Update utilities/utilities.go

Co-authored-by: Luca Rinaldi <lucarin@protonmail.com>

utilities/utilities.go

@@ -147,12 +147,16 @@
 		return nil, errors.New("invalid key")
 	}
 
 	parsedKey, err := x509.ParsePKIXPublicKey(block.Bytes)
 	if err != nil {
 		return nil, err
 	}
 
-	return parsedKey.(*rsa.PublicKey), nil
+ publicKey, ok := value.(*rsa.PublicKey)
+    if !ok {
+        return nil,fmt.Errorf("not an rsa key")
+    }
+return publicKey, nil
 }
 
 // MustParseRsaPublicKey parses a public key in PEM format and returns the rsa.PublicKey object.