CalDAV support (#15)

vendor/github.com/dgrijalva/jwt-go/rsa_utils.go

@@ -39,6 +39,38 @@ func ParseRSAPrivateKeyFromPEM(key []byte) (*rsa.PrivateKey, error) {
 	return pkey, nil
 }
 
+// Parse PEM encoded PKCS1 or PKCS8 private key protected with password
+func ParseRSAPrivateKeyFromPEMWithPassword(key []byte, password string) (*rsa.PrivateKey, error) {
+	var err error
+
+	// Parse PEM block
+	var block *pem.Block
+	if block, _ = pem.Decode(key); block == nil {
+		return nil, ErrKeyMustBePEMEncoded
+	}
+
+	var parsedKey interface{}
+
+	var blockDecrypted []byte
+	if blockDecrypted, err = x509.DecryptPEMBlock(block, []byte(password)); err != nil {
+		return nil, err
+	}
+
+	if parsedKey, err = x509.ParsePKCS1PrivateKey(blockDecrypted); err != nil {
+		if parsedKey, err = x509.ParsePKCS8PrivateKey(blockDecrypted); err != nil {
+			return nil, err
+		}
+	}
+
+	var pkey *rsa.PrivateKey
+	var ok bool
+	if pkey, ok = parsedKey.(*rsa.PrivateKey); !ok {
+		return nil, ErrNotRSAPrivateKey
+	}
+
+	return pkey, nil
+}
+
 // Parse PEM encoded PKCS1 or PKCS8 public key
 func ParseRSAPublicKeyFromPEM(key []byte) (*rsa.PublicKey, error) {
 	var err error