2017-06-15#

Best Practices OpenID Connect#

Minimal id_token verification#

• iss - this value MUST match the OpenID Connect Discovery issuer value
• aud - this MUST be your client_id
• nonce - This MUST be the nonce value you sent in your request
• exp - verify the assertion has not expired
• Verify the JWS Digital Signature of the JWT id_token

OPTIONAL id_token verifications:

• at_hash - verify that your are using the correct access Token
• s_hash - verify the hash of the OAuth state parameter
• iat - maybe you want an id_token that was issued within a certain time frame?
• auth_time - Perhaps it has been longer than you think is reasonable and you can send the OpenID Connect Provider a prompt Parameter (prompt=login) to the Authorization_endpoint

Read the OpenID Connect Implementer's Guides

Advanced OpenID Connect Clients#

• Use the Hybrid Flow
• Be sure you only send the Authorization Code to the correct issuer to prevent a IDP mix-up attack.
• Use a distinct redirect_uri for each OpenID Connect Provider
• If using a OAuth Public Client implement Proof Key for Code Exchange by OAuth Public Clients and use SHA-2
• Use TLS 1.2 or later and follow RFC 7525
• implement Mutual TLS Profiles for OAuth Clients or Token Binding Protocol
• Use acr_values sending in the OpenID Connect Authentication Request
  • default_acr-values can be registered in the OAuth 2.0 Client Registration
  • verify id_token for acceptable acr claim.
• Use FIDO
• Crypto Guidlines
  • RSA should use minimum 2048 bit keys
  • Elliptic Curve key should be minimum of 160 bits
  • client Secret should be minimum of 128 bits is using symmetric Key Cryptography
  • Use PS256 or ES256 Signature algorithms
  • OpenID Connect Federation provide3s an out-of-band Key-Exchange for signing keys.

OpenID Connect Client#

OpenID Connect DO THESE#

• Do use Form Post Response Mode
• Use and Verify non-static OAuth state parameter or nonce to stop Cross-site request forgery
  • at_hash or and verify the

OpenID Connect DO NOT THESE#

• client_secret_basic - Credentials are only encoded, (ie no Encryption)

More Information#

There might be more information for this subject on one of the following: ...nobody