Private/ConvertFrom-EncryptedBin.ps1
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function ConvertFrom-EncryptedBin { [CmdletBinding(SupportsShouldProcess, DefaultParameterSetName = "SomethingFromPipeline")] param( [Parameter(Mandatory)] [String]$Key, [Parameter(Mandatory, ValueFromPipeline, ParameterSetName="FromFile")] [String]$FileIn, [Parameter(Mandatory, ParameterSetName="FromFile")] [String]$FileOut, [Parameter(Mandatory, ValueFromPipeline, ParameterSetName="FromString")] [String]$String ) process { $Csp = [System.Security.Cryptography.AesCryptoServiceProvider]::New() $Csp.Padding = [System.Security.Cryptography.PaddingMode]::PKCS7 $Csp.Mode = [System.Security.Cryptography.CipherMode]::CBC $Csp.BlockSize = 128 $Csp.KeySize = 256 $SHA256 = [System.Security.Cryptography.SHA256]::Create() $KeySha = $SHA256.ComputeHash([System.Text.ASCIIEncoding]::UTF8.GetBytes($Key)) if($PsCmdlet.ParameterSetName -eq "FromString"){ $MemoryStream = ConvertTo-MemoryStream -String $String -FromBase64 $IV = New-Object byte[] 16 $MemoryStream.Read($IV, 0, $IV.Length) | Out-Null $Decryptor = $Csp.CreateDecryptor($KeySha,$IV) $CryptoStream = [System.Security.Cryptography.CryptoStream]::New($MemoryStream, $Decryptor, [System.Security.Cryptography.CryptoStreamMode]::Read) $Bytes = @() do { try { $Byte = $CryptoStream.ReadByte() } catch { Throw "Failed to decrypt, password may be incorrect" } if($Byte -ne -1){ $Bytes += $Byte } } while ($Byte -ne -1) $MemoryStream.Dispose() $CryptoStream.Dispose() [System.Text.Encoding]::UTF8.GetString($Bytes) } if($PsCmdlet.ParameterSetName -eq "FromFile"){ if($PSCmdlet.ShouldProcess($FileOut, "WriteByte")){ $FileInStream = [System.IO.FileStream]::New($FileIn,[System.IO.FileMode]::Open) $FileOutStream = [System.IO.FileStream]::new($FileOut,[System.IO.FileMode]::Create) $IV = New-Object byte[] 16 $FileInStream.Read($IV, 0, $IV.Length) $Decryptor = $Csp.CreateDecryptor($KeySha,$IV) $CryptoStream = [System.Security.Cryptography.CryptoStream]::New($FileInStream, $Decryptor, [System.Security.Cryptography.CryptoStreamMode]::Read) $ApproxSize = (Get-Item $FileIn).Length Write-Progress -Activity $FileOut -Status "Decrypting" -PercentComplete 0 $n = 0 $Completed = $False try { do { try { $Byte = $CryptoStream.ReadByte() } catch { Throw "Decryption failed" } if($Byte -ne -1){ $FileOutStream.WriteByte($Byte) $n++ } if(($n % 102400) -eq 0){ $CurrentSize = (Get-Item $FileOut).Length if($ApproxSize -gt 0){ $PercentComplete = [Math]::Round(((1 - ($ApproxSize - $CurrentSize)/$ApproxSize) * 100), 1) Write-Progress -Activity $FileOut -Status "Decrypting $PercentComplete%" -PercentComplete $PercentComplete } } } while ($Byte -ne -1) $Completed = $True } finally { if(-not $Completed){ Remove-Item $FileOut Throw "Decryption failed" } } $FileInStream.Dispose() $FileOutStream.Dispose() $CryptoStream.Dispose() } } } } |