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Why is hash function slow?
The calculation is intentionally slowed down to make it harder for an attacker to brute-force the user passwords in case the password database gets stolen for example. Because a hash function only works “one way”, to get the password for a hash you have to hash random passwords until you find one with a matching hash.
What is a slow hash?
Slow hashes, on the other hand, have different design goals. They are expected to be copied and subsequently attacked by crackers. Thus, they are designed to be inefficient and more difficult to calculate. Some examples of these slow hashes are bcrypt, PBKDF2 and scrypt.
What is the purpose of storing the hash of the password instead of the password itself?
Hashing a password is good because it is quick and it is easy to store. Instead of storing the user’s password as plain text, which is open for anyone to read, it is stored as a hash which is impossible for a human to read.
Is hash function slow?
According to Jeff Atwood, “hashes, when used for security, need to be slow.” A cryptographic hash function used for password hashing needs to be slow to compute because a rapidly computed algorithm could make brute-force attacks more feasible, especially with the rapidly evolving power of modern hardware.
Why is password hashing a one way operation?
The reason hashing is secure is simple: hashing is a one way operation. They cannot be reversed. Given a string “eeb7048c69b088739908f5f5144cd1f5”, there is no way to reverse the MD5 hash to return “Jamin Becker”.
Is it good or bad to use password hashing?
If the time to go from password -> hash value take considerat time, brute force cracking will take way to long time. If it is fast, then brute force would be resonable, if not it is to bad to use. So slow algorithms are good for security.
How can I get a password from a hash?
One method that is commonly used to get the plain text password from a hash is called a brute force attack. In this attack, the attacker will run through a giant wordlist and hash each word with the appropriate hashing algorithm. They can then compare the hashes in the wordlist to the ones they have obtained from the database.
How is password hashing solved in polynomial time?
However, the un-hashing algorithms (i.e “eeb7048c69b088739908f5f5144cd1f5” -> “Jamin Becker”) fall under the P class and can only efficiently be solved in polynomial time (i.e using a quantum computer significantly more advanced then the ones available today). So why is this good for security?