Deffee-Herman Key Exchange (Diffie–hellman) algorithm principle and PHP implementation version _php tutorial

Deffee-Herman Key Exchange (Diffie–hellman) algorithm principle and PHP implementation version

This article mainly introduces the Deffee-Herman Key Exchange (Diffie–hellman) algorithm principle and PHP implementation version, the need for friends can refer to the following

Deffee-Herman (Diffie–hellman) is an algorithm that allows both parties to establish secret keys on insecure public channels that can be used to encrypt (such as RC4) content later on.

The Deffee-Herman (Diffie–hellman) algorithm principle is simple:

As a principle, it is easy to prove (g^b%p) ^a%p = (g^a%p) ^b%p by mathematical principles, so they get an identical key.

The public keys above except A, a, B and the last are secret, and others can be passed on the public channel. The actual use of P is very large (more than 300), G usually take 2 or 5. It is almost impossible to work out a (discrete math problem) from P,g and g^a%p.

Many languages have implemented this algorithm, taking Crypt_diffiehellman in PHP package as an example:

?

1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21st 22 23 24

Include ' diffiehellman.php '; /* * Alice:prime = 563 * Generator = 5 * Private key = 9 * Bob:prime = 563 * Generator = 5 * Private key = 14 */ $p = 563; $g = 5; $alice = new Crypt_diffiehellman ($p, $g, 9); $alice _pubkey = $alice->generatekeys ()->getpublickey (); $bob = new Crypt_diffiehellman ($p, $g, 14); $bob _pubkey = $bob->generatekeys ()->getpublickey (); $alice _computekey = $alice->computesecretkey ($bob _pubkey)->getsharedsecretkey (); $bob _computekey = $bob->computesecretkey ($alice _pubkey)->getsharedsecretkey (); echo "{$alice _pubkey}-{$bob _pubkey}-{$alice _computekey}-{$bob _computekey}"; 78-534-117-117

http://www.bkjia.com/PHPjc/1000098.html www.bkjia.com true http://www.bkjia.com/PHPjc/1000098.html techarticle Deffee-Herman Key Exchange (Diffie–hellman) algorithm principle and PHP implementation version This article mainly introduces the Deffee-Herman Key Exchange (Diffiehellman) algorithm principle and the PHP implementation version, need ...

