**How It Works**

The distinguishing technique used in public-key cryptography is the use of asymmetric key algorithms, where the key used to encrypt a message is not the same as the key used to decrypt it. Each user has a pair of cryptographic keys - a **public encryption key** and a **private decryption key**. The publicly available encrypting-key is widely distributed, while the private decrypting-key is known only to the recipient. Messages are encrypted with the recipient's public key, and can be decrypted *only* with the corresponding private key. The keys are related mathematically, but the parameters are chosen so that determining the private key from the public key is either impossible or prohibitively expensive. The discovery of algorithms that could produce public/private key pairs revolutionized the practice of cryptography, beginning in the mid-1970s.

In contrast, symmetric-key algorithms - variations of which have been used for thousands of years - use a *single* secret key, which must be shared and kept private by both the sender and the receiver, for both encryption and decryption. To use a symmetric encryption scheme, the sender and receiver must securely share a key in advance.

Because symmetric key algorithms are nearly always much less computationally intensive than asymmetric ones, it is common to exchange a key using a key-exchange algorithm, then transmit data using that key and a symmetric key algorithm. PGP and the SSL/TLS family of schemes use this procedures, and are thus called *hybrid cryptosystems*.

Read more about this topic: Public-key Cryptography

### Other articles related to "how it works, works, it works":

**How It Works**

... Statnamic testing

**works**by accelerating a mass upward that in turn imparts a load onto the foundation pile below the Statnamic device ...

**How It Works**

... an excellent method for converting HDTV to standard definition television, but

**it works**very poorly in reverse ... The Nyquist subsampling method of systems conversion only

**works**for HDTV to Standard Definition Television, so as a standards conversion technology it has a very limited use ...

### Famous quotes containing the word works:

“The *works* of the great poets have never yet been read by mankind, for only great poets can read them. They have only been read as the multitude read the stars, at most astrologically, not astronomically.”

—Henry David Thoreau (1817–1862)