Cryptographers have once again put SSL/TLS (thats the padlock in HTTPS) in their gunsights and opened fire. The attack theyve devised doesnt work against all possible ways that TLS can be used; it requires you to capture somewhere between millions and billions of connections that all contain the same plaintext. But it reveals a deep-rooted problem in using the RC4 encryption algorithm to secure your TLS traffic. It only works well for the first 200 bytes or so of the transmitted data. But replacing or banning RC4 in existing cryptographic implementations is a much trickier problem.”]
Source: https://nakedsecurity.sophos.com/2013/03/16/has-https-finally-been-cracked/