(DataFlex) RSA Sign Binary Data and Verify (Recover the Original Data)

Demonstrates how to RSA sign binary data and then verify/recover the original data.

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

Note: This example requires Chilkat v11.0.0 or greater.

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

Use ChilkatAx-win32.pkg

Procedure Test
    Boolean iSuccess
    Variant vPrivKey
    Handle hoPrivKey
    Handle hoRsa
    String sOriginalData
    Variant vBd
    Handle hoBd
    Variant vPubKey
    Handle hoPubKey
    Handle hoRsa2
    Boolean iBVerified
    String sTemp1

    Move False To iSuccess

    // 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 = False) 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 ComUsePrivateKey Of hoRsa vPrivKey To iSuccess

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

    // If successful, the contents of bd are replaced with the RSA signature.
    Get pvComObject of hoBd to vBd
    Get ComSignRawBd Of hoRsa vBd To iSuccess
    If (iSuccess = False) Begin
        Get ComLastErrorText Of hoRsa To sTemp1
        Showln sTemp1
        Procedure_Return
    End

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

    // ------------------------------------------
    // Get the public key from the private key
    Get Create (RefClass(cComChilkatPublicKey)) To hoPubKey
    If (Not(IsComObjectCreated(hoPubKey))) Begin
        Send CreateComObject of hoPubKey
    End
    Get pvComObject of hoPubKey to vPubKey
    Get ComToPublicKey Of hoPrivKey vPubKey To iSuccess

    // Verify the signature and extract the original data.
    Get Create (RefClass(cComChilkatRsa)) To hoRsa2
    If (Not(IsComObjectCreated(hoRsa2))) Begin
        Send CreateComObject of hoRsa2
    End
    Get pvComObject of hoPubKey to vPubKey
    Get ComUsePublicKey Of hoRsa2 vPubKey To iSuccess

    Get pvComObject of hoBd to vBd
    Get ComVerifyRawBd Of hoRsa2 vBd To iBVerified
    Showln "signature verified: " iBVerified

    // Show the original data:
    Get ComGetEncoded Of hoBd "hex" To sTemp1
    Showln "original data: " sTemp1


End_Procedure