Shared key encryption using long keypads
First Claim
1. A method of securely communicating a message from a first terminal to a second terminal, comprising:
- generating a keypad by the first terminal comprising a random sequence of bits having a length L;
establishing a secure channel between the first terminal and the second terminal and transmitting the keypad from the first terminal to the second terminal over the secure channel;
encrypting the message at the first terminal using a bit string beginning at an offset O in the keypad; and
transmitting the encrypted message and an indicator of the offset O to the second terminal;
the method further comprising generating a secret key using a previously generated keypad to derive the secret key, and wherein establishing the secure channel between the first terminal and the second terminal comprises establishing a secret key encrypted communication channel between the first terminal and the second terminal using the secret key derived from the previously generated keypad.
1 Assignment
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Accused Products
Abstract
Methods of securely communicating a message from a first terminal to a second terminal include generating a keypad including a random sequence of bits having a length L, encrypting the message at the first terminal using a bit string beginning at an offset O in the keypad, and transmitting the encrypted message and an indicator of the offset O to the second terminal. A communication terminal includes a controller, a communication module configured to establish a location-limited communication channel, and an encryption unit configured to store a keypad including a random sequence of bits having a length L, to encrypt an outgoing message using the keypad, and to decrypt an incoming message using the keypad.
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Citations
21 Claims
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1. A method of securely communicating a message from a first terminal to a second terminal, comprising:
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generating a keypad by the first terminal comprising a random sequence of bits having a length L; establishing a secure channel between the first terminal and the second terminal and transmitting the keypad from the first terminal to the second terminal over the secure channel; encrypting the message at the first terminal using a bit string beginning at an offset O in the keypad; and transmitting the encrypted message and an indicator of the offset O to the second terminal; the method further comprising generating a secret key using a previously generated keypad to derive the secret key, and wherein establishing the secure channel between the first terminal and the second terminal comprises establishing a secret key encrypted communication channel between the first terminal and the second terminal using the secret key derived from the previously generated keypad. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20)
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21. A communication system, comprising:
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a first hardware terminal configured to generate a keypad comprising a random sequence of bits having a length L, to establish a secure channel, and to transmit the keypad over the secure channel; and a second hardware terminal configured to establish the secure channel with the first hardware terminal and to receive the keypad over the secure channel, wherein the first hardware terminal is further configured to encrypt a message using a bit string beginning at an offset O in the keypad, and to transmit the encrypted message and an indicator of the offset O to the second hardware terminal over a physically insecure channel; and the first hardware terminal is configured to generate a secret key using a previously generated keypad to derive the secret key, and to establish the secure channel by establishing a secret key encrypted communication channel between the first hardware terminal and the second hardware terminal using the secret key derived from the previously generated keypad.
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Specification