Encryption

Encryption

Asymmetric Encryption

An asymmetric encryption system has a public and private key. That`s why every communication partner needs his own set of keys. The keys are often very big (1024 or 2048 bit for example) because the security depends on math problems that cannot be solved efficient (but some of these problems can be solved on a quantum computer). Because of the big keys its slower than a symmetric encryption. That`s why asymmetric encryption is often only used for key exchange. There are key exchange protocols, like Diffie Hellman, that are based on asymmetric encryption.

RSA
ElGamal

Symmetric Encryption

In symmetric encryption systems every partie has often the same key to encrypt or decrypt a message. The keys are often not as big as in asymmetric encryption (for example 128 or 256 bit). That`s why it is faster an can be used for encryption of communication.

AES
Twofish

Hybride encryption:

Both encryption systems have their benefits. That`s why the asymmetric encryption can be used for exchanging the symmetric key at the begin of an encrypted communication and the symmetric encrpyption can be used to encrpyt the communication itself.

Asymmetric and symmetric encryption