Get-Credential

Get a security credential object based on a user name and password.

Syntax
      Get-Credential [-credential] PSCredential [CommonParameters]

key
   -credential 
       A user name e.g."User01" or "Domain01\User01"

   CommonParameters:
       -Verbose, -Debug, -ErrorAction, -ErrorVariable, -WarningAction, -WarningVariable,
       -OutBuffer -OutVariable.

When you enter the command, you will be prompted for a password.
If you omit PSCredential, you will be prompted for a user name and a password.

PowerShell can store passwords in 3 different forms:

String - Plain text strings are stored in memory as unsecure plain text and most cmdlets will not accept passwords in this form.

SecureString - This type is encrypted in memory. It uses reversible encryption so the password can be decrypted when needed, but only by the same user principal that encrypted it. [System.Security.SecureString]
A SecureString can be read in from the terminal with Read-Host -AsSecureString

PSCredential - This class is composed of username (string) plus a password (SecureString). This is the type that most cmdlets require for specifying credentials. [System.Management.Automation.PSCredential]

Whenever possible do not ask users for a password, use integrated Windows authentication instead.
Passwords should not be saved to disk or the registry as plain text. Use a plaintext representation of SecureString.

Examples

Get a credential and save into a variable:

PS C:\> $ss64Cred = Get-Credential

Use this credential (stored in the variable $ss64Cred) to run a Get-WmiObject command:

PS C:\> Get-WmiObject Win32_DiskDrive -ComputerName Server64 -Credential $ss64Cred

An alternative is to embed the Get-Credential cmdlet in an expression:

PS C:\> Get-WmiObject Win32_DiskDrive -ComputerName Server64 -Credential (get-credential Domain01\User64)

Create PSCredentials for the user (user64) with the (SecureString) password held in the variable $sec_password:

$UserName = "Domain\User64"
$Credentials = New-Object System.Management.Automation.PSCredential `
    -ArgumentList $UserName, $sec_password

Display the password from a PSCredential object using the GetNetworkCredential() method:

PS C:\> $PlainPassword = $Credentials.GetNetworkCredential().Password

#Please allow me to introduce myself I'm a man of wealth and taste# ~ The Rolling Stones

Related PowerShell Cmdlets:

ConvertFrom-SecureString - Convert a secure string into an encrypted standard string.
ConvertTo-SecureString - Convert an encrypted standard string into a secure string.
Get-AuthenticodeSignature - Get the signature object associated with a file.