DataFlex

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.

DataFlex

Use ChilkatAx-win32.pkg

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

    Move False To iSuccess

    // 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