The password breach, revealed on Wednesday, is significant due to the detailed personal data stored by LinkedIn and the chance for hackers to spear phish high-level executives or spread malicious links.

LinkedIn is telling some users to reset their passwords, but there is another way for users to see if their account was compromised.

converts a person's clear-text password into its corresponding cryptographic representation using the SHA-1 algorithm, which was stored by LinkedIn. It does that conversion in the browser using JavaScript and does not transmit the password elsewhere, wrote one of LeakedIn's developers, Chris Shiflett, on his .

LeakedIn then checks to see if the hash is on the list of breached passwords. Not all of the hashes in the list have been converted to original passwords yet, but it is likely hackers are working on it. Shiflett wrote that "I discovered that my password was not only one of the 6.5 million that had been leaked, it was also among those that had been cracked. I was a victim."

Password hashes can be converted to plain-text by using powerful graphics processors and free password cracking tools such as "John the Ripper," which can be used with a regular PC, and "oclHashcat." How long that process takes depends on the passwords' complexity.