My Samsung Galaxy Note II was infected by a virus called the "FBI virus." Fortunately, I've managed to remove the malware but my problem now is that all my files have been encrypted.
How can I decrypt these files and recover my data?
If the malware is same as the one identified as Andr/FBILock-A by anti-virus firm Sophos, they have detailed removal instructions here:
It appears that (according to Sophos) this malware does not actually encrypt files, so you may be the victim of some other attack.
this is an image they posted of the malware:
An online decryption tool is available from FireEye:
The thing to note here is that it is specific to certain types of Ransomwares. If you are encrypted by a new variant of Ransomware then it might not decrypt.