implement the FNV64a nullAEAD

It is not used yet.

crypto/null_aead_fnv128a.go

@@ -9,23 +9,23 @@ import (
 )
 
 // nullAEAD handles not-yet encrypted packets
-type nullAEAD struct {
+type nullAEADFNV128a struct {
 	perspective protocol.Perspective
 	version     protocol.VersionNumber
 }
 
-var _ AEAD = &nullAEAD{}
+var _ AEAD = &nullAEADFNV128a{}
 
 // NewNullAEAD creates a NullAEAD
 func NewNullAEAD(p protocol.Perspective, v protocol.VersionNumber) AEAD {
-	return &nullAEAD{
+	return &nullAEADFNV128a{
 		perspective: p,
 		version:     v,
 	}
 }
 
 // Open and verify the ciphertext
-func (n *nullAEAD) Open(dst, src []byte, packetNumber protocol.PacketNumber, associatedData []byte) ([]byte, error) {
+func (n *nullAEADFNV128a) Open(dst, src []byte, packetNumber protocol.PacketNumber, associatedData []byte) ([]byte, error) {
 	if len(src) < 12 {
 		return nil, errors.New("NullAEAD: ciphertext cannot be less than 12 bytes long")
 	}
@@ -52,7 +52,7 @@ func (n *nullAEAD) Open(dst, src []byte, packetNumber protocol.PacketNumber, ass
 }
 
 // Seal writes hash and ciphertext to the buffer
-func (n *nullAEAD) Seal(dst, src []byte, packetNumber protocol.PacketNumber, associatedData []byte) []byte {
+func (n *nullAEADFNV128a) Seal(dst, src []byte, packetNumber protocol.PacketNumber, associatedData []byte) []byte {
 	if cap(dst) < 12+len(src) {
 		dst = make([]byte, 12+len(src))
 	} else {

crypto/null_aead_fnv128a_test.go

@@ -6,7 +6,7 @@ import (
 	. "github.com/onsi/gomega"
 )
 
-var _ = Describe("Crypto/NullAEAD", func() {
+var _ = Describe("NullAEAD using FNV128a", 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.")
 	hash36 := []byte{0x98, 0x9b, 0x33, 0x3f, 0xe8, 0xde, 0x32, 0x5c, 0xa6, 0x7f, 0x9c, 0xf7}
@@ -16,12 +16,12 @@ var _ = Describe("Crypto/NullAEAD", func() {
 		aead := NewNullAEAD(protocol.PerspectiveServer, protocol.Version36)
 		res, err := aead.Open(nil, cipherText, 0, aad)
 		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.")))
+		Expect(res).To(Equal(plainText))
 	})
 
 	It("seals", func() {
 		aead := NewNullAEAD(protocol.PerspectiveServer, protocol.Version36)
-		Expect(aead.Seal(nil, plainText, 0, aad)).To(Equal(append(hash36, []byte("They are endowed with reason and conscience and should act towards one another in a spirit of brotherhood.")...)))
+		Expect(aead.Seal(nil, plainText, 0, aad)).To(Equal(append(hash36, plainText...)))
 	})
 
 	It("rejects short ciphertexts", func() {

crypto/null_aead_fnv64a.go

@@ -0,0 +1,46 @@
+package crypto
+
+import (
+	"encoding/binary"
+	"errors"
+	"hash/fnv"
+
+	"github.com/lucas-clemente/quic-go/internal/protocol"
+)
+
+type nullAEADFNV64a struct{}
+
+var _ AEAD = &nullAEADFNV64a{}
+
+// Open and verify the ciphertext
+func (n *nullAEADFNV64a) Open(dst, src []byte, packetNumber protocol.PacketNumber, associatedData []byte) ([]byte, error) {
+	if len(src) < 8 {
+		return nil, errors.New("NullAEAD: ciphertext cannot be less than 8 bytes long")
+	}
+	data := src[:len(src)-8]
+
+	hash := fnv.New64a()
+	hash.Write(associatedData)
+	hash.Write(data)
+
+	if hash.Sum64() != binary.BigEndian.Uint64(src[len(src)-8:]) {
+		return nil, errors.New("NullAEAD: failed to authenticate received data")
+	}
+	return data, nil
+}
+
+// Seal writes hash and ciphertext to the buffer
+func (n *nullAEADFNV64a) Seal(dst, src []byte, packetNumber protocol.PacketNumber, associatedData []byte) []byte {
+	if cap(dst) < 8+len(src) {
+		dst = make([]byte, 8+len(src))
+	} else {
+		dst = dst[:8+len(src)]
+	}
+
+	hash := fnv.New64a()
+	hash.Write(associatedData)
+	hash.Write(src)
+	copy(dst, src)
+	binary.BigEndian.PutUint64(dst[len(src):], hash.Sum64())
+	return dst
+}

crypto/null_aead_fnv64a_test.go

@@ -0,0 +1,64 @@
+package crypto
+
+import (
+	"encoding/binary"
+	"hash/fnv"
+
+	. "github.com/onsi/ginkgo"
+	. "github.com/onsi/gomega"
+)
+
+var _ = Describe("NullAEAD using FNV128a", func() {
+	var hash64 []byte
+	var aead AEAD
+	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.")
+
+	BeforeEach(func() {
+		aead = &nullAEADFNV64a{}
+		hash := fnv.New64a()
+		hash.Write(aad)
+		hash.Write(plainText)
+		hash64 = make([]byte, 8)
+		binary.BigEndian.PutUint64(hash64, hash.Sum64())
+	})
+
+	It("opens", func() {
+		data, err := aead.Open(nil, append(plainText, hash64...), 0, aad)
+		Expect(err).ToNot(HaveOccurred())
+		Expect(data).To(Equal(plainText))
+	})
+
+	It("fails", func() {
+		_, err := aead.Open(nil, append(plainText, hash64...), 0, append(aad, []byte{0x42}...))
+		Expect(err).To(MatchError("NullAEAD: failed to authenticate received data"))
+	})
+
+	It("rejects short ciphertexts", func() {
+		_, err := aead.Open(nil, []byte{1, 2, 3, 4, 5, 6, 7}, 0, []byte{})
+		Expect(err).To(MatchError("NullAEAD: ciphertext cannot be less than 8 bytes long"))
+	})
+
+	It("opens empty messages", func() {
+		hash := fnv.New64a()
+		h := make([]byte, 8)
+		binary.BigEndian.PutUint64(h, hash.Sum64())
+		data, err := aead.Open(nil, h, 0, []byte{})
+		Expect(err).ToNot(HaveOccurred())
+		Expect(data).To(BeEmpty())
+	})
+
+	It("seals", func() {
+		Expect(aead.Seal(nil, plainText, 0, aad)).To(Equal(append(plainText, hash64...)))
+	})
+
+	It("seals in-place", func() {
+		buf := make([]byte, 6, 6+8)
+		copy(buf, []byte("foobar"))
+		res := aead.Seal(buf[0:0], buf, 0, nil)
+		// buf = buf[:8+6]
+		Expect(buf[:6]).To(Equal([]byte("foobar")))
+		// Expect(res[:6]).To(Equal([]byte("foobar")))
+		Expect(buf[0 : 6+8]).To(Equal(res))
+	})
+})