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authorJakob Unterwurzacher2016-05-01 22:26:47 +0200
committerJakob Unterwurzacher2016-05-04 19:56:07 +0200
commitc92190bf07d27a4c7fbecba5778d11c77c52574e (patch)
tree0e6cfeaeb2580d3b20e90d056881432b7f61a293 /internal/stupidgcm/stupidgcm_test.go
parent1bb907b38e1fefdfb4ad66f1d423a607477deb3c (diff)
stupidgcm: add our own thin wrapper around openssl gcm
...complete with tests and benchmark. This will allow us to get rid of the dependency to spacemonkeygo/openssl that causes problems on Arch Linux ( https://github.com/rfjakob/gocryptfs/issues/21 )
Diffstat (limited to 'internal/stupidgcm/stupidgcm_test.go')
-rw-r--r--internal/stupidgcm/stupidgcm_test.go154
1 files changed, 154 insertions, 0 deletions
diff --git a/internal/stupidgcm/stupidgcm_test.go b/internal/stupidgcm/stupidgcm_test.go
new file mode 100644
index 0000000..dfd495d
--- /dev/null
+++ b/internal/stupidgcm/stupidgcm_test.go
@@ -0,0 +1,154 @@
+package stupidgcm
+
+import (
+ "bytes"
+ "crypto/aes"
+ "crypto/cipher"
+ "crypto/rand"
+ "encoding/hex"
+ "testing"
+)
+
+// Get "n" random bytes from /dev/urandom or panic
+func randBytes(n int) []byte {
+ b := make([]byte, n)
+ _, err := rand.Read(b)
+ if err != nil {
+ panic("Failed to read random bytes: " + err.Error())
+ }
+ return b
+}
+
+// TestEncryptDecrypt encrypts and decrypts using both stupidgcm and Go's built-in
+// GCM implemenatation and verifies that the results are identical.
+func TestEncryptDecrypt(t *testing.T) {
+ key := randBytes(32)
+ sGCM := New(key)
+ authData := randBytes(24)
+ iv := randBytes(16)
+ dst := make([]byte, 71) // 71 = random length
+
+ gAES, err := aes.NewCipher(key)
+ if err != nil {
+ t.Fatal(err)
+ }
+ gGCM, err := cipher.NewGCMWithNonceSize(gAES, 16)
+ if err != nil {
+ t.Fatal(err)
+ }
+
+ // Check all block sizes from 1 to 5000
+ for i := 1; i < 5000; i++ {
+ in := make([]byte, i)
+
+ sOut := sGCM.Seal(dst, iv, in, authData)
+ gOut := gGCM.Seal(dst, iv, in, authData)
+
+ // Ciphertext must be identical to Go GCM
+ if bytes.Compare(sOut, gOut) != 0 {
+ t.Fatalf("Compare failed for encryption, size %d", i)
+ t.Log("sOut:")
+ t.Log("\n" + hex.Dump(sOut))
+ t.Log("gOut:")
+ t.Log("\n" + hex.Dump(gOut))
+ }
+
+ sOut2, sErr := sGCM.Open(dst, iv, sOut[len(dst):], authData)
+ if sErr != nil {
+ t.Fatal(sErr)
+ }
+ gOut2, gErr := gGCM.Open(dst, iv, gOut[len(dst):], authData)
+ if gErr != nil {
+ t.Fatal(gErr)
+ }
+
+ // Plaintext must be identical to Go GCM
+ if bytes.Compare(sOut2, gOut2) != 0 {
+ t.Fatalf("Compare failed for decryption, size %d", i)
+ }
+ }
+}
+
+// TestCorruption verifies that changes in the ciphertext result in a decryption
+// error
+func TestCorruption(t *testing.T) {
+ key := randBytes(32)
+ sGCM := New(key)
+ authData := randBytes(24)
+ iv := randBytes(16)
+
+ in := make([]byte, 354)
+ sOut := sGCM.Seal(nil, iv, in, authData)
+ sOut2, sErr := sGCM.Open(nil, iv, sOut, authData)
+ if sErr != nil {
+ t.Fatal(sErr)
+ }
+ if bytes.Compare(in, sOut2) != 0 {
+ t.Fatalf("Compare failed")
+ }
+
+ // Corrupt first byte
+ sOut[0]++
+ sOut2, sErr = sGCM.Open(nil, iv, sOut, authData)
+ if sErr == nil || sOut2 != nil {
+ t.Fatalf("Should have gotten error")
+ }
+ sOut[0]--
+
+ // Corrupt last byte
+ sOut[len(sOut)-1]++
+ sOut2, sErr = sGCM.Open(nil, iv, sOut, authData)
+ if sErr == nil || sOut2 != nil {
+ t.Fatalf("Should have gotten error")
+ }
+ sOut[len(sOut)-1]--
+
+ // Append one byte
+ sOut = append(sOut, 0)
+ sOut2, sErr = sGCM.Open(nil, iv, sOut, authData)
+ if sErr == nil || sOut2 != nil {
+ t.Fatalf("Should have gotten error")
+ }
+}
+
+// $ go test -bench .
+// PASS
+// Benchmark4kEncStupidGCM-2 50000 25622 ns/op 159.86 MB/s
+// Benchmark4kEncGoGCM-2 10000 116544 ns/op 35.15 MB/s
+// ok github.com/rfjakob/gocryptfs/internal/stupidgcm 3.775s
+func Benchmark4kEncStupidGCM(b *testing.B) {
+ key := randBytes(32)
+ authData := randBytes(24)
+ iv := randBytes(16)
+ in := make([]byte, 4096)
+ b.SetBytes(int64(len(in)))
+
+ sGCM := New(key)
+
+ for i := 0; i < b.N; i++ {
+ // Encrypt and append to nonce
+ sGCM.Seal(iv, iv, in, authData)
+ }
+}
+
+func Benchmark4kEncGoGCM(b *testing.B) {
+ key := randBytes(32)
+ authData := randBytes(24)
+ iv := randBytes(16)
+ in := make([]byte, 4096)
+ b.SetBytes(int64(len(in)))
+
+ gAES, err := aes.NewCipher(key)
+ if err != nil {
+ b.Fatal(err)
+ }
+ gGCM, err := cipher.NewGCMWithNonceSize(gAES, 16)
+ if err != nil {
+ b.Fatal(err)
+ }
+
+ for i := 0; i < b.N; i++ {
+ // Encrypt and append to nonce
+ gGCM.Seal(iv, iv, in, authData)
+ }
+}