Protect-CmsMessage

Encrypts content by using the Cryptographic Message Syntax format.
Protect-CmsMessage [-To*] <CmsMessageRecipient[]> [-Content*] <PSObject> [[-OutFile] <String>] [<CommonParameters>]
Protect-CmsMessage [-To*] <CmsMessageRecipient[]> [-LiteralPath*] <String> [[-OutFile] <String>] [<CommonParameters>]
Protect-CmsMessage [-To*] <CmsMessageRecipient[]> [-Path*] <String> [[-OutFile] <String>] [<CommonParameters>]

The Protect-CmsMessage cmdlet encrypts content by using the Cryptographic Message Syntax (CMS) format.

The CMS cmdlets support encryption and decryption of content using the IETF format as documented by RFC5652.

The CMS encryption standard uses public key cryptography, where the keys used to encrypt content (the public key) and the keys used to decrypt content (the private key) are separate. Your public key can be shared widely, and is not sensitive data. If any content is encrypted with this public key, only your private key can decrypt it. For more information about Public Key Cryptography, see http://en.wikipedia.org/wiki/Public-key_cryptography.

Before you can run the Protect-CmsMessage cmdlet, you must have an encryption certificate set up. To be recognized in Windows PowerShell, encryption certificates require a unique extended key usage (EKU) ID to identify them as data encryption certificates (such as the IDs for Code Signing and Encrypted Mail). For an example of a certificate that would work for document encryption, see Example 1 in this topic.

Parameters
-Content <PSObject>

  • This value is required
  • Accepts pipeline input ByValue

Specifies a PSObject that contains content that you want to encrypt. For example, you can encrypt the content of an event message, and then use the variable containing the message ($Event, in this example) as the value of the Content parameter: $event = Get-WinEvent -ProviderName “PowerShell” -MaxEvents 1. You can also use the Get-Content cmdlet to get the contents of a file, such as a Microsoft Word document, and save the content in a variable that you use as the value of the Content parameter.

-LiteralPath <String>

  • This value is required

Specifies the path to content that you want to encrypt. Unlike Path, the value of LiteralPath is used exactly as it is typed. No characters are interpreted as wildcards. If the path includes escape characters, enclose it in single quotation marks. Single quotation marks tell Windows PowerShell not to interpret any characters as escape sequences.

-OutFile <String>

Specifies the path and file name of a file to which you want to send the encrypted content.

-Path <String>

  • This value is required

Specifies the path to content that you want to encrypt.

-To <CmsMessageRecipient[]>

  • This value is required

Specifies one or more CMS message recipients, identified in any of the following formats.

— An actual certificate (as retrieved from the certificate provider). — Path to the file containing the certificate.– Path to a directory containing the certificate.– Thumbprint of the certificate (used to look in the certificate store).– Subject name of the certificate (used to look in the certificate store).

<CommonParameters>

This cmdlet supports the common parameters: Verbose, Debug,ErrorAction, ErrorVariable, WarningAction, WarningVariable,OutBuffer, PipelineVariable, and OutVariable.

Examples
  1. Create a certificate for encrypting content:
    PS C:> [Version]
    Signature = "$Windows NT$"
    
       [Strings]
       szOID_ENHANCED_KEY_USAGE = "2.5.29.37"
       szOID_DOCUMENT_ENCRYPTION = "1.3.6.1.4.1.311.80.1"
       [NewRequest]
       Subject = "cn=youralias@emailaddress.com"
       MachineKeySet = false
       KeyLength = 2048
       KeySpec = AT_KEYEXCHANGE
       HashAlgorithm = Sha1
       Exportable = true
       RequestType = Cert
       KeyUsage = "CERT_KEY_ENCIPHERMENT_KEY_USAGE | CERT_DATA_ENCIPHERMENT_KEY_USAGE"
       ValidityPeriod = "Years"
       ValidityPeriodUnits = "1000"
       [Extensions]
       %szOID_ENHANCED_KEY_USAGE% = "{text}%szOID_DOCUMENT_ENCRYPTION%"
       After you have created your certificate file, run the following command to add the certificate file to the 
       certificate store.Now you are ready to encrypt and decrypt content with the next two examples.
    
    PS C:> Certreq -new DocumentEncryption.inf DocumentEncryption.cer
    
       Before you can run the Protect-CmsMessage cmdlet, you must create an encryption certificate. Using the following 
       text, change the name in the Subject line to your name, email, or other identifier, and save the certificate in a 
       file (such as DocumentEncryption.inf, as shown in this example).
  2. Encrypt a message sent by email:
    PS C:> $Protected = "Hello World" | Protect-CmsMessage -To "*youralias@emailaddress.com*"
    
       In the following example, you encrypt a message, Hello World, by saving the message in a variable, and then piping 
       it to the Protect-CmsMessage cmdlet. The To parameter uses the value of the Subject line in the certificate.
  3. View document encryption certificates:
    PS C:> 58 [Cert:currentusermy]
    >> Get-ChildItem -DocumentEncryptionCert
    
       To view document encryption certificates in the certificate provider, you can add the DocumentEncryptionCert 
       dynamic parameter of Get-ChildItem, available only when the certificate provider is loaded.
Related Links

Get-CmsMessage
Unprotect-CmsMessage