6. Security Considerations
Communication between NPs' RID systems must be protected. RID has
many security considerations built into the design of the protocol,
several of which are described in the following sub-sections. For a
complete view of security, considerations need to include the
availability, confidentiality, and integrity concerns for the
transport, storage, and exchange of information.
When considering the transport of RID messages, an out-of-band
network, either logical or physical, would prevent outside attacks
against RID communication. An out-of-band connection would be ideal,
but not necessarily practical. Authenticated encrypted tunnels
between RID systems MUST be used to provide confidentiality,
integrity, authenticity, and privacy for the data. Trust
relationships are based on consortiums and established trust
relationships of public key infrastructure (PKI) cross-certifications
of consortiums. By using RIDPolicy information, TLS, and the XML
security features of encryption [XMLencrypt] and digital signatures
[RFC3275], [XMLsig], RID takes advantage of existing security
standards. The standards provide clear methods to ensure that
messages are secure, authenticated, and authorized, and that the
messages meet policy and privacy guidelines and maintain integrity.
As specified in the relevant sections of this document, the XML
digital signature [RFC3275] and XML encryption [XMLencrypt] are used
in the following cases:
XML Digital Signature
o The originator of the TraceRequest or Investigation request MUST
use a detached signature to sign at least one of the original IP
packets included in the RecordItem class data to provide
authentication to all upstream participants in the trace of the
origin. All IP packets provided by the originator may be signed,
and additional packets added by upstream peers in the trace may be
signed by the peer adding the data, while maintaining the IP
packet and detached signature from the original requestor. This
signature MUST be passed to all recipients of the TraceRequest.
o For all message types, the full IODEF/RID document MUST be signed
using an enveloped signature by the sending peer to provide
authentication and integrity to the receiving RID system.
o The IODEF/RID document may be encrypted to provide an extra layer
of security between peers so that the message is not only
encrypted for the transport, but also while stored. This behavior
would be agreed upon between peers or a consortium, or determined
on a per-message basis, depending on security requirements. It
should be noted that there are cases for transport where the
RIDPolicy class needs to be presented in clear text, as detailed
in the transport document [RFC6046].
o An Investigation request, or any other message type that may be
relayed through RID systems other than the intended destination as
a result of trust relationships, may be encrypted for the intended
recipient. This may be necessary if the RID network is being used
for message transfer, the intermediate parties do not need to have
knowledge of the request contents, and a direct communication path
does not exist. In that case, the RIDPolicy class is used by
intermediate parties and is maintained in clear text.
o The action taken in the Result message may be encrypted using the
key of the request originator. In that case, the intermediate
parties can view the RIDPolicy information and know the trace has
been completed and do not need to see the action. If the use of
encryption were limited to sections of the message, the History
class information would be encrypted. Otherwise, it is
RECOMMENDED to encrypt the entire IODEF/RID document, using an
enveloped signature, for the originator of the request. The
existence of the Result message for an incident would tell any
intermediate parties used in the path of the incident
investigation that the incident handling has been completed.
The formation of policies is a very important aspect of using a
messaging system like RID to exchange potentially sensitive
information. Many considerations should be involved for peering
parties, and some guidelines to protect the data, systems, and
transport are covered in this section. Policies established should
provide guidelines for communication methods, security, and fall-back
The security considerations for the storage and exchange of
information in RID messaging may include adherence to local,
regional, or national regulations in addition to the obligations to
protect client information during an investigation. RID Policy is a
necessary tool for listing the requirements of messages to provide a
method to categorize data elements for proper handling. Controls are
also provided for the sending entity to protect messages from third
parties through XML encryption.
RID provides a method to exchange incident handling request and
Report messages to peer networks. Network administrators, who have
the ability to base the decision on the available resources and other
factors of their network, maintain control of incident investigations
within their own network. Thus, RID provides the ability for
participating networks to manage their own security controls,
leveraging the information listed in RIDPolicy.
6.1. Message Transport
The transport specifications are fully defined in a separate document
[RFC6046]. The specified transport protocols MUST use encryption to
provide an additional level of security and integrity, while
supporting mutual authentication through bi-directional certificate
usage. Any subsequent transport method defined should take advantage
of existing standards for ease of implementation and integration of
RID systems. Session encryption for the transport of RID messages is
enforced in the transport specification. The privacy and security
considerations are addressed fully in RID to protect sensitive
portions of documents and provide a method to authenticate the
messages. Therefore, RID messages do not rely on the security
provided by the transport layer alone. The encryption requirements
and considerations for RID are discussed at the beginning of
Section 6 of this document.
XML security functions such as the digital signature [RFC3275] and
encryption [XMLencrypt] provide a standards-based method to encrypt
and digitally sign RID messages. RID messages specify system use and
privacy guidelines through the RIDPolicy class. A public key
infrastructure (PKI) provides the base for authentication and
authorization, encryption, and digital signatures to establish trust
relationships between members of a RID consortium or a peering
XML security functions such as the digital signature [RFC3275] and
encryption [XMLencrypt] can be used within the contents of the
message for privacy and security in cases for which certain elements
must remain encrypted or signed as they traverse the path of a trace.
For example, the digital signature on a TraceRequest can be used to
verify the identity of the trace originator. The use of the XML
security features in RID messaging is in accordance with the
specifications for the IODEF model; however, the use requirements may
differ since RID also incorporates communication of security incident
6.2. Message Delivery Protocol - Integrity and Authentication
The RID protocol must be able to guarantee delivery and meet the
necessary security requirements of a state-of-the-art protocol. In
order to guarantee delivery, TCP should be considered as the
underlying protocol within the current network standard practices.
Security considerations must include the integrity, authentication,
privacy, and authorization of the messages sent between RID
communication systems or IHSs. The communication between RID systems
must be authenticated and encrypted to ensure the integrity of the
messages and the RID systems involved in the trace. Another concern
that needs to be addressed is authentication for a request that
traverses multiple networks. In this scenario, systems in the path
of the multi-hop TraceRequest need to authorize a trace from not only
their neighbor network, but also from the initiating RID system as
discussed in Section 6.4. Several methods can be used to ensure
integrity and privacy of the communication.
The transport mechanism selected MUST follow the defined transport
protocol [RFC6046] when using RID messaging to ensure consistency
among the peers. Consortiums may vary their selected transport
mechanisms and thus must decide upon a mutual protocol to use for
transport when communicating with peers in a neighboring consortium
using RID. RID systems MUST implement and deploy HTTPS as defined in
the transport document [RFC6046] and optionally support other
protocols such as the Blocks Extensible Exchange Protocol (BEEP).
RID, the XML security functions, and transport protocols must
properly integrate with a public key infrastructure (PKI) managed by
the consortium or one managed by a trusted entity. For the Internet,
an example of an existing effort that could be leveraged to provide
the supporting PKI could be the American Registry for Internet
Numbers (ARIN) and the Regional Internet Registry's (RIR's) PKI
hierarchy. Security and privacy considerations related to
consortiums are discussed in Sections 6.5 and 6.6.
6.3. Transport Communication
Out-of-band communications dedicated to NP interaction for RID
messaging would provide additional security as well as guaranteed
bandwidth during a denial-of-service attack. For example, an out-of-
band channel may consist of logical paths defined over the existing
network. Out-of-band communications may not be possible between all
network providers, but should be considered to protect the network
management systems used for RID messaging. Methods to protect the
data transport may also be provided through session encryption.
In order to address the integrity and authenticity of messages,
transport encryption MUST be used to secure the traffic sent between
RID systems. Systems with predefined relationships for RID would
include those who peer within a consortium with agreed-upon
appropriate use regulations and for peering consortiums. Trust
relationships may also be defined through a bridged or hierarchical
PKI in which both peers belong.
Systems used to send authenticated RID messages between networks MUST
use a secured system and interface to connect to a border network's
RID systems. Each connection to a RID system MUST meet the security
requirements agreed upon through the consortium regulations, peering,
or SLAs. The RID system MUST only listen for and send RID messages
on the designated port, which also MUST be over an encrypted tunnel
meeting the minimum requirement of algorithms and key lengths
established by the consortium, peering, or SLA. The selected
cryptographic algorithms for symmetric encryption, digital
signatures, and hash functions MUST meet minimum security levels of
the times. The encryption strength MUST adhere to import and export
regulations of the involved countries for data exchange.
6.4. Authentication of RID Protocol
In order to ensure the authenticity of the RID messages, a message
authentication scheme is used to secure the protocol. XML security
functions utilized in RID require a trust center such as a PKI for
the distribution of credentials to provide the necessary level of
security for this protocol. Layered transport protocols also utilize
encryption and rely on a trust center. Public key certificate pairs
issued by a trusted Certification Authority (CA) MAY be used to
provide the necessary level of authentication and encryption for the
RID protocol. The CA used for RID messaging must be trusted by all
involved parties and may take advantage of similar efforts, such as
the Internet2 federated PKI or the ARIN/RIR effort to provide a PKI
to network providers. The PKI used for authentication would also
provide the necessary certificates needed for encryption used for the
RID transport protocol [RFC6046].
The use of pre-shared keys may be considered for authentication. If
this option is selected, the specifications set forth in "Pre-Shared
Key Ciphersuites for Transport Layer Security (TLS)" [RFC4279] MUST
Hosts receiving a RID message MUST be able to verify that the sender
of the request is valid and trusted. Using digital signatures on a
hash of the RID message with an X.509 version 3 certificate issued by
a trusted party MUST be used to authenticate the request. The X.509
version 3 specifications as well as the digital signature
specifications and path validation standards set forth in [RFC5280]
MUST be followed in order to interoperate with a PKI designed for
similar purposes. The IODEF specification MUST be followed for
digital signatures to provide the authentication and integrity
aspects required for secure messaging between network providers. The
use of digital signatures in RID XML messages MUST follow the World
Wide Web Consortium (W3C) recommendations for signature syntax and
processing when either the XML encryption [XMLencrypt] or digital
signature [XMLsig], [RFC3275] is used within a document. Transport
specifications are detailed in a separate document [RFC6046].
It might be helpful to define an extension to the authentication
scheme that uses attribute certificates [RFC5755] in such a way that
an application could automatically determine whether human
intervention is needed to authorize a request; however, the
specification of such an extension is out of scope for this document.
6.4.1. Multi-Hop TraceRequest Authentication
Bilateral trust relations between network providers ensure the
authenticity of requests for TraceRequests from immediate peers in
the web of networks formed to provide the traceback capability. A
network provider several hops into the path of the RID trace must
trust the information from its own trust relationships as well as the
previous trust relationships in the downstream path. For practical
reasons, the NPs may want to prioritize incident handling events
based upon the immediate peer for a TraceRequest, the originator, and
the listed Confidence rating for the incident. In order to provide a
higher assurance level of the authenticity of the TraceRequest, the
originating RID system is included in the TraceRequest along with
contact information and the information of all RID systems in the
path the trace has taken. This information is provided through the
IODEF EventData class nesting the list of systems and contacts
involved in a trace, while setting the category attribute to
A second measure MUST be taken to ensure the identity of the
originating RID system. The originating RID system MUST include a
digital signature in the TraceRequest sent to all systems in the
upstream path. The digital signature from the RID system is
performed on the RecordItem class of the IODEF following the XML
digital signature specifications from W3C [XMLsig] using a detached
signature. The signature MUST be passed to all parties that receive
a TraceRequest, and each party MUST be able to perform full path
validation on the digital signature. Full path validation verifies
the chaining relationship to a trusted root and also performs a
certificate revocation check. In order to accommodate that
requirement, the IP packet in the RecordItem data MUST remain
unchanged as a request is passed along between providers and is the
only element for which the signature is applied. If additional
packets are included in the document at upstream peers, the initial
packet MUST still remain with the detached signature. The subsequent
packets may be signed by the peer adding the incident information for
the investigation. A second benefit to this requirement is that the
integrity of the filter used is ensured as it is passed to subsequent
NPs in the upstream trace of the packet. The trusted PKI also
provides the keys used to digitally sign the RecordItem class for
TraceRequests to meet the requirement of authenticating the original
request. Any host in the path of the trace should be able to verify
the digital signature using the trusted PKI.
In the case in which an enterprise network using RID sends a
TraceRequest to its provider, the signature from the enterprise
network MUST be included in the initial request. The NP may generate
a new request to send upstream to members of the NP consortium to
continue the trace. If the original request is sent, the originating
NP, acting on behalf of the enterprise network under attack, MUST
also digitally sign, with an enveloped signature, the full IODEF
document to assure the authenticity of the TraceRequest. An NP that
offers RID as a service may be using its own PKI to secure RID
communications between its RID system and the attached enterprise
networks. NPs participating in the trace MUST be able to determine
the authenticity of RID requests.
6.5. Consortiums and Public Key Infrastructures
Consortiums of NPs are an ideal way to establish a communication web
of trust for RID messaging. The consortium could provide centralized
resources, such as a PKI, and established guidelines for use of the
RID protocol. The consortium would also assist in establishing trust
relationships between the participating NPs to achieve the necessary
level of cooperation and experience-sharing among the consortium
entities. This may be established through PKI certificate policy
[RFC3647] reviews to determine the appropriate trust levels between
organizations or entities. The consortium may also be used for other
purposes to better facilitate communication among NPs in a common
area (Internet, region, government, education, private networks,
Using a PKI to distribute certificates used by RID systems provides
an already established method to link trust relationships between NPs
of consortiums that would peer with NPs belonging to a separate
consortium. In other words, consortiums could peer with other
consortiums to enable communication of RID messages between the
participating NPs. The PKI along with Memorandums of Agreement could
be used to link border directories to share public key information in
a bridge, a hierarchy, or a single cross-certification relationship.
Consortiums also need to establish guidelines for each participating
NP to adhere to. The RECOMMENDED guidelines include:
o Physical and logical practices to protect RID systems;
o Network and application layer protection for RID systems and
o Proper use guidelines for RID systems, messages, and requests; and
o A PKI to provide authentication, integrity, and privacy.
The functions described for a consortium's role would parallel that
of a PKI federation. The PKI federations that currently exist are
responsible for establishing security guidelines and PKI trust
models. The trust models are used to support applications to share
information using trusted methods and protocols.
A PKI can also provide the same level of security for communication
between an end entity (enterprise, educational, or government
customer network) and the NP. The PKI may be a subordinate CA or in
the CA hierarchy from the NP's consortium to establish the trust
relationships necessary as the request is made to other connected
6.6. Privacy Concerns and System Use Guidelines
Privacy issues raise many concerns when information-sharing is
required to achieve the goal of stopping or mitigating the effects of
a security incident. The RIDPolicy class is used to automate the
enforcement of the privacy concerns listed within this document. The
privacy and system use concerns that MUST be addressed in the RID
system and other integrated components include the following:
Network Provider Concerns:
o Privacy of data monitored and/or stored on IDSs for attack
o Privacy of data monitored and stored on systems used to trace
traffic across a single network.
Customer Attached Networks Participating in RID with NP:
o Customer networks may include an enterprise, educational,
government, or other attached networks to an NP participating in
RID and MUST be made fully aware of the security and privacy
considerations for using RID.
o Customers MUST know the security and privacy considerations in
place by their NP and the consortium of which the NP is a member.
o Customers MUST understand that their data can and will be sent to
other NPs in order to complete a trace unless an agreement stating
otherwise is made in the service level agreements between the
customer and NP.
Parties Involved in the Attack:
o Privacy of the identity of a host involved in an attack.
o Privacy of information such as the source and destination used for
communication purposes over the monitored or RID connected
o Protection of data from being viewed by intermediate parties in
the path of an Investigation request MUST be considered.
o System use restricted to security incident handling within the
local region's definitions of appropriate traffic for the network
monitored and linked via RID in a single consortium also abiding
by the consortium's use guidelines.
o System use prohibiting the consortium's participating NPs from
inappropriately tracing non-attack traffic to locate sources or
mitigate traffic unlawfully within the jurisdiction or region.
o System use between peering consortiums MUST also adhere to any
government communication regulations that apply between those two
regions, such as encryption export and import restrictions. This
may include consortiums that are categorized as
"BetweenConsortiums" or "AcrossNationalBoundaries".
o System use between consortiums MUST NOT request traffic traces and
actions beyond the scope intended and permitted by law or
o System use between consortiums classified as
"AcrossNationalBoundaries" MUST respect national boundary issues
and limit requests to appropriate system use and not to achieve
their own agenda to limit or restrict traffic that is otherwise
permitted within the country in which the peering consortium
The security and privacy considerations listed above are for the
consortiums, NPs, and enterprises to agree upon. The agreed-upon
policies may be facilitated through use of the RIDPolicy class. Some
privacy considerations are addressed through the RID guidelines for
encryption and digital signatures as described at the beginning of
RID is useful in determining the true source of a packet that
traverses multiple networks or to communicate security incidents and
automate the response. The information obtained from the trace may
determine the identity of the source host or the network provider
used by the source of the traffic. It should be noted that the trace
mechanism used across a single-network provider may also raise
privacy concerns for the clients of the network. Methods that may
raise concern include those that involve storing packets for some
length of time in order to trace packets after the fact. Monitoring
networks for intrusions and for tracing capabilities also raises
concerns for potentially sensitive valid traffic that may be
traversing the monitored network. IDSs and single-network tracing
are outside of the scope of this document, but the concern should be
noted and addressed within the use guidelines of the network. Some
IDSs and single-network trace mechanisms attempt to properly address
these issues. RID is designed to provide the information needed by
any single-network trace mechanism. The provider's choice of a
single trace mechanism depends on resources, existing solutions, and
local legislation. Privacy concerns in regard to the single-network
trace must be dealt with at the client-to-NP level and are out of
scope for RID messaging.
The identity of the true source of an attack packet being traced
through RID could be sensitive. The true identity listed in a Result
message can be protected through the use of encryption [XMLencrypt]
enveloping the IODEF document and RID Result information, using the
public encryption key of the originating NP. Alternatively, the
action taken may be listed without the identity being revealed to the
originating NP. The ultimate goal of the RID communication system is
to stop or mitigate attack traffic, not to ensure that the identity
of the attack traffic is known to involved parties. The NP that
identifies the source should deal directly with the involved parties
and proper authorities in order to determine the guidelines for the
release of such information, if it is regarded as sensitive. In some
situations, systems used in attacks are compromised by an unknown
source and, in turn, are used to attack other systems. In that
situation, the reputation of a business or organization may be at
stake, and the action taken may be the only additional information
reported in the Result message to the originating system. If the
security incident is a minor incident, such as a zombie system used
in part of a large-scale DDoS attack, ensuring the system is taken
off the network until it has been fixed may be sufficient. The
decision is left to the system users and consortiums to determine
appropriate data to be shared given that the goal of the
specification is to provide the appropriate technical options to
remain compliant. The textual descriptions should include details of
the incident in order to protect the reputation of the unknowing
attacker and prevent the need for additional investigation. Local,
state, or national laws may dictate the appropriate reporting action
for specific security incidents.
Privacy becomes an issue whenever sensitive data traverses a network.
For example, if an attack occurred between a specific source and
destination, then every network provider in the path of the trace
would become aware that the cyber attack occurred. In a targeted
attack, it may not be desirable that information about two nation
states that are battling a cyber war would become general knowledge
to all intermediate parties. However, it is important to allow the
traces to take place in order to halt the activity since the health
of the networks in the path could also be at stake during the attack.
This provides a second argument for allowing the Result message to
only include an action taken and not the identity of the offending
host. In the case of an Investigation request, where the originating
NP is aware of the NP that will receive the request for processing,
the free-form text areas of the document could be encrypted
[XMLencrypt] using the public key of the destination NP to ensure
that no other NP in the path can read the contents. The encryption
would be accomplished through the W3C [XMLencrypt] specification for
encrypting an element.
In some situations, all network traffic of a nation may be granted
through a single network provider. In that situation, options must
support sending Result messages from a downstream peer of that
network provider. That option provides an additional level of
abstraction to hide the identity and the NP of the identified source
of the traffic. Legal action may override this technical decision
after the trace has taken place, but that is out of the technical
scope of this document.
Privacy concerns when using an Investigation request to request
action close to the source of valid attack traffic needs to be
considered. Although the intermediate NPs may relay the request if
there is no direct trust relationship to the closest NP to the
source, the intermediate NPs do not require the ability to see the
contents of the packet or the text description field(s) in the
request. This message type does not require any action by the
intermediate RID systems, except to relay the packet to the next NP
in the path. Therefore, the contents of the request may be encrypted
for the destination system. The intermediate NPs would only need to
know how to direct the request to the manager of the ASN in which the
source IP address belongs.
Traces must be legitimate security-related incidents and not used for
purposes such as sabotage or censorship. An example of such abuse of
the system would include a request to block or rate-limit legitimate
traffic to prevent information from being shared between users on the
Internet (restricting access to online versions of papers) or
restricting access from a competitor's product in order to sabotage a
Intra-consortium RID communications raise additional issues,
especially when the peering consortiums reside in different regions
or nations. TraceRequests and requested actions to mitigate traffic
must adhere to the appropriate use guidelines and yet prevent abuse
of the system. First, the peering consortiums MUST identify the
types of traffic that can be traced between the borders of the
participating NPs of each consortium. The traffic traced should be
limited to security-incident-related traffic. Second, the traces
permitted within one consortium if passed to a peering consortium may
infringe upon the peering consortium's freedom of information laws.
An example would be a consortium in one country permitting a trace of
traffic containing objectionable material, outlawed within that
country. The RID trace may be a valid use of the system within the
confines of that country's network border; however, it may not be
permitted to continue across network boundaries where such content is
permitted under law. By continuing the trace in another country's
network, the trace and response could have the effect of improperly
restricting access to data. A continued trace into a second country
may break the laws and regulations of that nation. Any such traces
MUST cease at the country's border.
The privacy concerns listed in this section address issues among the
trusted parties involved in a trace within an NP, a RID consortium,
and peering RID consortiums. Data used for RID communications must
also be protected from parties that are not trusted. This protection
is provided through the authentication and encryption of documents as
they traverse the path of trusted servers. Each RID system MUST
perform a bi-directional authentication when sending a RID message
and use the public encryption key of the upstream or downstream peer
to send a message or document over the network. This means that the
document is decrypted and re-encrypted at each RID system via TLS
over the transport protocol [RFC6046]. The RID messages may be
decrypted at each RID system in order to properly process the request
or relay the information. Today's processing power is more than
sufficient to handle the minimal burden of encrypting and decrypting
relatively small typical RID messages.
7. IANA Considerations
This document uses URNs to describe XML namespaces and XML schemas
[XMLschema] conforming to a registry mechanism described in
Registration request for the iodef-rid namespace:
Registrant Contact: See the "Author's Address" section of this
XML: None. Namespace URIs do not represent an XML specification.
Registration request for the iodef-rid XML schema:
Registrant Contact: See the "Author's Address" section of this
XML: See Section 5, "RID Schema Definition", of this document.
Security incidents have always been difficult to trace as a result of
the spoofed sources, resource limitations, and bandwidth utilization
problems. Incident response is often slow even when the IP address
is known to be valid because of the resources required to notify the
responsible party of the attack and then to stop or mitigate the
attack traffic. Methods to identify and trace attacks near real time
are essential to thwarting attack attempts. Network providers need
policies and automated methods to combat the hacker's efforts. NPs
need automated monitoring and response capabilities to identify and
trace attacks quickly without resource-intensive side effects.
Integration with a centralized communication system to coordinate the
detection, tracing, and identification of attack sources on a single
network is essential. RID provides a way to integrate NP resources
for each aspect of attack detection, tracing, and source
identification and extends the communication capabilities among
network providers. The communication is accomplished through the use
of flexible IODEF XML-based documents passed between IHSs or RID
systems. A TraceRequest or Investigation request is communicated to
an upstream NP and may result in an upstream trace or in an action to
stop or mitigate the attack traffic. The messages are communicated
among peers with security inherent to the RID messaging scheme
provided through existing standards such as XML encryption and
digital signatures. Policy information is carried in the RID message
itself through the use of the RIDPolicy. RID provides the timely
communication among NPs, which is essential for incident handling.
9.1. Normative References
[RFC2119] Bradner, S., "Key words for use in RFCs to Indicate
Requirement Levels", BCP 14, RFC 2119, March 1997.
[RFC3275] Eastlake 3rd, D., Reagle, J., and D. Solo,
"(Extensible Markup Language) XML-Signature Syntax and
Processing", RFC 3275, March 2002.
[RFC3688] Mealling, M., "The IETF XML Registry", BCP 81, RFC
3688, January 2004.
[RFC4279] Eronen, P., Ed., and H. Tschofenig, Ed., "Pre-Shared
Key Ciphersuites for Transport Layer Security (TLS)",
RFC 4279, December 2005.
[RFC5070] Danyliw, R., Meijer, J., and Y. Demchenko, "The
Incident Object Description Exchange Format", RFC
5070, December 2007.
[RFC5280] Cooper, D., Santesson, S., Farrell, S., Boeyen, S.,
Housley, R., and W. Polk, "Internet X.509 Public Key
Infrastructure Certificate and Certificate Revocation
List (CRL) Profile", RFC 5280, May 2008.
[RFC5755] Farrell, S., Housley, R., and S. Turner, "An Internet
Attribute Certificate Profile for Authorization",
RFC 5755, January 2010.
[RFC6046] Moriarty, K. and B. Trammell, "Transport of Real-Time
Inter-Network Defense (RID) Messages," RFC 6046,
[XML1.0] "Extensible Markup Language (XML) 1.0 (Second
Edition)". W3C Recommendation. T. Bray, E. Maler, J.
Paoli, and C.M. Sperberg-McQueen. October 2000.
[XMLnames] "Namespaces in XML 1.0 (Third Edition)". W3C
Recommendation. T. Bray, D. Hollander, A. Layman, R.
Tobin, H. Thompson. December 2009.
[XMLencrypt] "XML Encryption Syntax and Processing". W3C
Recommendation. T. Imamura, B. Dillaway, and E.
Simon. December 2002.
[XMLschema] "XML Schema". E. Van der Vlist. O'Reilly. 2002.
[XMLsig] "XML-Signature Syntax and Processing (Second
Edition)". W3C Recommendation. M. Bartel, J. Boyer,
B. Fox, B. LaMacchia, and E. Simon. June 2008.
9.2. Informative References
[RFC1930] Hawkinson, J. and T. Bates, "Guidelines for creation,
selection, and registration of an Autonomous System
(AS)", BCP 6, RFC 1930, March 1996.
[RFC2827] Ferguson, P. and D. Senie, "Network Ingress Filtering:
Defeating Denial of Service Attacks which employ IP
Source Address Spoofing", BCP 38, RFC 2827, May 2000.
[RFC3647] Chokhani, S., Ford, W., Sabett, R., Merrill, C., and
S. Wu, "Internet X.509 Public Key Infrastructure
Certificate Policy and Certification Practices
Framework", RFC 3647, November 2003.
[RFC3917] Quittek, J., Zseby, T., Claise, B., and S. Zander,
"Requirements for IP Flow Information Export (IPFIX)",
RFC 3917, October 2004.
[RFC5735] Cotton, M. and L. Vegoda, "Special Use IPv4
Addresses", BCP 153, RFC 5735, January 2010.
[IPtrace] "Advanced and Authenticated Marking Schemes for IP
Traceback". D. Song and A. Perrig. IEEE INFOCOM
[HASH-IPtrace] "Hash-Based IP Traceback". A. Snoeren, C. Partridge,
L. Sanchez, C. Jones, F. Tchakountio, S. Kent, and W.
Strayer. SIGCOMM'01. August 2001.
[ICMPtrace] Bellovin, S., Leech, M., and T. Taylor, "ICMP
Traceback Messages", Work in Progress, February 2003.
[NTWK-IPtrace] "Practical network support for IP traceback". S.
Savage, D. Wetherall, A. Karlin, and T. Anderson.
SIGCOMM'00. August 2000.
[DoS] "Trends in Denial of Service Attack Technology". K.
Houle, G. Weaver, N. Long, and R. Thomas. CERT
Coordination Center. October 2001.
Many thanks to coworkers and the Internet community for reviewing and
commenting on the document as well as providing recommendations to
simplify and secure the protocol: Robert K. Cunningham, Ph.D, Cynthia
D. McLain, Dr. William Streilein, Iljitsch van Beijnum, Steve
Bellovin, Yuri Demchenko, Jean-Francois Morfin, Stephen Northcutt,
Jeffrey Schiller, Brian Trammell, Roman Danyliw, Tony Tauber, and
Sandra G. Dykes, Ph.D.
This work was sponsored by the Air Force under Air Force Contract
FA8721-05-C-0002, while working at MIT Lincoln Laboratory.
"Opinions, interpretations, conclusions, and recommendations are
those of the author and are not necessarily endorsed by the United
Kathleen M. Moriarty
RSA, The Security Division of EMC
174 Middlesex Turnpike
Bedford, MA 01730