Microsoft has disabled support for the RC4 cipher in Internet Explorer 11 and Edge as part of an update distributed by the company.
Microsoft stated that RC4 was “now deprecated” as part of its KB3151631 update.
“There is consensus across the industry that RC4 is no longer cryptographically secure,” said Microsoft.
RC4 is a stream cipher that has been widely supported across web browsers and online services, said Microsoft.
“Modern attacks have demonstrated that RC4 can be broken within hours or days.”
“Previously, Microsoft Edge and Internet Explorer 11 allowed RC4 during a fallback from TLS 1.2 or 1.1 to TLS 1.0.