Abstract: A secure signal transmitter, such as an LED, is disposed in an intended observation scope of a secure stream capture device, such as a video camera. The secure signal transmitter continuously transmits a secure signal that an observer/processor in a remote location can verify, to thereby confirm that the video being sent from the camera actually encompasses the intended scope.

Abstract: A hand-held sonic token can be used as a pseudorandom oracle for a requesting application, which can generate a challenge that is sent to the token. The user of the token decides whether to allow the token to function as an oracle, and if so, the user causes the token to digitally sign the challenge and send it back to the requesting application, for use of the digitally signed challenge as an encryption key. After encryption the requesting application deletes the signed challenge, with subsequent decryption essentially following the encryption process.

Abstract: A hand-held token can be operated to generate an acoustic signal representing the digital signature generated by a private key of a public key/private key pair. Verifiers that might be located at, e.g., buildings, in vehicles, at bank ATMs, etc. receive the signal and retrieve the corresponding public key to selectively grant access authorization to components served by the verifiers. Methods and systems permit adding and removing a token from the access list of a verifier. Other methods and systems enable the token to be used with several verifiers that are nearby each other, such as might be the case with multiple vehicles owned by the same user and parked nearby each other, without more than one verifier being operated to grant access.

Abstract: A hand-held token can be operated to generate an acoustic or other wireless signal representing a digital signature produced from the private key of a public key/private key pair, with the public key being confidential in that it is known only to authorized entities, such as bank computers. The signal from the token can be received by, e.g., a receiver at a bank ATM that also requires a PIN for account access. The user enters the PIN into the ATM, and the ATM encrypts the signal from the token with the PIN and sends it on to the bank computer over a link that need not be secure, since even if the PIN is guessed there is no way to verify that it is the correct PIN without also knowing the confidential public key held by the bank computer.

Abstract: An apparatus and method for authentication having a processor and at least one activator coupled to the processor is claimed. A signature generator is coupled to the processor and capable of generating a secure identifier. An emitter coupled to the signal generator capable of emitting the secure identifier. A receiver receives the emitted secure identifier and verifies that the secure identifier was appropriately transmitted. The public key corresponding to the key identifier transmitted is accessed to determine the validity of the secure identifier using the accessed key and that the time indicated in the received secure identifier is verified to be within acceptable time tolerances.