diff --git a/autospec/config.py b/autospec/config.py
index e336b96..ddd4fbf 100644
--- a/autospec/config.py
+++ b/autospec/config.py
@@ -60,6 +60,7 @@ git_uri = None
 config_file = None
 old_version = None
 old_patches = list()
+old_keyid = None
 profile_payload = None
 signature = None
 
@@ -188,6 +189,7 @@ def setup_patterns():
 def parse_existing_spec(path, name):
     global old_version
     global old_patches
+    global old_keyid
 
     spec = os.path.join(path, "{}.spec".format(name))
     if not os.path.exists(spec):
@@ -196,6 +198,9 @@ def parse_existing_spec(path, name):
     with open(spec, "r", encoding="latin-1") as inp:
         for line in inp.readlines():
             line = line.strip().replace("\r", "").replace("\n", "")
+            if "Source0 file verified with key" in line:
+                keyidx = line.find('0x') + 2
+                old_keyid = line[keyidx:].split()[0] if keyidx > 2 else old_keyid
             if ":" not in line:
                 continue
             spl = line.split(":")
diff --git a/autospec/pkg_integrity.py b/autospec/pkg_integrity.py
index 55c9e98..8fb29ee 100644
--- a/autospec/pkg_integrity.py
+++ b/autospec/pkg_integrity.py
@@ -212,6 +212,17 @@ def get_signature_url(package_url):
     return None
 
 
+def compare_keys(newkey, oldkey):
+    if newkey != oldkey:
+        print_error('Public key has changed:\n'
+                    '            old key: {}\n'
+                    '            new key: {}\n'
+                    'this is a critical security error, quitting...'
+                    .format(oldkey, newkey))
+        exit(1)
+
+
+
 # GPG Verification
 class GPGVerifier(Verifier):
 
@@ -279,6 +290,8 @@ class GPGVerifier(Verifier):
             return None
         sign_status = verify_cli(pub_key, self.package_path, self.package_sign_path)
         if sign_status is None:
+            if config.old_keyid:
+                compare_keys(KEYID_TRY, config.old_keyid)
             self.print_result(self.package_path)
             KEYID = KEYID_TRY
             config.signature = self.key_url