Method of deriving a per-message signature for a DSS or El Gamal encryption system
AssigneeDigital Equipment Corp., Patent Law Group
InventorsCharles W. Kaufman, Radia J. Perlman
Life of this patent
Estimating the term…
Abstract
A signature system, such as an El Gamal or DSS system, involving the use of a long-term secret number and a per-message secret number generates the per-message secret number without the use of a random number generator or non-volatile storage. The per-message secret number is generated by applying a one-way hash function to a combination of the long-term secret number and the message itself.
Claims12
A message authentication system of the type in which a signature of an originator of a message MSG, hereinafter the message originator, is transmitted to a recipient of the message and verified by the recipient, the message originator having a secret number S.sub.L and a corresponding public number P.sub.L, said system comprising:
- means for receiving the MSG;
- means for generating a secret message for each message, a per-message secret number, S.sub.M by applying a one-way hash function to a combination of MSG and a generated secret number of the message originator,
- means for generating a signature as a function of S.sub.L, S.sub.M and MSG.
A message authentication system comprising:
- A. a data terminal including:
- 1. means for receiving a message input and
- 2. means for communicating with a smart card, and
- B. the smart card configured to communicate with said terminal and including:
- 1. means for storing a secret number specific to an owner of the smart card,
- 2. means for generating a secret number for each message, hereinafter referred to as a per-message secret number by, applying a one-way hash function to a combination of (a) a secret number specific to the owner of the smart card and (b) a message received by said terminal by way of said message input means,
- 3. means for generating a signature as a function of said secret number, said per-message secret number and said message,
- 4. means for generating a per-message public number as a function of said per-message secret number;
- 5. means for transmitting to said terminal the signature and the per-message public number;
- and
- 6. means for verifying in the terminal.
A smart card for use in authenticating messages, said smart card including:
- A. means for storing a secret number specific to an owner of the smart card,
- B. means for receiving a message to be authenticated,
- C. means for generating a secret number for each message, hereinafter referred to as a per-message secret number, by applying a one-way hash function to a combination of said message and a secret number specific to said owner,
- D. means for generating a signature as a function of said secret number, said per-message secret number and said message, and
- E. means for transmitting said signature to a recipient.
A method for enabling verification of an originator of a message, said method comprising the steps of:
- A. generating a secret number for each message, hereinafter referred to as a per-message secret number, by applying a one-way hash function to a concatenation of said message with a secret number specific to the originator of the message,
- B. generating a signature as a function of a secret number specific to the originator of the message, the short-term secret number, and the message;
- and
- C. transmitting said signature and the message to a recipient for verification.
Dependencies are inferred from the claim text.