Any unchanging information such as password or biometrics can be recorded and used later to simulate authenticity. Others including Verizon Communications, offer their opinions as well. Symmetric cryptography. Encryption system that uses the same key for encryption and decryption. Sometimes called cryptography secret key. 3.

Authentication technologies There are a number of different classes of authentication from its complete absence to very strict controls. For different purposes can be used different types of authentication. 3.1. Lack of authentication simplest authentication system has no authentication at all. Isolated from the network of privately owned personal computer is an example where authentication is not needed. Another example is the publicly available stand-alone workstation, which serves some of the conference, where the disclosure or modification are not critical. 3.2. Authentication mechanisms are vulnerable passive attack is simple password check is the most common form of authentication.

Simple authentication checks have different forms: the key may be a password memorized by the user, it can be physical or digital objects, belonging to the user, it can be a unique biological characteristics. Simple authentication systems are considered 'Open', as if the key is transmitted over the network, it can be intercepted by an attacker. There are reports of successful passive attacks in the Internet using the "split" is already a computer CERT94. Disclosing authentication mechanisms are vulnerable to attack "play." Access keys can be stored in the target machine, and in the presence of a security breach can access all the passwords. Typically, the storage form of passwords allows them to reconcile, but not reading.