Transport Layer Security (TLS) is a hybrid cryptographic protocol to provide secure communication over the internet. Cryptographic methods ensure that the instances that communicate with each other are those that they pretend to be and that the information to be exchanged cannot be read or manipulated by a third party. TLS provides a completely transparent communication channel for higher-level protocols. Existing application logic requires only minimal changes to be able to use secure communication this way. Examples of existing protocols, which use TLS as a secure tunnel are HTTPS, POPS and IMAPS. Early versions of TLS were called Secure Socket Layer (SSL), which is still widely used as a synonym for TLS.