diff --git a/fdroidserver/common.py b/fdroidserver/common.py
index 7160809e..3905c45e 100644
--- a/fdroidserver/common.py
+++ b/fdroidserver/common.py
@@ -3408,13 +3408,45 @@ def verify_apks(signed_apk, unsigned_apk, tmp_dir, v1_only=None):
     return None
 
 
-def verify_deprecated_jar_signature(jar):
+def verify_jar_signature(jar):
     """Verify the signature of a given JAR file.
 
     jarsigner is very shitty: unsigned JARs pass as "verified"! So
     this has to turn on -strict then check for result 4, since this
     does not expect the signature to be from a CA-signed certificate.
 
+    Raises
+    ------
+    VerificationException
+        If the JAR's signature could not be verified.
+
+    """
+    error = _('JAR signature failed to verify: {path}').format(path=jar)
+    try:
+        output = subprocess.check_output(
+            [config['jarsigner'], '-strict', '-verify', jar], stderr=subprocess.STDOUT
+        )
+        raise VerificationException(error + '\n' + output.decode('utf-8'))
+    except subprocess.CalledProcessError as e:
+        if e.returncode == 4:
+            logging.debug(_('JAR signature verified: {path}').format(path=jar))
+        else:
+            raise VerificationException(error + '\n' + e.output.decode('utf-8')) from e
+
+
+def verify_deprecated_jar_signature(jar):
+    """Verify the signature of a given JAR file, allowing deprecated algorithms.
+
+    index.jar (v0) and index-v1.jar are both signed by MD5/SHA1 by
+    definition, so this method provides a way to verify those.  Also,
+    apksigner has different deprecation rules than jarsigner, so this
+    is our current hack to try to represent the apksigner rules when
+    executing jarsigner.
+
+    jarsigner is very shitty: unsigned JARs pass as "verified"! So
+    this has to turn on -strict then check for result 4, since this
+    does not expect the signature to be from a CA-signed certificate.
+
     Also used to verify the signature on an archived APK, supporting deprecated
     algorithms.
 
diff --git a/tests/common.TestCase b/tests/common.TestCase
index d4658308..c3ca5dda 100755
--- a/tests/common.TestCase
+++ b/tests/common.TestCase
@@ -529,6 +529,35 @@ class CommonTest(unittest.TestCase):
         self.assertRaises(VerificationException, fdroidserver.common.verify_deprecated_jar_signature, 'urzip-badsig.apk')
         self.assertRaises(VerificationException, fdroidserver.common.verify_deprecated_jar_signature, 'urzip-release-unsigned.apk')
 
+    def test_verify_jar_signature(self):
+        """Sign entry.jar and make sure it validates"""
+        config = fdroidserver.common.read_config(fdroidserver.common.options)
+        config['jarsigner'] = fdroidserver.common.find_sdk_tools_cmd('jarsigner')
+        config['keystore'] = os.path.join(self.basedir, 'keystore.jks')
+        config['repo_keyalias'] = 'sova'
+        config['keystorepass'] = 'r9aquRHYoI8+dYz6jKrLntQ5/NJNASFBacJh7Jv2BlI='
+        config['keypass'] = 'r9aquRHYoI8+dYz6jKrLntQ5/NJNASFBacJh7Jv2BlI='
+        fdroidserver.common.config = config
+        fdroidserver.signindex.config = config
+        repo_dir = Path(self.testdir) / 'repo'
+        repo_dir.mkdir()
+        shutil.copy('repo/entry.json', repo_dir)
+        shutil.copy('repo/index-v2.json', repo_dir)
+        os.chdir(self.testdir)
+        fdroidserver.signindex.sign_index('repo', 'entry.json')
+        fdroidserver.common.verify_jar_signature('repo/entry.jar')
+
+    def test_verify_jar_signature_fails(self):
+        """Test verify_jar_signature fails on unsigned and deprecated algorithms"""
+        config = fdroidserver.common.read_config(fdroidserver.common.options)
+        config['jarsigner'] = fdroidserver.common.find_sdk_tools_cmd('jarsigner')
+        fdroidserver.common.config = config
+        source_dir = os.path.join(self.basedir, 'signindex')
+        for f in ('unsigned.jar', 'testy.jar', 'guardianproject.jar', 'guardianproject-v1.jar'):
+            testfile = os.path.join(source_dir, f)
+            with self.assertRaises(fdroidserver.index.VerificationException):
+                fdroidserver.common.verify_jar_signature(testfile)
+
     def test_verify_deprecated_jar_signature(self):
         config = fdroidserver.common.read_config(fdroidserver.common.options)
         config['jarsigner'] = fdroidserver.common.find_sdk_tools_cmd('jarsigner')