diff --git a/udp/connection.go b/udp/connection.go
index ce4d063..49b2c1a 100644
--- a/udp/connection.go
+++ b/udp/connection.go
@@ -11,11 +11,14 @@ import (
 	"crypto/rand"
 )
 
+// ConnectionIDGenerator represents the logic to generate 64-bit UDP
+// connection IDs from peer IP addresses.
 type ConnectionIDGenerator struct {
 	iv, iv2 []byte
 	block   cipher.Block
 }
 
+// Init generates the AES key and sets up the first initialization vector.
 func (g *ConnectionIDGenerator) Init() error {
 	key := make([]byte, 16)
 	_, err := rand.Read(key)
@@ -31,6 +34,7 @@ func (g *ConnectionIDGenerator) Init() error {
 	return g.NewIV()
 }
 
+// Generate returns the 64-bit connection ID for an IP
 func (g *ConnectionIDGenerator) Generate(ip []byte) []byte {
 	return g.generate(ip, g.iv)
 }
@@ -55,6 +59,8 @@ func (g *ConnectionIDGenerator) generate(ip []byte, iv []byte) []byte {
 	return ct[:8]
 }
 
+// Matches checks if the given connection ID matches an IP with the current or
+// previous initialization vectors.
 func (g *ConnectionIDGenerator) Matches(id []byte, ip []byte) bool {
 	if expected := g.generate(ip, g.iv); bytes.Equal(id, expected) {
 		return true
@@ -69,6 +75,7 @@ func (g *ConnectionIDGenerator) Matches(id []byte, ip []byte) bool {
 	return false
 }
 
+// NewIV generates a new initialization vector and rotates the current one.
 func (g *ConnectionIDGenerator) NewIV() error {
 	newiv := make([]byte, 16)
 	if _, err := rand.Read(newiv); err != nil {
diff --git a/udp/protocol.go b/udp/protocol.go
index 6948ad7..15c0ef8 100644
--- a/udp/protocol.go
+++ b/udp/protocol.go
@@ -129,8 +129,6 @@ func (s *Server) newAnnounce(packet []byte, ip net.IP) (*models.Announce, error)
 		ip = ipv4
 	}
 
-	// TODO(pushrax): what exactly is the key "key" used for?
-
 	numWant := binary.BigEndian.Uint32(packet[92:96])
 	port := binary.BigEndian.Uint16(packet[96:98])
 
diff --git a/udp/writer.go b/udp/writer.go
index a2b503f..2d26f9f 100644
--- a/udp/writer.go
+++ b/udp/writer.go
@@ -43,7 +43,7 @@ func (w *Writer) WriteAnnounce(res *models.AnnounceResponse) error {
 	return nil
 }
 
-// WriteAnnounce encodes a scrape response according to the UDP spec.
+// WriteScrape encodes a scrape response according to the UDP spec.
 func (w *Writer) WriteScrape(res *models.ScrapeResponse) error {
 	w.writeHeader(2)