# Is SHA-256 safe and difficult to crack? [duplicate]

I am trying to crack a SHA-256 hash but I am not sure how to approach this in an efficient way. The following is known of the original non-hashed content:

• 64 characters long
• only consists 0-9 and a-z (no capital letters)
• the original content does not consist dictionary words
• the hash is not salted

I have done some reading on the subject of cracking hashes and some information I have read is conflicting. For example, one said on a public forum that SHA-256 is virtually impossible to crack while the other said that it's a rather poor method for password storage as it could be cracked easily.

Is SHA-256 a safe method to hash passwords with (if not, what are the alternatives) and how do I crack a given hash in an efficient way (assuming the given criteria above).

• If 'does not consist of dictionary words' means 'each character random' (even mostly), no hope. If it means 'is not entirely dictionary words, but is largely words with some added dingbats and leeting and such' that's where modern password crackers like John and ocl aim and might succeed. – dave_thompson_085 May 29 '16 at 6:10

• To elaborate on the "you won't be able", the password has $36^{64}$ possible values equaling $\log_2(36^{64})\approx 330$ bit key strength which is physically impossible to crack. – SEJPM May 28 '16 at 13:42