Cryptography Questions Long
A key stretching algorithm is a cryptographic technique used to enhance the security of passwords. It is designed to make it computationally expensive and time-consuming for an attacker to guess or crack the password.
The concept of a key stretching algorithm involves repeatedly applying a one-way function, such as a cryptographic hash function, to the password. This process is performed multiple times, with each iteration introducing a delay or additional computational effort. The number of iterations is typically set to a high value, making it more difficult for an attacker to guess the password through brute-force or dictionary attacks.
By using a key stretching algorithm, the time required to verify a password is increased, which in turn slows down an attacker's ability to guess the correct password. This added delay makes it less feasible for an attacker to perform large-scale password cracking attempts, as the computational cost becomes prohibitively high.
Furthermore, key stretching algorithms also provide resistance against precomputed tables or rainbow tables. These tables are precomputed lists of hash values for commonly used passwords, which can significantly speed up the process of cracking passwords. However, with key stretching, the repeated application of the one-way function makes it impractical to precompute tables for all possible password combinations.
In summary, the concept of a key stretching algorithm enhances password security by increasing the computational cost and time required to guess or crack passwords. It effectively slows down attackers, making large-scale password cracking attempts more difficult and time-consuming. Additionally, it provides resistance against precomputed tables, further strengthening the security of passwords.