The document discusses the JSON-based Identity Protocol Suite, which defines standards for JSON Web Tokens (JWTs), JSON Web Encryption (JWE), JSON Web Keys (JWK), and JSON Web Signatures (JWS). JWTs are compact tokens passed in HTTP that contain claims and can be signed or encrypted. JWE defines how to encrypt JWTs using symmetric or asymmetric encryption. JWK defines public key representations in JSON. JWS defines how to digitally sign JWTs using symmetric or asymmetric signatures. These standards are defined by the IETF and provide a common way to securely transmit identity and authorization data.

1. The JSON-based Identity Protocol Suite
By Travis Spencer
Copyright © 2013 Twobo Technologies AB.

2. Overview of the Protocol Suite
 JavaScript Object Notation (JSON) – Data
encoding format popularized by AJAX & REST
 All being defined in IETF
 Used to encode OAuth 2.0 security model
 Tokens (JWT) Encryption (JWE)
 Keys (JWK) Signatures (JWS)
 OAuth 2.0 Bearer Token spec binds it to OAuth
 Basis of OAuth and OpenID Connect
Copyright © 2013 Twobo Technologies AB.

3. Overview of JWT
 JWT – pronounced “jot” – are lightweight tokens
passed in HTTP headers & query strings
 Three basic sections – header, claims, signature
 Akin to SAML tokens
 Less expressive
 Less security options
 Encoded w/ JSON not XML for compactness
Copyright © 2013 Twobo Technologies AB.

4. Basic Layout & Wire Format
Header
Claims
Crypto
JWT Token
base64url(Header) + “.” + base64url(Claims) +
“.” + base64url(Crypto)
Copyright © 2013 Twobo Technologies AB.

5. Claims Section
 Reserved (but optional) claim names
 Expiration time (exp) Issuer (iss)
 Not before (nbf) Type (typ)
 Issued at (iat) Audience (aud)
 Public claim names
 IANA JWT claims registry
 Domain name, OID, or UUID
 Private claim names – Any unused name
 Value can be any JSON type
Copyright © 2013 Twobo Technologies AB.

6. Overview of JWE
 Used to encrypt JWTs
 Supports symmetric & asymmetric encryption
 Three basic sections – header, key, ciphertext
 Plaintext may be signed first
 Encryption algorithm
 RSA1_5 A(128|256)KW
 RSA-OAEP A(128|256)GCM
 ECDH-ES
 Cyphertext is put in the crypto section of the JWT
Copyright © 2013 Twobo Technologies AB.

7. Basic Layout & Wire Format
Header
Key
Ciphertext
JWE
JWE = base64url(Header) + “.” +
base64url(Key) + “.” + base64url(Ciphertext)
Copyright © 2013 Twobo Technologies AB.

8. Overview of JWK
 Array of public keys encoded as JSON objects
 Intended for inclusion in JWS for signature
verification
 Explicit support for Elliptic Curve and RSA keys
Copyright © 2013 Twobo Technologies AB.

9. JWK Example
{“keyvalues” : {“algorithm” : “RSA”,
[ “modulus” : “…”,
{“algorithm” : “EC”, “exponent” : “…”,
“curve” : “P-256”, “keyid” : “…”}
]
“x” : “…”,
}
“y” : “…”,
“use” : “encryption”,
“keyid” : “1”},
Copyright © 2013 Twobo Technologies AB.

10. Overview of JWS
 Header input is JWT header
 Payload input is JWT claims
 Output is appended to JWT inputs & (optionally)
points to the JWK that was used
 Supports symmetric & asymmetric signing
algorithms
 HMAC SHA RSA SHA
 ECDSA w/ curve P & SHA
Copyright © 2013 Twobo Technologies AB.

11. Basic Layout & Wire Format
Header
Payload
JWS
JWS = base64url(sig(base64url(Header) + “.” +
base64url(Payload)))
Copyright © 2013 Twobo Technologies AB.

12. Questions & Thanks
@2botech
@travisspencer
www.2botech.com
www.travisspencer.com
Copyright © 2013 Twobo Technologies AB.