$re = '/(?!(value|id)(\":\s\"|\':\su\'))\b[a-fA-F\d]{32}/m';
$str = '"value": "ef51be4506d7d287abc8c26ea6c495f6", "u_jira_status": "", "u_quarter_closed": "", "file_hash": "ef51be4506d7d287abc8c26ea6c495f6", "escalation": "0", "upon_approval": "proceed", "correlation_id": "ef51be4506d7d287abc8c26ea6c495f6", "cyber_kill_change": "ef51be4506d7d287abc8c26ea6c495f6", "sys_id": "ef51be4506d7d287abc8c26ea6c495f6", "u_business_service": "", "destination_ip": "ef51be4506d7d287abc8c26ea6c495f6", u\'valuee\': u\'9db92f08db4f951423c87d84f39619ef\'
';
preg_match_all($re, $str, $matches, PREG_SET_ORDER, 0);
// Print the entire match result
var_dump($matches);
Please keep in mind that these code samples are automatically generated and are not guaranteed to work. If you find any syntax errors, feel free to submit a bug report. For a full regex reference for PHP, please visit: http://php.net/manual/en/ref.pcre.php