| ADD WG | T. Reddy |
| Internet-Draft | McAfee |
| Intended status: Standards Track | D. Wing |
| Expires: January 27, 2021 | Citrix |
| M. Richardson | |
| Sandelman Software Works | |
| M. Boucadair | |
| Orange | |
| July 26, 2020 |
DNS Server Selection: DNS Server Information with Assertion Token
draft-reddy-add-server-policy-selection-04
The document defines a mechanism that allows communication of DNS resolver information to DNS clients for use in server selection decisions. In particular, the document defines a mechanism for a DNS server to communicate its filtering policy and privacy statement URL to DNS clients. This information is cryptographically signed to attest its authenticity. Such information is used for the selection of DNS resolvers. Typically, evaluating the DNS privacy statement, filtering policy, and the signatory, DNS clients with minimum human intervention can select the DNS server that best supports the user's desired privacy and filtering policy.
This assertion is useful for encrypted DNS (e.g., DNS-over-TLS and DNS-over-HTTPS) servers that are either public resolvers or are discovered in a local network.
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 Task Force (IETF). Note that other groups may also distribute working documents as Internet-Drafts. The list of current Internet-Drafts is at https://datatracker.ietf.org/drafts/current/.
Internet-Drafts are draft documents valid for a maximum of six months and may be updated, replaced, or obsoleted by other documents at any time. It is inappropriate to use Internet-Drafts as reference material or to cite them other than as "work in progress."
This Internet-Draft will expire on January 27, 2021.
Copyright (c) 2020 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 Provisions Relating to IETF Documents (https://trustee.ietf.org/license-info) in effect on the date of publication of this document. Please review these documents carefully, as they describe your rights and restrictions with respect to this document. Code Components extracted from this document must include Simplified BSD License text as described in Section 4.e of the Trust Legal Provisions and are provided without warranty as described in the Simplified BSD License.
[RFC7626] discusses DNS privacy considerations in both "on the wire" (Section 2.4 of [RFC7626]) and "in the server" (Section 2.5 of [RFC7626]) contexts. Examples of protocols that provide encrypted channels between DNS clients and servers are DNS-over-HTTPS (DoH) [RFC8484] and DNS-over-TLS (DoT) [RFC7858].
DNS clients can discover and authenticate encrypted DNS (e.g., DoH and DoT) servers provided by a local network, for example using the techniques proposed in [I-D.btw-add-home]. If the mechanism used to discover the encrypted DNS server is insecure, the DNS client needs evidence about the encrypted server to assess its trustworthiness and a way to appraise such evidence. The mechanism specified in this document can be used by the DNS client to cryptographically identify it is connecting to an encrypted DNS server hosted by a specific organization (e.g., ISP or Enterprise).
The DNS Recursive Operator Privacy (DROP) statement explained in [I-D.ietf-dprive-bcp-op] outlines the recommended contents a DNS operator should publish, thereby providing a means for users to evaluate the privacy properties of a given DNS service. While a human can review the privacy statement of a DNS server operator, the challenge is the user has to search to find the URL that points to the human readable privacy policy information of the DNS server. Also, a user does not know if a DNS server (public or local) performs DNS-based content filtering.
This document simplifies the user experience by supporting a mechanism to retrieve the DNS server policy permitting the user to review human-readable privacy policy information of the DNS server and to assess whether that DNS server performs DNS-based content filtering.
This document also defines a mechanism for DNS clients to gather a set of information related to discovered (or pre-configured) servers and use that information to feed a DNS server selection procedure. The following parameters are supported in this version:
The cryptographically signed policy allows a DNS client to, e.g., connect to multiple DNS servers and prompt the user to review the DNS privacy statements to select the DNS server that adheres to the privacy preserving data policy and DNS filtering expectations of the user. How a user instructs a DNS client about his/her preferences and how/whether the DNS client prompts a user are out of scope.
The mechanism for a DNS server to communicate its cryptographically signed policies to DNS clients contributes to solve the following problems in various deployments:
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 [RFC2119][RFC8174] when, and only when, they appear in all capitals, as shown here.
This document makes use of the terms defined in [RFC8499] and [I-D.ietf-dnsop-terminology-ter].
'DoH/DoT' refers to DNS-over-HTTPS and/or DNS-over-TLS.
'Encrypted DNS' refers to a DNS protocol that provides an encrypted channel between a DNS client and server (e.g., DoT or DoH).
JSON Web Token (JWT) [RFC7519] and JSON Web Signature (JWS) [RFC7515] and related specifications define a standard token format that can be used as a way of encapsulating claimed or asserted information with an associated digital signature using X.509 based certificates. JWT provides a set of claims in JSON format that can accommodate asserted policy information of the DoH/DoT server. Additionally, JWS provides a path for updating methods and cryptographic algorithms used for the associated digital signatures.
JWS defines the use of JSON data structures in a specified canonical format for signing data corresponding to JOSE header, JWS Payload, and JWS Signature. The next sections define the header and claims that MUST be minimally used with JWT and JWS for privacy assertion token.
The Policy Assertion Token (PAT) specifically uses this token format and defines claims that convey the policy information of DoH/DoT server. If the DoT session is established, the client can retrieve the PAT object using the RESINFO RRtype defined in [I-D.pp-add-resinfo] and QNAME of the domain name that is used to authenticate the privacy-enabling DNS server (referred to as ADN in [RFC8310]). If the DoH session is established, the DoH client can retrieve the PAT object using the the well-known URI defined in [I-D.btw-add-rfc8484-clarification]. If the special-use domain name "resolver-info.arpa/IN" defined in [I-D.pp-add-resinfo] is used to discover the DoH/DoT server, the client can retrieve the PAT object using the RESINFO RRtype and QNAME of the special-use domain name.
The signature of PAT object can be validated by the DNS client. If the signer and the contents of the PAT object comply with the user's requirements, the user's client software can use that DNS server.
The PAT object is signed by the DNS server's domain that is authoritative to assert the DNS server policy information. This authority is represented by the certificate credentials and the signature.
For example, the PAT object could be created by the organization hosting the DoH/DoT server and optionally by a third party who performed privacy and security audit of the DoH/DoT server. The DNS client needs to have the capability to verify the digital signature and to parse the PAT object.
The JWS token header is a JOSE header (Section 4 of [RFC7515]) that defines the type and encryption algorithm used in the token.
PAT header MUST include, at a minimum, the header parameters defined in Sections 5.1, 5.2, and 5.3.
The 'typ' (Type) Header Parameter is defined Section 4.1.9 of [RFC7515] to declare the media type of the complete JWS.
For PAT Token the 'typ' header MUST be the string 'pat'. This represents that the encoded token is a JWT of type pat.
The 'alg' (Algorithm) Header Parameter is defined in Section 4.1.1 of [RFC7515]. It specifies the JWS signature cryptographic algorithm. It also refers to a list of defined 'alg' values as part of a registry established by JSON Web Algorithms (JWA) [RFC7518] Section 3.1.
For the creation and verification of PAT tokens and their digital signatures, implementations MUST support ES256 as defined in Section 3.4 of [RFC7518]. Implementations MAY support other algorithms registered in the JSON Web Signature and Encryption Algorithms registry created by [RFC7518]. The content of that registry may be updated in the future depending on cryptographic strength requirements guided by current security best practice. The mandatory-to-support algorithm for PAT tokens may likewise be updated in the future.
Implementations of PAT digital signatures using ES256 as defined above SHOULD use deterministic ECDSA when supported for the reasons stated in [RFC6979].
As defined in Section 4.1.5 of [RFC7515], the 'x5u' header parameter defines a URI [RFC3986] referring to the resource for the X.509 public key certificate or certificate chain [RFC5280] corresponding to the key used to digitally sign the JWS. Generally, as defined in Section 4.1.5 of [RFC7515] this corresponds to an HTTPS or DNSSEC resource using integrity protection.
An example of the PAT header is shown in Figure 1. It includes the specified PAT type, ES256 algorithm, and an URI referencing the network location of the certificate needed to validate the PAT signature.
{
"typ":"pat",
"alg":"ES256",
"x5u":"https://cert.example.com/pat.cer"
}
Figure 1: A PAT Header Example
The token claims consists of the policy information of the DNS server which needs to be verified at the DNS client. These claims follow the definition of a JWT claim (Secion 4 of [RFC7519]) and are encoded as defined by the JWS Payload (Section 3 of [RFC7515]).
PAT defines the use of a standard JWT-defined claim as well as custom claims corresponding to the DoT or DoH servers.
Claim names MUST use the US-ASCII character set. Claim values MAY contain characters that are outside the ASCII range, however they MUST follow the default JSON serialization defined in Section 7 of [RFC7519].
The JSON claim MUST include the 'iat' (Section 4.1.6 of [RFC7519]) defined claim "Issued At". The 'iat' should be set to the date and time of issuance of the JWT. The time value should be of the format (NumericDate) defined in Section 2 of [RFC7519].
The JSON claim MUST include the 'exp' (Section 4.1.4 of [RFC7519]) defined "claim Expiration Time". The 'exp' should be set to specify the expiration time on or after which the JWT is not accepted for processing. The PAT object should expire after a reasonable duration. A short expiration time for the PAT object periodically reaffirms the policy information of the DNS server to the DNS client and ensures the DNS client does not use outdated policy information. If the DNS client knows the PAT object has expired, it should make another request to get the new PAT object from the DNS server. For example, the client can compute a hash of the resolver information, retreive the information after the expiration time, computes the hash of the newly retrieved resolver information, and compares with the old hash to detect policy updates. A quality implementation can perform automatic analysis and avoid presenting this information to the user if the DNS server's policies have not changed.
The DNS server identity is represented by a claim that is required for PAT: the 'server' claim. The 'server' MUST contain claim values that are identity claim JSON objects where the child claim name represents an identity type and the claim value is the identity string, both defined in subsequent subsections.
These identities can be represented as either authentication domain name (ADN) (defined in [RFC8310]) or Uniform Resource Indicators (URI).
The DNS client constructs a reference identifier for the DNS server based on the ADN or the domain portion in the URI of the DNS server identity. The domain name in the DNS-ID identifier type within subjectAltName entry in the DNS server certificate conveyed in the TLS handshake is matched with the reference identifier. If the match is not successful, the client MUST not accept the PAT for further processing.
If the DNS server identity is an ADN, the claim name representing the identity MUST be 'adn'. The claim value for the 'adn' claim is the ADN.
If the DNS server identity is of the form URI, as defined in [RFC3986], the claim name representing the identity MUST be 'uri' and the claim value is the URI form of the DNS server identity.
As a reminder, if DoH is supported by the DNS server, the DNS client uses the https URI scheme (Section 3 of [RFC8484]).
The 'policyinfo' claim MUST be formatted as a JSON object. The 'policyinfo' claim contains the policy information of the DNS server, it includes the following attributes:
Figure 2 shows an example of policy information.
{
"server":{
"adn":["example.com"]
},
"iat":1443208345,
"exp":1443640345,
"policyinfo": {
"filtering": {
"malwareblocking": true,
"policyblocking": false
},
"qnameminimization":false,
"privacyurl": "https://example.com/commitment-to-privacy/"
}
}
Figure 2: An Example of Policy Information
The signature of the PAT is created as specified in Section 5.1 of [RFC7515] (Steps 1 through 6). PAT MUST use the JWS Protected Header.
For the JWS Payload and the JWS Protected Header, the lexicographic ordering and white space rules described in Section 5 and Section 6, and JSON serialization rules in Section 9 MUST be followed.
The PAT is cryptographically signed by the domain hosting the DNS server and optionally by a third party who performed privacy and security audit of the DNS server.
The policy information is attested using "Organization Validation" (OV) or "Extended Validation" (EV) certificates to avoid bad actors taking advantage of this mechanism to advertise encrypted DNS servers for illegitimate and fraudulent purposes meant to trick DNS clients into believing that they are using a legitimate encrypted DNS server hosted to provide privacy for DNS transactions.
Alternatively, a DNS client has to be configured to trust the leaf of the signer of the PAT object. That is, trust of the signer MUST NOT be determined by validating the signer via the OS or the browser trust chain because that would allow any arbitrary entity to operate a DNS server and assert any sort of policy.
Appendix A provides an example of how to follow the steps to create the JWS Signature.
JWS JSON serialization (Step 7 in Section 5.1 of [RFC7515]) is supported for PAT to enable multiple signatures to be applied to the PAT object. For example, the PAT object can be cryptographically signed by the domain hosting the DNS server and by a third party who performed privacy and security audit of the DNS server.
Appendix B includes an example of the full JWS JSON serialization representation with multiple signatures.
Section 5.1 of [RFC7515] (Step 8) describes the method to create the final JWS Compact Serialization form of the PAT Token.
PAT includes the minimum set of claims needed to securely assert the policy information of the DNS server. JWT supports a mechanism to add additional asserted or signed information by simply adding new claims. PAT can be extended beyond the defined base set of claims to represent other DNS server information requiring assertion or validation. Specifying new claims follows the baseline JWT procedures (Section 10.1 of). Understanding new claims on the DNS client is optional. The creator of a PAT object cannot assume that the DNS client will understand the new claims.
JSON objects can include spaces and line breaks, and key value pairs can occur in any order. It is therefore a non-deterministic string format. In order to make the digital signature verification work deterministically, the JSON representation of the JWS Protected Header object and JWS Payload object MUST be computed as follows.
The JSON object MUST follow the following rules. These rules are based on the thumbprint of a JSON Web Key (JWK) as defined in Section 3 of [RFC7638] (Step 1).
This section demonstrates the deterministic JSON serialization for the example PAT Payload shown in Section 6.2.3.
The initial JSON object is shown in Figure 3.
{
"server":{
"adn":["example.com"]
},
"iat":1443208345,
"exp":1443640345,
"policyinfo": {
"qnameminimization":false,
"privacyurl": "https://example.com/commitment-to-privacy/"
}
}
Figure 3: Initial JSON Object
The parent members of the JSON object are as follows, in lexicographic order: "exp", "iat", "policyinfo", "server".
The final constructed deterministic JSON serialization representation, with whitespace and line breaks removed, (with line breaks used for display purposes only) is:
{"exp":1443640345,"iat":1443208345,
"policyinfo":{"privacyurl":"https://example.com/commitment-to-privacy/",
"qnameminimization":false},"server":{"adn":["example.com"]}}
Figure 4: Deterministic JSON Form
Users are expected to indicate to their system in some way that they trust certain PAT signers (e.g., if working for Example, Inc., the user's system is configured to trust "example.com" signing the PAT). By doing so, the DNS client can automatically discover encrypted DNS server in specific networks, validate the PAT signature and the user can check if the human readable privacy policy information of the DNS server complies with user's privacy needs, prior to using that encrypted DNS server for DNS queries.
The DNS client MUST retrieve the human-readable privacy statement from the 'privacyurl' attribute to assist with that decision (e.g., display the privacy statement when it changes, show differences in previously-retrieved version, etc.). With the steps above, user can review the human-readable privacy policy information of the DoH/DoT server.
Another scenario is bootstrapping a networking device to use the encrypted DNS server in the local network. Secure Zero Touch Provisioning [RFC8572] defines a bootstrapping strategy for enabling devices to securely obtain the required configuration information with no user input. If the encrypted DNS server is insecurely discovered and not pre-configured in the networking device, the client can validate the Policy Assertion Token signature using the owner certificate as per Section 3.2 of [RFC8572].
The use of PAT object based on the validation of the digital signature and the associated certificate requires consideration of the authentication and authority or reputation of the signer to attest the policy information of the DNS server being asserted. Bad actors can host encrypted DNS servers, and claim the servers offer privacy but exactly do the opposite to invade the privacy of the user. Bad actor can get a domain name, host encrypted DNS servers, and get the DNS server certificate signed by a CA. The policy information will have to be attested using OV/EV certificates or a PAT object signer trusted by the DNS client to prevent the attack.
The CA that issued the OV/EV certificate does not attest the resolver information. The organization hosting the DNS server attests the resolver information using the OV/EV certificate and the client uses the OV/EV certificate to identify the organization (e.g., ISP or Enterprise) hosting the DNS server.
If the PAT object is asserted by a third party, it can do a "time of check" but the DNS server is susceptible of "time of use" attack. For example, changes to the policy of the DNS server can cause a disagreement between the auditor and the DNS server operation, hence the PAT object needs to be also asserted by the domain hosting the DNS server. In addition, the PAT object needs to have a short expiration time (e.g., 7 days) to ensure the DNS server's domain re-asserts the policy information and limits the damage from change in policy and mis-issuance.
This section registers the 'application/pat' media type [RFC2046] in the 'Media Types' registry in the manner described in [RFC6838], which can be used to indicate that the content is a PAT defined JWT.
IANA will add the names filtering, qnameminimization, privacyurl and auditurl to the DNS Resolver Information registry defined in Section 4.2 of [I-D.pp-add-resinfo].
This specification leverages some of the work that has been done in [RFC8225]. Thanks to Ted Lemon, Paul Wouters, Neil Cook, Vittorio Bertola, Vinny Parla and Shashank Jain for the discussion and comments.
| [I-D.btw-add-home] | Boucadair, M., Reddy.K, T., Wing, D. and N. Cook, "Encrypted DNS Discovery and Deployment Considerations for Home Networks", Internet-Draft draft-btw-add-home-07, July 2020. |
| [I-D.btw-add-rfc8484-clarification] | Boucadair, M., Cook, N., Reddy.K, T. and D. Wing, "Supporting Redirection for DNS Queries over HTTPS (DoH)", Internet-Draft draft-btw-add-rfc8484-clarification-02, July 2020. |
| [I-D.ietf-dnsop-extended-error] | Kumari, W., Hunt, E., Arends, R., Hardaker, W. and D. Lawrence, "Extended DNS Errors", Internet-Draft draft-ietf-dnsop-extended-error-16, May 2020. |
| [I-D.ietf-dnsop-terminology-ter] | Hoffman, P., "Terminology for DNS Transports and Location", Internet-Draft draft-ietf-dnsop-terminology-ter-01, February 2020. |
| [I-D.ietf-dprive-bcp-op] | Dickinson, S., Overeinder, B., Rijswijk-Deij, R. and A. Mankin, "Recommendations for DNS Privacy Service Operators", Internet-Draft draft-ietf-dprive-bcp-op-14, July 2020. |
| [I-D.pp-add-resinfo] | Sood, P. and P. Hoffman, "DNS Resolver Information Self-publication", Internet-Draft draft-pp-add-resinfo-02, June 2020. |
| [RFC7626] | Bortzmeyer, S., "DNS Privacy Considerations", RFC 7626, DOI 10.17487/RFC7626, August 2015. |
| [RFC7816] | Bortzmeyer, S., "DNS Query Name Minimisation to Improve Privacy", RFC 7816, DOI 10.17487/RFC7816, March 2016. |
| [RFC8225] | Wendt, C. and J. Peterson, "PASSporT: Personal Assertion Token", RFC 8225, DOI 10.17487/RFC8225, February 2018. |
| [RFC8310] | Dickinson, S., Gillmor, D. and T. Reddy, "Usage Profiles for DNS over TLS and DNS over DTLS", RFC 8310, DOI 10.17487/RFC8310, March 2018. |
| [RFC8572] | Watsen, K., Farrer, I. and M. Abrahamsson, "Secure Zero Touch Provisioning (SZTP)", RFC 8572, DOI 10.17487/RFC8572, April 2019. |
| [RFC8765] | Pusateri, T. and S. Cheshire, "DNS Push Notifications", RFC 8765, DOI 10.17487/RFC8765, June 2020. |
| [UNICODE] | The Unicode Consortium, "The Unicode Standard", June 2016. |
For PAT, there will always be a JWS with the following members:
This example will follow the steps in JWS [RFC7515] Section 5.1, steps 1-6 and 8 and incorporates the additional serialization steps required for PAT.
Step 1 for JWS references the JWS Payload, an example PAT Payload is as follows:
{
"server":{
"adn":["example.com"]
},
"iat":1443208345,
"exp":1443640345,
"policyinfo": {
"filtering": {
"malwareblocking": true,
"policyblocking": false
},
"qnameminimization":false,
"privacyurl": "https://example.com/commitment-to-privacy/"
}
}
This would be serialized to the form (with line break used for display purposes only):
{"exp":1443640345,"iat":1443208345,"policyinfo":{
"filtering":{"malwareblocking": true,"policyblocking": false},
"privacyurl":"https://example.com/commitment-to-privacy/",
"qnameminimization":false},"server":{"adn":["example.com"]}}
Step 2 Computes the BASE64URL(JWS Payload) producing this value (with line break used for display purposes only):
eyJleHAiOjE0NDM2NDAzNDUsImlhdCI6MTQ0MzIwODM0NSwicG9saWN5aW5mbyI6e yJmaWx0ZXJpbmciOnsibWFsd2FyZWJsb2NraW5nIjp0cnVlLCJwb2xpY3libG9ja2 luZyI6ZmFsc2V9LCJwcml2YWN5dXJsIjoiaHR0cHM6Ly9leGFtcGxlLmNvbS9jb21 taXRtZW50LXRvLXByaXZhY3kvIiwicW5hbWVtaW5pbWl6YXRpb24iOmZhbHNlfSwi c2VydmVyIjp7ImFkbiI6WyJleGFtcGxlLmNvbSJdfX0
For Step 3, an example PAT Protected Header comprising the JOSE Header is as follows:
{
"alg":"ES256",
"typ":"pat",
"x5u":"https://cert.example.com/pat.cer"
}
This would be serialized to the form (with line break used for display purposes only):
{"alg":"ES256","typ":"pat","x5u":"https://cert.example.com
/pat.cer"}
Step 4 Performs the BASE64URL(UTF8(JWS Protected Header)) operation and encoding produces this value (with line break used for display purposes only):
eyJhbGciOiJFUzI1NiIsInR5cCI6InBhdCIsIng1dSI6Imh0dHBzOi8vY2VydC5l eGFtcGxlLmNvbS9wYXQuY2VyIn0
Step 5 and Step 6 performs the computation of the digital signature of the PAT Signing Input ASCII(BASE64URL(UTF8(JWS Protected Header)) || ‘.’ || BASE64URL(JWS Payload)) using ES256 as the algorithm and the BASE64URL(JWS Signature).
4vQEAF_Vlp1Tr6sJmS4pnIKDRmIjH8EZzY5BMT2qJCHD8PmjBktWVnlmbmyHs05G KauRBdIFnfp3oDPbE0Jq4w
Step 8 describes how to create the final PAT token, concatenating the values in the order Header.Payload.Signature with period (‘.’) characters. For the above example values this would produce the following (with line breaks between period used for readability purposes only):
eyJhbGciOiJFUzI1NiIsInR5cCI6InBhdCIsIng1dSI6Imh0dHBzOi8vY2VydC5l eGFtcGxlLmNvbS9wYXQuY2VyIn0 . eyJleHAiOjE0NDM2NDAzNDUsImlhdCI6MTQ0MzIwODM0NSwicG9saWN5aW5mbyI6e yJmaWx0ZXJpbmciOnsibWFsd2FyZWJsb2NraW5nIjp0cnVlLCJwb2xpY3libG9ja2 luZyI6ZmFsc2V9LCJwcml2YWN5dXJsIjoiaHR0cHM6Ly9leGFtcGxlLmNvbS9jb21 taXRtZW50LXRvLXByaXZhY3kvIiwicW5hbWVtaW5pbWl6YXRpb24iOmZhbHNlfSwi c2VydmVyIjp7ImFkbiI6WyJleGFtcGxlLmNvbSJdfX0 . 4vQEAF_Vlp1Tr6sJmS4pnIKDRmIjH8EZzY5BMT2qJCHD8PmjBktWVnlmbmyHs05G KauRBdIFnfp3oDPbE0Jq4w
-----BEGIN PRIVATE KEY----- MIGHAgEAMBMGByqGSM49AgEGCCqGSM49AwEHBG0wawIBAQQgevZzL1gdAFr88hb2 OF/2NxApJCzGCEDdfSp6VQO30hyhRANCAAQRWz+jn65BtOMvdyHKcvjBeBSDZH2r 1RTwjmYSi9R/zpBnuQ4EiMnCqfMPWiZqB4QdbAd0E7oH50VpuZ1P087G -----END PRIVATE KEY-----
-----BEGIN PUBLIC KEY----- MFkwEwYHKoZIzj0CAQYIKoZIzj0DAQcDQgAEEVs/o5+uQbTjL3chynL4wXgUg2R9 q9UU8I5mEovUf86QZ7kOBIjJwqnzD1omageEHWwHdBO6B+dFabmdT9POxg== -----END PUBLIC KEY-----
The JWS payload used in this example as follows.
{
"server":{
"adn":["example.com"]
},
"iat":1443208345,
"exp":1443640345,
"policyinfo": {
"filtering": {
"malwareblocking": true,
"policyblocking": false
},
"qnameminimization":false,
"privacyurl": "https://example.com/commitment-to-privacy/"
}
}
This would be serialized to the form (with line break used for display purposes only):
{"exp":1443640345,"iat":1443208345,"policyinfo":{
"filtering":{"malwareblocking": true,"policyblocking": false},
"privacyurl":"https://example.com/commitment-to-privacy/",
"qnameminimization":false},"server":{"adn":["example.com"]}}
The JWS protected Header value used for the first signature is same as that used in the example in Appendix A. The X.509 private key used for generating the first signature is same as that used in the example in Appendix A.1.
The JWS Protected Header value used for the second signature is:
{
"alg":"ES384",
"typ":"pat",
"x5u":"https://cert.audit-example.com/pat.cer"
}
The complete JWS JSON Serialization for these values is as follows (with line breaks within values for display purposes only):
{
"payload":
"eyJleHAiOjE0NDM2NDAzNDUsImlhdCI6MTQ0MzIwODM0NSwicG9saWN5aW5mbyI6
eyJmaWx0ZXJpbmciOnsibWFsd2FyZWJsb2NraW5nIjp0cnVlLCJwb2xpY3libG9j
a2luZyI6ZmFsc2V9LCJwcml2YWN5dXJsIjoiaHR0cHM6Ly9leGFtcGxlLmNvbS9j
b21taXRtZW50LXRvLXByaXZhY3kvIiwicW5hbWVtaW5pbWl6YXRpb24iOmZhbHNl
fSwic2VydmVyIjp7ImFkbiI6WyJleGFtcGxlLmNvbSJdfX0",
"signatures":[
{"protected":"eyJhbGciOiJFUzI1NiIsInR5cCI6InBhdCIsIng1dSI6Imh0dHB
zOi8vY2VydC5leGFtcGxlLmNvbS9wYXQuY2VyIn0",
"signature": "4vQEAF_Vlp1Tr6sJmS4pnIKDRmIjH8EZzY5BMT2qJCHD8PmjBk
tWVnlmbmyHs05GKauRBdIFnfp3oDPbE0Jq4w"},
{"protected":"eyJhbGciOiJFUzM4NCIsInR5cCI6InBhdCIsIng1dSI6Imh0dHB
zOi8vY2VydC5hdWRpdC1leGFtcGxlLmNvbS9wYXQuY2VyIn0",
"signature":666ag_mAqDa3Oyxo1DGXUocr0MmRjpXwq8kWp1S21mvs2-kPCIq3
0xsBJt4apy-sq3VyJgIqzjijoFYURhHvupF0obo-IFUGSZ1YHBCX_MiyBwJQJjtp
S91ujDatRTtZ"}]
}
-----BEGIN PRIVATE KEY----- MIGHAgEAMBMGByqGSM49AgEGCCqGSM49AwEHBG0wawIBAQQgevZzL1gdAFr88hb2 OF/2NxApJCzGCEDdfSp6VQO30hyhRANCAAQRWz+jn65BtOMvdyHKcvjBeBSDZH2r 1RTwjmYSi9R/zpBnuQ4EiMnCqfMPWiZqB4QdbAd0E7oH50VpuZ1P087G -----END PRIVATE KEY-----
-----BEGIN PUBLIC KEY----- MFkwEwYHKoZIzj0CAQYIKoZIzj0DAQcDQgAEEVs/o5+uQbTjL3chynL4wXgUg2R9 q9UU8I5mEovUf86QZ7kOBIjJwqnzD1omageEHWwHdBO6B+dFabmdT9POxg== -----END PUBLIC KEY-----