I'm mainly posting this for anyone else that needs it since there seems to be a great lack of resources on the internet for this. The samples I did find seemed hobbled together at best and never worked for me. If you see or find anything wrong with this class, I'd love to know. Note that this class is slightly modified for my particular implementation but should work fine against version 1.7 of the Bouncy Castle .Net source code.
Imports System.IO
Imports Org.BouncyCastle.Bcpg.OpenPgp
Public Class PgpDecrypt
Private _mPublicKeyPath As String = "C:\MyPgpKeys\MyKey - Public.asc"
Private _mPrivateKeyPath As String = "C:\MyPgpKeys\MyKey - Private.asc"
Private _mPassPhrase As String = "<passwoid>"
Public Function Decrypt(ByVal srcPath As String, ByVal dstPath As String) As Boolean
Dim stEnc As Stream = PgpUtilities.GetDecoderStream(File.OpenRead(srcPath))
Dim pof As New PgpObjectFactory(stEnc)
Dim pked As PgpPublicKeyEncryptedData = Nothing
Dim keyPrivate As PgpPrivateKey = Nothing
For Each pked In GetEncryptedDataList(pof).GetEncryptedDataObjects
keyPrivate = ReadPrivateKey(pked.KeyId)
If Not keyPrivate Is Nothing Then Exit For
Next
If keyPrivate Is Nothing Then Return False
Dim stDec As Stream = pked.GetDataStream(keyPrivate)
pof = New PgpObjectFactory(stDec)
Dim o As PgpObject = pof.NextPgpObject
If TypeOf o Is PgpCompressedData Then
pof = New PgpObjectFactory(DirectCast(o, PgpCompressedData).GetDataStream)
o = pof.NextPgpObject
End If
While Not TypeOf o Is PgpLiteralData
o = pof.NextPgpObject
If o Is Nothing Then Return False
End While
Dim ld As PgpLiteralData = DirectCast(o, PgpLiteralData)
Dim stOut As Stream = File.Create(dstPath)
Dim stUnc As Stream = ld.GetInputStream
Org.BouncyCastle.OpenPgp.Utilities.IO.Streams.PipeAll(stUnc, stOut)
stOut.Close()
Return True
End Function
Private Function GetEncryptedDataList(ByVal pof As PgpObjectFactory) As PgpEncryptedDataList
Dim o As PgpObject = Nothing
While Not TypeOf o Is PgpEncryptedDataList
o = pof.NextPgpObject
If o Is Nothing Then Return Nothing
End While
Return DirectCast(o, PgpEncryptedDataList)
End Function
Private Function ReadPublicKey(Optional ByVal useEmbedded As Boolean = False) As PgpPublicKey
If useEmbedded Then
Using st As Stream = Reflection.Assembly.GetExecutingAssembly.GetManifestResourceStream(GetAssemblyName() & ".MyKey - Public.asc")
Dim bundle As PgpSecretKeyRingBundle = New PgpSecretKeyRingBundle(PgpUtilities.GetDecoderStream(st))
For Each ring As PgpPublicKeyRing In bundle.GetKeyRings
For Each key As PgpPublicKey In ring.GetPublicKeys
If key.IsEncryptionKey Then Return key
Next
Next
End Using
Else
Using st As Stream = File.OpenRead(_mPublicKeyPath)
Dim bundle As PgpPublicKeyRingBundle = New PgpPublicKeyRingBundle(PgpUtilities.GetDecoderStream(st))
For Each ring As PgpPublicKeyRing In bundle.GetKeyRings
For Each key As PgpPublicKey In ring.GetPublicKeys
If key.IsEncryptionKey Then Return key
Next
Next
End Using
End If
Return Nothing
End Function
Private Function ReadSecretKey(Optional ByVal useEmbedded As Boolean = False) As PgpSecretKey
If useEmbedded Then
Using st As Stream = Reflection.Assembly.GetExecutingAssembly.GetManifestResourceStream(GetAssemblyName() & ".MyKey - Private.asc")
Dim bundle As PgpSecretKeyRingBundle = New PgpSecretKeyRingBundle(PgpUtilities.GetDecoderStream(st))
For Each ring As PgpSecretKeyRing In bundle.GetKeyRings
For Each key As PgpSecretKey In ring.GetSecretKeys
If key.IsSigningKey Then Return key
Next
Next
End Using
Else
Using st As Stream = File.OpenRead(_mPrivateKeyPath)
Dim bundle As PgpSecretKeyRingBundle = New PgpSecretKeyRingBundle(PgpUtilities.GetDecoderStream(st))
For Each ring As PgpSecretKeyRing In bundle.GetKeyRings
For Each key As PgpSecretKey In ring.GetSecretKeys
If key.IsSigningKey Then Return key
Next
Next
End Using
End If
Return Nothing
End Function
Private Function ReadPrivateKey(ByVal keyId As Long, Optional ByVal useEmbedded As Boolean = False) As PgpPrivateKey
If useEmbedded Then
Using st As Stream = Reflection.Assembly.GetExecutingAssembly.GetManifestResourceStream(GetAssemblyName() & ".MyKey - Private.asc")
Dim bundle As PgpSecretKeyRingBundle = New PgpSecretKeyRingBundle(PgpUtilities.GetDecoderStream(st))
Dim key As PgpSecretKey = bundle.GetSecretKey(keyId)
If key Is Nothing Then Return Nothing
Return key.ExtractPrivateKey(_mPassPhrase)
End Using
Else
Using st As Stream = File.OpenRead(_mPrivateKeyPath)
Dim bundle As PgpSecretKeyRingBundle = New PgpSecretKeyRingBundle(PgpUtilities.GetDecoderStream(st))
Dim key As PgpSecretKey = bundle.GetSecretKey(keyId)
If key Is Nothing Then Return Nothing
Return key.ExtractPrivateKey(_mPassPhrase)
End Using
End If
End Function
Private Function GetAssemblyName() As String
Dim names() As String = Reflection.Assembly.GetExecutingAssembly.GetManifestResourceNames
If names.Length > 0 Then
Return names(0).Split(".").First
Else
Return String.Empty
End If
End Function
End Class
