functions/Get-DbaDbMasterKey.ps1

function Get-DbaDbMasterKey {
    <#
        .SYNOPSIS
            Gets specified database master key
 
        .DESCRIPTION
            Gets specified database master key
 
        .PARAMETER SqlInstance
            The target SQL Server instance
 
        .PARAMETER SqlCredential
            Allows you to login to SQL Server using alternative credentials
 
        .PARAMETER Database
            Get master key from specific database
 
        .PARAMETER ExcludeDatabase
            The database(s) to exclude - this list is auto-populated from the server
 
        .PARAMETER WhatIf
            Shows what would happen if the command were to run. No actions are actually performed
 
        .PARAMETER Confirm
            Prompts you for confirmation before executing any changing operations within the command
 
        .PARAMETER EnableException
            By default, when something goes wrong we try to catch it, interpret it and give you a friendly warning message.
            This avoids overwhelming you with "sea of red" exceptions, but is inconvenient because it basically disables advanced scripting.
            Using this switch turns this "nice by default" feature off and enables you to catch exceptions with your own try/catch.
 
        .NOTES
            Tags: Certificate, Database
            Author: Chrissy LeMaire (@cl), netnerds.net
 
            Website: https://dbatools.io
            Copyright: (C) Chrissy LeMaire, clemaire@gmail.com
            License: MIT https://opensource.org/licenses/MIT
 
        .EXAMPLE
            PS C:\> Get-DbaDbMasterKey -SqlInstance sql2016
 
            Gets all master database keys
 
        .EXAMPLE
            PS C:\> Get-DbaDbMasterKey -SqlInstance Server1 -Database db1
 
            Gets the master key for the db1 database
    #>

    [CmdletBinding()]
    param (
        [parameter(Mandatory, ValueFromPipeline)]
        [Alias("ServerInstance", "SqlServer")]
        [DbaInstanceParameter[]]$SqlInstance,
        [PSCredential]$SqlCredential,
        [object[]]$Database,
        [object[]]$ExcludeDatabase,
        [Alias('Silent')]
        [switch]$EnableException
    )

    process {
        foreach ($instance in $SqlInstance) {
            try {
                Write-Message -Level Verbose -Message "Connecting to $instance"
                $server = Connect-SqlInstance -SqlInstance $instance -SqlCredential $sqlcredential
            }
            catch {
                Stop-Function -Message "Failure" -Category ConnectionError -ErrorRecord $_ -Target $instance -Continue
            }

            $databases = $server.Databases | Where-Object IsAccessible

            if ($Database) {
                $databases = $databases | Where-Object Name -In $Database
            }
            if ($ExcludeDatabase) {
                $databases = $databases | Where-Object Name -NotIn $ExcludeDatabase
            }

            foreach ($db in $databases) {
                if (!$db.IsAccessible) {
                    Write-Message -Level Warning -Message "Database $db is not accessible. Skipping."
                    continue
                }

                $masterkey = $db.MasterKey

                if (!$masterkey) {
                    Write-Message -Message "No master key exists in the $db database on $instance" -Target $db -Level Verbose
                    continue
                }

                Add-Member -Force -InputObject $masterkey -MemberType NoteProperty -Name ComputerName -value $server.ComputerName
                Add-Member -Force -InputObject $masterkey -MemberType NoteProperty -Name InstanceName -value $server.ServiceName
                Add-Member -Force -InputObject $masterkey -MemberType NoteProperty -Name SqlInstance -value $server.DomainInstanceName
                Add-Member -Force -InputObject $masterkey -MemberType NoteProperty -Name Database -value $db.Name

                Select-DefaultView -InputObject $masterkey -Property ComputerName, InstanceName, SqlInstance, Database, CreateDate, DateLastModified, IsEncryptedByServer
            }
        }
    }
    end {
        Test-DbaDeprecation -DeprecatedOn "1.0.0" -EnableException:$false -Alias Get-DbaDatabaseMasterKey
    }
}