add verification of messages

This commit adds back the possibility to verify a message through a
public key and a signature. It works a little bit different than before
as it always prints the base64 version, but it makes it easier to use.

1 files changed, 17 insertions, 7 deletions

diff --git a/private_key.go b/private_key.go
index 3e6aee3..0591e18 100644
--- a/private_key.go
+++ b/private_key.go
@@ -5,25 +5,22 @@ import (
   "github.com/gibheer/pki"
 )
 
-const (
-  TypeLabelRSA   = "RSA PRIVATE KEY"
-  TypeLabelECDSA = "EC PRIVATE KEY"
-)
-
 var (
   ErrNoPKFound = errors.New("no private key found")
+  ErrNoPUFound = errors.New("no public key found")
+  ErrUnknownFormat = errors.New("key is an unknown format")
 )
 
 // Read the private key from the path and try to figure out which type of key it
 // might be.
 func ReadPrivateKeyFile(path string) (pki.PrivateKey, error) {
-  raw_pk, err := readSectionFromFile(path, TypeLabelECDSA)
+  raw_pk, err := readSectionFromFile(path, pki.PemLabelEcdsa)
   if err == nil {
     pk, err := pki.LoadPrivateKeyEcdsa(raw_pk)
     if err != nil { return nil, err }
     return pk, nil
   }
-  raw_pk, err = readSectionFromFile(path, TypeLabelRSA)
+  raw_pk, err = readSectionFromFile(path, pki.PemLabelRsa)
   if err == nil {
     pk, err := pki.LoadPrivateKeyRsa(raw_pk)
     if err != nil { return nil, err }
@@ -31,3 +28,16 @@ func ReadPrivateKeyFile(path string) (pki.PrivateKey, error) {
   }
   return nil, ErrNoPKFound
 }
+
+// read the public key and try to figure out what kind of key it might be
+func ReadPublicKeyFile(path string) (pki.PublicKey, error) {
+  raw_pu, err := readSectionFromFile(path, pki.PemLabelPublic)
+  if err != nil { return nil, ErrNoPUFound }
+
+  var public pki.PublicKey
+  public, err = pki.LoadPublicKeyEcdsa(raw_pu)
+  if err == nil { return public, nil }
+  public, err = pki.LoadPublicKeyRsa(raw_pu)
+  if err == nil { return public, nil }
+  return nil, ErrUnknownFormat
+}