diff --git a/dns.go b/dns.go
index b70ba3e4..4a5a6967 100644
--- a/dns.go
+++ b/dns.go
@@ -18,7 +18,7 @@
 //
 //      r := new(dns.MX)
 //      r.Hdr = dns.RR_Header{Name: "miek.nl.", Rrtype: dns.TypeMX, Class: dns.ClassINET, Ttl: 3600}
-//      r.Pref = 10
+//      r.Preference = 10
 //      r.Mx = "mx.miek.nl."
 //
 // Or directly from a string:
diff --git a/dnssec.go b/dnssec.go
index 83a018eb..2dd77fd1 100644
--- a/dnssec.go
+++ b/dnssec.go
@@ -201,7 +201,7 @@ func (k *DNSKEY) ToDS(h int) *DS {
 }
 
 // Sign signs an RRSet. The signature needs to be filled in with
-// the values: Inception, Expiration, KeyTag, SignerName and Algorithm.
+// the values: OrigTtl, Inception, Expiration, KeyTag, SignerName and Algorithm.
 // The rest is copied from the RRset. Sign returns true when the signing went OK,
 // otherwise false.
 // There is no check if RRSet is a proper (RFC 2181) RRSet.
@@ -217,7 +217,9 @@ func (rr *RRSIG) Sign(k PrivateKey, rrset []RR) error {
 	rr.Hdr.Rrtype = TypeRRSIG
 	rr.Hdr.Name = rrset[0].Header().Name
 	rr.Hdr.Class = rrset[0].Header().Class
-	rr.OrigTtl = rrset[0].Header().Ttl
+	if rr.OrigTtl == 0 { // If set don't override
+		rr.OrigTtl = rrset[0].Header().Ttl
+	}
 	rr.TypeCovered = rrset[0].Header().Rrtype
 	rr.TypeCovered = rrset[0].Header().Rrtype
 	rr.Labels = uint8(CountLabel(rrset[0].Header().Name))
diff --git a/kscan.go b/kscan.go
index 22492c27..6c477b80 100644
--- a/kscan.go
+++ b/kscan.go
@@ -20,10 +20,10 @@ func (k *DNSKEY) NewPrivateKey(s string) (PrivateKey, error) {
 	return k.ReadPrivateKey(strings.NewReader(s), "")
 }
 
-// NewPrivateKey reads a private key from the io.Reader q. The string file is
+// ReadPrivateKey reads a private key from the io.Reader q. The string file is
 // only used in error reporting.
 // The public key must be
-// known, because some cryptographics algorithms embed the public inside the privatekey.
+// known, because some cryptographic algorithms embed the public inside the privatekey.
 func (k *DNSKEY) ReadPrivateKey(q io.Reader, file string) (PrivateKey, error) {
 	m, e := parseKey(q, file)
 	if m == nil {
diff --git a/labels.go b/labels.go
index ff25453f..8d93228d 100644
--- a/labels.go
+++ b/labels.go
@@ -110,7 +110,7 @@ func Split(s string) []int {
 	if s == "." {
 		return nil
 	}
-	idx := []int{0}
+	idx := make([]int, 1, 3)
 	off := 0
 	end := false
 
diff --git a/msg.go b/msg.go
index 98978a2f..45024ce1 100644
--- a/msg.go
+++ b/msg.go
@@ -1602,10 +1602,12 @@ func Copy(r RR) RR {
 // Put the parts of the name in the compression map.
 func compressionLenHelper(c map[string]int, s string) {
 	pref := ""
-	lbs := SplitDomainName(s)
+	lbs := Split(s)
 	for j := len(lbs) - 1; j >= 0; j-- {
-		c[lbs[j]+"."+pref] = 1 + len(pref) + len(lbs[j])
-		pref = lbs[j] + "." + pref
+		l := 1 + len(pref)
+		pref = s[lbs[j]:]
+		l += len(pref)
+		c[pref] = l
 	}
 }