diff --git a/dnssec.go b/dnssec.go
index b4c28387..f89f8afe 100644
--- a/dnssec.go
+++ b/dnssec.go
@@ -1,4 +1,27 @@
 package dns
 
-// All verification for RRSIG and RRsets i
-// Done here
+import "time"
+
+// All DNSSEC verification 
+
+const (
+	Year68 = 2 << (32 - 1)
+)
+
+// Translate the RRSIG's incep. and expir. time
+// to the correct date, taking into account serial
+// arithmetic
+func timeToDate(t uint32) string {
+	utc := time.UTC().Seconds()
+	mod := (int64(t) - utc) / Year68
+
+        // If needed assume wrap around(s)
+        ti := time.SecondsToUTC(int64(t) + (mod * Year68)) // abs()? TODO
+	return ti.Format("20060102030405")
+}
+
+// Is the signature (RRSIG) valid?
+func validSignaturePeriod(start, end uint32) bool {
+        utc := time.UTC().Seconds()       // maybe as parameter?? TODO MG
+        return int64(start) <= utc && utc <= int64(end)
+}
diff --git a/edns_test.go b/edns_test.go
index 19cac42d..8e1fd0ee 100644
--- a/edns_test.go
+++ b/edns_test.go
@@ -3,17 +3,16 @@ package dns
 // Test EDNS RR records
 import (
 	"testing"
-        "fmt"
 )
 
 func TestEDNS_RR(t *testing.T) {
-        edns := new(RR_OPT)
-        edns.Hdr.Name = "."      // must . be for edns
-        edns.Hdr.Rrtype = TypeOPT
-        edns.Hdr.Class = ClassINET
-        edns.Hdr.Ttl = 3600
-        edns.Option = make([]Option, 1)
-        edns.Option[0].Code = OptionCodeNSID
-        edns.Option[0].Data = "lalalala"
-        fmt.Printf("%v\n", edns)
+	edns := new(RR_OPT)
+	edns.Hdr.Name = "." // must . be for edns
+	edns.Hdr.Rrtype = TypeOPT
+	edns.Hdr.Class = ClassINET
+	edns.Hdr.Ttl = 3600
+	edns.Option = make([]Option, 1)
+	edns.Option[0].Code = OptionCodeNSID
+	edns.Option[0].Data = "lalalala"
+	//t..Logf("%v\n", edns)
 }
diff --git a/pack_test.go b/pack_test.go
index 00d64628..35e6d0f8 100644
--- a/pack_test.go
+++ b/pack_test.go
@@ -3,7 +3,6 @@ package dns
 import (
 	"testing"
 	"net"
-        "fmt"
 )
 
 func TestPackUnpack(t *testing.T) {
@@ -89,15 +88,15 @@ func TestPackUnpack(t *testing.T) {
 
         _, ok = packRR(edns, msg, 0)
         if !ok {
+                t.Logf("%v\n", edns)
                 t.Log("Failed")
                 t.Fail()
         }
-        fmt.Printf("%v\n", edns)
 
         unpacked, _, ok := unpackRR(msg, 0)
         if  !ok {
+                t.Logf("%v\n", unpacked)
                 t.Log("Failed")
                 t.Fail()
         }
-        fmt.Printf("%v\n", unpacked)
 }
diff --git a/resolverEdns_test.go b/resolverEdns_test.go
index 5c41263b..a51e5231 100644
--- a/resolverEdns_test.go
+++ b/resolverEdns_test.go
@@ -3,7 +3,6 @@ package dns
 import (
 	"testing"
 	"time"
-	"fmt"
 )
 
 func TestResolverEdns(t *testing.T) {
@@ -34,17 +33,14 @@ func TestResolverEdns(t *testing.T) {
 	m.Question[0] = Question{"miek.nl", TypeSOA, ClassINET}
 	m.Ns[0] = edns
 
-	fmt.Printf("Sending: %v\n", m)
-
 	ch <- DnsMsg{m, nil}
 	in := <-ch
 
 	if in.Dns.Rcode != RcodeSuccess {
+                t.Logf("Recv: %v\n", in.Dns)
 		t.Log("Failed to get an valid answer")
 		t.Fail()
 	}
-	fmt.Printf("Recv: %v\n", in.Dns)
-
 	ch <- DnsMsg{nil, nil}
-	time.Sleep(1.0e9)
+	time.Sleep(0.5e9)
 }
diff --git a/resolver_test.go b/resolver_test.go
index 562b5db4..b3566ab4 100644
--- a/resolver_test.go
+++ b/resolver_test.go
@@ -3,7 +3,6 @@ package dns
 import (
 	"testing"
 	"time"
-	"fmt"
 )
 
 
@@ -27,7 +26,7 @@ func TestResolver(t *testing.T) {
 	if in.Dns.Rcode != RcodeSuccess {
 		t.Log("Failed to get an valid answer")
 		t.Fail()
-	        fmt.Printf("%v\n", in)
+	        t.Logf("%v\n", in)
 	}
 
 	// ask something
@@ -38,9 +37,9 @@ func TestResolver(t *testing.T) {
 	if in.Dns.Rcode != RcodeSuccess {
 		t.Log("Failed to get an valid answer")
 		t.Fail()
-	        fmt.Printf("%v\n", in)
+	        t.Logf("%v\n", in)
 	}
 
 	ch <- DnsMsg{nil, nil}
-	time.Sleep(1.0e9)
+	time.Sleep(0.5e9)
 }
diff --git a/signature_test.go b/signature_test.go
new file mode 100644
index 00000000..118e8809
--- /dev/null
+++ b/signature_test.go
@@ -0,0 +1,30 @@
+package dns
+
+import (
+	"testing"
+)
+
+func TestSignature(t *testing.T) {
+	sig := new(RR_RRSIG)
+	sig.Hdr.Name = "miek.nl."
+	sig.Hdr.Rrtype = TypeRRSIG
+	sig.Hdr.Class = ClassINET
+	sig.Hdr.Ttl = 3600
+	sig.TypeCovered = TypeDNSKEY
+	sig.Algorithm = AlgRSASHA1
+	sig.Labels = 2
+	sig.OrigTtl = 4000
+	sig.Expiration = 1000
+	sig.Inception = 800
+	sig.KeyTag = 34641
+	sig.SignerName = "miek.nl."
+	sig.Sig = "AwEAAaHIwpx3w4VHKi6i1LHnTaWeHCL154Jug0Rtc9ji5qwPXpBo6A5sRv7cSsPQKPIwxLpyCrbJ4mr2L0EPOdvP6z6YfljK2ZmTbogU9aSU2fiq/4wjxbdkLyoDVgtO+JsxNN4bjr4WcWhsmk1Hg93FV9ZpkWb0Tbad8DFqNDzr//kZ"
+
+	// Should not be valid
+	if validSignaturePeriod(sig.Inception, sig.Expiration) {
+		t.Log("Should not be valid")
+		t.Fail()
+	} else {
+	        t.Logf("Valid sig period:\n%v\n", sig)
+        }
+}
diff --git a/types.go b/types.go
index 18d105ec..ff6393fc 100644
--- a/types.go
+++ b/types.go
@@ -10,7 +10,6 @@ package dns
 import (
 	"net"
 	"strconv"
-	"time"
 )
 
 // Packet formats
@@ -382,29 +381,14 @@ func (rr *RR_RRSIG) Header() *RR_Header {
 	return &rr.Hdr
 }
 
-// Also, I might need more of these helper function
-// where to put them if there are more
-// Define a new interface??
-// needs serial stuff
-// starts when 1970 has been 68 years ago??
-func intToDate(t uint32) string {
-	// als meer dan 68 jaar geleden, dan 68 jaar bij bedrag optellen
-	// TODO
-	ti := time.SecondsToUTC(int64(t))
-	return ti.Format("20060102030405")
-}
-
-
 func (rr *RR_RRSIG) String() string {
 	return rr.Hdr.String() +
 		" " + rr_str[rr.TypeCovered] +
 		" " + strconv.Itoa(int(rr.Algorithm)) +
 		" " + strconv.Itoa(int(rr.Labels)) +
 		" " + strconv.Itoa(int(rr.OrigTtl)) +
-		//		" " + strconv.Itoa(int(rr.Expiration)) + // date calc! TODO
-		" " + intToDate(rr.Expiration) +
-		//		" " + strconv.Itoa(int(rr.Inception)) + // date calc! TODO
-		" " + intToDate(rr.Inception) +
+		" " + timeToDate(rr.Expiration) +
+		" " + timeToDate(rr.Inception) +
 		" " + strconv.Itoa(int(rr.KeyTag)) +
 		" " + rr.SignerName +
 		" " + rr.Sig