libgocryptfs/README.md
2015-09-06 13:13:47 +02:00

2.0 KiB

GoCryptFS

A minimal encrypted overlay filesystem written in Go.

Built on top of the native Go FUSE library bazil.org/fuse and the ClueFS loopback file system.

Inspired by EncFS.

Design

  • Authenticated encryption of file contents using AES-GCM-128
  • Because GCM handles blocks of arbitrary size, there is no special handling for the last file block
  • 4096 byte blocks per default
  • 28 bytes of overhead per block (16 bytes auth tag, 12 byte nonce)
  • uses openssl through spacemonkeygo/openssl for a 3x speedup compared to crypto/cipher (see go-vs-openssl.md) for details
  • Per-write unique 96 bit nonces
  • starts from a random value (generated at mount time) and counts up
  • Flename encryption using AES-CBC-128
  • Padded to 16-byte blocks acc. to RFC5652 section 6.3
  • base64 encoded acc. to RFC4648 section 5

Current Status

Not ready for anything but testing and debugging

  • File and directory creation and deletion works
  • Thread-safe nonce generation works
  • Filename and content encryption works
  • Key is set to static all-zero
  • Reading and writing works
  • Streaming performance is already reasonable
  • But we should be able to get another 50% speedup
  • Symlinks and hard links not yet implemented
  • Memory usage is insane

Install

go get github.com/rfjakob/gocryptfs

Testing

Run ./main_benchmark.bash to run the test suite and the streaming read/write benchmark.

The output should look like this:

$ ./main_benchmark.bash
+ go build
+ go test -bench=.
PASS
BenchmarkStreamWrite	     100	  14062281 ns/op	  74.57 MB/s
BenchmarkStreamRead 	     100	  11267741 ns/op	  93.06 MB/s
ok  	github.com/rfjakob/gocryptfs	7.569s