Asymmetric cryptography can also be used to perform digital signatures and key exchange. See audit trail. Authentication can be used to provide high assurance that the purported identity is, in fact, the correct identity associated with the entity that provides it.
Text is used categorically for any digitized material.
Such algorithms are also the basis for digital signatures and key exchange. Today, cryptography can be used for many applications that do not involve confidentiality. Often it is important that the stamp be certified by some authority to establish legal or other special status. Such a service can be provided by a cryptographic procedure. Commonly, the digest has a fixed length and is not dependent on the length of the original message.