Lately I have received email stating that a few things are changing in Authorize.net payment. Among a few items (changing urls, longer ids, tls 1.1 force etc) one is:
RC4 Cipher Disablement In an effort to ensure that all of your server-to-server communications with the Authorize.Net platform (both transactional and otherwise) maintain the highest levels of security, we will be disabling the RC4 cipher suite during the first half of 2016. A follow-up notification will be sent out once specific dates for the disablement are ready for the sandbox and production environments.
For now, if you have a solution that relies on RC4 to communicate with our servers, please update it to a current, high-security cipher as soon as possible. Please review our API best practices blog post for more information.
I haven't been able to find anything mentioning rc4 in civicrm authorize.net payment processor. Does anyone know if this relates to CiviCRM?