DSC Syntax for Binary Registry Key

The format of the DSC MSFT_Registry Binary type ValueData is a string with contiguous pairs of byte values, with an optional leading "0x"

The trick is this bit of code from the resource in $env:windir\Windows\System32\WindowsPowerShell\v1.0\Modules\PSDesiredStateConfiguration\DSCResources\MSFT_Registry.psm1.

It parses the value with:

    $binaryVal = $null
    $val = $Data[0].TrimStart("0x")
    if ($val.Length % 2 -ne 0)
    {
        $val = $val.PadLeft($val.Length+1, "0")
    }

    try
    {
        $byteArray = [Byte[]]@()

        for ($i = 0 ; $i -lt ($val.Length-1) ; $i = $i+2)
        {
            $byteArray += [Byte]::Parse($val.Substring($i, 2), "HexNumber")                                    
        }

        $ReturnValue.Value = [Byte[]]$byteArray
    }

Example

Using a slight variation on your input data:

$reg = "01,00,04,80,64,00,00,00,70,00,00,00,00,00,00,00,
  14,00,00,00,02,00,50,00,03,00,00,00,00,00,18,00,03,00,0f,00,01,02,00,00,00,
  00,00,05,20,00,00,00,20,02,00,00,00,00,18,00,03,00,0f,00,01,02,00,00,00,00,
  00,05,20,00,00,00,25,02,00,00,00,00,18,00,03,00,0f,00,01,02,00,00,00,00,00,
  05,20,00,00,00,27,02,00,00,01,01,00,00,00,00,00,05,12,00,00,00,01,01,00,00,
  00,00,00,05,12,00,00,00"

You can create a properly formatted string with this:

$val = [String]::Join("",$reg.Split(",").Trim())

In the MOF, you'll see this:

 ValueData = {
    "010004806400000070000000000000001400000002005000030000000000180003000f00010200000000000520000000200200000000180003000f00010200000000000520000000250200000000180003000f0001020000000000052000000027020000010100000000000512000000010100000000000512000000"
};

Here's an entire test sample to prove the point:

   $reg = "01,00,04,80,64,00,00,00,70,00,00,00,00,00,00,00,
  14,00,00,00,02,00,50,00,03,00,00,00,00,00,18,00,03,00,0f,00,01,02,00,00,00,
  00,00,05,20,00,00,00,20,02,00,00,00,00,18,00,03,00,0f,00,01,02,00,00,00,00,
  00,05,20,00,00,00,25,02,00,00,00,00,18,00,03,00,0f,00,01,02,00,00,00,00,00,
  05,20,00,00,00,27,02,00,00,01,01,00,00,00,00,00,05,12,00,00,00,01,01,00,00,
  00,00,00,05,12,00,00,00"

$val = [String]::Join("",$reg.Split(",").Trim())

Configuration RegistryTest
{
    param([string] $Path, [string] $Name, [string] $BinaryValue)

    Import-DscResource -ModuleName PSDesiredStateConfiguration    
    Registry test
    {
        Key = $Path
        ValueName = $Name
        ValueData = $val
        ValueType = "Binary"
    }
}

$args = @{ 
    Path = "HKLM:\SOFTWARE\StackOverflow"
    Name = "BinaryTest"
}

Remove-ItemProperty @args
Get-ItemProperty @args -ErrorAction Continue # Nothing up my sleeve!
$o = RegistryTest @args -BinaryValue $val -outputpath $env:temp
Start-DscConfiguration ($o | split-path) -Wait -Verbose -force
Get-ItemProperty @args

That results in the following output:

Get-ItemProperty : Property BinaryTest does not exist at path 
HKEY_LOCAL_MACHINE\SOFTWARE\StackOverflow.
At C:\scratch\test.ps1:30 char:1
+ Get-ItemProperty @args -ErrorAction Continue # Nothing up my sleeve!
+ ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
    + CategoryInfo          : InvalidArgument: (BinaryTest:String) [Get-ItemProperty], PSArgu 
   mentException
    + FullyQualifiedErrorId : System.Management.Automation.PSArgumentException,Microsoft.Powe 
   rShell.Commands.GetItemPropertyCommand

VERBOSE: Perform operation 'Invoke CimMethod' with following parameters, ''methodName' = SendCo
nfigurationApply,'className' = MSFT_DSCLocalConfigurationManager,'namespaceName' = root/Microso
ft/Windows/DesiredStateConfiguration'.
VERBOSE: An LCM method call arrived from computer STACKOVERFLOW with user sid S-...
VERBOSE: [STACKOVERFLOW]: LCM:  [ Start  Set      ]
VERBOSE: [STACKOVERFLOW]: LCM:  [ Start  Resource ]  [[Registry]test]
VERBOSE: [STACKOVERFLOW]: LCM:  [ Start  Test     ]  [[Registry]test]
VERBOSE: [STACKOVERFLOW]:                            [[Registry]test] Registry key value 'HKLM:\SOFTW
ARE\StackOverflow\BinaryTest' does not exist
VERBOSE: [STACKOVERFLOW]: LCM:  [ End    Test     ]  [[Registry]test]  in 0.2130 seconds.
VERBOSE: [STACKOVERFLOW]: LCM:  [ Start  Set      ]  [[Registry]test]
VERBOSE: [STACKOVERFLOW]:                            [[Registry]test] (SET) Set registry key value 'H
KLM:\SOFTWARE\StackOverflow\BinaryTest' to '(1, 0, 4, 128, 100, 0, 0, 0, 112, 0, 0, 0, 0, 0, 0,
 0, 20, 0, 0, 0, 2, 0, 80, 0, 3, 0, 0, 0, 0, 0, 24, 0, 3, 0, 15, 0, 1, 2, 0, 0, 0, 0, 0, 5, 32,
 0, 0, 0, 32, 2, 0, 0, 0, 0, 24, 0, 3, 0, 15, 0, 1, 2, 0, 0, 0, 0, 0, 5, 32, 0, 0, 0, 37, 2, 0,
 0, 0, 0, 24, 0, 3, 0, 15, 0, 1, 2, 0, 0, 0, 0, 0, 5, 32, 0, 0, 0, 39, 2, 0, 0, 1, 1, 0, 0, 0, 
0, 0, 5, 18, 0, 0, 0, 1, 1, 0, 0, 0, 0, 0, 5, 18, 0, 0, 0)' of type 'Binary'
VERBOSE: [STACKOVERFLOW]: LCM:  [ End    Set      ]  [[Registry]test]  in 0.1390 seconds.
VERBOSE: [STACKOVERFLOW]: LCM:  [ End    Resource ]  [[Registry]test]
VERBOSE: [STACKOVERFLOW]: LCM:  [ End    Set      ]
VERBOSE: [STACKOVERFLOW]: LCM:  [ End    Set      ]    in  0.7010 seconds.
VERBOSE: Operation 'Invoke CimMethod' complete.
VERBOSE: Time taken for configuration job to complete is 0.799 seconds


BinaryTest   : {1, 0, 4, 128...}
PSPath       : Microsoft.PowerShell.Core\Registry::HKEY_LOCAL_MACHINE\SOFTWARE\StackOverflow
PSParentPath : Microsoft.PowerShell.Core\Registry::HKEY_LOCAL_MACHINE\SOFTWARE
PSChildName  : StackOverflow
PSDrive      : HKLM
PSProvider   : Microsoft.PowerShell.Core\Registry

Looking at both a Server 2016 and a Windows 10 machine where I ran this, the registry looks correct.