Index: typo3/sysext/openid/lib/php-openid/Auth/OpenID/Consumer.php
===================================================================
--- typo3/sysext/openid/lib/php-openid/Auth/OpenID/Consumer.php	(revision 7119)
+++ typo3/sysext/openid/lib/php-openid/Auth/OpenID/Consumer.php	(working copy)
@@ -957,7 +957,11 @@
             }
 
             if (!$assoc->checkMessageSignature($message)) {
-                return new Auth_OpenID_FailureResponse(null,
+				// If we get a "bad signature" here, it means that the association
+				// is unrecoverabley corrupted in some way. Any futher attempts
+				// to login with this association is likely to fail. Drop it.
+				$this->store->removeAssociation($server_url, $assoc_handle);
+				return new Auth_OpenID_FailureResponse(null,
                                                        "Bad signature");
             }
         } else {
Index: typo3/sysext/openid/sv1/class.tx_openid_store.php
===================================================================
--- typo3/sysext/openid/sv1/class.tx_openid_store.php	(revision 7119)
+++ typo3/sysext/openid/sv1/class.tx_openid_store.php	(working copy)
@@ -102,8 +102,13 @@
 
 		$result = null;
 		if (is_array($row)) {
-			$result = @unserialize($row['content']);
-			$this->updateAssociationTimeStamp($row['tstamp']);
+			$result = @unserialize(base64_decode($row['content']));
+			if ($result === false) {
+				$result = null;
+			}
+			else {
+				$this->updateAssociationTimeStamp($row['tstamp']);
+			}
 		}
 		return $result;
 	}
@@ -201,7 +206,7 @@
 			time());
 		$serializedAssociation = serialize($association);
 		$values = array(
-			'content' => $serializedAssociation,
+			'content' => base64_encode($serializedAssociation),
 			'tstamp' => time(),
 		);
 		$GLOBALS['TYPO3_DB']->exec_UPDATEquery(self::ASSOCIATION_TABLE_NAME, $where, $values);
@@ -218,7 +223,7 @@
 		$serializedAssociation = serialize($association);
 		$values = array(
 			'assoc_handle' => $association->handle,
-			'content' => $serializedAssociation,
+			'content' => base64_encode($serializedAssociation),
 			'crdate' => $association->issued,
 			'tstamp' => time(),
 			'expires' => $association->issued + $association->lifetime - self::ASSOCIATION_EXPIRATION_SAFETY_INTERVAL,