This document defines a "manifest" for use in the Resource Public Key Infrastructure (RPKI). A manifest is a signed object (file) that contains a listing of all the signed objects (files) in the repository publication point (directory) associated with an authority responsible for publishing in the repository. For each certificate, Certificate Revocation List (CRL), or other type of signed objects issued by the authority that are published at this repository publication point, the manifest contains both the name of the file containing the object and a hash of the file content. Manifests are intended to enable a relying party (RP) to detect certain forms of attacks against a repository. Specifically, if an RP checks a manifest's contents against the signed objects retrieved from a repository publication point, then the RP can detect replay attacks, and unauthorized in-flight modification or deletion of signed objects. This document obsoletes RFC 6486.

This is an Internet Standards Track document. This document is a product of the Internet Engineering Task Force (IETF). It represents the consensus of the IETF community. It has received public review and has been approved for publication by the Internet Engineering Steering Group (IESG). Further information on Internet Standards is available in Section 2 of RFC 7841. Information about the current status of this document, any errata, and how to provide feedback on it may be obtained at https://www.rfc-editor.org/info/rfc9286.

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The Resource Public Key Infrastructure (RPKI) [RFC 6480] makes use of a distributed repository system [RFC 6481] to make available a variety of objects needed by relying parties (RPs). Because all of the objects stored in the repository system are digitally signed by the entities that created them, attacks that modify these published objects are detectable by RPs. However, digital signatures alone provide no protection against attacks that substitute "stale" versions of signed objects (i.e., objects that were valid and have not yet expired, but have since been superseded), or in-flight attacks that remove an object that should be present in the repository. To assist in the detection of such attacks, RPKI repository systems make use of a signed object called a "manifest". A manifest is a signed object that enumerates all the signed objects (files) in the repository publication point (directory) that are associated with an authority responsible for publishing at that publication point. Each manifest contains both the name of the file containing the object and a hash of the file content, for every signed object issued by an authority that is published at the authority's repository publication point. A manifest is intended to allow an RP to detect unauthorized object removal or the substitution of stale versions of objects at a publication point. A manifest also is intended to allow an RP to detect similar outcomes that may result from an on-path attack during the retrieval of objects from the repository. Manifests are intended to be used in Certification Authority (CA) publication points in repositories (directories containing files that are subordinate certificates and Certificate Revocation Lists (CRLs) issued by this CA and other signed objects that are verified by End-Entity (EE) certificates issued by this CA). Manifests are modeled on CRLs, as the issues involved in detecting stale manifests and potential attacks using manifest replays, etc., are similar to those for CRLs. The syntax of the manifest payload differs from CRLs, since RPKI repositories contain objects not covered by CRLs, e.g., digitally signed objects, such as Route Origin Authorizations (ROAs) [RFC 6482]. This document obsoletes [RFC 6486].

The key words "MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL NOT", "SHOULD", "SHOULD NOT", "RECOMMENDED", "NOT RECOMMENDED", "MAY", and "OPTIONAL" in this document are to be interpreted as described in BCP 14 [RFC 2119] [RFC 8174] when, and only when, they appear in all capitals, as shown here.

A manifest associated with a CA's repository publication point contains a list of:

• the set of (non-expired, non-revoked) certificates issued and published by this CA,
• the most recent CRL issued by this CA, and
• all published signed objects that are verifiable using EE certificates [RFC 6487] issued by this CA (other than the manifest itself).

Every RPKI signed object includes, in the Cryptographic Message Syntax (CMS) [RFC 5652] wrapper of the object, the EE certificate used to verify it [RFC 6488]. Thus, there is no requirement to separately publish that EE certificate at the CA's repository publication point. Where multiple CA instances share a common publication point, as can occur when a CA performs a key-rollover operation [RFC 6489], the repository publication point will contain multiple manifests. In this case, each manifest describes only the collection of published products of its associated CA instance.

A CA's manifest is verified using an EE certificate. The SubjectInfoAccess (SIA) field of this EE certificate contains the accessMethod Object Identifier (OID) of id-ad-signedObject. The CA MUST sign only one manifest with each generated private key and MUST generate a new key pair for each new version of the manifest. An associated EE certificate used in this fashion is termed a "one-time-use" EE certificate (see Section 3 of RFC 6487).

A manifest is an RPKI signed object, as specified in [RFC 6488]. The RPKI signed object template requires specification of the following data elements in the context of the manifest structure.

The eContentType for a manifest is defined as id-ct-rpkiManifest and has the numerical OID of 1.2.840.113549.1.9.16.1.26.

The content of a manifest is ASN.1 encoded using the Distinguished Encoding Rules (DER) [X.690]. The content of a manifest is defined as follows:

The manifestNumber, thisUpdate, and nextUpdate fields are modeled after the corresponding fields in X.509 CRLs (see [RFC 5280]). Analogous to CRLs, a manifest is nominally current until the time specified in nextUpdate or until a manifest is issued with a greater manifest number, whichever comes first. Because a "one-time-use" EE certificate is employed to verify a manifest, the EE certificate MUST be issued with a validity period that coincides with the interval from thisUpdate to nextUpdate in the manifest, to prevent needless growth of the CA's CRL. The data elements of the manifest structure are defined as follows:

version:

The version number of this version of the manifest specification MUST be 0.

manifestNumber:

This field is an integer that is incremented (by 1) each time a new manifest is issued for a given publication point. This field allows an RP to detect gaps in a sequence of published manifests.

As the manifest is modeled on the CRL specification, the manifestNumber is analogous to the CRLNumber, and the guidance in [RFC 5280] for CRLNumber values is appropriate as to the range of number values that can be used for the manifestNumber. Manifest numbers can be expected to contain long integers. Manifest verifiers MUST be able to process number values up to 20 octets. Conforming manifest issuers MUST NOT use number values longer than 20 octets. The issuer MUST increase the value of this field monotonically for each newly generated manifest. Each RP MUST verify that a purported "new" manifest contains a higher manifestNumber than previously validated manifests. If the purported "new" manifest contains a manifestNumber value equal to or lower than manifestNumber values of previously validated manifests, the RP SHOULD use locally cached versions of objects, as described in Section 6.6.

thisUpdate:

This field contains the time when the manifest was created. This field has the same format constraints as specified in [RFC 5280] for the CRL field of the same name. The issuer MUST ensure that the value of this field is more recent than any previously generated manifest. Each RP MUST verify that this field value is greater (more recent) than the most recent manifest it has validated. If this field in a purported "new" manifest is smaller (less recent) than previously validated manifests, the RP SHOULD use locally cached versions of objects, as described in Section 6.6.

nextUpdate:

This field contains the time at which the next scheduled manifest will be issued. The value of nextUpdate MUST be later than the value of thisUpdate. The specification of the GeneralizedTime value is the same as required for the thisUpdate field.

If the authority alters any of the items that it has published in the repository publication point, then the authority MUST issue a new manifest. Even if no changes are made to objects at a publication point, a new manifest MUST be issued before the nextUpdate time. Each manifest encompasses a CRL, and the nextUpdate field of the manifest SHOULD match that of the CRL's nextUpdate field, as the manifest will be reissued when a new CRL is published. When a new manifest is issued before the time specified in nextUpdate of the current manifest, the CA MUST also issue a new CRL that revokes the EE certificate corresponding to the old manifest.

fileHashAlg:

This field contains the OID of the hash algorithm used to hash the files that the authority has placed into the repository. The hash algorithm used MUST conform to the RPKI Algorithms and Key Size Profile specification [RFC 7935].

fileList:

This field is a sequence of FileAndHash objects. There is one FileAndHash entry for each currently valid signed object that has been published by the authority (at this publication point). Each FileAndHash is an ordered pair consisting of the name of the file in the repository publication point (directory) that contains the object in question and a hash of the file's contents.

Names that appear in the fileList MUST consist of one or more characters chosen from the set a-z, A-Z, 0-9, - (HYPHEN), or _ (UNDERSCORE), followed by a single . (DOT), followed by a three- letter extension. The extension MUST be one of those enumerated in the "RPKI Repository Name Schemes" registry maintained by IANA [IANA-NAMING]. As an example, 'vixxBTS_TVXQ-2pmGOT7.cer' is a valid file name. The example above contains a mix of uppercase and lowercase characters in the file name. CAs and RPs MUST be able to perform filesystem operations in a case-sensitive, case-preserving manner.

The mandatory content-type attribute MUST have its attrValues field set to the same OID as eContentType. This OID is id-ct-rpkiManifest and has the numerical value of 1.2.840.113549.1.9.16.1.26.

To determine whether a manifest is valid, the RP MUST perform the following checks in addition to those specified in [RFC 6488]:

1. The eContentType in the EncapsulatedContentInfo is id-ad- rpkiManifest (OID 1.2.840.113549.1.9.16.1.26).
2. The version of the rpkiManifest is 0.
3. In the rpkiManifest, thisUpdate precedes nextUpdate.

Note: Although the thisUpdate and nextUpdate fields in the manifest eContent MUST match the corresponding fields in the CRL associated with the manifest, RPs MUST NOT reject a manifest solely because these fields are not identical. If the above procedure indicates that the manifest is invalid, then the manifest MUST be discarded and treated as though no manifest were present.

For a CA publication point in the RPKI repository system, a CA MUST perform the following steps to generate a manifest:

1. Generate a new key pair for use in a "one-time-use" EE certificate.
2. Issue an EE certificate for this key pair. The CA MUST revoke the EE certificate used for the manifest being replaced. This EE certificate MUST have an SIA extension access description field with an accessMethod OID value of id-ad-signedObject, where the associated accessLocation references the publication point of the manifest as an object URL. (RPs are required to verify both of these syntactic constraints.) This EE certificate MUST describe its Internet Number Resources (INRs) using the "inherit" attribute, rather than an explicit description of a resource set (see [RFC 3779]). (RPs are required to verify this.) The validity interval of the EE certificate MUST exactly match the thisUpdate and nextUpdate times specified in the manifest's eContent. (An RP MUST NOT consider misalignment of the validity interval in and of itself to be an error.)
3. The EE certificate MUST NOT be published in the authority's repository publication point.
4. Construct the manifest content. The manifest content is described in Section 4.2.1. The manifest's fileList includes the file name and hash pair for each object issued by this CA that has been published at this repository publication point (directory). The collection of objects to be included in the manifest includes all certificates issued by this CA that are published at the CA's repository publication point, the most recent CRL issued by the CA, and all objects verified by EE certificates that were issued by this CA that are published at this repository publication point. (Sections [6.1] through [6.5] describe the checks that an RP MUST perform in support of the manifest content noted here.) Note that the manifest does not include a self reference (i.e., its own file name and hash), since it would be impossible to compute the hash of the manifest itself prior to it being signed.
5. Encapsulate the manifest content using the CMS SignedData content type (as specified in Section 4), sign the manifest using the private key corresponding to the subject key contained in the EE certificate, and publish the manifest in the repository system publication point that is described by the manifest. (RPs are required to verify the CMS signature.)
6. Because the key pair is to be used only once, the private key associated with this key pair MUST now be destroyed.

A new manifest MUST be issued and published before the nextUpdate time. An authority MUST issue a new manifest in conjunction with the finalization of changes made to objects in the publication point. If any named objects in the publication point are replaced, the authority MUST ensure that the file hash for each replaced object is updated accordingly in the new manifest. Additionally, the authority MUST revoke the certificate associated with each replaced object (other than a CRL), if it is not expired. An authority MAY perform a number of object operations on a publication repository within the scope of a repository change before issuing a single manifest that covers all the operations within the scope of this change. Repository operators MUST implement some form of repository update procedure that mitigates, to the extent possible, the risk that RPs that are performing retrieval operations on the repository are exposed to inconsistent, transient, intermediate states during updates to the repository publication point (directory) and the associated manifest. Since the manifest object URL is included in the SIA of issued certificates, a new manifest MUST NOT invalidate the manifest object URL of previously issued certificates. This implies that the manifest's publication name in the repository, in the form of an object URL, is unchanged across manifest generation cycles. When a CA entity is performing a key rollover, the entity MAY choose to have two CA instances simultaneously publishing into the same repository publication point. In this case, there will be one manifest associated with each active CA instance that is publishing into the common repository publication point (directory).

Each RP MUST use the current manifest of a CA to control addition of listed files to the set of signed objects the RP employs for validating basic RPKI objects: certificates, ROAs, and CRLs. Any files not listed on the manifest MUST NOT be used for validation of these objects. However, files not listed on a manifest MAY be employed to validate other signed objects, if the profile of the object type explicitly states that such behavior is allowed (or required). Note that relying on files not listed in a manifest may allow an attacker to effect substitution attacks against such objects. As noted earlier, manifests are designed to allow an RP to detect manipulation of repository data, errors by a CA or repository manager, and/or active attacks on the communication channel between an RP and a repository. Unless all of the files enumerated in a manifest can be obtained by an RP during a fetch operation, the fetch is considered to have failed and the RP MUST retry the fetch later. [RFC 6480] suggests (but does not mandate) that the RPKI model employ fetches that are incremental, e.g., an RP transfers files from a publication point only if they are new/changed since the previous, successful fetch represented in the RP's local cache. This document avoids language that relies on details of the underlying file transfer mechanism employed by an RP and a publication point to effect this operation. Thus, the term "fetch" refers to an operation that attempts to acquire the full set of files at a publication point, consistent with the id-ad-rpkiManifest URI extracted from a CA certificate's SIA (see below). If a fetch fails, it is assumed that a subsequent fetch will resolve problems encountered during the fetch. Until such time as a successful fetch is executed, an RP SHOULD use cached data from a previous, successful fetch. This response is intended to prevent an RP from misinterpreting data associated with a publication point and thus possibly treating invalid routes as valid, or vice versa. The processing described below is designed to cause all RPs with access to the same local cache and RPKI repository data to acquire the same set of validated repository files. It does not ensure that the RPs will achieve the same results with regard to validation of RPKI data, since that depends on how each RP resolves any conflicts that may arise in processing the retrieved files. Moreover, in operation, different RPs will access repositories at different times, and some RPs may experience local cache failures, so there is no guarantee that all RPs will achieve the same results with regard to acquisition or validation of RPKI data. Note also that there is a "chicken and egg" relationship between the manifest and the CRL for a given CA instance. If the EE certificate for the current manifest is revoked, i.e., it appears in the current CRL, then the CA or publication point manager has made a serious error. In this case, the fetch has failed; proceed to Section 6.6. Similarly, if the CRL is not listed on a valid, current manifest, acquired during a fetch, the fetch has failed; proceed to Section 6.6, because the CRL is considered missing.

For a given publication point, an RP MUST perform a series of tests to determine which signed object files at the publication point are acceptable. The tests described below (Sections [6.2] through [6.5]) are to be performed using the manifest identified by the id-ad- rpkiManifest URI extracted from a CA certificate's SIA. All of the files referenced by the manifest MUST be located at the publication point specified by the id-ad-caRepository URI from the (same) CA certificate's SIA. The manifest and the files it references MUST reside at the same publication point. If an RP encounters any files that appear on a manifest but do not reside at the same publication point as the manifest, the RP MUST treat the fetch as failed, and a warning MUST be issued (see Section 6.6 below). Note that, during CA key rollover [RFC 6489], signed objects for two or more different CA instances will appear at the same publication point. Manifest processing is to be performed separately for each CA instance, guided by the SIA id-ad-rpkiManifest URI in each CA certificate.

The RP MUST fetch the manifest identified by the SIA id-ad- rpkiManifest URI in the CA certificate. If an RP cannot retrieve a manifest using this URI or if the manifest is not valid (Section 4.4), an RP MUST treat this as a failed fetch; proceed to Section 6.6. Otherwise, proceed to Section 6.3.

The RP MUST check that the current time (translated to UTC) is between thisUpdate and nextUpdate. If the current time lies within this interval, proceed to Section 6.4. If the current time is earlier than thisUpdate, the CA may have made an error or the RP's local notion of time may be in error. The RP MUST treat this as a failed fetch; proceed to Section 6.6. If the current time is later than nextUpdate, then the manifest is stale; the RP MUST treat this as a failed fetch. Proceed to Section 6.6. Otherwise, proceed to Section 6.4.

The RP MUST acquire all of the files enumerated in the manifest (fileList) from the publication point. If there are files listed in the manifest that cannot be retrieved from the publication point, the RP MUST treat this as a failed fetch. Proceed to Section 6.6. Otherwise, proceed to Section 6.5.

The RP MUST verify that the hash value of each file listed in the manifest matches the value obtained by hashing the file acquired from the publication point. If the computed hash value of a file listed on the manifest does not match the hash value contained in the manifest, then the fetch has failed, and the RP MUST respond accordingly. Proceed to Section 6.6.

If a fetch fails for any of the reasons cited in Sections [6.2] through [6.5], the RP MUST issue a warning indicating the reason(s) for termination of processing with regard to this CA instance. It is RECOMMENDED that a human operator be notified of this warning. Termination of processing means that the RP SHOULD continue to use cached versions of the objects associated with this CA instance, until such time as they become stale or they can be replaced by objects from a successful fetch. This implies that the RP MUST NOT try to acquire and validate subordinate signed objects, e.g., subordinate CA certificates, until the next interval when the RP is scheduled to fetch and process data for this CA instance.

The RPKI publication system model requires that every publication point be associated with one or more CAs and be non-empty. Upon creation of the publication point associated with a CA, the CA MUST create and publish a manifest as well as a CRL. A CA's manifest will always contain at least one entry, i.e., a CRL issued by the CA [RFC 6481], corresponding to the scope of this manifest. Every published signed object in the RPKI [RFC 6488] is published in the repository publication point of the CA that issued the EE certificate, and is listed in the manifest associated with that CA certificate.

Manifests provide an additional level of protection for RPKI RPs. Manifests can assist an RP in determining if a repository object has been deleted, occluded, or otherwise removed from view, or if a publication of a newer version of an object has been suppressed (and an older version of the object has been substituted). Manifests cannot repair the effects of such forms of corruption of repository retrieval operations. However, a manifest enables an RP to determine if a locally maintained copy of a repository is a complete and up-to-date copy, even when the repository retrieval operation is conducted over an insecure channel. In cases where the manifest and the retrieved repository contents differ, the manifest can assist in determining which repository objects form the difference set in terms of missing, extraneous, or superseded objects. The signing structure of a manifest and the use of the nextUpdate value allow an RP to determine if the manifest itself is the subject of attempted alteration. The requirement for every repository publication point to contain at least one manifest allows an RP to determine if the manifest itself has been occluded from view. Such attacks against the manifest are detectable within the time frame of the regular schedule of manifest updates. Forms of replay attacks within finer-grained time frames are not necessarily detectable by the manifest structure.

The "RPKI Signed Objects" registry was originally created and populated by [RFC 6488]. The "RPKI Repository Name Schemes" registry was created by [RFC 6481] and created four of the initial three-letter file name extensions. IANA has updated the reference for the "Manifest" row in the "RPKI Signed Objects" registry to point to this document. IANA has also updated the following entries to refer to this document instead of RFC 6486:

• id-mod-rpkiManifest (60) in the "SMI Security for S/MIME Module Identifier (1.2.840.113549.1.9.16.0)" registry
• id-ct-rpkiManifest (26) in the "SMI Security for S/MIME CMS Content Type (1.2.840.113549.1.9.16.1)" registry
• the "Security considerations" entry in the application media type registration for rpki-manifest

No other actions are required.

[IANA-NAMING]

IANA, "RPKI Repository Name Schemes",
<https://www.iana.org/assignments/rpki/>.

[RFC2119]

S. Bradner, "Key words for use in RFCs to Indicate Requirement Levels", BCP 14, RFC 2119, DOI 10.17487/RFC2119, March 1997,
<https://www.rfc-editor.org/info/rfc2119>.

[RFC5280]

D. Cooper, S. Santesson, S. Farrell, S. Boeyen, R. Housley, and W. Polk, "Internet X.509 Public Key Infrastructure Certificate and Certificate Revocation List (CRL) Profile", RFC 5280, DOI 10.17487/RFC5280, May 2008,
<https://www.rfc-editor.org/info/rfc5280>.

[RFC6481]

G. Huston, R. Loomans, and G. Michaelson, "A Profile for Resource Certificate Repository Structure", RFC 6481, DOI 10.17487/RFC6481, February 2012,
<https://www.rfc-editor.org/info/rfc6481>.

[RFC6482]

M. Lepinski, S. Kent, and D. Kong, "A Profile for Route Origin Authorizations (ROAs)", RFC 6482, DOI 10.17487/RFC6482, February 2012,
<https://www.rfc-editor.org/info/rfc6482>.

[RFC6487]

G. Huston, G. Michaelson, and R. Loomans, "A Profile for X.509 PKIX Resource Certificates", RFC 6487, DOI 10.17487/RFC6487, February 2012,
<https://www.rfc-editor.org/info/rfc6487>.

[RFC6488]

M. Lepinski, A. Chi, and S. Kent, "Signed Object Template for the Resource Public Key Infrastructure (RPKI)", RFC 6488, DOI 10.17487/RFC6488, February 2012,
<https://www.rfc-editor.org/info/rfc6488>.

[RFC7935]

G. Huston, and G. Michaelson, "The Profile for Algorithms and Key Sizes for Use in the Resource Public Key Infrastructure", RFC 7935, DOI 10.17487/RFC7935, August 2016,
<https://www.rfc-editor.org/info/rfc7935>.

[RFC8174]

B. Leiba, "Ambiguity of Uppercase vs Lowercase in RFC 2119 Key Words", BCP 14, RFC 8174, DOI 10.17487/RFC8174, May 2017,
<https://www.rfc-editor.org/info/rfc8174>.

[X.690]

International Telecommunication Union, "Information technology - ASN.1 encoding rules: Specification of Basic Encoding Rules (BER), Canonical Encoding Rules (CER) and Distinguished Encoding Rules (DER)", February 2021,
<https://www.itu.int/rec/T-REC-X.690-202102-I/en>.

[RFC3779]

C. Lynn, S. Kent, and K. Seo, "X.509 Extensions for IP Addresses and AS Identifiers", RFC 3779, DOI 10.17487/RFC3779, June 2004,
<https://www.rfc-editor.org/info/rfc3779>.

[RFC5652]

R. Housley, "Cryptographic Message Syntax (CMS)", STD 70, RFC 5652, DOI 10.17487/RFC5652, September 2009,
<https://www.rfc-editor.org/info/rfc5652>.

[RFC6480]

M. Lepinski, and S. Kent, "An Infrastructure to Support Secure Internet Routing", RFC 6480, DOI 10.17487/RFC6480, February 2012,
<https://www.rfc-editor.org/info/rfc6480>.

[RFC6486]

R. Austein, G. Huston, S. Kent, and M. Lepinski, "Manifests for the Resource Public Key Infrastructure (RPKI)", RFC 6486, DOI 10.17487/RFC6486, February 2012,
<https://www.rfc-editor.org/info/rfc6486>.

[RFC6489]

G. Huston, G. Michaelson, and S. Kent, "Certification Authority (CA) Key Rollover in the Resource Public Key Infrastructure (RPKI)", BCP 174, RFC 6489, DOI 10.17487/RFC6489, February 2012,
<https://www.rfc-editor.org/info/rfc6489>.

In 2019, it came to light that multiple RP implementations were in a vulnerable position, possibly due to perceived ambiguity in the original [RFC 6486] specification. This document attempts to clarify the innovative concept and application of RPKI manifests in light of real-world deployment experience in the global Internet routing system, to avoid future problematic cases. The following list summarizes the changes between RFC 6486 and this document:

• Forbidding "sequential-use" EE certificates and instead mandating "one-time-use" EE certificates.
• Clarifying that manifest EE certificates are to be issued with a validity period that coincides with the interval specified in the manifest eContent, which coincides with the CRL's thisUpdate and nextUpdate.
• Clarifying that the manifestNumber is monotonically incremented in steps of 1.
• Recommending that CA issuers include the applicable CRL's nextUpdate with the manifest's nextUpdate.
• Constraining the set of valid characters in FileAndHash file names.
• Clarifying that an RP unable to obtain the full set of files listed on a manifest is considered to be in a failure state, in which case cached data from a previous attempt should be used (if available).
• Clarifying the requirement for a current CRL to be present, listed, and verified.
• Removing the notion of "local policy".

The authors would like to acknowledge the contributions from George Michaelson and Randy Bush in the preparation of the manifest specification. Additionally, the authors would like to thank Mark Reynolds and Christopher Small for assistance in clarifying manifest validation and RP behavior. The authors also wish to thank Tim Bruijnzeels, Job Snijders, Oleg Muravskiy, Sean Turner, Adianto Wibisono, Murray Kucherawy, Francesca Palombini, Roman Danyliw, Lars Eggert, Robert Wilton, and Benjamin Kaduk for their helpful review of this document.

Rob Austein

Geoff Huston

Stephen Kent

Matt Lepinski