Patent ID: 11968202
Assignee: AVAST SOFTWARE S.R.O.
Field: Digital communication (Electrical engineering)
Classification: CPC H | IPC H

Claim 8:
9. A method of authenticating a user to a computer in an adverse environment, comprising:
receiving a user's password in a trusted user device;
initiating a login process in the computer;
generating a random challenge comprising a character string in the computer;
encoding generated random challenge in a first message and appending a known prefix and a known suffix to the first message to generate a random challenge message in the computer;
sending the random challenge message to the trusted user device via a display coupled to the computer, wherein the generated random challenge is used a single time in authenticating the user;
receiving the random challenge message in the trusted user device via a camera coupled to the trusted user device;
validating the received random challenge message by finding the known prefix and the known suffix in the random challenge message and extracting the generated random challenge in the trusted user device;
encoding the extracted random challenge using a hash of the user's password in the trusted user device to generate an entered password hash-encoded random challenge, wherein encoding the random challenge comprises performing a bitwise exclusive-OR of the hash of the user's received password and the random challenge;
sending the entered password hash-encoded random challenge from the user's trusted device to the computer via a display coupled to the user's trusted device;
receiving the entered password hash-encoded random challenge in the computer via a camera coupled to the computer;
encoding the random challenge using a known hash value of the user's password to generate a known password hash-encoded random challenge; and
authenticating the user by comparing the known password hash-encoded random challenge to the entered password hash-encoded random challenge in the computer.