#Pwsafe opens slowly trial

This process does not alter the original key-space entropy. This is because the user's computer only has to compute the stretching function once upon the user entering their password, whereas the attacker must compute it for every guess in the attack. Even if the attacker has much greater computing resources than the user, the key stretching will still slow the attacker down while not seriously affecting the usability of the system for any legitimate user. If the attacker uses the same class of hardware as the user, each guess will take the similar amount of time to process as it took the user (for example, one second).

#Pwsafe opens slowly trial

Attempt possible combinations of the weaker initial key, potentially commencing with a dictionary attack if the initial key is a password or passphrase, but the attacker's added effort for each trial could render the attack uneconomic should the costlier computation and memory consumption outweigh the expected profit.Attempt possible combinations of the enhanced key, but this is infeasible if the enhanced key is sufficiently long and unpredictable ( ⁠i.e., the algorithm mimics randomness well enough that the attacker must trial the entire stretched key space).Key stretching leaves an attacker with two options: If this added effort compares to a brute-force key search of all keys with a certain key length, then the input key may be described as stretched by that same length. This compels brute-force attackers to expend the same effort for each attempt. The algorithm must have no known shortcut, so the most efficient way to relate the input and cipher is to repeat the key stretching algorithm itself. Key stretching algorithms depend on an algorithm which receives an input key and then expends considerable effort to generate a stretched cipher (called an enhanced key ) mimicking randomness and longer key length. ( February 2020) ( Learn how and when to remove this template message)

Unsourced material may be challenged and removed. Please help improve this section by adding citations to reliable sources. Another way is to use cryptographic hash functions that have large memory requirements – these can be effective in frustrating attacks by memory-bound adversaries. For example, in applications where the key is used for a cipher, the key schedule in the cipher may be modified so that it takes a specific length of time to perform. One way is to apply a cryptographic hash function or a block cipher repeatedly in a loop. There are several ways to perform key stretching. Key stretching also improves security in some real-world applications where the key length has been constrained, by mimicking a longer key length from the perspective of a brute-force attacker. Passwords or passphrases created by humans are often short or predictable enough to allow password cracking, and key stretching is intended to make such attacks more difficult by complicating a basic step of trying a single password candidate. In cryptography, key stretching techniques are used to make a possibly weak key, typically a password or passphrase, more secure against a brute-force attack by increasing the resources (time and possibly space) it takes to test each possible key. JSTOR ( February 2020) ( Learn how and when to remove this template message).Please help improve this article by adding citations to reliable sources. This article needs additional citations for verification.