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) } }