add pem support to public key

This adds pem support to public keys which can now be handled the same
way as private keys.

ecdsa.go

@@ -1,4 +1,4 @@
-package pkilib
+package pki
 
 import (
   "crypto"
@@ -63,6 +63,14 @@ func (pr EcdsaPrivateKey) MarshalPem() (marshalledPemBlock, error) {
   return pem.EncodeToMemory(&pem_block), nil
 }
 
+// marshal the public key to a pem block
+func (pu *EcdsaPublicKey) MarshalPem() (marshalledPemBlock, error) {
+  asn1, err := x509.MarshalPKIXPublicKey(pu.public_key)
+  if err != nil { return nil, err }
+  pem_block := pem.Block{Type: PemLabelPublic, Bytes: asn1}
+  return pem.EncodeToMemory(&pem_block), nil
+}
+
 // verify a message using the ecdsa public key
 func (pu *EcdsaPublicKey) Verify(message []byte, signature []byte) (bool, error) {
   return false, errors.New("not implemented yet!")

pem_marshal.go

@@ -1,4 +1,4 @@
-package pkilib
+package pki
 
 import (
   "io"

rsa.go

@@ -1,4 +1,4 @@
-package pkilib
+package pki
 
 import (
   "crypto"
@@ -49,6 +49,10 @@ func (pr RsaPrivateKey) MarshalPem() (marshalledPemBlock, error) {
   return nil, errors.New("not implemented yet!")
 }
 
+func (pu *RsaPublicKey) MarshalPem() (marshalledPemBlock, error) {
+  return nil, errors.New("not implemented yet!")
+}
+
 func (pu *RsaPublicKey) Verify(message []byte, signature []byte) (bool, error) {
   return false, errors.New("not implemented yet!")
 }

types.go

@@ -1,4 +1,4 @@
-package pkilib
+package pki
 
 import (
   "crypto"
@@ -7,6 +7,8 @@ import (
 // this file holds all the interfaces used in the program until it can be split
 // properly
 
+const PemLabelPublic = "PUBLIC KEY"
+
 type (
   // interface for any private key
   PrivateKey interface {
@@ -21,6 +23,7 @@ type (
 
   // interface for any public key
   PublicKey interface {
+    Pemmer
     // use the public key to verify a message against a signature
     Verify(message []byte, signature []byte) (bool, error)
   }