diff --git a/README.md b/README.md
index 8a40027..b63ffa2 100644
--- a/README.md
+++ b/README.md
@@ -9,7 +9,7 @@
 ```go
 import "github.com/jbenet/go-multiaddr"
 
-m := multiaddr.NewString("/ip4/127.0.0.1/udp/1234")
+m := multiaddr.NewMultiaddr("/ip4/127.0.0.1/udp/1234")
 // <Multiaddr /ip4/127.0.0.1/udp/1234>
 m.buffer
 // <Buffer >
@@ -45,9 +45,9 @@ m.Url(buf)
 ### En/decapsulate
 
 ```go
-m.Encapsulate(m.NewString("/sctp/5678"))
+m.Encapsulate(m.NewMultiaddr("/sctp/5678"))
 // <Multiaddr /ip4/127.0.0.1/udp/1234/sctp/5678>
-m.Decapsulate(m.NewString("/udp")) // up to + inc last occurrence of subaddr
+m.Decapsulate(m.NewMultiaddr("/udp")) // up to + inc last occurrence of subaddr
 // <Multiaddr /ip4/127.0.0.1>
 ```
 
@@ -56,11 +56,11 @@ m.Decapsulate(m.NewString("/udp")) // up to + inc last occurrence of subaddr
 Multiaddr allows expressing tunnels very nicely.
 
 ```js
-printer := multiaddr.NewString("/ip4/192.168.0.13/tcp/80")
-proxy := multiaddr.NewString("/ip4/10.20.30.40/tcp/443")
+printer := multiaddr.NewMultiaddr("/ip4/192.168.0.13/tcp/80")
+proxy := multiaddr.NewMultiaddr("/ip4/10.20.30.40/tcp/443")
 printerOverProxy := proxy.Encapsulate(printer)
 // <Multiaddr /ip4/10.20.30.40/tcp/443/ip4/192.168.0.13/tcp/80>
 
-proxyAgain := printerOverProxy.Decapsulate(multiaddr.NewString("/ip4"))
+proxyAgain := printerOverProxy.Decapsulate(multiaddr.NewMultiaddr("/ip4"))
 // <Multiaddr /ip4/10.20.30.40/tcp/443>
 ```
diff --git a/codec.go b/codec.go
index 3e056a9..93bee7c 100644
--- a/codec.go
+++ b/codec.go
@@ -50,7 +50,7 @@ func BytesToString(b []byte) (ret string, err error) {
     s = strings.Join([]string{s, "/", p.Name}, "")
     b = b[1:]
 
-    a := AddressBytesToString(p, b)
+    a := AddressBytesToString(p, b[:(p.Size / 8)])
     if len(a) > 0 {
       s = strings.Join([]string{s, "/", a}, "")
     }
diff --git a/index.go b/index.go
index ec0e054..6e54fb5 100644
--- a/index.go
+++ b/index.go
@@ -2,13 +2,14 @@ package multiaddr
 
 import (
   "fmt"
+  "strings"
 )
 
 type Multiaddr struct {
   Bytes []byte
 }
 
-func NewString(s string) (*Multiaddr, error) {
+func NewMultiaddr(s string) (*Multiaddr, error) {
   b, err := StringToBytes(s)
   if err != nil {
     return nil, err
@@ -42,3 +43,27 @@ func (m *Multiaddr) Protocols() (ret []*Protocol, err error) {
   }
   return ps, nil
 }
+
+func (m *Multiaddr) Encapsulate(o *Multiaddr) *Multiaddr {
+  b := make([]byte, len(m.Bytes) + len(o.Bytes))
+  b = append(m.Bytes, o.Bytes...)
+  return &Multiaddr{Bytes: b}
+}
+
+func (m *Multiaddr) Decapsulate(o *Multiaddr) (*Multiaddr, error) {
+  s1, err := m.String()
+  if err != nil {
+    return nil, err
+  }
+
+  s2, err := o.String()
+  if err != nil {
+    return nil, err
+  }
+
+  i := strings.LastIndex(s1, s2)
+  if i < 0 {
+    return nil, fmt.Errorf("%s not contained in %s", s2, s1)
+  }
+  return NewMultiaddr(s1[:i])
+}
diff --git a/multiaddr_test.go b/multiaddr_test.go
index 60deda4..777ced8 100644
--- a/multiaddr_test.go
+++ b/multiaddr_test.go
@@ -41,7 +41,7 @@ func TestBytesToString(t *testing.T) {
       t.Error("failed to convert", b)
     }
 
-    if s1 == s2 {
+    if s1 != s2 {
       t.Error("failed to convert", b, "to", s1, "got", s2)
     }
   }
@@ -51,7 +51,7 @@ func TestBytesToString(t *testing.T) {
 
 
 func TestProtocols(t *testing.T) {
-  m, err := NewString("/ip4/127.0.0.1/udp/1234")
+  m, err := NewMultiaddr("/ip4/127.0.0.1/udp/1234")
   if err != nil {
     t.Error("failed to construct", "/ip4/127.0.0.1/udp/1234")
   }
@@ -72,3 +72,40 @@ func TestProtocols(t *testing.T) {
   }
 
 }
+
+func TestEncapsulate(t *testing.T) {
+  m, err := NewMultiaddr("/ip4/127.0.0.1/udp/1234")
+  if err != nil {
+    t.Error(err)
+  }
+
+  m2, err := NewMultiaddr("/udp/5678")
+  if err != nil {
+    t.Error(err)
+  }
+
+  b := m.Encapsulate(m2)
+  if s, _ := b.String(); s != "/ip4/127.0.0.1/udp/1234/udp/5678" {
+    t.Error("encapsulate /ip4/127.0.0.1/udp/1234/udp/5678 failed.", s)
+  }
+
+  m3, _ := NewMultiaddr("/udp/5678")
+  c, err := b.Decapsulate(m3)
+  if err != nil {
+    t.Error("decapsulate /udp failed.", err)
+  }
+
+  if s, _ := c.String(); s != "/ip4/127.0.0.1/udp/1234" {
+    t.Error("decapsulate /udp failed.", "/ip4/127.0.0.1/udp/1234", s)
+  }
+
+  m4, _ := NewMultiaddr("/ip4/127.0.0.1")
+  d, err := c.Decapsulate(m4)
+  if err != nil {
+    t.Error("decapsulate /ip4 failed.", err)
+  }
+
+  if s, _ := d.String(); s != "" {
+    t.Error("decapsulate /ip4 failed.", "/", s)
+  }
+}