What does token mean?

I always hear the word token, eg. request a token.

I usually replace that word with "key".

But what does it mean exactly开发者_Go百科?

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A token is a unit of information (as opposed to a unit of data witch could be an integer). It is the smallest chunk of data that composes information.

for instance, in a compiler tokenizer, the char array {'c', 'l', 'a', 's', 's'} would be a chunk of data composing the token "class" (Because a complete word is, in most cases, the smallest kind of information a compiler deals with).

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It depends on what kind of "token" you're talking about.

If you're talking about a hardware token, it's a piece of hardware that gives each user an identification number. That number is then paired with their username/password to provide an extra level of authentication.

If you're talking about a software token, then it's simply a piece of identifying information that is given to you after you authenticate with a system.

Once you have a token, you can provide that token to the authentication system to prove that you're already an authenticated user.

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http://computer.yourdictionary.com/token

In authentication systems, a hardware device (e.g., smart card, calculator-line device, or flash drive), or software on a client computer, that stores the user's credentials and generates a one-time password. The authentication process commonly involves a challenge-response dialogue between the token and a dedicated authentication server. In conjunction with a personal identification number (PIN) and supplemental password, a token is an excellent security mechanism. See also authentication, password, and security.