Patent ID: 7945776

Claim:
A method of restricting access to a target system, comprising: receiving an encrypted passphrase, wherein the encrypted passphrase is resented by a user requesting access to the target system; obtaining a secret key associated with the target system; receiving unencrypted information associated with the encrypted passphrase; receiving a user PIN; generating a token key using the secret key associated with the target system and the unencrypted information associated with the encrypted passphrase; generating an encryption key using the secret key, the user PIN, and the unencrypted information; generating a decrypted passphrase from the encrypted passphrase using the encryption key to decrypt the encrypted passphrase, the decrypted passphrase including a first portion and a second portion, wherein the first portion of the decrypted passphrase is generated by one-way encoding at least a portion of access credentials of the user using the token key, wherein the second portion of the decrypted passphrase includes the portion of the access credentials; one-way encoding the second portion of the decrypted passphrase using the token key to provide a one-way encoded portion of the decrypted passphrase; comparing the one-way encoded portion of the decrypted passphrase with the first portion of the decrypted passphrase; and denying access into the target system if the one-way encoded portion of the decrypted passphrase does not match the first portion of the decrypted passphrase.