What is one common technique used to protect a password file?

• A. Storing passwords in plain text
• B. Using hashed passwords with a salt value
• C. Encrypting files with symmetric encryption
• D. Backing up passwords to a cloud service

Answer: (B)

Using hashed passwords with a salt value is a widely recognized method for securing password files. This technique enhances password security by transforming the original password into a fixed-length string of characters, known as a hash, using a hashing algorithm. A key aspect of this method is the incorporation of a salt value, which is a random string added to the password before hashing. The purpose of the salt is to ensure that even if two users have the same password, their hashed values will be uniquely different because of the unique salts.

This approach provides protection against common attacks such as rainbow table attacks, where attackers use precomputed tables of hashed values to crack passwords quickly. By salting passwords, the complexity of these attacks increases significantly, making it much harder for attackers to gain access to user accounts.

Moreover, storing passwords in plain text or encrypting files with symmetric encryption can introduce vulnerabilities. Plain text storage leaves passwords exposed if the file is accessed unauthorizedly, while symmetric encryption, although securing the data in transit, requires careful management of the encryption key, which could also be targeted by attackers. Backing up passwords to a cloud service poses additional risks, especially if proper security measures are not implemented, making the use of salted hashes a more robust solution for password protection.