(Visual FoxPro) Verify JWT Using an RSA Public Key (RS256, RS384, RS512)

Demonstrates how to verify a JWT that was signed using an RSA private key.

This example verifies the RSA signature. It also does the following:

• Checks to see if the time constraints ("nbf" and "exp") are valid.
• Recovers the original JOSE header.
• Recovers the original claims JSON.

Chilkat ActiveX Downloads ActiveX for 32-bit and 64-bit Windows

LOCAL loPubKey
LOCAL lnSuccess
LOCAL loJwt
LOCAL lcToken
LOCAL lnSigVerified
LOCAL lnLeeway
LOCAL lnBTimeValid
LOCAL lcPayload
LOCAL loJson
LOCAL lcJoseHeader

* Demonstrates how to verify an JWT using an RSA public key.

* This example requires the Chilkat API to have been previously unlocked.
* See Global Unlock Sample for sample code.

* For versions of Chilkat < 10.0.0, use CreateObject('Chilkat_9_5_0.PublicKey')
loPubKey = CreateObject('Chilkat.PublicKey')
lnSuccess = loPubKey.LoadFromFile("qa_data/pem/rsa_public.pem")

* For versions of Chilkat < 10.0.0, use CreateObject('Chilkat_9_5_0.Jwt')
loJwt = CreateObject('Chilkat.Jwt')

lcToken = "eyJhbGciOiJSUzI1NiIsInR5cCI6IkpXVCJ9.eyJpc3MiOiJodHRwOi8vZXhhbXBsZS5vcmciLCJzdWIiOiJKb2huIiwiYXVkIjoiaHR0cDovL2V4YW1wbGUuY29tIiwiaWF0IjoxNDYzNDQ1MjM4LCJuYmYiOjE0NjM0NDUyMzgsImV4cCI6MTQ2MzQ0ODgzOH0.XRtqed6nuJ9lrp0wbNdDX3fCkSh_d9cHAniPbNcqm7G-5N3mtI5ntQvZBDP3pHtECVqufuDwW7XgUtzAi0ZXhyiRm1iZ3wMSN5lHWv52OQJmMHPA7VPd8Q1hDG-tx-QswzJKd75OEUHP7wIXq2Mg_YVElfDvJI6TGjGyS1y-RLHlz-ldlGsEwIBkO0PtzIYTVov97x8p9KCsPNhS4lZUIqKOYoTZUV5LpuAWARl-636DfMEB_A5_IEaw_W8leh2suP2ULVZxwE-Tk1kBC9tsSGrBrPTtg7sziaV4Lbb0JRANmh98uTRu5f8ji9CVOnpbMiAzjsJSy56kz_olweXSuA"

* First verify the signature.
lnSigVerified = loJwt.VerifyJwtPk(lcToken,loPubKey)
? "verified: " + STR(lnSigVerified)

* Let's see if the time constraints, if any, are valid.
* The above JWT was created on the afternoon of 16-May-2016, with an expiration of 1 hour.
* If the current system time is before the "nbf" time, or after the "exp" time,
* then IsTimeValid will return false/0.
* Also, we'll allow a leeway of 60 seconds to account for any clock skew.
* Note: If the token has no "nbf" or "exp" claim fields, then IsTimeValid is always true.
lnLeeway = 60
lnBTimeValid = loJwt.IsTimeValid(lcToken,lnLeeway)
? "time constraints valid: " + STR(lnBTimeValid)

* Now let's recover the original claims JSON (the payload).
lcPayload = loJwt.GetPayload(lcToken)
* The payload will likely be in compact form:
? lcPayload

* We can format for human viewing by loading it into Chilkat's JSON object
* and emit.
* For versions of Chilkat < 10.0.0, use CreateObject('Chilkat_9_5_0.JsonObject')
loJson = CreateObject('Chilkat.JsonObject')
lnSuccess = loJson.Load(lcPayload)
loJson.EmitCompact = 0
? loJson.Emit()

* We can recover the original JOSE header in the same way:
lcJoseHeader = loJwt.GetHeader(lcToken)
* The payload will likely be in compact form:
? lcJoseHeader

* We can format for human viewing by loading it into Chilkat's JSON object
* and emit.
lnSuccess = loJson.Load(lcJoseHeader)
loJson.EmitCompact = 0
? loJson.Emit()

RELEASE loPubKey
RELEASE loJwt
RELEASE loJson