Public key Encryption

Public-key cryptography, or asymmetric cryptography, is a cryptographic system that uses pairs of keys: public keys which may be disseminated widely, and the private keys which are known only to the owner.

Important properties of public key encryption:

• Different keys are used for encryption and decryption. This is the property which sets this scheme different than symmetric encryption scheme.

• each receiver possesses a unique decryption key, generally referred to as private key.

• Receiver needs to publish an encryption key referred to as public key.

• Encryption algorithm is complex enough to prohibit attacker deducing the plain text from the cipher text and the encryption key.

• Though Public  and the private keys are related mathematically, it is not possible to calculate the private key from the public key.