Say, are you wanting to encrypt your computer's hard drive? Not sure which style or method of encryption you ought to use? Have I got a suggestion for you! Do what Josh Powell did.
Way back in 2009, police confiscated a 1TB Western Digital “My Book World Edition” external hard drive from Josh Powell's home because they thought it might contain evidence to help find his missing wife Susan. The entire drive was locked with encryption. All the police needed to do was crack its password. On television, this process only takes a few minutes--how hard could it be?
The first attempt was made by the Intermountain West Regional Computer Forensics Laboratory in Salt Lake City. There, FBI agents and West Valley Police detectives worked together and successfully mirrored the drive, but all of their forensic software tools failed to crack it. They also tried numerous "brute force" attacks, but these also failed to crack the password-protected drive.
Next, the lab sent a mirror of the drive to FBI headquarters in Quantico, Virginia. After more than a year, FBI headquarters gave up and returned the drive to Utah, still uncracked.
After that, West Valley police requested help from AccessData, the company that produced the forensic tool kits used by the federal government. The city then submitted a mirror of the drive to the Secret Service, but in May 2011, the Secret Service reported that it was also unable to crack the encryption.
In October of 2013, after the case had gone "cold" and a judge had lifted its secrecy order, Susan’s father suggested that police enlist a Utah company called Decipher Forensics. The police submitted a mirror to them in December of 2013. Four years later, Decipher had still not succeeded in cracking the drive.
So if you want your data to be secure from the local police, the FBI, the Secret Service, and the companies which write the very software used to crack encryption, I suggest you follow Josh Powell's example by using long, very strong passwords.