(DataFlex) RSA Hash Binary Data and Sign (and Verify)

Demonstrates how to sign the hash of binary data. Also demonstrates how to verify the RSA signature.

Note: This example uses methods introduced in Chilkat v9.5.0.77.

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

Use ChilkatAx-win32.pkg

Procedure Test
    Variant vPrivKey
    Handle hoPrivKey
    Boolean iSuccess
    Handle hoRsa
    String sOriginalData
    Variant vBdData
    Handle hoBdData
    Variant vBdSignature
    Handle hoBdSignature
    Variant vPubKey
    Handle hoPubKey
2    Handle hoRsa2
    Boolean iBVerified
    String sTemp1

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

    // Load an RSA private key for signing.
    Get Create (RefClass(cComChilkatPrivateKey)) To hoPrivKey
    If (Not(IsComObjectCreated(hoPrivKey))) Begin
        Send CreateComObject of hoPrivKey
    End
    Get ComLoadEncryptedPemFile Of hoPrivKey "qa_data/pem/rsa_passwd.pem" "passwd" To iSuccess
    If (iSuccess <> True) Begin
        Get ComLastErrorText Of hoPrivKey To sTemp1
        Showln sTemp1
        Procedure_Return
    End

    Get Create (RefClass(cComChilkatRsa)) To hoRsa
    If (Not(IsComObjectCreated(hoRsa))) Begin
        Send CreateComObject of hoRsa
    End
    Get pvComObject of hoPrivKey to vPrivKey
    Get ComImportPrivateKeyObj Of hoRsa vPrivKey To iSuccess

    // We have some binary data (in hex) to sign
    Move "0102030405060708090A" To sOriginalData
    Get Create (RefClass(cComChilkatBinData)) To hoBdData
    If (Not(IsComObjectCreated(hoBdData))) Begin
        Send CreateComObject of hoBdData
    End
    Get ComAppendEncoded Of hoBdData sOriginalData "hex" To iSuccess

    // Hash (SHA-256) and sign the hash:
    Get Create (RefClass(cComChilkatBinData)) To hoBdSignature
    If (Not(IsComObjectCreated(hoBdSignature))) Begin
        Send CreateComObject of hoBdSignature
    End
    Get pvComObject of hoBdData to vBdData
    Get pvComObject of hoBdSignature to vBdSignature
    Get ComSignBd Of hoRsa vBdData "sha256" vBdSignature To iSuccess
    If (iSuccess <> True) Begin
        Get ComLastErrorText Of hoRsa To sTemp1
        Showln sTemp1
        Procedure_Return
    End

    // Show the RSA signature in base64
    Get ComGetEncoded Of hoBdSignature "base64" To sTemp1
    Showln sTemp1

    // ------------------------------------------
    // Get the public key from the private key
    Get ComGetPublicKey Of hoPrivKey To vPubKey
    If (IsComObject(vPubKey)) Begin
        Get Create (RefClass(cComChilkatPublicKey)) To hoPubKey
        Set pvComObject Of hoPubKey To vPubKey
    End

    // Verify the signature..
    Get Create (RefClass(cComChilkatRsa)) To hoRsa2
    If (Not(IsComObjectCreated(hoRsa2))) Begin
        Send CreateComObject of hoRsa2
    End
    Get ComImportPublicKeyObj Of hoRsa2 vPubKey To iSuccess

    Get pvComObject of hoBdData to vBdData
    Get pvComObject of hoBdSignature to vBdSignature
    Get ComVerifyBd Of hoRsa2 vBdData "sha256" vBdSignature To iBVerified
    Showln "signature verified: " iBVerified

    Send Destroy of hoPubKey


End_Procedure