(DataFlex) Duplicate openssl dgst -sha256 -verify pubKey.pem -signature signature.sig in.dat

Demonstrates how to duplicate this OpenSSL command:

openssl dgst -sha256 -verify pubKey.pem -signature signature.sig in.dat

1. Creates a SHA256 digest of the contents of the input file.
2. Verifies the SHA256 digest using the public key.

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

Use ChilkatAx-win32.pkg

Procedure Test
    Variant vPubKey
    Handle hoPubKey
    Boolean iSuccess
    Variant vBdFileData
    Handle hoBdFileData
    Variant vBdSig
    Handle hoBdSig
    Handle hoRsa
    String sTemp1

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

    Get Create (RefClass(cComChilkatPublicKey)) To hoPubKey
    If (Not(IsComObjectCreated(hoPubKey))) Begin
        Send CreateComObject of hoPubKey
    End

    // Load the public key from an PEM file:
    Get ComLoadFromFile Of hoPubKey "pubKey.pem" To iSuccess
    If (iSuccess <> True) Begin
        Get ComLastErrorText Of hoPubKey To sTemp1
        Showln sTemp1
        Procedure_Return
    End

    // Load the data of the original file that was signed.
    Get Create (RefClass(cComChilkatBinData)) To hoBdFileData
    If (Not(IsComObjectCreated(hoBdFileData))) Begin
        Send CreateComObject of hoBdFileData
    End
    Get ComLoadFile Of hoBdFileData "in.dat" To iSuccess

    // Load the signature.
    Get Create (RefClass(cComChilkatBinData)) To hoBdSig
    If (Not(IsComObjectCreated(hoBdSig))) Begin
        Send CreateComObject of hoBdSig
    End
    Get ComLoadFile Of hoBdSig "signature.sig" To iSuccess

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

    // Import the public key into the RSA component:
    Get pvComObject of hoPubKey to vPubKey
    Get ComImportPublicKeyObj Of hoRsa vPubKey To iSuccess
    If (iSuccess <> True) Begin
        Get ComLastErrorText Of hoRsa To sTemp1
        Showln sTemp1
        Procedure_Return
    End

    // OpenSSL uses big-endian.
    Set ComLittleEndian Of hoRsa To False

    Get pvComObject of hoBdFileData to vBdFileData
    Get pvComObject of hoBdSig to vBdSig
    Get ComVerifyBd Of hoRsa vBdFileData "sha256" vBdSig To iSuccess
    If (iSuccess <> True) Begin
        Get ComLastErrorText Of hoRsa To sTemp1
        Showln sTemp1
        Showln "The signature was invalid."
        Procedure_Return
    End

    Showln "The signature was verified."


End_Procedure