I am very new to jwt and signature validation. I had a very basic query.
I am generating a token from MSAL(AAD).
When I use the token in jwt.io, I can see that it automatically populates the secret key and marks the signature as verified. How does jwt.io know about this?
From generating token point of view, I didn't mention anywhere explicitly to generate the token with any secret.
You don't show the details of your token here (which is ok), but I assume the token has a kid and maybe also a jku in the header.
The kidis the Key Id, and the jku the JSON Web Key Set URL.
Under that URL (you can paste it to your browser to see) you can find a set of JWKs (JSON Web Keys), basically a collection of public keys in a special format. In case of tokens issued by AAD you the JWKS_URI can be found on https://login.microsoftonline.com/common/v2.0/.well-known/openid-configuration.
JWT.io can read this information and find the key with the given kid and verify the token based on that.
This Q/A explains the verification of JWTs issued by AAD in more detail.
Related
When building a Conversational Action with the new Actions SDK or Action Builder, you can define a webhook to handle business logic. This webhook then receives fulfillment requests with the following headers, among others:
Google-Actions-API-Version: "3"
Google-Assistant-Signature: "eyJhbGciOiJSUzI1NiIsImtpZC..."
How should that signature be verified? It's a JWT claim, but the key ID with which it was signed does not exist in the GCP account linked with the Action, and is not mentioned in the new Actions SDK documentation or in the Node.js fulfillment library documentation.
The signature is a JSON Web Token, which is an encoded way of transmitting some assertions that have been signed in a verifiable way. There are libraries that will both decode and verify JWTs. The general steps (some of which you can cache or shortcut) are:
Decode the header to get the kid (key id) and the payload to get the iss (issuer) fields. You'll also want the nbf (not before) and exp (expiration) fields to verify this was set recently and the aud field to verify that it matches your Google Cloud project ID.
Based on the issuer, access the well known openid configuration. Since the issuer is "https://accounts.google.com" you can access this at "https://accounts.google.com/.well-known/openid-configuration"
From the configuration document, you want the jwks_uri field, which is the URL to get the current JWT certificates. For Google, this is probably "https://www.googleapis.com/oauth2/v3/certs"
The certificate document should contain an array of keys. You want a key with the kid that matches the kid from the JWT. Note that these keys change frequently, but as long as you're within the window of the nbf and exp fields from the signature header, the key should exist in the certificate document.
With all this, you can then verify the signature portion of the JWT.
In the API, jwt.sign will create a key and sends along with the response let's say while login. So, when the client make another request, the API/Server uses jwt.verify to check the user logged in is authentic. Here to verify the key, the server has to store the same right? So how can it be stateless?
I am pretty confused and could be wrong in this case, but please do advise.
jwt.sign creates a signed token in which the signature is a hash calculated with the token content and a secret key. The secret key is fix. The signed token is sent to the client who requested it. When the client sends a request containing the token in the authorization header, the token will be veryfied by again calculating the hash. There's no need to store the token or signature anywhere.
I'm implementing "Log In with PayPal" functionality. Should be fairly simple, but unfortunately PayPal lacks documentation (only some basic things are described).
I get authorization_code using "Log In with PayPal" widget. Than I make a request to https://api.sandbox.paypal.com/v1/identity/openidconnect/tokenservice and get JSON with access_token, refresh_token and id_token. I want to get unique user identifier, so I decode id_token, but I'm not able to verify signature of my id_token. Id_token header contains {"alg": "HS256", "typ": "JWT"}.
What secret should I use? Tried my app's secret (same that I use to access tokenservice), but it didn't work (using https://jwt.io/ debugger).
PayPal is not OpenID connect compliant. This answer explains the reasons.
PayPal expose a configuration endpoint - https://www.paypalobjects.com/.well-known/openid-configuration.It only support HS256 and does not support or mention about RS256. This could be due to a proprietary validation for ID token. For example a id token used as a bearer token.
Alternative solution would be to invoke userinfo endpoint as described by document. This endpoint can be invoked using access token and document says it would return the user_id
user_id - identifier for the end-user at the issuer.
Although it seems that user_id found in the userinfo is different from sub that could be extracted from id_token.
How to find public keys if signing algorithm is RS256
ID token is a JWT. As you have found out, it contains a JWS signature which acts as a MAC.
This signature is a signed using a private key. The receiver of the id token can validate the token using the public key. To find the public key, openid conenct specify a discovery document. You can read more about this from the specification
In the discovery document, you get a special endpoint to infer the configuration .well-known/openid-configuration. And one of the must have metadata of the configuration response is jwk_url
jwks_uri
REQUIRED. URL of the OP's JSON Web Key Set [JWK] document. This
contains the signing key(s) the RP uses to validate signatures from
the OP. The JWK Set MAY also contain the Server's encryption key(s),
which are used by RPs to encrypt requests to the Server. When both
signing and encryption keys are made available, a use (Key Use)
parameter value is REQUIRED for all keys in the referenced JWK Set to
indicate each key's intended usage. Although some algorithms allow the
same key to be used for both signatures and encryption, doing so is
NOT RECOMMENDED, as it is less secure. The JWK x5c parameter MAY be
used to provide X.509 representations of keys provided. When used, the
bare key values MUST still be present and MUST match those in the
certificate.
I am working on Amazon cognito. I am trying to decode from https://jwt.io
eyJraWQiOiJRaGF4STZGbXB5Y3Z3dUV5TUZJUk9FTm5MTDJKTiswMzVVak5MNTEycjZvPSIsImFsZyI6IlJTMjU2In0.eyJzdWIiOiJhYjI0YzExYS1mNjZhLTRjMjktOWVhNy0yMWQwMTc2NmZlN2IiLCJhdWQiOiIxY2ZxNjJubjNlZmNpdWFpYnFldmlxbHU4OSIsInRva2VuX3VzZSI6ImlkIiwiYXV0aF90aW1lIjoxNDk0Njg1MjQwLCJpc3MiOiJodHRwczpcL1wvY29nbml0by1pZHAudXMtZWFzdC0xLmFtYXpvbmF3cy5jb21cL3VzLWVhc3QtMV9oM3F4WGVPQzQiLCJjb2duaXRvOnVzZXJuYW1lIjoidGVzdHNhbmRlZXAxIiwiZXhwIjoxNDk0Njg4ODQwLCJpYXQiOjE0OTQ2ODUyNDAsImVtYWlsIjoic2FuZGVlcC5qYWtrYXJhanVAZm9jYWxjeG0uY29tIn0.ZRsYZZwxUnqL4FfuWhD-w8xQWoQQkuj4rYCYPqQehcq1SMe0Vww2GIY4-sr9RgwjVxhOo4WqIQT8LzSn_tFBF504h5xGpp5fD37rIJZ49rC3naH7tC0nHwKSswi6C6x8BlIPi4QAnlP49SZMoIEPEnQig9F6wzlDfb-cjw0R2q61Em-e0cpBM8lbjxCrgBF2-PbXFqwEfncEUkwb93qZHo4Wk3pYH3d-9aXzZg6Xc4CNZfehAUZ7qknq2qtaSI3tH-EXGYmytjoVwcF5jIvej2OATrQf_JbfBNSxC96oA_CglWVKvp2rPrqlZzDCd0Se68TjZvKSbW7XtKX_DzI5ww
It says the signature invalid. I have tried many tokens I am always getting this.
Why does it report that the signature is invalid?
#jps is correct. You need to download the JWKs for your Cognito User Pool before you can verify the signature of the JWT.
Download your Cognito User Pools JWK file: https://cognito-idp.{region}.amazonaws.com/{userPoolId}/.well-known/jwks.json. This for your User Pool is: https://cognito-idp.us-east-1.amazonaws.com/us-east-1_h3qxXeOC4/.well-known/jwks.json
Find your Identities kid value. The value from the token you provided is: "QhaxI6FmpycvwuEyMFIROENnLL2JN+035UjNL512r6o=".
You then need to generate the Public Key that matches the data provided from the JWKs file, that matches your kid key. This is blogged about here: https://aws.amazon.com/blogs/mobile/integrating-amazon-cognito-user-pools-with-api-gateway/ (look further down the blog post for how to generate the Public Key).
I’m using openam OAuth 2.0/OpenID access_token end-point to get an id_token. The id_token contains a RS256 signature.
I need to verify this token. So from where can I get the “public certificate” that used to sign this token?
I found a public key certificate in here,
%BASE_DIR%/%SERVER_URI%/keystore.jks. But it says invalid after validating with this certificate.
You can use the well-known configuration endpoint to find out the jwks_uri for the OIDC provider. Then it will be just a matter of selecting the right key from the jwks_uri response based on the "kid" value in the JWT.
Of course looking at jwks_uri endpoint will only make sense if the signing algorithm for the JWT is based on asymmetric keys (RS*, ES*).