SHA512 is NOT a form of encryption, it is a form of hashing. Hashing is one-way - i.e. it cannot be decrypted. The only way to find a value from a hash is by rainbow tables, which is not an exact science, to say the least.
As such, SHA512 is more secure than an encryption method when it comes to a password, as you are never storing something that can be easily decrypted, merely collided with.
与恶龙缠斗过久,自身亦成为恶龙;凝视深渊过久,深渊将回以凝视…