Multiple Repository Publication Points support in the Resource Public Key Infrastructure (RPKI)

The key words "MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL NOT", "SHOULD", "SHOULD NOT", "RECOMMENDED", "MAY", and "OPTIONAL" in this document are to be interpreted as described in .

The RPKI repository system described in requires scalability and diversity in order to address challenges such as Distributed Denial of Service (DDoS) attacks, to secure the availability of the system when performing maintenance activities and against possible security incidents in one particular implementation. Additionally, when a single operator manages a RPKI Repository Publication Point, it is more probable to introduce circular dependencies when the Route Origin Authorization (ROA) signed objects for the Repository Publication Point IP addresses are hosted in servers that uses those same addresses. The current toolset for a CA to diversify its repository system is limited for both TA distribution and CA publication point management. In the case of trust anchors, requires a unique URI per key on each TAL file. Conversely, in the case of the different publication points and although supported by , there is no current guidance on how RPs should support multiple publication points for the same object. When using a single URI, the options for diversity and scalability are reduced to: Give the content to a Content Delivery Network (CDN) to have the content distributed (as long as the CDN supports the CA's access method , which is not currently the case for rsync). The implementation will typically require the configuration of a CNAME resource record in the authoritative server pointing to a server farm inside the CDN who will handle load-balancing by using a set of internally defined metrics. If, for the sake of diversity, a CA administrator would like to use two different CDNs for the same URI it will need to modify the authoritative name server behavior to break RFC1034 standard behavior and allow multiple CNAME records for the same alias. This modification is not available by default on most of the more widely deployed DNS servers. Copy the content to different Repository Publication Points around the globe (i.e. using ) and load balance the content using different Domain Name System (DNS) techniques. The load balancing implementation will need to verify the availability of the target server before providing a DNS response to avoid blackholes caused by unavailable servers or clusters. This "feature" needs also be added to the authoritative name server or the full DNS resolution or outsourced to a third party (which would introduce another non-diversified element). This document addresses this problem by enabling multiple operators for trust anchor material, and, while not making it mandatory, recommends the use of multiple publication points in signed objects. The main idea is that the a CA will host its RPKI signed objects in different locations, using diverse routing paths and diverse DNS resolution. The RP will have more processing to perform to fetch the different objects when dealing with exceptions. The first thing that is needed is to add multiple URIs support for each Trust Anchor. requires that each TAL file includes a unique URI. This document removes this requirement by allowing one or more URI for each public key in a TAL file. In steady state, an RP should receive the same material from each of the different URI for the same root certificate. An exception could happen when the certificate is been updated or rolled-over, a process which should not have operational consequences. For the root certificate trust anchor, this proposal has an additional consequence: it would create the idea of root-CA repository operators. This concept has worked well in the case of DNS, where one organization is responsible for creating the root zone material and a number of different organizations are responsible in running the root servers. A CA can add support for multiple Repository Publication Points operators by adding more than one respective object for the Authority Information Access (AIA), the Subject Information Access (SIA) and the CRL Distribution Points (CRLDP) and which is supported by and . This document provides guidance on the RP expected behavior when analyzing signed objects with multiple Repository Publication Points in .

The idea of multiples operators support for a TA certificate expressed on its TAL file is similar to the support for several Root Server operators in a DNS hints file. An example of such a TAL file with 3 operators would be:

As we can see in this example, a RP would have different URI where to fetch the self-signed certificate for the trust anchor. In each location, the same result should be expected as all the URI share the same public key. In order to increase diversity, It is RECOMMENDED that the different FQDN could be resolved to IP addresses included in ROA objects from different CAs and hosted in diverse repository publication points.

The following text will replace the last paragraph on Section 2.1 of RFC 6490: The TAL is an ordered sequence of: 1) One or more rsync URI [RFC5781], 2) A <CRLF> or <LF> line break after each URI, 3) A line containing a single <CRLF> or <LF> line break, and 4) A subjectPublicKeyInfo [RFC5280] in DER format [X.509], encoded in Base64 (see Section 4 of [RFC4648]).A

A RP can use different rules to select the URI from where fetch the Trust Anchor certificate. Some examples are: Using the order provided in the TAL file Selecting the URI randomly from the available list Creating a prioritized list of URIs based on RP specific parameters such as connection establishment delay If the connection to the preferred URI fails or the fetched certificate public key does not match the TAL public key, the RP SHOULD fetch the TA certificate from the next URI of preference.

The support for multiple operators in the RPKI Certificate Authority (CA) and End Entity (EE) certificates is supported as the RFC 5082 allows multiple repository publication point operators as the SIA, AIA and CRLDP are implemented as sequences. Consequently, no changes are needed on the existing RPKI standard and this section could be considered informative. In the case of the SIA extension, for each operator, the accessMethods for both the CA repository publication point and for the correspondent manifest needs to be added.

A RP can use different rules to select the URI to fetch the different repository objects and when performing the validation. When a RP needs to fetch one or more object from a list of possible URIs, it can chose the URI by adopting a locally defined rule that could be: Using the order provided in the correspondent certificate Selecting the URI randomly from the available list Creating a prioritized list of URIs based on RP specific parameters such as connection establishment delay If the connection to the preferred URI fails , the RP SHOULD fetch the repository objects from the next URI of preference.

No IANA requirements

TBA

TBA.