Add symmetric OpenPGP encryption

asink/client.go

@@ -31,6 +31,8 @@ type AsinkGlobals struct {
 	port           int
 	username       string
 	password       string
+	encrypted      bool
+	key            string
 }
 
 var globals AsinkGlobals
@@ -99,6 +101,12 @@ func StartClient(args []string) {
 	globals.username, err = config.GetString("server", "username")
 	globals.password, err = config.GetString("server", "password")
 
+	//TODO check errors on encryption settings
+	globals.encrypted, err = config.GetBool("encryption", "enabled")
+	if globals.encrypted {
+		globals.key, err = config.GetString("encryption", "key")
+	}
+
 	globals.db, err = GetAndInitDB(config)
 	if err != nil {
 		panic(err)
@@ -209,15 +217,28 @@ func ProcessLocalEvent(globals AsinkGlobals, event *asink.Event) {
 			if err != nil {
 				panic(err)
 			}
-			defer uploadWriteCloser.Close()
 
 			uploadFile, err := os.Open(cachedFilename)
 			if err != nil {
+				uploadWriteCloser.Close()
 				panic(err)
 			}
-			defer uploadFile.Close()
 
-			_, err = io.Copy(uploadWriteCloser, uploadFile)
+			if globals.encrypted {
+				encrypter, err := NewEncrypter(uploadWriteCloser, globals.key)
+				if err != nil {
+					uploadWriteCloser.Close()
+					uploadFile.Close()
+					panic(err)
+				}
+				_, err = io.Copy(encrypter, uploadFile)
+				encrypter.Close()
+			} else {
+				_, err = io.Copy(uploadWriteCloser, uploadFile)
+			}
+			uploadFile.Close()
+			uploadWriteCloser.Close()
+
 			StatStopUpload()
 			if err != nil {
 				panic(err)
@@ -289,7 +310,15 @@ func ProcessRemoteEvent(globals AsinkGlobals, event *asink.Event) {
 				panic(err)
 			}
 			defer downloadReadCloser.Close()
-			_, err = io.Copy(outfile, downloadReadCloser)
+			if globals.encrypted {
+				decrypter, err := NewDecrypter(downloadReadCloser, globals.key)
+				if err != nil {
+					panic(err)
+				}
+				_, err = io.Copy(outfile, decrypter)
+			} else {
+				_, err = io.Copy(outfile, downloadReadCloser)
+			}
 
 			outfile.Close()
 			StatStopDownload()

asink/encryption.go

@@ -0,0 +1,38 @@
+/*
+ Copyright (C) 2013 Aaron Lindsay <aaron@aclindsay.com>
+*/
+
+package main
+
+import (
+	"code.google.com/p/go.crypto/openpgp"
+	"io"
+)
+
+func NewEncrypter(writer io.WriteCloser, key string) (plaintextWriter io.WriteCloser, err error) {
+	return openpgp.SymmetricallyEncrypt(writer, []byte(key), nil, nil)
+}
+
+type Decrypter struct {
+	details *openpgp.MessageDetails
+}
+
+func NewDecrypter(ciphertextReader io.ReadCloser, key string) (decrypter io.Reader, err error) {
+	prompt := func(keys []openpgp.Key, symmetric bool) ([]byte, error) {
+		return []byte(key), nil
+	}
+
+	details, err := openpgp.ReadMessage(ciphertextReader, nil, prompt, nil)
+	if err != nil {
+		decrypter = nil
+		return
+	}
+
+	decrypter = Decrypter{details}
+
+	return
+}
+
+func (d Decrypter) Read(p []byte) (n int, err error) {
+	return d.details.UnverifiedBody.Read(p)
+}