A certificate policy (CP) is a document which aims to state what are the different entities of a

public key infrastructure A public key infrastructure (PKI) is a set of roles, policies, hardware, software and procedures needed to create, manage, distribute, use, store and revoke digital certificates and manage public-key encryption. The purpose of a PKI is to facilit ...

(PKI), their roles and their duties. This document is published in the PKI perimeter. When in use with

X.509 In cryptography, X.509 is an International Telecommunication Union (ITU) standard defining the format of public key certificates. X.509 certificates are used in many Internet protocols, including TLS/SSL, which is the basis for HTTPS, the secu ...

certificates, a specific field can be set to include a link to the associated certificate policy. Thus, during an exchange, any relying party has an access to the assurance level associated with the certificate, and can decide on the level of trust to put in the certificate.

RFC 3647

The reference document for writing a certificate policy is, , . The RFC proposes a framework for the writing of certificate policies and

Certification Practice Statement A Certification Practice Statement (CPS) is a document from a certificate authority or a member of a web of trust which describes their practice for issuing and managing public key certificates. Some elements of a CPS include documenting practices ...

s (CPS). The points described below are based on the framework presented in the RFC.

Main points

Architecture

The document should describe the general architecture of the related PKI, present the different entities of the PKI and any exchange based on certificates issued by this very same PKI.

Certificate uses

An important point of the certificate policy is the description of the authorized and prohibited certificate uses. When a certificate is issued, it can be stated in its attributes what use cases it is intended to fulfill. For example, a certificate can be issued for

digital signature A digital signature is a mathematical scheme for verifying the authenticity of digital messages or documents. A valid digital signature, where the prerequisites are satisfied, gives a recipient very high confidence that the message was created b ...

e-mail Electronic mail (email or e-mail) is a method of exchanging messages ("mail") between people using electronic devices. Email was thus conceived as the electronic ( digital) version of, or counterpart to, mail, at a time when "mail" meant ...

(aka

S/MIME S/MIME (Secure/Multipurpose Internet Mail Extensions) is a standard for public key encryption and signing of MIME data. S/MIME is on an IETF standards track and defined in a number of documents, most importantly . It was originally developed by R ...

encryption In cryptography, encryption is the process of encoding information. This process converts the original representation of the information, known as plaintext, into an alternative form known as ciphertext. Ideally, only authorized parties can decip ...

of data,

authentication Authentication (from ''authentikos'', "real, genuine", from αὐθέντης ''authentes'', "author") is the act of proving an assertion, such as the identity of a computer system user. In contrast with identification, the act of indicati ...

(e.g. of a

Web server A web server is computer software and underlying hardware that accepts requests via HTTP (the network protocol created to distribute web content) or its secure variant HTTPS. A user agent, commonly a web browser or web crawler, initiate ...

, as when one uses

HTTPS Hypertext Transfer Protocol Secure (HTTPS) is an extension of the Hypertext Transfer Protocol (HTTP). It is used for secure communication over a computer network, and is widely used on the Internet. In HTTPS, the communication protocol is enc ...

) or further issuance of certificates (delegation of authority). Prohibited uses are specified in the same way.

Naming, identification and authentication

The document also describes how certificates names are to be chosen, and besides, the associated needs for

identification Identification or identify may refer to: *Identity document, any document used to verify a person's identity Arts, entertainment and media * ''Identify'' (album) by Got7, 2014 * "Identify" (song), by Natalie Imbruglia, 1999 * Identification ( ...

and

. When a certification application is filled, the

certification authority In cryptography, a certificate authority or certification authority (CA) is an entity that stores, signs, and issues digital certificates. A digital certificate certifies the ownership of a public key by the named subject of the certificate. Thi ...

(or, by delegation, the

registration authority Registration authorities exist for many standards organizations, such as ANNA (Association of National Numbering Agencies for ISIN), the Object Management Group, W3C, IEEE and others. In general, registration authorities all perform a similar fun ...

) is in charge of checking the information provided by the applicant, such as his identity. This is to make sure that the CA does not take part in an

identity theft Identity theft occurs when someone uses another person's personal identifying information, like their name, identifying number, or credit card number, without their permission, to commit fraud or other crimes. The term ''identity theft'' was co ...

Key generation

The

generation A generation refers to all of the people born and living at about the same time, regarded collectively. It can also be described as, "the average period, generally considered to be about 20–⁠30 years, during which children are born and gr ...

of the

key Key or The Key may refer to: Common meanings * Key (cryptography), a piece of information that controls the operation of a cryptography algorithm * Key (lock), device used to control access to places or facilities restricted by a lock * Key (map ...

s is also mentioned in a certificate policy. Users may be allowed to generate their own keys and submit them to the CA for generation of an associated certificate. The PKI may also choose to prohibit user-generated keys, and provide a separated and probably more secure way of generating the keys (for example, by using a

hardware security module A hardware security module (HSM) is a physical computing device that safeguards and manages secrets (most importantly digital keys), performs encryption and decryption functions for digital signatures, strong authentication and other cryptograp ...

Procedures

The different procedures for certificate application, issuance, acceptance, renewal, re-key, modification and revocation are a large part of the document. These procedures describe how each actor of the PKI has to act in order for the whole assurance level to be accepted.

Operational controls

Then, a chapter is found regarding physical and procedural controls,

audit An audit is an "independent examination of financial information of any entity, whether profit oriented or not, irrespective of its size or legal form when such an examination is conducted with a view to express an opinion thereon.” Auditing ...

and logging procedures involved in the PKI to ensure

data integrity Data integrity is the maintenance of, and the assurance of, data accuracy and consistency over its entire Information Lifecycle Management, life-cycle and is a critical aspect to the design, implementation, and usage of any system that stores, proc ...

availability In reliability engineering, the term availability has the following meanings: * The degree to which a system, subsystem or equipment is in a specified operable and committable state at the start of a mission, when the mission is called for at a ...

and

confidentiality Confidentiality involves a set of rules or a promise usually executed through confidentiality agreements that limits the access or places restrictions on certain types of information. Legal confidentiality By law, lawyers are often required ...

Technical controls

This part describes what are the technical requirements regarding key sizes, protection of private keys (by use of

key escrow Key escrow (also known as a "fair" cryptosystem) is an arrangement in which the keys needed to decrypt encrypted data are held in escrow so that, under certain circumstances, an authorized third party may gain access to those keys. These third pa ...

) and various types of controls regarding the technical environment (computers, network).

Certificate revocation lists

Those

lists A ''list'' is any set of items in a row. List or lists may also refer to: People * List (surname) Organizations * List College, an undergraduate division of the Jewish Theological Seminary of America * SC Germania List, German rugby unio ...

are a vital part of any public key infrastructure, and as such, a specific chapter is dedicated to the description of the management associated with these lists, to ensure consistency between certificate status and the content of the list.

Audit and assessments

The PKI needs to be audited to ensure it complies with the rules stated in its documents, such as the certificate policy. The procedures used to assess such compliance are described here.

Other

This last chapter tackles all remaining points, by example all the PKI-associated legal matters.

References

* {{TLS/SSL Key management Public key infrastructure