A security token service (STS) is a software-based identity provider responsible for issuing security tokens as part of a claims-based identity system. In a typical usage scenario, a client requests access to a secure software application, often called a relying party. Instead of the application authenticating the client, the client is redirected to an STS. The STS authenticates the client and issues a security token. Finally, the client is redirected back to the relying party where it presents the security token. The token is the data record in which claims are packed and is protected from manipulation with strong cryptography.