(Visual FoxPro) Verify JWT with EdDSA / Ed25519 Signature

Note: This example requires Chilkat v9.5.0.84 or greater.

Demonstrates how to verify a JWT that was signed using an Ed25519 private key.

This example verifies the EdDSA 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 data.

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

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

* Demonstrates how to verify a JWT with an EdDSA/Ed25519 Signature
* *** Requires Chilkat v9.5.0.84 or greater.

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

* Use this Ed25519 public key for verification

lcJsonPubKey = '{"kty": "OKP","alg": "EdDSA","crv": "Ed25519","x": "11qYAYKxCrfVS_7TyWQHOg7hcvPapiMlrwIaaPcHURo"}'

* For versions of Chilkat < 10.0.0, use CreateObject('Chilkat_9_5_0.PublicKey')
loPubKey = CreateObject('Chilkat.PublicKey')
lnSuccess = loPubKey.LoadFromString(lcJsonPubKey)
IF (lnSuccess = 0) THEN
    ? loPubKey.LastErrorText
    RELEASE loPubKey
    CANCEL
ENDIF

* For versions of Chilkat < 10.0.0, use CreateObject('Chilkat_9_5_0.Jwt')
loJwt = CreateObject('Chilkat.Jwt')
lcToken = "eyJhbGciOiJFZERTQSJ9.RXhhbXBsZSBvZiBFZDI1NTE5IHNpZ25pbmc.hgyY0il_MGCjP0JzlnLWG1PPOt7-09PGcvMg3AIbQR6dWbhijcNR4ki4iylGjg5BhVsPt9g7sVvpAr_MuM0KAg"

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

IF (lnSigVerified = 0) THEN
    ? loJwt.LastErrorText
    RELEASE loPubKey
    RELEASE loJwt
    CANCEL
ENDIF

* 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)

* Recover the original data (the payload).
lcPayload = loJwt.GetPayload(lcToken)
? lcPayload

* Recover the original JOSE header in the same way:
lcJoseHeader = loJwt.GetHeader(lcToken)
? lcJoseHeader

RELEASE loPubKey
RELEASE loJwt