Xbase++

Verify JWT with EdDSA / Ed25519 Signature

See more JSON Web Token (JWT) Examples

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.

Xbase++

LOCAL nSuccess
LOCAL cJsonPubKey
LOCAL oPubKey
LOCAL oJwt
LOCAL cToken
LOCAL nSigVerified
LOCAL nLeeway
LOCAL nBTimeValid
LOCAL cPayload
LOCAL cJoseHeader

nSuccess := 0

//  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

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

oPubKey := CreateObject("Chilkat.PublicKey")
nSuccess := oPubKey:LoadFromString(cJsonPubKey)
IF (nSuccess == 0)
    ? oPubKey:LastErrorText
    oPubKey:destroy()
    RETURN
ENDIF

oJwt := CreateObject("Chilkat.Jwt")
cToken := "eyJhbGciOiJFZERTQSJ9.RXhhbXBsZSBvZiBFZDI1NTE5IHNpZ25pbmc.hgyY0il_MGCjP0JzlnLWG1PPOt7-09PGcvMg3AIbQR6dWbhijcNR4ki4iylGjg5BhVsPt9g7sVvpAr_MuM0KAg"

//  First verify the signature.
nSigVerified := oJwt:VerifyJwtPk(cToken, oPubKey)
? "verified: " + Str(nSigVerified)

IF (nSigVerified == 0)
    ? oJwt:LastErrorText
    oPubKey:destroy()
    oJwt:destroy()
    RETURN
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.
nLeeway := 60
nBTimeValid := oJwt:IsTimeValid(cToken, nLeeway)
? "time constraints valid: " + Str(nBTimeValid)

//  Recover the original data (the payload).
cPayload := oJwt:GetPayload(cToken)
? cPayload

//  Recover the original JOSE header in the same way:
cJoseHeader := oJwt:GetHeader(cToken)
? cJoseHeader

oPubKey:destroy()
oJwt:destroy()