EnvelopedData.Decrypt method

Article
03/22/2021

[CAPICOM is a 32-bit only component that is available for use in the following operating systems: Windows Server 2008, Windows Vista, and Windows XP. Instead, use the EnvelopedCms Class in the System.Security.Cryptography.Pkcs namespace.]

The Decrypt method decrypts enveloped content. Decryption is done if the recipient of the message has access to the private key paired with one of the public keys used to envelop the message. Calling the Decrypt method resets the state of the object. If the Decrypt method succeeds, the Content property of the EnvelopedData object is set to the plaintext message.

Syntax

EnvelopedData.Decrypt( _
  ByVal EnvelopedMessage _
)

Parameters

EnvelopedMessage [in]: String that contains the enveloped data to be decrypted.

Return value

This method does not return a value.

Remarks

The decrypted data becomes the Content property value for the EnvelopedData object.

If the user of this method does not have access to a private key that matches one of the public keys used to envelop the message, the method fails. This method will fail if the certificate for the associated private key is not in either the local computer MY store or the current user MY store.

Important

When this method is called from a web script, the script needs to use your private key to decrypt the data. Allowing untrusted websites to use your private key is a security risk. A dialog box that asks whether the website can use your private key appears when this method is first called. If you allow the script to use your private key and select "Do not ask me this again," the dialog box will no longer appear for any script that uses your private key to decrypt data within that domain. However, scripts outside that domain that attempt to use your private key to decrypt data will still cause this dialog box to appear. If you do not allow the script to use your private key and select "Do not ask me this again," scripts within that domain will automatically be refused the ability to use your private key to decrypt data.

Requirements

Requirement	Value
End of client support	Windows Vista
End of server support	Windows Server 2008
Redistributable	CAPICOM 2.0 or later on Windows Server 2003 and Windows XP
DLL	Capicom.dll