner alone. The important thing is that it is supposed to be impossible to derive the Private key from the Public key. When the owner wants to send a message, the use the Private key to encrypt it or to sign it. Since only the corresponding Public key can decrypt it, that establishes that the sender is who they say they are (because only they should have the Private key). If the sender used their Private key to sign the message, the receiver can use the Public key verify that the message has not been tampered with. On the flip side, some can encrypt a message to the owner of the Private key by using that person's Public key. Only the holder of the Private key can decrypt the message. This can provide confidentiality. Two correspondents can establish secure communications by using each others Public keys to encrypt their messages. Often the public key is deposited with a trusted Certificate Authority. Assuming the user trusts the key repository, they can use them to authenticate the key they are using as belonging to the person it is supposed to belong to. To get more details on the mathematics of encryption and decrption using Public Key Encryption, aka asymmetric encryption. Do a web search for the particular algorithm involved, be it SSH, PGP, TLS, or some other protocol.
PGP does not compress messages. It encrypts them. PGP is used to ensure that confidential emails to do fall into the wrong hands, and that a message is in fact from the person you think it is.• Developed by Phil Zimmerman in 1995.• Documentation and source code is freely available.• The package is independent of operating system and processor.• PGP does not rely on the "establishment" and it's popularity and use have grown extensively since 1995.• PGP combines the best available cryptographic algorithms to achieve secure e-mail communication. • It is assumed that all users are using public key cryptography and have generated a private/public key pair.• Either RSA (with RSA digital signatures) or El Gamel (with DSA) can be used.• All users also use a symmetric key system such as triple DES or Rijndael.
PGP-RTB was created in 1958.
PGP-RTS was created in 1958.
The population of PGP Corporation is 2,006.
PGP Corporation was created in 2002.
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Asymmetric
They can be sent or stored separately, which is useful to maintain a separate log of messages sent and received, if more than one party must sign a document, or to monitor data integrity.
Pimco Global Stocksplus & Income Fund (PGP)had its IPO in 2005.
"Evaluating cryptography is difficult since without 'breaking' the encryption its hard to say whether one encryption is better or not. Pretty Good Encryption (PGP) is asymmetric, that is the encryption and decryption keys are different which may give it an edge on symmetric encryption."
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