(DataFlex) RSA Sign with PKCS8 Encrypted Key

Demonstrates how to load a private key from an encrypted PKCS8 file and create an RSA digital signature (and then verify it).

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

Use ChilkatAx-9.5.0-win32.pkg

Procedure Test
    Handle hoPkey
    Boolean iSuccess
    String sPkeyXml
    Handle hoRsa
    String sStrData
    String sHexSig
    Handle hoCert
    Variant vPubKey
    Handle hoPubKey
    String sPubKeyXml
2    Handle hoRsa2
    String sTemp1

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

    Get Create (RefClass(cComChilkatPrivateKey)) To hoPkey
    If (Not(IsComObjectCreated(hoPkey))) Begin
        Send CreateComObject of hoPkey
    End

    // Load the private key from an RSA PEM file:
    Get ComLoadPkcs8EncryptedFile Of hoPkey "raul_privateKey.key" "a0123456789" To iSuccess

    // Get the private key in XML format:
    Get ComGetXml Of hoPkey To sPkeyXml

    Get Create (RefClass(cComChilkatRsa)) To hoRsa
    If (Not(IsComObjectCreated(hoRsa))) Begin
        Send CreateComObject of hoRsa
    End

    // Import the private key into the RSA component:
    Get ComImportPrivateKey Of hoRsa sPkeyXml To iSuccess
    If (iSuccess <> True) Begin
        Get ComLastErrorText Of hoRsa To sTemp1
        Showln sTemp1
        Procedure_Return
    End

    // This example will sign a string, and receive the signature
    // in a hex-encoded string.  Therefore, set the encoding mode
    // to "hex":
    Set ComEncodingMode Of hoRsa To "hex"

    Move "This is the string to be signed." To sStrData

    // Sign the string using the sha-1 hash algorithm.
    // Other valid choices are "md2" and "md5".
    Get ComSignStringENC Of hoRsa sStrData "sha-1" To sHexSig

    Showln sHexSig

    // Now verify with the public key.
    // This example shows how to use the public key from 
    // a digital certificate (.cer file)
    Get Create (RefClass(cComChilkatCert)) To hoCert
    If (Not(IsComObjectCreated(hoCert))) Begin
        Send CreateComObject of hoCert
    End
    Get ComLoadFromFile Of hoCert "raul_publicKey.cer" To iSuccess
    If (iSuccess <> True) Begin
        Get ComLastErrorText Of hoCert To sTemp1
        Showln sTemp1
        Procedure_Return
    End

    Get ComExportPublicKey Of hoCert To vPubKey
    If (IsComObject(vPubKey)) Begin
        Get Create (RefClass(cComChilkatPublicKey)) To hoPubKey
        Set pvComObject Of hoPubKey To vPubKey
    End

    // Get the private key in XML format:
    Get ComGetXml Of hoPubKey To sPubKeyXml

    Get Create (RefClass(cComChilkatRsa)) To hoRsa2
    If (Not(IsComObjectCreated(hoRsa2))) Begin
        Send CreateComObject of hoRsa2
    End
    Get ComImportPublicKey Of hoRsa2 sPubKeyXml To iSuccess
    If (iSuccess <> True) Begin
        Get ComLastErrorText Of hoRsa2 To sTemp1
        Showln sTemp1
        Procedure_Return
    End

    // Verify the signature against the original data:
    Set ComEncodingMode Of hoRsa2 To "hex"
    Get ComVerifyStringENC Of hoRsa2 sStrData "sha-1" sHexSig To iSuccess
    If (iSuccess <> True) Begin
        Get ComLastErrorText Of hoRsa2 To sTemp1
        Showln sTemp1
        Procedure_Return
    End

    Showln "Signature verified!"

    // Verify with incorrect data:
    Get ComVerifyStringENC Of hoRsa2 "something else" "sha-1" sHexSig To iSuccess
    If (iSuccess <> True) Begin
        Showln "Signature not verified! (which was expected in this case)"
    End
    Else Begin
        Showln "Hmmm... that's not right..."
    End

    Send Destroy of hoPubKey


End_Procedure