Internet Engineering Task Force P. Hallam-Baker
Internet-Draft Comodo Group Inc.
Intended status: Standards Track May 17, 2013
Expires: November 18, 2013
OmniBroker Protocol
draft-hallambaker-omnibroker-03
Abstract
An Omnibroker is an agent chosen and trusted by an Internet user to
provide information such as name and certificate status information
that are in general trusted even if they are not trustworthy. Rather
than acting as a mere conduit for information provided by existing
services, an Omnibroker is responsible for curating those sources to
protect the user.
The Omnibroker Protocol (OBP) provides an aggregated interface to
trusted Internet services including DNS, OCSP and various forms of
authentication service. Multiple transport bindings are supported to
permit efficient access in virtually every common deployment scenario
and ensure access in any deployment scenario in which access is not
being purposely denied.
Status of this Memo
This Internet-Draft is submitted in full conformance with the
provisions of BCP 78 and BCP 79.
Internet-Drafts are working documents of the Internet Engineering
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This Internet-Draft will expire on November 18, 2013.
Copyright Notice
Copyright (c) 2013 IETF Trust and the persons identified as the
document authors. All rights reserved.
This document is subject to BCP 78 and the IETF Trust's Legal
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Table of Contents
1. Definitions . . . . . . . . . . . . . . . . . . . . . . . . . 4
1.1. Requirements Language . . . . . . . . . . . . . . . . . . 4
2. Purpose . . . . . . . . . . . . . . . . . . . . . . . . . . . 4
2.1. A Curated Service . . . . . . . . . . . . . . . . . . . . 4
2.2. Connection Broker . . . . . . . . . . . . . . . . . . . . 6
2.2.1. Service Connection Broker . . . . . . . . . . . . . . 6
2.2.2. Peer Connection Broker . . . . . . . . . . . . . . . . 7
2.2.3. Connection Broker API . . . . . . . . . . . . . . . . 7
2.3. Service Advertisement . . . . . . . . . . . . . . . . . . 8
2.3.1. Connection Advertisement API . . . . . . . . . . . . . 8
2.4. Credential Validation Broker . . . . . . . . . . . . . . . 8
2.5. Authentication Gateway . . . . . . . . . . . . . . . . . . 8
2.6. Credential Announcement . . . . . . . . . . . . . . . . . 8
3. Omnibroker Query Service . . . . . . . . . . . . . . . . . . . 9
3.1. Illustrative example . . . . . . . . . . . . . . . . . . . 9
3.2. OBPQuery . . . . . . . . . . . . . . . . . . . . . . . . . 11
3.2.1. Message: Payload . . . . . . . . . . . . . . . . . . . 11
3.2.2. Message: Message . . . . . . . . . . . . . . . . . . . 11
3.2.3. Message: Request . . . . . . . . . . . . . . . . . . . 11
3.2.4. Message: Response . . . . . . . . . . . . . . . . . . 11
3.2.5. Structure: Identifier . . . . . . . . . . . . . . . . 11
3.2.6. Structure: Connection . . . . . . . . . . . . . . . . 12
3.2.7. Structure: Advice . . . . . . . . . . . . . . . . . . 13
3.2.8. Structure: Service . . . . . . . . . . . . . . . . . . 13
3.2.9. QueryConnect . . . . . . . . . . . . . . . . . . . . . 13
3.2.10. Message: QueryConnectRequest . . . . . . . . . . . . . 13
3.2.11. Message: QueryConnectResponse . . . . . . . . . . . . 14
3.2.12. Advertise . . . . . . . . . . . . . . . . . . . . . . 14
3.2.13. Message: AdvertiseRequest . . . . . . . . . . . . . . 14
3.2.14. Message: AdvertiseResponse . . . . . . . . . . . . . . 15
3.2.15. Validate . . . . . . . . . . . . . . . . . . . . . . . 15
3.2.16. Message: ValidateRequest . . . . . . . . . . . . . . . 15
3.2.17. Message: ValidateResponse . . . . . . . . . . . . . . 15
3.2.18. QueryCredentialPassword . . . . . . . . . . . . . . . 16
3.2.19. Message: CredentialPasswordRequest . . . . . . . . . . 16
3.2.20. Message: CredentialPasswordResponse . . . . . . . . . 16
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4. Transport Bindings . . . . . . . . . . . . . . . . . . . . . . 16
4.1. HTTP over TLS . . . . . . . . . . . . . . . . . . . . . . 17
4.1.1. Message Encapsulation . . . . . . . . . . . . . . . . 17
4.1.2. Example . . . . . . . . . . . . . . . . . . . . . . . 17
4.2. DNS Tunnel . . . . . . . . . . . . . . . . . . . . . . . . 17
4.2.1. Request . . . . . . . . . . . . . . . . . . . . . . . 17
4.2.2. Response . . . . . . . . . . . . . . . . . . . . . . . 18
4.2.3. Example . . . . . . . . . . . . . . . . . . . . . . . 18
4.3. UDP . . . . . . . . . . . . . . . . . . . . . . . . . . . 18
4.3.1. Request . . . . . . . . . . . . . . . . . . . . . . . 18
4.3.2. Response . . . . . . . . . . . . . . . . . . . . . . . 18
4.3.3. Example . . . . . . . . . . . . . . . . . . . . . . . 19
5. Acknowledgements . . . . . . . . . . . . . . . . . . . . . . . 19
6. Security Considerations . . . . . . . . . . . . . . . . . . . 19
6.1. Denial of Service . . . . . . . . . . . . . . . . . . . . 19
6.2. Breach of Trust . . . . . . . . . . . . . . . . . . . . . 19
6.3. Coercion . . . . . . . . . . . . . . . . . . . . . . . . . 19
7. To do . . . . . . . . . . . . . . . . . . . . . . . . . . . . 19
8. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 20
9. Normative References . . . . . . . . . . . . . . . . . . . . . 20
Appendix A. Example Data. . . . . . . . . . . . . . . . . . . . . 20
A.1. Ticket A . . . . . . . . . . . . . . . . . . . . . . . . . 20
A.2. Ticket B . . . . . . . . . . . . . . . . . . . . . . . . . 20
Author's Address . . . . . . . . . . . . . . . . . . . . . . . . . 20
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1. Definitions
1.1. Requirements Language
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 RFC 2119 [RFC2119].
2. Purpose
An Omnibroker is an agent chosen and trusted by an Internet user to
provide information such as name and certificate status information
that are in general trusted even if they are not trustworthy. Rather
than acting as a mere conduit for information provided by existing
services, an Omnibroker is responsible for curating those sources and
providing autheticated, curated results to the endpoint client.
Unlike the traditional trusted information services that are expected
to deliver the same response to a query regardless of who asks the
question, OBP permits an Omnibroker to return a response that is
tailored to the specific party asking the question. This permits the
use of an authentication approach that has negligible impact on
performance and permits an Omnibroker to answer questions that a
traditional public Internet information service could not. In
particular, an Omnibroker can broker peer to peer connections
2.1. A Curated Service
In the traditional configuration, an Internet host accepts DNS
service from the IP address specified by the local network provider,
frequently the DNS server advertised by the local DHCP service. This
approach creates an obvious security risk as DNS is clearly a trusted
service and a random DNS service advertised by the local DNS is
clearly not trustworthy.
A policy of only using a chosen DNS service provides a reduction in
risk but only a modest one since the standard DNS service does not
provide authenticated results. Many local area networks intercept
all DNS traffic and process it through the local DNS server
regardless of the intended destination IP address. This practice is
highly desirable if it would prevent a client from accessing an
untrustworthy DNS service in place of a trustworthy local DNS service
and extreemly undesirable in the contrary case.
In addition to ensuring the authenticity of DNS resolution responses,
such services frequently provide filtering of Internet addresses the
network provider considers undesirable. Many workplaces block access
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to Web sites that are considered detrimental to productivity. Many
parent subscribe to services that filter content they consider
undesirable. While the value of such services is debatable they are
services that those customers have chosen to deploy on their networks
to meet their perceived security requirements. New security
proposals that do not support such capabilities or seek to actually
circumvent them will not be acceptable to those constituencies.
While DNS filtering is a form of censorship, not all forms of DNS
filering are intrinsically undesirable censorship. Spam filtering is
also a form of censorship albeit one that is not normally regarded as
such because it most Internet users now consider it to be an
essential security control. Anti-Virus tools are also a form of
censorship. DNS filtering tools that block access to sites that
distribute malware are also a form of censorship and are rapidly
gaining popularity for the same reason.
While all forms of censorship raise civil liberties concerns,
censorship should not automatically raise civil liberties objections.
It is not the fact that filtering is taking place but the party that
is in control of the filtering that should raise civil liberties
concerns. In an Internet of 2 billion users, all users are obliged
to perform some filtering. OBP is designed to make the party that is
in control of the filtering process apparent and provide the end user
with the ability to select the Omnibroker of their choice.
DNSSEC provides a means of determining that a DNS record is the
authentic record published by the source but this capability alone
does not meet the security requirements for DNS resolution services
as they have come to be understood since the protocol was first
proposed.
Internet users want to be safe from all forms of attack, not just the
DNS resolver mani-in-the-middle attack that 'end-to-end' deployment
of DNSSEC is designed to address. An Internet user is far more
likely to be directed to a site with a DNS name controlled by a
criminal gang than be subject to a man-in-the-middle attack.
Most users would prefer to have an Internet connection that is
'curated' to remove at least some of the locations they consider to
be undesirable. The fact that an organised criminal gang has put a
host on the Internet does not mean that any other Internet user
should be obliged to allow it to connect to any of the machines that
they own.
The same argument for curating the raw results applies to other forms
of trusted information service. The fact that a Certificate
Authority has issued a digital certificate and considers it to be
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valid should not mean that the end party is automatically considered
trustworthy by anyone and for any purpose.
The deployment of security policy capabilities presents another case
in which direct reliance on raw data is undesirable. While security
policies such as 'host always offers TLS' or 'mail server always
signs outgoing mail with DKIM' can provide considerable security
advantages, only some of the security policy information that is
published is accurate and kept up to date. Curating such data
sources typically proves essential if an unacceptable rate of false
positives is to be avoided.
Although a client is permitted to curate its own data sources it
rarely has a sufficient amount of data to make decisions as
accurately as a network service that can draw on a wide variety of
additional data including tracking of communication patterns,
historical data series and third party reputation services.
Curation in the network offers better asgility than the client
approach. Agility is an important consideration when an attacker
changes their strategy rapidly and repeatedly to counter new
defensive controls.
While curating trusted data sources is an established and proven
practice, current practice has been to curate each source
individually. This approach avoids the need to write a new protocol
but limits the information a curator can leverage to detect potential
danger. Leveraging multiple data sources simultaneously allows
better accuracy than applying each individually.
2.2. Connection Broker
The OBP service connection broker answers the query 'what connection
parameters should be used to establish the best connection to
interract with party X according to protocol Y. Where 'best' is
determined by the Omnibroker which MAY take into account parameters
specified by the relying party.
2.2.1. Service Connection Broker
The OBP service connection broker supports and extends the
traditional DNS resolution service that resolves a DNS name (e.g.
www.example.com) to return an IP address (e.g. 10.1.2.3).
When using an Omnibroker as a service connection broker, a client
specifies both the DNS name (e.g. www.example.com) and the Internet
protocol to be used (e.g. _http._tcp). The returned connection
parameters MAY include:
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The IP protocol version, address and port number to establish a
connection to.
If appropriate, a security transport such as TLS or IPSEC.
If appropriate, a description of a service credential such as a
TLS certificate or a constraint on the type of certificates that
the client should consider acceptable.
If appropriate, application protocol details such as version and
protocol options.
If an attempt to connect with the parameters specified fails, a
client MAY report the failure and request a new set of parameters.
2.2.2. Peer Connection Broker
Each OBP request identifies both the account under which the request
is made and the device from which it is made. An OBP broker is thus
capable of acting as a peer connection broker service or providing a
gateway to such a service.
When using Omnibroker as a peer connection broker, a client specifies
the account name and DNS name of the party with which a connection is
to be established (e.g. alice@example.com) and the connection
protocol to be used (e.g. _xmpp-client._tcp)
The returned connection parameters are similar to those returned in
response to a service broker query.
2.2.3. Connection Broker API
In the traditional BSD sockets API a network client performs a series
of calls to resolve a network name to a list of IP addresses, selects
one and establishes an IP connection to a port specified by the
chosen application protocol.
OBP anticipates a higher level abstract API that encapsulates this
complexity, hiding it from the application code.
In the case that one (or more) OBP services are configured, the
library supporting the SHOULD obtain connection parameters from the
OBP service. Otherwise, it SHOULD establish a connection using the
traditional calling sequence of resolving a host name to obtain an IP
address, etc.
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2.3. Service Advertisement
Service advertisement is the converse of service resolution. An
Internet application wishing to accept inbound connections specifies
one or more sets of connection parameters for the Omnibroker to
register with whatever naming, discovery or other services may be
appropriate.
2.3.1. Connection Advertisement API
OBP anticipates the use of a high level API for connection
advertisement that is the converse of the Connection broker API.
Instead of establishing a connection, the API is used to advertise
that a connection is offered either as a service or a peer.
An application MAY offer multiple types of connection with different
connection properties (e.g. IPv4/IPv6, with and without SSL, etc.).
This MAY be supported by marking certain properties as being optional
and/or by permitting the API to be called multiple times with
different properties specified.
2.4. Credential Validation Broker
A credential validation broker reports on the validity and
trustworthiness of credentials presented to a client by Internet
services and/or peers.
The service provided by OBP is similar to that provided by OCSP and
SCVP. Like SCVP, OBP is an agent selected by the relying party to
validate certificates and/or construct trust paths on its behalf.
2.5. Authentication Gateway
Every OBP request is strongly authenticated by means of a shared
secret that is unique to the account and the device. This may be
leveraged to permit use as an authentication gateway, providing
access to other credentials that the client has established the right
to use.
An Authentication Gateway MAY provide access to account names and
passwords that the account holder has chosen to store in the cloud
for access to sites that do not support a stronger, cryptographically
based form of authentication such as OAuth.
2.6. Credential Announcement
An Authentication Gateway can only provide access to credentials that
it has notice of. A client uses the Credential Announcement
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transaction to advise the service of a new credential.
3. Omnibroker Query Service
3.1. Illustrative example
[For illustrative purposes, all the examples in this section are
shown using the Web Services Transport binding. Examples of other
transport bindgins are shown in section [TBS].]
The Alice of the previous example uses her Web browser to access the
URL www.example.com://www.example.com/. Assuming this was done while
the prior binding was still active (i.e. before the UnbindRequest
message was sent), the Web browser would send a QueryConnectRequest
request to obtain the best connection parameters for the http
protocol at www.example.com:
Post / HTTP/1.1
Host: example.com
Cache-Control: no-store
Content-Type: Application/json;charset=UTF-8
Content-Length: 131
Content-Integrity:
mac=9ZSkLYKFMYenvqt/MwkAtvetqvM7Nydh6Rc2bvbKTbM=;
ticket=jpBXvI7/0WTmwI2NN4n7Vvw96nbS9LpSsSNMIkdapiUoLikSkjpgMrtbVK
z5lHOPloCgAyZXxfZpQRsp4oPY4BcRaMw6F5na62IHnBVDeXg=
{
"QueryConnectRequest": {
"Identifier": {
"Name": "http",
"Service": "www.example.com",
"Port": 80}}}
The service responds with an ordered list of possible connections.
In this case the site is accessible via plain TCP transport or with
TLS. Since TLS is the preferred protocol, that connection is listed
first.
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HTTP/1.1 200
Content-Type: application/json;charset=UTF-8
Content-Length: 347
Content-Integrity:
mac=1oFa8fNsRbKiCCnwd4feSqq+h/by+tCLbw2bzf235TU=;
ticket=jpBXvI7/0WTmwI2NN4n7Vvw96nbS9LpSsSNMIkdapiUoLikSkjpgMrtbVK
z5lHOPloCgAyZXxfZpQRsp4oPY4BcRaMw6F5na62IHnBVDeXg=
{
"QueryConnectResponse": {
"Status": 200,
"Connection": [{
"IPAddress": "10.3.2.1",
"IPPort": 443,
"Transport": "TLS",
"TransportPolicy": "TLS=Optional",
"ProtocolPolicy": "Strict"},
{
"IPAddress": "10.3.2.1",
"IPPort": 80,
"ProtocolPolicy": "Strict"}]}}
Although the QueryConnectResponse returned the hash of a PKIX
certificate considered valid for that connection, the server returns
a different certificate which the client verifies using the
ValidateRequest query.
Post / HTTP/1.1
Host: example.com
Cache-Control: no-store
Content-Type: Application/json;charset=UTF-8
Content-Length: 124
Content-Integrity:
mac=S+xlW2U6z1REQmbNHiOnAw4xpUXP8wJXZiCJzMzQelc=;
ticket=jpBXvI7/0WTmwI2NN4n7Vvw96nbS9LpSsSNMIkdapiUoLikSkjpgMrtbVK
z5lHOPloCgAyZXxfZpQRsp4oPY4BcRaMw6F5na62IHnBVDeXg=
{
"ValidateRequest": {
"Credential": {
"Type": "application/x-x509-server-cert",
"Data": "AAECAwQ="}}}
The service validates the certificate according to the Omnibroker
service policy.
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HTTP/1.1 200
Content-Type: application/json;charset=UTF-8
Content-Length: 47
Content-Integrity:
mac=jrsfxojksHBVs1WWxVbX3nn+CaIIix2JrrTTQn0X43k=;
ticket=jpBXvI7/0WTmwI2NN4n7Vvw96nbS9LpSsSNMIkdapiUoLikSkjpgMrtbVK
z5lHOPloCgAyZXxfZpQRsp4oPY4BcRaMw6F5na62IHnBVDeXg=
{
"ValidateResponse": {
"Status": 200}}
3.2. OBPQuery
3.2.1. Message: Payload
3.2.2. Message: Message
3.2.3. Message: Request
Every query request contains the following common elements:
Index : Integer [0..1]
Index used to request a specific response when multiple
responses are available.
3.2.4. Message: Response
Every Query Response contains the following common elements:
Status : Integer [1..1]
Status return code value
Index : Integer [0..1]
Index of the current response.
Count : Integer [0..1]
Number of responses available.
3.2.5. Structure: Identifier
Specifies an Internet service by means of a DNS address and either a
DNS service prefix, an IP port number or both. An Internet peer
connection MAY be specified by additionally specifying an account.
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Name : Name [1..1]
The DNS name of the service to connect to.
Internationalized DNS names MUST be encoded in punycode
encoding.
Account : Label [0..1]
Identifies the account to connect to in the case that a peer
connection is to be established.
Service : Name [0..1]
The DNS service prefix defined for use with DNS records that
take a service prefix including SRV.
Port : Integer [0..1]
IP Port number.
A service identifier MUST specify either a service or a port or
both.
3.2.6. Structure: Connection
IPVersion : Integer [0..1]
Contains the IP version field. If absent, IPv4 is assumed.
IPProtocol : Integer [0..1]
Contains the IP protocol field. If absent, TCP is assumed.
IPAddress : Binary [0..1]
IP address in network byte order. This will normally be an
IPv4 (32 bit) or IPv6 (128 bit) address.
IPPort : Integer [0..1]
IP port. 1-65535
TransportPolicy : String [0..1]
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Transport security policy as specified in [TBS]
ProtocolPolicy : String [0..1]
Application security policy specification as specified by the
application protocol.
Advice : Advice [0..1]
Additional information that a service MAY return to support a
service connection identification.
3.2.7. Structure: Advice
Additional information that a service MAY return to support a service
connection identification. For example, DNSSEC signatures chains,
SAML assertions, DANE records, Certificate Transparency proof chains,
etc.
Type : Label [0..1]
The IANA MIME type of the content type
Data : Binary [0..1]
The advice data.
3.2.8. Structure: Service
Describes a service connection
Identifier : Identifier [0..Many]
Internet addresses to which the service is to be bound.
Connection : Connection [0..1]
Service connection parameters.
3.2.9. QueryConnect
Requests a connection context to connect to a specified Internet
service or peer.
3.2.10. Message: QueryConnectRequest
Specifies the Internet service or peer that a connection is to be
established to and the acceptable security policies.
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Identifier : Identifier [0..1]
Identifies the service or peer to which a connection is
requested.
Policy : Label [0..Many]
Acceptable credential validation policy.
ProveIt : Boolean [0..1]
If set the broker SHOULD send advice to permit the client to
validate the proposed connection context.
3.2.11. Message: QueryConnectResponse
Returns one or more connection contexts in response to a
QueryConnectRequest Message.
Connection : Connection [0..Many]
An ordered list of connection contexts with the preferred
connection context listed first.
Advice : Advice [0..1]
Proof information to support the proposed connection context.
Policy : Label [0..Many]
Policy under which the credentials have been verified.
3.2.12. Advertise
Advises a broker that one or more Internet services are being offered
with particular attributes.
3.2.13. Message: AdvertiseRequest
Specifies the connection(s) to be established.
The attributes required depend on the infrastructure(s) that the
broker is capable of registering the service with.
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Service : Service [0..Many]
Describes a connection to be established.
3.2.14. Message: AdvertiseResponse
Specifies the connection(s)
Service : Service [0..Many]
Describes a connection that was established.
3.2.15. Validate
The Validate query requests validation of credentials presented to
establish a connection. For example credentials presented by a
server in the process of setting up a TLS session.
3.2.16. Message: ValidateRequest
Specifies the credentials to be validated and the purpose for which
they are to be used.
Service : Service [0..1]
Describes the service for which the credentials are presented
for access.
Credential : Credential [0..1]
List of credentials for which validation is requested.
Policy : Label [0..Many]
Policy under which the credentials have been verified.
3.2.17. Message: ValidateResponse
Reports the status of the credential presented.
Policy : Label [0..Many]
Policy under which the credentials have been verified.
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3.2.18. QueryCredentialPassword
The QueryCredentialPassword query is used to request a password
credential that the user has previously chosen to store at the
broker.
3.2.19. Message: CredentialPasswordRequest
Requests a password for the specified account.
Account : String [0..1]
The account for which a password is requested.
3.2.20. Message: CredentialPasswordResponse
Returns a password for the specified account.
Password : String [0..1]
The requested password.
4. Transport Bindings
To achieve an optimal balance of efficiency and availability, three
transport bindings are defined:
Supports all forms of OBP transaction in all network environments.
Provides efficient support for a subset of OBP query transactions
that is accessible in most network environments.
Provides efficient support for all OBP query transactions and is
accessible in most network environments.
Support for the HTTP over TLS binding is REQUIRED.
An OBP message consists of three parts:
Ticket [As necessary] If specified, identifies the cryptographic key
and algorithm parameters to be used to secure the message payload.
Payload [Required] If the ticket context does not specify use of an
encryption algorithm, contains the message data. Otherwise
contains the message data encrypted under the encryption algorithm
and key specified in the ticket context.
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Authenticator [Optional] If the ticket context specifies use of a
Message Authentication Code (MAC), contains the MAC value
calculated over the payload data using the authentication key
bound to the ticket.
Note that although each of the transport bindings defined in this
specification entail the use of a JSON encoding for the message data,
this is not a necessary requirement for a transport binding.
4.1. HTTP over TLS
OBP requests and responses are mapped to HTTP POST requests and
responses respectively. Java Script Object Notation (JSON) encoding
is used to encode requests and responses.
4.1.1. Message Encapsulation
Requests and responses are mapped to HTTP POST transactions. The
content of the HTTP message is the message payload. The Content-Type
MUST be specified as application/json. The Character set MUST be
specified as UTF-8.
The Ticket and Authenticator are specified using the Integrity header
as follows:
Integrity: <base64 (authenticator)> ; ticket=<base64 (ticket)>
4.1.2. Example
[To be generated from spec]
4.2. DNS Tunnel
The DNS Tunnel mode of operation makes use of DNS TXT resource record
requests and responses to tunnel OBP Query requests. Due to the
constraints of this particular mode of operation, use of this
transport is in practice limited to supporting transactions that can
be expressed within 500 bytes. These include the QueryConnect and
ValidateRequest interactions.
4.2.1. Request
Requests are mapped to DNS TXT queries. The request is mapped onto
the DNS name portion of the query by encoding the Ticket,
Authenticator and JSON encoded Payload using Base32 encoding and
appending the result to the service prefix to create a DNS name as
follows:
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<base32(payload)>.<base32(authenticator)>.<base32(ticket)>.Suffix
The payload MAY be split across multiple DNS labels at any point.
4.2.2. Response
Responses are mapped to DNS TXT records by encoding the Authenticator
and JSON encoded Payload using Base64 encoding and cocatenating the
result with a periods as a separator as follows:
<base32(payload)>.<base32(authenticator)>
4.2.3. Example
[To be generated from spec]
4.3. UDP
The UDP transport MAY be used for transactions where the request fits
into a single UDP packet and the response can be accomadated in 16
UDP packets. As with the Web Service Binding, Java Script Object
Notation (JSON) encoding is used to encode requests and responses.
4.3.1. Request
The request consists of four message segments containing a Header,
Ticket, Payload and Authenticator. Each message segment begins with
a two byte field that specified the length of the following data
segment in network byte order. The Payload is encoded in JSON
encoding and the remaining fields as binary data without additional
encoding.
The header field for this version of the protocol (1.0) contains two
bytes that specify the Major and Minor version number of the
transport protocol being 1 and 0 respectively. Future versions of
the transport protocol MAY specify additional data fields.
[TBS diagram]
4.3.2. Response
The response consists of a sequence of packets. Each packet consists
of a header section and a data section.
The header section consists of a two byte length field followed by
two bytes that speciofy the Major and Minor version number of the
transport protocol (1 and 0), two bytes that specify the frame number
and the total number of frames and two bytes that specify the message
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identifier.
[TBS diagram]
[Question, should the authenticator be over the whole message or
should each packet have its own authenticator?]
4.3.3. Example
[To be generated from spec]
5. Acknowledgements
[List of contributors]
6. Security Considerations
6.1. Denial of Service
6.2. Breach of Trust
6.3. Coercion
7. To do
The specification should define and use a JSON security object.
Formatting of the abstract data items needs to be improved
Need to specify the UDP transport binding
Should specify how each data item is represented in JSON format
somewhere. This is obvious for some of the data types but needs
to be fully specified for things like DateTime.
Run the code to produce proper examples.
Write a tool to transclude the example and other xml data into the
document source.
Fully document the API section.
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8. IANA Considerations
[TBS list out all the code points that require an IANA registration]
9. Normative References
[RFC1035] Mockapetris, P., "Domain names - implementation and
specification", STD 13, RFC 1035, November 1987.
[RFC2119] Bradner, S., "Key words for use in RFCs to Indicate
Requirement Levels", BCP 14, RFC 2119, March 1997.
[RFC4366] Blake-Wilson, S., Nystrom, M., Hopwood, D., Mikkelsen, J.,
and T. Wright, "Transport Layer Security (TLS)
Extensions", RFC 4366, April 2006.
[X.509] International Telecommunication Union, "ITU-T
Recommendation X.509 (11/2008): Information technology -
Open systems interconnection - The Directory: Public-key
and attribute certificate frameworks", ITU-T
Recommendation X.509, November 2008.
[X.680] International Telecommunication Union, "ITU-T
Recommendation X.680 (11/2008): Information technology -
Abstract Syntax Notation One (ASN.1): Specification of
basic notation", ITU-T Recommendation X.680,
November 2008.
Appendix A. Example Data.
A.1. Ticket A
A.2. Ticket B
Author's Address
Phillip Hallam-Baker
Comodo Group Inc.
Email: philliph@comodo.com
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