OK before I go any further on this I should go back and check it against the tests.

lib/common/certificate.go

@@ -51,6 +51,7 @@ type CertificateInterface interface {
 	Length() (length int, err error)
 	Data() (data []byte, err error)
 	Type() (cert_type int, err error)
+	SignatureSize() (size int)
 }
 
 type Certificate struct {
@@ -61,6 +62,10 @@ type Certificate struct {
 
 var ci CertificateInterface = &Certificate{}
 
+func (certificate Certificate) SignatureSize() (size int) {
+	return 40
+}
+
 func (certificate Certificate) Cert() []byte {
 	var ret []byte
 	ret = append(ret, IntegerBytes(certificate.CertType)...)

lib/common/destination.go

@@ -31,7 +31,7 @@ func (destination Destination) SigningPublicKey() (crypto.SigningPublicKey, erro
 	return destination.KeysAndCert.GetSigningPublicKey()
 }
 
-func (destination Destination) Certificate() (Certificate, error) {
+func (destination Destination) Certificate() (CertificateInterface, error) {
 	return destination.KeysAndCert.GetCertificate()
 }
 

lib/common/key_certificate.go

@@ -75,6 +75,7 @@ const (
 )
 
 type KeyCertificate struct {
+	Certificate
 	PKType   int
 	PKExtra  []byte
 	SPKType  int
@@ -86,7 +87,7 @@ type KeyCertificate struct {
 //
 func (key_certificate KeyCertificate) Data() ([]byte, error) {
 	var r []byte
-
+	r = append(r, key_certificate.Certificate.Cert()...)
 	pk := IntegerBytes(key_certificate.PKType)
 	r = append(r, pk...)
 	spk := IntegerBytes(key_certificate.SPKType)
@@ -225,6 +226,11 @@ func (key_certificate KeyCertificate) SignatureSize() (size int) {
 // Read a KeyCertificate from a slice of bytes
 //
 func ReadKeyCertificate(data []byte) (key_certificate KeyCertificate, err error) {
+	cert, data, err := ReadCertificate(data)
+	if err != nil {
+		return
+	}
+	key_certificate.Certificate = cert
 	data_len := len(data)
 	if data_len < 2 {
 		log.WithFields(log.Fields{

lib/common/keys_and_cert.go

@@ -68,7 +68,16 @@ type KeysAndCertInterface interface {
 type KeysAndCert struct {
 	crypto.SigningPublicKey
 	crypto.PublicKey
-	Certificate
+	CertificateInterface
+}
+
+func (keys_and_cert KeysAndCert) Bytes() (bytes []byte) { //, err error) {
+	elg_key := keys_and_cert.PublicKey.(crypto.ElgPublicKey)
+	dsa_key := keys_and_cert.SigningPublicKey.(crypto.DSAPublicKey)
+	bytes = append(bytes, dsa_key[:]...)
+	bytes = append(bytes, elg_key[:]...)
+	bytes = append(bytes, keys_and_cert.CertificateInterface.Cert()...)
+	return
 }
 
 //
@@ -113,12 +122,12 @@ func (keys_and_cert KeysAndCert) GetSigningPublicKey() (signing_public_key crypt
 // Return the Certificate contained in the KeysAndCert and any errors encountered while parsing the
 // KeysAndCert or Certificate.
 //
-func (keys_and_cert KeysAndCert) GetCertificate() (cert Certificate, err error) {
-	_, err = keys_and_cert.Certificate.Type()
+func (keys_and_cert KeysAndCert) GetCertificate() (cert CertificateInterface, err error) {
+	_, err = keys_and_cert.CertificateInterface.Type()
 	if err != nil {
 		return
 	}
-	cert = keys_and_cert.Certificate
+	cert = keys_and_cert.CertificateInterface
 	return
 }
 
@@ -142,15 +151,14 @@ func ReadKeysAndCert(data []byte) (keys_and_cert KeysAndCert, remainder []byte,
 	if err != nil {
 		return
 	}
-	cert, _ = keys_and_cert.GetCertificate()
 	spk, pk, remainder, err := ReadKeys(data, cert)
 	if err != nil {
 		return
 	}
 	keys_and_cert = KeysAndCert{
-		SigningPublicKey: spk,
-		PublicKey:        pk,
-		Certificate:      cert,
+		SigningPublicKey:     spk,
+		PublicKey:            pk,
+		CertificateInterface: cert,
 	}
 	return
 }
@@ -221,7 +229,7 @@ func ReadKeys(data []byte, cert CertificateInterface) (spk crypto.SigningPublicK
 			spk = dsa_pk
 		}
 	}
-	cert_len, cert_len_err := cert.Length()
+	cert_len, err := cert.Length()
 	if cert_len == 0 {
 		remainder = data[KEYS_AND_CERT_MIN_SIZE:]
 		return

lib/common/router_info.go

@@ -97,7 +97,7 @@ func (router_info RouterInfo) IdentHash() (h Hash, err error) {
 	var ri RouterIdentity
 	ri, err = router_info.RouterIdentity()
 	if err == nil {
-		h = HashData(ri)
+		h = HashData(ri.Bytes())
 	}
 	return
 }
@@ -210,7 +210,7 @@ func (router_info RouterInfo) Signature() (signature Signature) {
 	head := router_info.optionsLocation()
 	size := head + router_info.optionsSize()
 	ident, _ := router_info.RouterIdentity()
-	keyCert := KeyCertificate(ident)
+	keyCert := ident.CertificateInterface //KeyCertificate(ident)
 	sigSize := keyCert.SignatureSize()
 	signature = Signature(router_info[size : size+sigSize])
 	return
@@ -224,7 +224,7 @@ func (router_info RouterInfo) optionsLocation() (location int) {
 	if err != nil {
 		return
 	}
-	location += len(data)
+	location += len(data.Bytes())
 
 	remainder_len := len(remainder)
 	if remainder_len < 9 {