PowerShell compression \ decompression. I manage to get 50% decreasse on a small input stream.

comp_decomp.ps1

Compression:
$s = @'YourInputHere"@
$ms = New-Object System.IO.MemoryStream
$cs = New-Object System.IO.Compression.GZipStream($ms, [System.IO.Compression.CompressionMode]::Compress)
$sw = New-Object System.IO.StreamWriter($cs)
$sw.Write($s)
$sw.Close();
$s = [System.Convert]::ToBase64String($ms.ToArray())

Decompression:
$data = [System.Convert]::FromBase64String("CompressedBase64StreamHere")
$ms = New-Object System.IO.MemoryStream
$ms.Write($data, 0, $data.Length)
$ms.Seek(0,0) | Out-Null
$sr = New-Object System.IO.StreamReader(New-Object System.IO.Compression.GZipStream($ms, [System.IO.Compression.CompressionMode]::Decompress))