File: gnupg.info, Node: Glossary, Next: Option Index, Prev: Contributors, Up: Top Glossary ******** 'ARL' The _Authority Revocation List_ is technical identical to a CRL but used for CAs and not for end user certificates. 'Chain model' Verification model for X.509 which uses the creation date of a signature as the date the validation starts and in turn checks that each certificate has been issued within the time frame, the issuing certificate was valid. This allows the verification of signatures after the CA's certificate expired. The validation test also required an online check of the certificate status. The chain model is required by the German signature law. See also _Shell model_. 'CMS' The _Cryptographic Message Standard_ describes a message format for encryption and digital signing. It is closely related to the X.509 certificate format. CMS was formerly known under the name 'PKCS#7' and is described by 'RFC3369'. 'CRL' The _Certificate Revocation List_ is a list containing certificates revoked by the issuer. 'CSR' The _Certificate Signing Request_ is a message send to a CA to ask them to issue a new certificate. The data format of such a signing request is called PCKS#10. 'OpenPGP' A data format used to build a PKI and to exchange encrypted or signed messages. In contrast to X.509, OpenPGP also includes the message format but does not explicitly demand a specific PKI. However any kind of PKI may be build upon the OpenPGP protocol. 'Keygrip' This term is used by GnuPG to describe a 20 byte hash value used to identify a certain key without referencing to a concrete protocol. It is used internally to access a private key. Usually it is shown and entered as a 40 character hexadecimal formatted string. 'OCSP' The _Online Certificate Status Protocol_ is used as an alternative to a CRL. It is described in 'RFC 2560'. 'PSE' The _Personal Security Environment_ describes a database to store private keys. This is either a smartcard or a collection of files on a disk; the latter is often called a Soft-PSE. 'Shell model' The standard model for validation of certificates under X.509. At the time of the verification all certificates must be valid and not expired. See also _Chain model_. 'X.509' Description of a PKI used with CMS. It is for example defined by 'RFC3280'.