Symmetric Key Algorithms are a class of algorithms for cryptography that use trivially related, often identical, cryptographic keys for both decryption and encryption. The encryption key is trivially related to the decryption key, in that they may be identical or there is a simple transformation to go between the two keys. The keys, in practice, represent a shared secret between two or more parties that can be used to maintain a private information link. Symmetric key encryption is faster and more efficient than public key encryption.

Public key cryptography is a cryptographic approach which involves the use of asymmetric key algorithms instead of or in addition to symmetric key algorithms. Unlike symmetric key algorithms, it does not require a secure initial exchange of one or more secret keys to both sender and receiver. The asymmetric key algorithms are used to create a mathematically related key pair: a secret private key and a published public key. Asymmetric key encryption is often used to securely transmit a symmetric key, after which the sender and receiver use that symmetric key for high-speed encryption and message authentication.

Public Key Infrastructureis a set of hardware, software, people, policies, and procedures needed to create, manage, distribute, use, store, and revoke digital certificates