diff --git a/go.mod b/go.mod
index 837669a..8cd2d22 100644
--- a/go.mod
+++ b/go.mod
@@ -4,6 +4,7 @@ go 1.17
 
 require (
 	github.com/ipfs/go-cid v0.0.7
+	github.com/multiformats/go-multibase v0.0.3
 	github.com/multiformats/go-multihash v0.0.14
 	github.com/multiformats/go-varint v0.0.6
 	github.com/stretchr/testify v1.7.0
@@ -16,7 +17,6 @@ require (
 	github.com/mr-tron/base58 v1.1.3 // indirect
 	github.com/multiformats/go-base32 v0.0.3 // indirect
 	github.com/multiformats/go-base36 v0.1.0 // indirect
-	github.com/multiformats/go-multibase v0.0.3 // indirect
 	github.com/pmezard/go-difflib v1.0.0 // indirect
 	github.com/spaolacci/murmur3 v1.1.0 // indirect
 	golang.org/x/crypto v0.0.0-20190611184440-5c40567a22f8 // indirect
diff --git a/multiaddr_test.go b/multiaddr_test.go
index ee6ecf2..1eb9d73 100644
--- a/multiaddr_test.go
+++ b/multiaddr_test.go
@@ -74,6 +74,8 @@ func TestConstructFails(t *testing.T) {
 		"/ip4/127.0.0.1/tcp/jfodsajfidosajfoidsa",
 		"/ip4/127.0.0.1/tcp",
 		"/ip4/127.0.0.1/quic/1234",
+		"/ip4/127.0.0.1/udp/1234/quic/webtransport/certhash",
+		"/ip4/127.0.0.1/udp/1234/quic/webtransport/certhash/b2uaraocy6yrdblb4sfptaddgimjmmp", // 1 character missing from certhash
 		"/ip4/127.0.0.1/ipfs",
 		"/ip4/127.0.0.1/ipfs/tcp",
 		"/ip4/127.0.0.1/p2p",
@@ -157,6 +159,9 @@ func TestConstructSucceeds(t *testing.T) {
 		"/ip4/127.0.0.1/tcp/1234",
 		"/ip4/127.0.0.1/tcp/1234/",
 		"/ip4/127.0.0.1/udp/1234/quic",
+		"/ip4/127.0.0.1/udp/1234/quic/webtransport",
+		"/ip4/127.0.0.1/udp/1234/quic/webtransport/certhash/b2uaraocy6yrdblb4sfptaddgimjmmpy",
+		"/ip4/127.0.0.1/udp/1234/quic/webtransport/certhash/b2uaraocy6yrdblb4sfptaddgimjmmpy/certhash/zQmbWTwYGcmdyK9CYfNBcfs9nhZs17a6FQ4Y8oea278xx41",
 		"/ip4/127.0.0.1/ipfs/QmcgpsyWgH8Y8ajJz1Cu72KnS5uo2Aa2LpzU7kinSupNKC",
 		"/ip4/127.0.0.1/ipfs/QmcgpsyWgH8Y8ajJz1Cu72KnS5uo2Aa2LpzU7kinSupNKC/tcp/1234",
 		"/ip4/127.0.0.1/ipfs/k2k4r8oqamigqdo6o7hsbfwd45y70oyynp98usk7zmyfrzpqxh1pohl7",
@@ -542,6 +547,7 @@ func TestRoundTrip(t *testing.T) {
 		"/ip4/127.0.0.1/tcp/123/tls",
 		"/ip4/127.0.0.1/udp/123",
 		"/ip4/127.0.0.1/udp/123/ip6/::",
+		"/ip4/127.0.0.1/udp/1234/quic/webtransport/certhash/uEiDDq4_xNyDorZBH3TlGazyJdOWSwvo4PUo5YHFMrvDE8g",
 		"/p2p/QmbHVEEepCi7rn7VL7Exxpd2Ci9NNB6ifvqwhsrbRMgQFP",
 		"/p2p/QmbHVEEepCi7rn7VL7Exxpd2Ci9NNB6ifvqwhsrbRMgQFP/unix/a/b/c",
 	} {
diff --git a/protocols.go b/protocols.go
index 5895894..28b3959 100644
--- a/protocols.go
+++ b/protocols.go
@@ -15,6 +15,8 @@ const (
 	P_IP6ZONE           = 0x002A
 	P_IPCIDR            = 0x002B
 	P_QUIC              = 0x01CC
+	P_WEBTRANSPORT      = 0x01D1
+	P_CERTHASH          = 0x01D2
 	P_SCTP              = 0x0084
 	P_CIRCUIT           = 0x0122
 	P_UDT               = 0x012D
@@ -178,6 +180,18 @@ var (
 		Code:  P_QUIC,
 		VCode: CodeToVarint(P_QUIC),
 	}
+	protoWEBTRANSPORT = Protocol{
+		Name:  "webtransport",
+		Code:  P_WEBTRANSPORT,
+		VCode: CodeToVarint(P_WEBTRANSPORT),
+	}
+	protoCERTHASH = Protocol{
+		Name:       "certhash",
+		Code:       P_CERTHASH,
+		VCode:      CodeToVarint(P_CERTHASH),
+		Size:       LengthPrefixedVarSize,
+		Transcoder: TranscoderCertHash,
+	}
 	protoHTTP = Protocol{
 		Name:  "http",
 		Code:  P_HTTP,
@@ -257,6 +271,8 @@ func init() {
 		protoUTP,
 		protoUDT,
 		protoQUIC,
+		protoWEBTRANSPORT,
+		protoCERTHASH,
 		protoHTTP,
 		protoHTTPS,
 		protoP2P,
diff --git a/transcoders.go b/transcoders.go
index 9238ffb..764bb29 100644
--- a/transcoders.go
+++ b/transcoders.go
@@ -11,6 +11,7 @@ import (
 	"strings"
 
 	"github.com/ipfs/go-cid"
+	"github.com/multiformats/go-multibase"
 	mh "github.com/multiformats/go-multihash"
 )
 
@@ -373,3 +374,20 @@ func dnsStB(s string) ([]byte, error) {
 func dnsBtS(b []byte) (string, error) {
 	return string(b), nil
 }
+
+var TranscoderCertHash = NewTranscoderFromFunctions(certHashStB, certHashBtS, nil)
+
+func certHashStB(s string) ([]byte, error) {
+	_, data, err := multibase.Decode(s)
+	if err != nil {
+		return nil, err
+	}
+	if _, err := mh.Decode(data); err != nil {
+		return nil, err
+	}
+	return data, nil
+}
+
+func certHashBtS(b []byte) (string, error) {
+	return multibase.Encode(multibase.Base64url, b)
+}