# Encryption Types

## Types

### Symmetric key / Private key

In symmetric-key schemes,^{[1]} the encryption and decryption keys are the same. Communicating parties must have the same key before they can achieve secure communication.

### Public key

In public-key encryption schemes, the encryption key is published for anyone to use and encrypt messages. However, only the receiving party has access to the decryption key that enables messages to be read.^{[2]} Public-key encryption was first described in a secret document in 1973;^{[3]} before then all encryption schemes were symmetric-key (also called private-key).^{[4]}Template:Rp

A publicly available public key encryption application called Pretty Good Privacy (PGP) was written in 1991 by Phil Zimmermann, and distributed free of charge with source code; it was purchased by Symantec in 2010 and is regularly updated.^{[5]}

- ↑ Symmetric-key encryption software
- ↑ Bellare, Mihir. "Public-Key Encryption in a Multi-user Setting: Security Proofs and Improvements." Springer Berlin Heidelberg, 2000. Page 1.
- ↑ "Public-Key Encryption - how GCHQ got there first!". gchq.gov.uk. Archived from the original on May 19, 2010. https://web.archive.org/web/20100519084635/http://www.gchq.gov.uk/history/pke.html.
- ↑ Goldreich, Oded. Foundations of Cryptography: Volume 2, Basic Applications. Vol. 2. Cambridge university press, 2004.
- ↑ "Symantec buys encryption specialist PGP for $300M". Computerworld. 2010-04-29. http://www.computerworld.com/s/article/9176121/Symantec_buys_encryption_specialist_PGP_for_300M. Retrieved 2010-04-29.