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    Explains how to sign scripts so that they comply with the Windows 
    PowerShell execution policies. 


    The Restricted execution policy does not permit any scripts to run. 
    The AllSigned and RemoteSigned execution policies prevent Windows 
    PowerShell from running scripts that do not have a digital signature. 
    This topic explains how to run selected scripts that are not signed, 
    even while the execution policy is RemoteSigned, and how to sign 
    scripts for your own use. 
    For more information about Windows PowerShell execution policies, 
    see about_Execution_Policy. 


    When you start Windows PowerShell on a computer for the first time, the  
    Restricted execution policy (the default) is likely to be in effect. 
    The Restricted policy does not permit any scripts to run. 
    To find the effective execution policy on your computer, type: 
    To run unsigned scripts that you write on your local computer and 
    signed scripts from other users, start Windows PowerShell with the  
    Run as Administrator option and then use the following command to  
    change the execution policy on the computer to RemoteSigned:  
Set-ExecutionPolicy RemoteSigned 
    For more information, see the help topic for the  
    Set-ExecutionPolicy cmdlet. 


    If your Windows PowerShell execution policy is RemoteSigned, Windows  
    PowerShell will not run unsigned scripts that are downloaded from the 
    Internet, including unsigned scripts you receive through e-mail and instant 
    messaging programs. 
    If you try to run a downloaded script, Windows PowerShell displays the 
    following error message: 
        The file <file-name> cannot be loaded. The file  
        <file-name> is not digitally signed. The script 
        will not execute on the system. Please see "Get-Help 
        about_Signing" for more details. 
    Before you run the script, review the code to be sure that you trust it. 
    Scripts have the same effect as any executable program. 
    To run an unsigned script, use the Unblock-File cmdlet or use the 
    Following procedure. 
        1. Save the script file on your computer.  
        2. Click Start, click My Computer, and locate the saved script file.  
        3. Right-click the script file, and then click Properties.  
        4. Click Unblock. 
    If a script that was downloaded from the Internet is digitally signed, but 
    you have not yet chosen to trust its publisher, Windows PowerShell displays 
    the following message: 
        Do you want to run software from this untrusted publisher?  
        The file <file-name> is published by CN=<publisher-name>. This  
        publisher is not trusted on your system. Only run scripts 
        from trusted publishers. 
        [V] Never run  [D] Do not run  [R] Run once  [A] Always run   
        [?] Help (default is "D"): 
        If you trust the publisher, select "Run once" or "Always run."  
        If you do not trust the publisher, select either "Never run" or  
        "Do not run." If you select "Never run" or "Always run," Windows 
        PowerShell will not prompt you again for this publisher. 


    You can sign the scripts that you write and the scripts that you obtain  
    from other sources. Before you sign any script, examine each command 
    to verify that it is safe to run. 
    For best practices about code signing, see "Code-Signing 
    Best Practices" at http://go.microsoft.com/fwlink/?LinkId=119096.  
    For more information about how to sign a script file, see  
    The New-SelfSignedCertificate cmdlet, introduced in the PKI module 
    in Windows PowerShell 3.0, creates a self-signed certificate that is  
    Appropriate for testing. For more information, see the help 
    topic for the New-SelfSignedCertificate cmdlet. 
    To add a digital signature to a script, you must sign it with a code  
    signing certificate. Two types of certificates are suitable for signing 
    a script file:  
        -- Certificates that are created by a certification authority: 
           For a fee, a public certification authority verifies your 
           identity and gives you a code signing certificate.  When 
           you purchase your certificate from a reputable certification 
           authority, you are able to share your script with users 
           on other computers that are running Windows because those other 
           computers trust the certification authority. 
        -- Certificates that you create: 
           You can create a self-signed certificate for which 
           your computer is the authority that creates the certificate. 
           This certificate is free of charge and enables you to write, 
           sign, and run scripts on your computer. However, a script 
           signed by a self-signed certificate will not run on other 
    Typically, you would use a self-signed certificate only to sign  
    scripts that you write for your own use and to sign scripts that you get 
    from other sources that you have verified to be safe. It is not 
    appropriate for scripts that will be shared, even within an enterprise. 
    If you create a self-signed certificate, be sure to enable strong 
    private key protection on your certificate. This prevents malicious 
    programs from signing scripts on your behalf. The instructions are 
    included at the end of this topic. 


    To create a self-signed certificate in use the New-SelfSignedCertificate 
    cmdlet in the PKI module. This module is introduced in Windows PowerShell 
    3.0 and is included in Windows 8 and Windows Server 2012. For more  
    information, see the help topic for the New-SelfSignedCertificate cmdlet. 
    To create a self-signed certificate in earlier versions of Windows, use  
    the Certificate Creation tool (MakeCert.exe). This  tool is included in  
    the Microsoft .NET Framework SDK (versions 1.1 and later) and in the  
    Microsoft Windows SDK.  
    For more information about the syntax and the parameter descriptions of the 
    MakeCert.exe tool, see "Certificate Creation Tool (MakeCert.exe)" in the  
    MSDN (Microsoft Developer Network) library at  
    To use the MakeCert.exe tool to create a certificate, run the following  
    commands in an SDK Command Prompt window.  
    Note: The first command creates a local certification authority for 
          your computer. The second command generates a personal 
          certificate from the certification authority.  
    Note: You can copy or type the commands exactly as they appear. 
          No substitutions are necessary, although you can change the  
          certificate name.  
            makecert -n "CN=PowerShell Local Certificate Root" -a sha1 ` 
                -eku -r -sv root.pvk root.cer ` 
                -ss Root -sr localMachine 
            makecert -pe -n "CN=PowerShell User" -ss MY -a sha1 ` 
                -eku -iv root.pvk -ic root.cer 
    The MakeCert.exe tool will prompt you for a private key password. The  
    password ensures that no one can use or access the certificate without 
    your consent. Create and enter a password that you can remember. You will  
    use this password later to retrieve the certificate. 
    To verify that the certificate was generated correctly, use the 
    following command to get the certificate in the certificate 
    store on the computer. (You will not find a certificate file in the 
    file system directory.) 
    At the Windows PowerShell prompt, type: 
            get-childitem cert:\CurrentUser\my -codesigning 
    This command uses the Windows PowerShell Certificate provider to view 
    information about the certificate. 
    If the certificate was created, the output shows the thumbprint 
    that identifies the certificate in a display that resembles the following: 
        Directory: Microsoft.PowerShell.Security\Certificate::CurrentUser\My 
        Thumbprint                                Subject 
        ----------                                ------- 
        4D4917CB140714BA5B81B96E0B18AAF2C4564FDF  CN=PowerShell User ] 


    After you create a self-signed certificate, you can sign scripts. If you 
    use the AllSigned execution policy, signing a script permits you to run  
    the script on your computer.  
    The following sample script, Add-Signature.ps1, signs a script. However, 
    if you are using the AllSigned execution policy, you must sign the  
    Add-Signature.ps1 script before you run it. 
    To use this script, copy the following text into a text file, and 
    name it Add-Signature.ps1. 
    Note: Be sure that the script file does not have a .txt file name  
          extension. If your text editor appends ".txt", enclose the file name 
          in quotation marks: "add-signature.ps1". 
            ## add-signature.ps1 
            ## Signs a file 
            param([string] $file=$(throw "Please specify a filename.")) 
            $cert = @(Get-ChildItem cert:\CurrentUser\My -codesigning)[0] 
            Set-AuthenticodeSignature $file $cert 
    To sign the Add-Signature.ps1 script file, type the following commands at 
    the Windows PowerShell command prompt:  
        $cert = @(Get-ChildItem cert:\CurrentUser\My -codesigning)[0] 
        Set-AuthenticodeSignature add-signature.ps1 $cert 
    After the script is signed, you can run it on the local computer. 
    However, the script will not run on computers on which the Windows 
    PowerShell execution policy requires a digital signature from a 
    trusted authority. If you try, Windows PowerShell displays the following 
    error message: 
        The file C:\remote_file.ps1 cannot be loaded. The signature of the  
        certificate cannot be verified. 
        At line:1 char:15 
        + .\ remote_file.ps1 <<<< 
    If Windows PowerShell displays this message when you run a 
    script that you did not write, treat the file as you would treat any  
    unsigned script. Review the code to determine whether you can trust the 


    If you have a private certificate on your computer, malicious 
    programs might be able to sign scripts on your behalf, which 
    authorizes Windows PowerShell to run them.  
    To prevent automated signing on your behalf, use Certificate 
    Manager (Certmgr.exe) to export your signing certificate to 
    a .pfx file. Certificate Manager is included in the Microsoft 
    .NET Framework SDK, the Microsoft Windows SDK, and in Internet 
    Explorer 5.0 and later versions. 
    To export the certificate: 
        1. Start Certificate Manager. 
        2. Select the certificate issued by PowerShell Local Certificate Root. 
        3. Click Export to start the Certificate Export Wizard. 
        4. Select "Yes, export the private key", and then click Next. 
        5. Select "Enable strong protection." 
        6. Type a password, and then type it again to confirm. 
        7. Type a file name that has the .pfx file name extension. 
        8. Click Finish. 
    To re-import the certificate: 
        1. Start Certificate Manager. 
        2. Click Import to start the Certificate Import Wizard. 
        3. Open to the location of the .pfx file that you created during the 
           export process. 
        4. On the Password page, select "Enable strong private key protection", 
           and then enter the password that you assigned during the export  
        5. Select the Personal certificate store. 
        6. Click Finish. 


     The digital signature in a script is valid until the signing certificate 
     expires or as long as a time stamp server can verify that the script was 
     signed while the signing certificate was valid.  
     Because most signing certificates are valid for one year only, using a 
     time stamp server ensures that users can use your script for many years 
     to come.  


"Introduction to Code Signing" (http://go.microsoft.com/fwlink/?LinkId=106296)