diff --git a/crypto/AEAD.go b/crypto/AEAD.go
index d68041796..f92b90b42 100644
--- a/crypto/AEAD.go
+++ b/crypto/AEAD.go
@@ -1,8 +1,11 @@
 package crypto
 
-import "io"
+import (
+	"bytes"
+	"io"
+)
 
 // An AEAD implements QUIC's authenticated encryption and associated data
 type AEAD interface {
-	Open(associatedData []byte, ciphertext io.Reader) (io.Reader, error)
+	Open(associatedData []byte, ciphertext io.Reader) (*bytes.Reader, error)
 }
diff --git a/crypto/NullAEAD.go b/crypto/NullAEAD.go
index 90c34b3e0..7b726ac34 100644
--- a/crypto/NullAEAD.go
+++ b/crypto/NullAEAD.go
@@ -14,7 +14,7 @@ type NullAEAD struct{}
 var _ AEAD = &NullAEAD{}
 
 // Open and verify the ciphertext
-func (*NullAEAD) Open(associatedData []byte, r io.Reader) (io.Reader, error) {
+func (*NullAEAD) Open(associatedData []byte, r io.Reader) (*bytes.Reader, error) {
 	ciphertext, err := ioutil.ReadAll(r)
 	if err != nil {
 		return nil, err
diff --git a/crypto/NullAEAD_test.go b/crypto/NullAEAD_test.go
index acd3da107..25952613a 100644
--- a/crypto/NullAEAD_test.go
+++ b/crypto/NullAEAD_test.go
@@ -22,4 +22,14 @@ var _ = Describe("Crypto/NullAEAD", func() {
 		Expect(err).ToNot(HaveOccurred())
 		Expect(res).To(Equal([]byte("They are endowed with reason and conscience and should act towards one another in a spirit of brotherhood.")))
 	})
+
+	It("fails", func() {
+		aad := []byte("All human beings are born free and equal in dignity and rights..")
+		plainText := []byte("They are endowed with reason and conscience and should act towards one another in a spirit of brotherhood.")
+		hash := []byte{0x98, 0x9b, 0x33, 0x3f, 0xe8, 0xde, 0x32, 0x5c, 0xa6, 0x7f, 0x9c, 0xf7}
+		cipherText := append(hash, plainText...)
+		aead := &crypto.NullAEAD{}
+		_, err := aead.Open(aad, bytes.NewReader(cipherText))
+		Expect(err).To(HaveOccurred())
+	})
 })
diff --git a/crypto/fnv.go b/crypto/fnv.go
index 3fb99b28e..932f2fd52 100644
--- a/crypto/fnv.go
+++ b/crypto/fnv.go
@@ -4,6 +4,8 @@ package crypto
 // created by Glenn Fowler, Landon Curt Noll, and Phong Vo.
 // See https://en.wikipedia.org/wiki/Fowler-Noll-Vo_hash_function.
 
+// Write() algorithm taken and modified from github.com/romain-jacotin/quic
+
 import "hash"
 
 // Hash128 is the common interface implemented by all 128-bit hash functions.
@@ -38,7 +40,6 @@ func (s *sum128a) Sum128() (uint64, uint64) {
 
 func (s *sum128a) Write(data []byte) (int, error) {
 	var t0, t1, t2, t3 uint64
-	// Taken and slightly modified from github.com/romain-jacotin/quic
 	const fnv128PrimeLow = 0x0000013B
 	const fnv128PrimeShift = 24