Secure user authentication from personal computer

Claim 3

The method of claim 1 wherein the storage medium is received by a powered down computing machine.

Claim 4

The method of claim 1 further comprising the step of: (a) determining whether the user's storage medium is write protected; and (b) if so, clearing the password from the computing machine's memory, terminating the hash of the password, and halting the computing machine's operations.

Claim 5

The method of claim 1 further comprising the step of writing to the user's storage medium the number of passwords entered.

Claim 6

The method of claim 4 further including the step of halting the computing machine's operations when the number of passwords entered exceeds a preselected number.

Claim 7

The method of claim 1 wherein the computing machine's memory contains an operating system and the user's storage medium contains a list of acceptable values representing acceptable operating system files, the method further comprising the steps of: (a) computing a value as a specified function of the operating system file of the computing machine; (b) comparing the computed value to the list of acceptable values; and (c) advising the user if the calculated value does not match any of the values on the list of values representing acceptable operating systems.

Claim 9

A security device for authenticating a user on a computer, the security device comprising a machine-readable storage medium on which is recorded: (a) a machine readable embodiment of the user's long term private encryption key, wherein the private encryption key is encrypted under a key consisting of a slow hash of the user's password; (b) a first group of trusted machine executable instructions for carrying out cryptographic calculations; and (c) a second group of trusted machine executable instructions for performing a slow hash of received passwords.

Claim 10

A security device for authenticating a user on a computer, the security device comprising a machine-readable storage medium on which is recorded: (a) a machine readable embodiment of the user's long term private encryption key, wherein the private encryption key is encrypted under a key consisting of a slow hash of the user's password; (b) a first group of trusted machine executable instructions for carrying out cryptographic calculations; and (c) a second group of trusted machine executable instructions for performing a slow hash of received passwords.

Claim 11

The security device of claim 8 further comprising a machine readable representation of the public key of the user's certifying authority.

Claim 12

The security device of claim 8 further comprising a machine readable representation of the time of the user's last login.

Claim 13

The security device of claim 8 further comprising a machine readable representation of the number of incorrect passwords entered.

Claim 14

The security device of claim 8 further comprising a machine readable representation of a list of names and message digests of acceptable operating system images which the user is willing to boot the computer with.

Claim 15

The security device of claim 8 wherein the security device is a floppy disk.

Claim 16

A security device for authenticating a user on a computer, the user having a public and private key and a certifying authority, comprising a floppy disk containing a machine readable representation of: (a) the user's long term secret, a private key encrypted under a key consisting of a slow hash of a password known only to the user; (b) the public key of the user's certifying authority; (c) the time of the user's last login; (d) the number of incorrect passwords entered; (e) a first machine executable trusted program that can carry out cryptographic calculations and authentications; (f) a second machine executable trusted program that can carry out a slow hash of a password and a trusted message program; and (g) a list of names and message digests of acceptable operating system images with which the user is willing to boot the personal computer.

Claim 17

A security device for authenticating a user on a computer, the user having a public and private key and a certifying authority, comprising a floppy disk containing a machine readable representation of: (a) the user's long term secret, a private key encrypted under a key consisting of a slow hash of a password known only to the user; (b) the public key of the user's certifying authority; (c) the time of the user's last login; (d) the number of incorrect passwords entered; (e) a first machine executable trusted program that can carry out cryptographic calculations and authentications; (f) a second machine executable trusted program that can carry out a slow hash of a password and a trusted message program; and (g) a list of names and message digests of acceptable operating system images with which the user is willing to boot the personal computer.