Q <- 4. Definitions -> S


R

   $ RA
      (I) See: registration authority.
   $ RA domains
      (I) A feature of a CAW that allows a CA to divide the
      responsibility for certificate requests among multiple RAs.
      Tutorial: This ability might be used to restrict access to private
      authorization data that is provided with a certificate request,
      and to distribute the responsibility to review and approve
      certificate requests in high-volume environments. RA domains might
      segregate certificate requests according to an attribute of the
      certificate's subject, such as an organizational unit.
   $ RADIUS
      (I) See: Remote Authentication Dial-In User Service.
   $ Rainbow Series
      (O) /COMPUSEC/ A set of more than 30 technical and policy
      documents with colored covers, issued by the NCSC, that discuss in
      detail the TCSEC and provide guidance for meeting and applying the
      criteria. (See: Green Book, Orange Book, Red Book, Yellow Book.)
   $ random
      (I) In essence, "random" means "unpredictable". [SP22, Knut,
      R4086] (See: cryptographic key, pseudorandom.)
      -  "Random sequence": A sequence in which each successive value is
         obtained merely by chance and does not depend on the preceding
         values of the sequence. In a random sequence of bits, each bit
         is unpredictable; i.e., (a) the probability of each bit being a
         "0" or "1" is 1/2, and (b) the value of each bit is independent
         of any other bit in the sequence.
      -  "Random value": An individual value that is unpredictable;
         i.e., each value in the total population of possibilities has
         equal probability of being selected.
   $ random number generator
      (I) A process that is invoked to generate a random sequence of
      values (usually a sequence of bits) or an individual random value.
      Tutorial: There are two basic types of generators. [SP22]
      -  "(True) random number generator": It uses one or more non-
         deterministic bit sources (e.g., electrical circuit noise,
         timing of human processes such as key strokes or mouse
         movements, semiconductor quantum effects, and other physical

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         phenomena) and a processing function that formats the bits, and
         it outputs a sequence of values that is unpredictable and
         uniformly distributed.
      -  "Pseudorandom number generator": It uses a deterministic
         computational process (usually implemented by software) that
         has one or more inputs called "seeds", and it outputs a
         sequence of values that appears to be random according to
         specified statistical tests.
   $ RBAC
      (N) See: role-based access control, rule-based access control.
      Deprecated Usage: IDOCs that use this term SHOULD state a
      definition for it because the abbreviation is ambiguous.
   $ RC2, RC4, RC6
      (N) See: Rivest Cipher #2, #4, #6.
   $ read
      (I) /security model/ A system operation that causes a flow of
      information from an object to a subject. (See: access mode.
      Compare: write.)
   $ realm
      (I) /Kerberos/ A domain consisting of a set of Kerberized clients,
      Kerberized application servers, and one or more Kerberos
      authentication servers and ticket-granting servers that support
      the clients and applications, all operating under the same
      security policy. (See: domain.)
   $ recovery
      1. (I) /cryptography/ The process of learning or obtaining
      cryptographic data or plain text through cryptanalysis. (See: key
      recovery, data recovery.)
      2a. (I) /system integrity/ The process of restoring a secure state
      in a system after there has been an accidental failure or a
      successful attack. (See: secondary definition under "security",
      system integrity.)
      2b. (I) /system integrity/ The process of restoring an information
      system's assets and operation following damage or destruction.
      (See: contingency plan.)
   $ RED
      1. (N) Designation for data that consists only of clear text, and
      for information system equipment items and facilities that handle


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      clear text. Example: "RED key". (See: BCR, color change, RED/BLACK
      separation. Compare: BLACK.)
      Derivation: From the practice of marking equipment with colors to
      prevent operational errors.
      2. (O) /U.S. Government/ Designation applied to information
      systems, and to associated areas, circuits, components, and
      equipment, "in which unencrypted national security information is
      being processed." [C4009]
   $ RED/BLACK separation
      (N) An architectural concept for cryptographic systems that
      strictly separates the parts of a system that handle plain text
      (i.e., RED information) from the parts that handle cipher text
      (i.e., BLACK information). (See: BLACK, RED.)
   $ Red Book
      (D) /slang/ Synonym for "Trusted Network Interpretation of the
      Trusted Computer System Evaluation Criteria" [NCS05].
      Deprecated Term: IDOCs SHOULD NOT use this term. Instead, use the
      full proper name of the document or, in subsequent references, a
      more conventional abbreviation, e.g., TNI-TCSEC. (See: TCSEC,
      Rainbow Series, Deprecated Usage under "Green Book".)
   $ RED key
      (N) A cleartext key, which is usable in its present form (i.e., it
      does not need to be decrypted before being used). (See: RED.
      Compare: BLACK key.)
   $ reference monitor
      (I) "An access control concept that refers to an abstract machine
      that mediates all accesses to objects by subjects." [NCS04] (See:
      security kernel.)
      Tutorial: This concept was described in the Anderson report. A
      reference monitor should be (a) complete (i.e., it mediates every
      access), (b) isolated (i.e., it cannot be modified by other system
      entities), and (c) verifiable (i.e., small enough to be subjected
      to analysis and tests to ensure that it is correct).
   $ reflection attack
      (I) An attack in which a valid data transmission is replayed to
      the originator by an attacker who intercepts the original
      transmission. (Compare: indirect attack, replay attack.)



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   $ reflector attack
      (D) Synonym for "indirect attack".
      Deprecated Term: IDOCs SHOULD NOT use this term; it could be
      confused with "reflection attack", which is a different concept.
   $ registered user
      (I) A system entity that is authorized to receive a system's
      products and services or otherwise access system resources. (See:
      registration, user.)
   $ registration
      1. (I) /information system/ A system process that (a) initializes
      an identity (of a system entity) in the system, (b) establishes an
      identifier for that identity, (c) may associate authentication
      information with that identifier, and (d) may issue an identifier
      credential (depending on the type of authentication mechanism
      being used). (See: authentication information, credential,
      identifier, identity, identity proofing.)
      2. (I) /PKI/ An administrative act or process whereby an entity's
      name and other attributes are established for the first time at a
      CA, prior to the CA issuing a digital certificate that has the
      entity's name as the subject. (See: registration authority.)
      Tutorial: Registration may be accomplished either directly, by the
      CA, or indirectly, by a separate RA. An entity is presented to the
      CA or RA, and the authority either records the name(s) claimed for
      the entity or assigns the entity's name(s). The authority also
      determines and records other attributes of the entity that are to
      be bound in a certificate (such as a public key or authorizations)
      or maintained in the authority's database (such as street address
      and telephone number). The authority is responsible, possibly
      assisted by an RA, for verifying the entity's identity and vetting
      the other attributes, in accordance with the CA's CPS.
      Among the registration issues that a CPS may address are the
      following [R3647]:
      -  How a claimed identity and other attributes are verified.
      -  How organization affiliation or representation is verified.
      -  What forms of names are permitted, such as X.500 DN, domain
         name, or IP address.
      -  Whether names are required to be meaningful or unique, and
         within what domain.
      -  How naming disputes are resolved, including the role of
         trademarks.
      -  Whether certificates are issued to entities that are not
         persons.

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      -  Whether a person is required to appear before the CA or RA, or
         can instead be represented by an agent.
      -  Whether and how an entity proves possession of the private key
         matching a public key.
   $ registration authority (RA)
      1. (I) An optional PKI entity (separate from the CAs) that does
      not sign either digital certificates or CRLs but has
      responsibility for recording or verifying some or all of the
      information (particularly the identities of subjects) needed by a
      CA to issue certificates and CRLs and to perform other certificate
      management functions. (See: ORA, registration.)
      2. (I) /PKIX/ An optional PKI component, separate from the CA(s).
      The functions that the RA performs will vary from case to case but
      may include identity authentication and name assignment, key
      generation and archiving of key pairs, token distribution, and
      revocation reporting. [R4210]
      Tutorial: Sometimes, a CA may perform all certificate management
      functions for all end users for which the CA signs certificates.
      Other times, such as in a large or geographically dispersed
      community, it may be necessary or desirable to offload secondary
      CA functions and delegate them to an assistant, while the CA
      retains the primary functions (signing certificates and CRLs). The
      tasks that are delegated to an RA by a CA may include personal
      authentication, name assignment, token distribution, revocation
      reporting, key generation, and archiving.
      An RA is an optional PKI entity, separate from the CA, that is
      assigned secondary functions. The duties assigned to RAs vary from
      case to case but may include the following:
      -  Verifying a subject's identity, i.e., performing personal
         authentication functions.
      -  Assigning a name to a subject. (See: distinguished name.)
      -  Verifying that a subject is entitled to have the attributes
         requested for a certificate.
      -  Verifying that a subject possesses the private key that matches
         the public key requested for a certificate.
      -  Performing functions beyond mere registration, such as
         generating key pairs, distributing tokens, handling revocation
         reports, and archiving data. (Such functions may be assigned to
         a PKI component that is separate from both the CA and the RA.)
      3. (O) /SET/ "An independent third-party organization that
      processes payment card applications for multiple payment card
      brands and forwards applications to the appropriate financial
      institutions." [SET2]

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   $ regrade
      (I) Deliberately change the security level (especially the
      hierarchical classification level) of information in an authorized
      manner. (See: downgrade, upgrade.)
   $ rekey
      (I) Change the value of a cryptographic key that is being used in
      an application of a cryptographic system. (See: certificate
      rekey.)
      Tutorial: Rekey is required at the end of a cryptoperiod or key
      lifetime.
   $ reliability
      (I) The ability of a system to perform a required function under
      stated conditions for a specified period of time. (Compare:
      availability, survivability.)
   $ reliable human review
      (I) Any manual, automated, or hybrid process or procedure that
      ensures that a human examines a digital object, such as text or an
      image, to determine whether the object may be permitted, according
      to some security policy, to be transferred across a controlled
      interface. (See: guard.)
   $ relying party
      (I) Synonym for "certificate user".
      Usage: Used in a legal context to mean a recipient of a
      certificate who acts in reliance on that certificate. (See: ABA
      Guidelines.)
   $ remanence
      (I) Residual information that can be recovered from a storage
      medium after clearing. (See: clear, magnetic remanence, purge.)
   $ Remote Authentication Dial-In User Service (RADIUS)
      (I) An Internet protocol [R2865] for carrying dial-in users'
      authentication information and configuration information between a
      shared, centralized authentication server (the RADIUS server) and
      a network access server (the RADIUS client) that needs to
      authenticate the users of its network access ports. (See: TACACS.)
      User presents authentication and possibly other information to the
      RADIUS client (e.g., health information regarding the user
      device).



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      Tutorial: A user presents authentication information and possibly
      other information to the RADIUS client, and the client passes that
      information to the RADIUS server. The server authenticates the
      client using a shared secret value and checks the presented
      information, and then returns to the client all authorization and
      configuration information needed by the client to serve the user.
   $ renew
      See: certificate renewal.
   $ reordering
      (I) /packet/ See: secondary definition under "stream integrity
      service".
   $ replay attack
      (I) An attack in which a valid data transmission is maliciously or
      fraudulently repeated, either by the originator or by a third
      party who intercepts the data and retransmits it, possibly as part
      of a masquerade attack. (See: active wiretapping, fresh, liveness,
      nonce. Compare: indirect attack, reflection attack.)
   $ repository
      1. (I) A system for storing and distributing digital certificates
      and related information (including CRLs, CPSs, and certificate
      policies) to certificate users. (Compare: archive, directory.)
      2. (O) "A trustworthy system for storing and retrieving
      certificates or other information relevant to certificates." [DSG]
      Tutorial: A certificate is published to those who might need it by
      putting it in a repository. The repository usually is a publicly
      accessible, on-line server. In the FPKI, for example, the expected
      repository is a directory that uses LDAP, but also may be an X.500
      Directory that uses DAP, or an HTTP server, or an FTP server that
      permits anonymous login.
   $ repudiation
      1. (I) Denial by a system entity that was involved in an
      association (especially a communication association that transfers
      data) of having participated in the relationship. (See:
      accountability, non-repudiation service.)
      2. (I) A type of threat action whereby an entity deceives another
      by falsely denying responsibility for an act. (See: deception.)





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      Usage: This type of threat action includes the following subtypes:
      -  False denial of origin: Action whereby an originator denies
         responsibility for sending data.
      -  False denial of receipt: Action whereby a recipient denies
         receiving and possessing data.
      3. (O) /OSIRM/ "Denial by one of the entities involved in a
      communication of having participated in all or part of the
      communication." [I7498-2]
   $ Request for Comment (RFC)
      1. (I) One of the documents in the archival series that is the
      official channel for IDOCs and other publications of the Internet
      Engineering Steering Group, the Internet Architecture Board, and
      the Internet community in general. (RFC 2026, 2223) (See: Internet
      Standard.)
      2. (D) A popularly misused synonym for a document on the Internet
      Standards Track, i.e., an Internet Standard, Draft Standard, or
      Proposed Standard. (See: Internet Standard.)
      Deprecated Definition: IDOCs SHOULD NOT use this term with
      definition 2 because many other types of documents also are
      published as RFCs.
   $ residual risk
      (I) The portion of an original risk or set of risks that remains
      after countermeasures have been applied. (Compare: acceptable
      risk, risk analysis.)
   $ restore
      See: card restore.
   $ reverse engineering
      (I) /threat action/ See: secondary definition under "intrusion".
   $ revocation
      See: certificate revocation.
   $ revocation date
      (N) /X.509/ In a CRL entry, a date-time field that states when the
      certificate revocation occurred, i.e., when the CA declared the
      digital certificate to be invalid. (See: invalidity date.)
      Tutorial: The revocation date may not resolve some disputes
      because, in the worst case, all signatures made during the
      validity period of the certificate may have to be considered
      invalid. However, it may be desirable to treat a digital signature

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      as valid even though the private key used to sign was compromised
      after the signing. If more is known about when the compromise
      actually occurred, a second date-time, an "invalidity date", can
      be included in an extension of the CRL entry.
   $ revocation list
      See: certificate revocation list.
   $ revoke
      (I) See: certificate revocation.
   $ RFC
      (I) See: Request for Comment.
   $ Rijndael
      (N) A symmetric, block cipher that was designed by Joan Daemen and
      Vincent Rijmen as a candidate for the AES, and that won that
      competition. [Daem] (See: Advanced Encryption Standard.)
   $ risk
      1. (I) An expectation of loss expressed as the probability that a
      particular threat will exploit a particular vulnerability with a
      particular harmful result. (See: residual risk.)
      2. (O) /SET/ "The possibility of loss because of one or more
      threats to information (not to be confused with financial or
      business risk)." [SET2]
      Tutorial: There are four basic ways to deal with a risk [SP30]:
      -  "Risk avoidance": Eliminate the risk by either countering the
         threat or removing the vulnerability. (Compare: "avoidance"
         under "security".)
      -  "Risk transference": Shift the risk to another system or
         entity; e.g., buy insurance to compensate for potential loss.
      -  "Risk limitation": Limit the risk by implementing controls that
         minimize resulting loss.
      -  "Risk assumption": Accept the potential for loss and continue
         operating the system.
   $ risk analysis
      (I) An assessment process that systematically (a) identifies
      valuable system resources and threats to those resources, (b)
      quantifies loss exposures (i.e., loss potential) based on
      estimated frequencies and costs of occurrence, and (c)
      (optionally) recommends how to allocate available resources to
      countermeasures so as to minimize total exposure. (See: risk
      management, business-case analysis. Compare: threat analysis.)


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      Tutorial: Usually, it is financially and technically infeasible to
      avoid or transfer all risks (see: "first corollary" of "second
      law" under "Courtney's laws"), and some residual risks will
      remain, even after all available countermeasures have been
      deployed (see: "second corollary" of "second law" under
      "Courtney's laws"). Thus, a risk analysis typically lists risks in
      order of cost and criticality, thereby determining where
      countermeasures should be applied first. [FP031, R2196]
      In some contexts, it is infeasible or inadvisable to attempt a
      complete or quantitative risk analysis because needed data, time,
      and expertise are not available. Instead, basic answers to
      questions about threats and risks may be already built into
      institutional security policies. For example, U.S. DoD policies
      for data confidentiality "do not explicitly itemize the range of
      expected threats" but instead "reflect an operational approach ...
      by stating the particular management controls that must be used to
      achieve [confidentiality] ... Thus, they avoid listing threats,
      which would represent a severe risk in itself, and avoid the risk
      of poor security design implicit in taking a fresh approach to
      each new problem". [NRC91]
   $ risk assumption
      (I) See: secondary definition under "risk".
   $ risk avoidance
      (I) See: secondary definition under "risk".
   $ risk limitation
      (I) See: secondary definition under "risk".
   $ risk management
      1. (I) The process of identifying, measuring, and controlling
      (i.e., mitigating) risks in information systems so as to reduce
      the risks to a level commensurate with the value of the assets
      protected. (See: risk analysis.)
      2. (I) The process of controlling uncertain events that may affect
      information system resources.
      3. (O) "The total process of identifying, controlling, and
      mitigating information system-related risks. It includes risk
      assessment; cost-benefit analysis; and the selection,
      implementation, test, and security evaluation of safeguards. This
      overall system security review considers both effectiveness and
      efficiency, including impact on the mission and constraints due to
      policy, regulations, and laws." [SP30]


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   $ risk transference
      (I) See: secondary definition under "risk".
   $ Rivest Cipher #2 (RC2)
      (N) A proprietary, variable-key-length block cipher invented by
      Ron Rivest for RSA Data Security, Inc.
   $ Rivest Cipher #4 (RC4)
      (N) A proprietary, variable-key-length stream cipher invented by
      Ron Rivest for RSA Data Security, Inc.
   $ Rivest Cipher #6 (RC6)
      (N) A symmetric, block cipher with 128-bit or longer key length,
      developed by Ron Rivest for RSA Data Security, Inc. as a candidate
      for the AES.
   $ Rivest-Shamir-Adleman (RSA)
      (N) An algorithm for asymmetric cryptography, invented in 1977 by
      Ron Rivest, Adi Shamir, and Leonard Adleman [RSA78].
      Tutorial: RSA uses exponentiation modulo the product of two large
      prime numbers. The difficulty of breaking RSA is believed to be
      equivalent to the difficulty of factoring integers that are the
      product of two large prime numbers of approximately equal size.
      To create an RSA key pair, randomly choose two large prime
      numbers, p and q, and compute the modulus, n = pq. Randomly choose
      a number e, the public exponent, that is less than n and
      relatively prime to (p-1)(q-1). Choose another number d, the
      private exponent, such that ed-1 evenly divides (p-1)(q-1). The
      public key is the set of numbers (n,e), and the private key is the
      set (n,d).
      It is assumed to be difficult to compute the private key (n,d)
      from the public key (n,e). However, if n can be factored into p
      and q, then the private key d can be computed easily. Thus, RSA
      security depends on the assumption that it is computationally
      difficult to factor a number that is the product of two large
      prime numbers. (Of course, p and q are treated as part of the
      private key, or else are destroyed after computing n.)
      For encryption of a message, m, to be sent to Bob, Alice uses
      Bob's public key (n,e) to compute m**e (mod n) = c. She sends c to
      Bob. Bob computes c**d (mod n) = m. Only Bob knows d, so only Bob
      can compute c**d (mod n) to recover m.
      To provide data origin authentication of a message, m, to be sent
      to Bob, Alice computes m**d (mod n) = s, where (d,n) is Alice's

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      private key. She sends m and s to Bob. To recover the message that
      only Alice could have sent, Bob computes s**e (mod n) = m, where
      (e,n) is Alice's public key.
      To ensure data integrity in addition to data origin authentication
      requires extra computation steps in which Alice and Bob use a
      cryptographic hash function h (see: digital signature). Alice
      computes the hash value h(m) = v, and then encrypts v with her
      private key to get s. She sends m and s. Bob receives m' and s',
      either of which might have been changed from the m and s that
      Alice sent. To test this, he decrypts s' with Alice's public key
      to get v'. He then computes h(m') = v". If v' equals v", Bob is
      assured that m' is the same m that Alice sent.
   $ robustness
      (N) See: level of robustness.
   $ role
      1. (I) A job function or employment position to which people or
      other system entities may be assigned in a system. (See: role-
      based access control. Compare: duty, billet, principal, user.)
      2. (O) /Common Criteria/ A pre-defined set of rules establishing
      the allowed interactions between a user and the TOE.
   $ role-based access control
      (I) A form of identity-based access control wherein the system
      entities that are identified and controlled are functional
      positions in an organization or process. [Sand] (See:
      authorization, constraint, identity, principal, role.)
      Tutorial: Administrators assign permissions to roles as needed to
      perform functions in the system. Administrators separately assign
      user identities to roles. When a user accesses the system in an
      identity (for which the user has been registered) and initiates a
      session using a role (to which the user has been assigned), then
      the permissions that have been assigned to the role are available
      to be exercised by the user.
      The following diagram shows that role-based access control
      involves five different relationships: (a) administrators assign
      identities to roles, (b) administrators assign permissions to
      roles, (c) administrators assign roles to roles, (d) users select
      identities in sessions, and (e) users select roles in sessions.
      Security policies may define constraints on these assignments and
      selections.



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         (c) Permission Inheritance Assignments (i.e., Role Hierarchy)
                               [Constraints]
                                  +=====+
                                  |     |
                   (a) Identity   v     v  (b) Permission
      +----------+  Assignments  +-------+  Assignments  +----------+
      |Identities|<=============>| Roles |<=============>|Permissions|
      +----------+ [Constraints] +-------+ [Constraints] +----------+
           |   |                   ^   ^
           |   |   +-----------+   |   |       +---------------------+
           |   |   | +-------+ |   |   |       |       Legend        |
           |   +====>|Session|=====+   |       |                     |
           |       | +-------+ |       |       |     One-to-One      |
           |       |    ...   |       |       | =================== |
           |       | +-------+ |       |       |                     |
           +========>|Session|=========+       |     One-to-Many     |
      (d) Identity | +-------+ |  (e) Role     | ==================> |
       Selections  |           | Selections    |                     |
      [Constraints]|  Access   |[Constraints]  |    Many-to-Many     |
                   | Sessions  |               | <=================> |
                   +-----------+               +---------------------+
   $ role certificate
      (I) An organizational certificate that is issued to a system
      entity that is a member of the set of users that have identities
      that are assigned to the same role. (See: role-based access
      control.)
   $ root, root CA
      1. (I) /PKI/ A CA that is directly trusted by an end entity. (See:
      trust anchor, trusted CA.)
      2. (I) /hierarchical PKI/ The CA that is the highest level (most
      trusted) CA in a certification hierarchy; i.e., the authority upon
      whose public key all certificate users base their validation of
      certificates, CRLs, certification paths, and other constructs.
      (See: top CA.)
      Tutorial: The root CA in a certification hierarchy issues public-
      key certificates to one or more additional CAs that form the
      second-highest level. Each of these CAs may issue certificates to
      more CAs at the third-highest level, and so on. To initialize
      operation of a hierarchical PKI, the root's initial public key is
      securely distributed to all certificate users in a way that does
      not depend on the PKI's certification relationships, i.e., by an
      out-of-band procedure. The root's public key may be distributed
      simply as a numerical value, but typically is distributed in a
      self-signed certificate in which the root is the subject. The

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      root's certificate is signed by the root itself because there is
      no higher authority in a certification hierarchy. The root's
      certificate is then the first certificate in every certification
      path.
      3. (I) /DNS/ The base of the tree structure that defines the name
      space for the Internet DNS. (See: domain name.)
      4. (O) /MISSI/ A name previously used for a MISSI policy creation
      authority, which is not a root as defined above for general usage,
      but is a CA at the second level of the MISSI hierarchy,
      immediately subordinate to a MISSI policy approving authority.
      5. (O) /UNIX/ A user account (a.k.a. "superuser") that has all
      privileges (including all security-related privileges) and thus
      can manage the system and its other user accounts.
   $ root certificate
      1. (I) /PKI/ A certificate for which the subject is a root. (See:
      trust anchor certificate, trusted certificate.)
      2. (I) /hierarchical PKI/ The self-signed public-key certificate
      at the top of a certification hierarchy.
   $ root key
      (I) /PKI/ A public key for which the matching private key is held
      by a root. (See: trust anchor key, trusted key.)
   $ root registry
      (O) /MISSI/ A name previously used for a MISSI PAA.
   $ ROT13
      (I) See: secondary definition under "Caesar cipher".
   $ router
      1a. (I) /IP/ A networked computer that forwards IP packets that
      are not addressed to the computer itself. (Compare: host.)
      1b. (I) /IPS/ A gateway that operates in the IPS Internet Layer to
      connect two or more subnetworks.
      1c. (N) /OSIRM/ A computer that is a gateway between two networks
      at OSIRM Layer 3 and that relays and directs data packets through
      that internetwork. (Compare: bridge, proxy.)
   $ RSA
      (N) See: Rivest-Shamir-Adleman.


Shirey                       Informational                    [Page 256]
RFC 4949         Internet Security Glossary, Version 2       August 2007

   $ rule
      See: policy rule.
   $ rule-based security policy
      (I) "A security policy based on global rules [i.e., policy rules]
      imposed for all users. These rules usually rely on comparison of
      the sensitivity of the resource being accessed and the possession
      of corresponding attributes of users, a group of users, or
      entities acting on behalf of users." [I7498-2] (Compare: identity-
      based security policy, policy rule, RBAC.)
   $ rules of behavior
      (I) A body of security policy that has been established and
      implemented concerning the responsibilities and expected behavior
      of entities that have access to a system. (Compare: [R1281].)
      Tutorial: For persons employed by a corporation or government, the
      rules might cover such matters as working at home, remote access,
      use of the Internet, use of copyrighted works, use of system
      resources for unofficial purpose, assignment and limitation of
      system privileges, and individual accountability.

Q <- 4. Definitions -> S