Abstract: This document presents a framework to assist the writers of certificate policies or certification practice statements for participants within public key infrastructures, such as certification authorities, policy authorities, and communities of interest that wish to rely on certificates. In particular, the framework provides a comprehensive list of topics that potentially (at the writer's discretion) need to be covered in a certificate policy or a certification practice statement. This document supersedes RFC 2527.

Abstract: Certification will be performed without the use of any external certification organizations in an organization such as an enterprise. A server and a plurality of clients are connected via a network to thereby constitute a certification system for the entire enterprise. A public secondary memory in the server holds a server name, a certificate list, a temporary registrant list and the like. The certificate list includes individual and group certificates, and the certificate includes specifying information on a certification target, a public key and signature by an responsible person of a group, to which the certification target belongs. The group responsible person signs the public key of the group member and specifying information by using the information on a registrant list to generate a certificate.

Abstract: Public-key infrastructure manages trust in exchanges conducted by email, over the web and by other electronic means. The principal elements used for maintaining that trust are the contents of the certificates and the security safeguards in effect in the environments of the various parties involved. These two elements are derived by a risk management procedure from the business purpose of the exchanges, as captured in the certificate policy. In this paper we describe a high-level procedure for deriving certificate contents and security safeguards from the business purpose associated with the keys, by way of a certificate policy and security policies for each of the subscriber, relying party and authority environments.

Abstract: A certification method, system and program which involve processing a public key of a public/private key pair generated by a system of a person, to generate a communicable code representative of the public key. The person is identified by having the person convey the communicable code, and a digital certificate is generated including the public key and identifying information of the person. The certificate binds the public key and the identifying information. The communicable code is a limited character string, which may be generated using a secure one-way hash function.

Abstract: Security issues are key factors for the deployment and acceptance of agent based systems in the telecommunication area. This fact is most obvious in electronic commerce applications, where security services have to be offered. These services are needed to ensure secure communication, fair exchange of goods and payment. Public key cryptography techniques are an often employed mechanism. Keys are distributed by using a certificate to store them and to provably associate them to a principal. This document deals with the design of an agent-based certificate authority (CA) and key distribution center (KDC).

Abstract: This paper discusses the importance of a unique digital certificate for the world wide use of public-key infrastructure and the impact such a unique digital certificate will have on the players. First, the basic concepts of public-key infrastructure are presented. Special interest is put on the concepts important for the use of identity-based digital certificates. Then, an overview of the Austrian situation in the international context is given and the key factors for the success of digital certificates are presented. Digital certificates There is a broad range of applications for digital certificates: electronic banking, electronic payment systems, email communication, identification in communication with public authorities (e.g. tax declaration, court documents, electronic passports, public health service, etc.), electronic contracts, selective web access, selective database access, etc. In this context, several questions come up: • Which players will provide the future infrastructure for digital certificates (governmental institutions, financial service providers, IT companies or others)? • What are the key-factors for a successful provider of digital certificates? • How should governments regulate the emerging market of digital certificates? • Can nationally isolated solutions successfully survive? • Is the combination of access-control, encryption and signature in one ”product” important for the success? To get the answers to the above questions it is first necessary to understand the concepts of public-key infrastructure and then examine the behaviour of the players in this market. Public-key cryptography Public-key cryptography is a key-factor for the solution of the transaction security problems arising with the commercial use of the internet: authenticity, integrity, confidentiality and non-repudiation (Bhimani, 1996). Public-key algorithms are mainly used in two ways: • Encryption and decryption Messages which are encrypted with the public key of the recipient can only be decrypted with the respective private key. In this way, only the possessor of the recipient’s private key can read the message which can be encrypted by any person, provided that the key management guarantees the correct distribution of the public key to the potential senders. In reality the message is first encrypted with a symmetric algorithm, and then the symmetric key is encrypted with the public key of the recipient. This is called a digital envelope (PKCS, 1993), (Kaliski and Kingdon, 1997). With public-key-encryption, the authenticity of the recipient and the confidentiality can be guaranteed. • Digital signatures Messages can be signed encrypting a message digest (created by a hash function) with the private key of the sender. Any person in possession of the public key of the sender is in grade of verifying the signature by decrypting the message digest with the public key of the sender and comparing the result to the message digest of the received message created by the same hash function. Digital signatures guarantee the integrity of the message and the authenticity of the sender. Additionally, non-repudiation can be realised by the signing of both sender and recipient. Key and certificate management In the procedures described above, the distribution and management of the public key is the crucial point. It must be guaranteed that the key really belongs to the respective person (or e-mail address or authorisation role). A means to guarantee this, is the use of digital certificates. They are digital documents containing the public key, the name of the possessor, the digital signature of the certification authority (CA) that issued the certificate and the certificate validity period. In this way the problem of key management is reduced to the public key of the CA. Once in possession of the trustworthy public key, the end user is able to verify all certificates issued by the certification authority. The function of a CA is therefore the verification of the identity of the certificate holder. This process follows the certification practice statement (CPS) of the CA (Chokhani and Ford, 1998).

Abstract: Implementations of security services in a globalnetwork are strongly based on asymmetriccryptography, which in turn depends on a publickey certification infrastructure. Its properties andbehaviour should prevent threats. Moreover, theinfrastructure should be efficiently manageable andit should meet users' expectations regarding trust.Flexible guidelines and procedures are given in thispaper, where all certification infrastructure securityissues are logically structured. Thus it is easier tounderstand and to find possible solutions in aneasier way.Keywords: certification infrastructure, CA structurerequirements, certificate management. I. Introduction Asymmetric cryptography is of immenseimportance for provision of security services in aglobal computer network. Proper binding between auser and his/her public key is required for thecorrect operation of protocols using public keycryptography. A certificate [4] has been introducedas an object providing that binding, which is issuedby a trusted authority, called Certification Authority(CA). To serve the whole Internet community, aglobal system of CAs has to be established and ithas to be supported by appropriate database.The aim of this paper is to address a logicalstructure on all security issues of a certificationinfrastructure and to identify their inter-relationships. The starting point is prevention ofthreats that are present in every securityinfrastructure. Although the basic idea of a CAstructure (and a security infrastructure in general)seemed clear and easy to implement, it turned out tobe a hard problem. It' s been already many yearssince first standards [6, 7] in this field have beenlaunched, but the only operational certificationinfrastructure has been established withinPASSWORD [8, 9]. Even this one was not widelyused, as experiments with Privacy Enhanced Mail(PEM, [7]) have shown that setting up a CAinfrastructure is a complex task. Prevention ofnumerous threats is interleaved with policy and bothdepend on technical matters. Besides,corresponding standards include many implicitassumptions.In the following sections questions aboutprevention of threats, management issues and userexpectations along with scalability will beaddressed. This paper presents a logical structure onsecurity issues related to a public key certificationinfrastructure: