(DataFlex) 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

Use ChilkatAx-win32.pkg

Procedure Test
    String sJsonPubKey
    Variant vPubKey
    Handle hoPubKey
    Boolean iSuccess
    Handle hoJwt
    String sToken
    Boolean iSigVerified
    Integer iLeeway
    Boolean iBTimeValid
    String sPayload
    String sJoseHeader
    String sTemp1

    // 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

    Move '{"kty": "OKP","alg": "EdDSA","crv": "Ed25519","x": "11qYAYKxCrfVS_7TyWQHOg7hcvPapiMlrwIaaPcHURo"}' To sJsonPubKey

    Get Create (RefClass(cComChilkatPublicKey)) To hoPubKey
    If (Not(IsComObjectCreated(hoPubKey))) Begin
        Send CreateComObject of hoPubKey
    End
    Get ComLoadFromString Of hoPubKey sJsonPubKey To iSuccess
    If (iSuccess = False) Begin
        Get ComLastErrorText Of hoPubKey To sTemp1
        Showln sTemp1
        Procedure_Return
    End

    Get Create (RefClass(cComChilkatJwt)) To hoJwt
    If (Not(IsComObjectCreated(hoJwt))) Begin
        Send CreateComObject of hoJwt
    End
    Move "eyJhbGciOiJFZERTQSJ9.RXhhbXBsZSBvZiBFZDI1NTE5IHNpZ25pbmc.hgyY0il_MGCjP0JzlnLWG1PPOt7-09PGcvMg3AIbQR6dWbhijcNR4ki4iylGjg5BhVsPt9g7sVvpAr_MuM0KAg" To sToken

    // First verify the signature.
    Get pvComObject of hoPubKey to vPubKey
    Get ComVerifyJwtPk Of hoJwt sToken vPubKey To iSigVerified
    Showln "verified: " iSigVerified

    If (iSigVerified = False) Begin
        Get ComLastErrorText Of hoJwt To sTemp1
        Showln sTemp1
        Procedure_Return
    End

    // 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.
    Move 60 To iLeeway
    Get ComIsTimeValid Of hoJwt sToken iLeeway To iBTimeValid
    Showln "time constraints valid: " iBTimeValid

    // Recover the original data (the payload).
    Get ComGetPayload Of hoJwt sToken To sPayload
    Showln sPayload

    // Recover the original JOSE header in the same way:
    Get ComGetHeader Of hoJwt sToken To sJoseHeader
    Showln sJoseHeader


End_Procedure