Abstract:
A method for protecting digital information which places a financial risk on a purchaser of digital information if the digital information is illegally copied is disclosed. The digital information being purchased is first encoded using a public key before being distributed to the purchaser. Each time the digital information is used, the digital information must be decoded using a private key which is stored on a smart card such as a credit card or an identification card, wherein the private key can not be used until the user of the smart card has been properly authenticated.

Description:
FIELD OF THE INVENTION  
         [0001]    The invention relates to the distribution of data, and more particularly to controlling the use of the distributed data so as to make it financially risky for the user to illegally copy and distribute the data.  
         BACKGROUND OF THE INVENTION  
         [0002]    The explosion in the use of computers and networks such as the Internet has lead to problems with respect to the protection of rights to data and information. These problems are a result of the ease at which digital information can be transmitted and copied.  
           [0003]    The storage of information in digital form depends on the ability to encode information in binary form to arbitrary precision and to record that binary form in a physical medium that can take on two distinct characteristics. Preserving the fidelity of information recorded in binary is easily accomplished. For example, a compact disc stores information as the presence or absence of a hole that reflects or does not reflect light. Compared to the analog recording of phonographic records, the information stored in each hole is unambiguously a binary digit, the value of which is either zero or one. No other values are possible. Digitally stored information may include binary data, computer software, text, graphics, audio, and video. The uses of this information include news, entertainment, education and analysis. Information may be distributed in many ways, including networks, magnetic media, CD-ROM, semiconductor memory modules, and wireless broadcast.  
           [0004]    A digital file can be copied with no loss of fidelity. As a result, it is now almost impossible to differentiate a digital copy from the digital original. In a network environment, recording materials, reproduction equipment and distribution are not implements to copying. Consequently, in the digital domain, the threshold inhibiting the making of illegal copies is significantly lowered. This is a particular problem for computer software, music, literature, audio and/or video information. This illegal copying of digital information results in billions of dollars worth of lost sales.  
           [0005]    To combat the illegal copying of digital information, many different technical solutions have been developed. Unfortunately, these technical solutions usually make it harder for the purchasing consumer to use the software or information. In addition, people intent on illegally copying the digital information simply devise new ways of getting around the protection schemes. As a result, many companies have abandoned these technical solutions.  
           [0006]    Another problem with illegal copying is that many consumers do not realize that their actions are in fact illegal. They do not view making a copy of a new computer game for a friend to be illegal. Furthermore, even if the person does realize that his/her actions are illegal, the person knows that the software company or music company will not be coming after individual people so long as the illegal copying is kept to just several copies. In other words, there is virtually no risk involved for the “small time” copier.  
           [0007]    Another method for protecting digital information is disclosed in U.S. Pat. No. 6,005,935. In this method, the purchaser provides the seller of the digital information with personal information such as purchaser&#39;s name, address, telephone number, mother&#39;s maiden name, spouse&#39;s name, children&#39;s names, birthdate, social security number, credit card number, and/or bank account information. The seller then encrypts the digital information using a key made up from some of the personal information. The purchaser is then prompted to enter the personal information before being granted access to the digital information. The problem with this solution is that prospective purchasers will very wary of giving all of this personal information to an individual or company who they do not know. With all of this personal information, the seller can make fraudulent purchases which would be charged to the innocent purchaser. As a result, the prospective purchaser will be more inclined to buy the digital information or a suitable equivalent of the digital information from another seller who does not require such personal information from their purchasers.  
           [0008]    Thus, there is a need for a method for protecting digital information which provides protection for both the seller and purchaser while placing a risk on each purchaser of digital information if the information is illegally copied.  
         SUMMARY OF THE INVENTION  
         [0009]    It is an object of the invention to overcome the above-described deficiencies of the prior art by disclosing a method for protecting digital information which places a financial risk on a purchaser of digital information if the digital information is illegally copied. According to one embodiment of the invention, the digital information being purchased is first encoded using a public key before being distributed to the purchaser. Each time the digital information is used, the digital information must be decoded using a private key which is stored on a smart card such as a credit card or an identification card, wherein the private key can not be used until the user of the smart card has been properly authenticated.  
           [0010]    According to one embodiment of the invention, a method for controlling the use of data on a device by a user is disclosed. A smart card is issued to the user by a first party, wherein a private key which is assigned to the user is stored on the smart card, wherein the private key is usable but not known by the user and the private key can not be used until the card is activated by authenticating that the user is authorized to use the smart card. The data to be sent to the user is encrypted using a public key assigned to the user before distributing the data to the user. After distribution of the data to the user, the user is prompted to enter a private key each time the user wants to use the data, wherein the user inserts the smart card into a smart card reader connected to the device and activates the smart card, wherein the device decrypts the encrypted data using the private key.  
           [0011]    According to another embodiment of the invention, a method for controlling the use of data on a device by a user is disclosed. A smart card is issued to the user by a first party, wherein a first private key which is assigned to the user is stored on the smart card, wherein the first private key is usable but not known by the user and the first private key can not be used until the card is activated by authenticating that the user is authorized to use the smart card. The user then obtains at least a second set of public and private keys and storing the at least second private key on the smart card. The data to be sent to the user is encrypted using a first public key assigned to the user and the second public key before distributing the data to the user. After distribution of the data to the user, the user is prompted to enter the first and at least second private keys each time the user wants to use the data, wherein the user inserts the smart card into a smart card reader connected to the device and activates the smart card, wherein the device decrypts the encrypted data using the first and at least second private keys.  
           [0012]    According to another embodiment of the invention, a method for controlling the use of data on a device by a user is disclosed. The data to be sent to the user is encrypted using at least one public key assigned to the user before distributing the data to the user. After distribution of the data to the user, the user is prompted to enter at least one private key each time the user wants to use the data, wherein the at least one private key is stored on a smart and the at least one private key is usable but not known by the user and the at least one private key can not be used until the card is activated by authenticating that the user is authorized to use the smart card, wherein the user inserts the smart card into a smart card reader connected to the device and activates the smart card, wherein the device decrypts the encrypted data using the private key.  
           [0013]    These and other aspects of the invention will be apparent from and elucidated with reference to the embodiments described hereafter. 
       
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS  
       [0014]    The invention will now be described, by way of example, with reference to the accompanying drawings, wherein:  
         [0015]    [0015]FIG. 1 is a block diagram of a system in which the various embodiment of the invention can operate;  
         [0016]    [0016]FIG. 2 is a flow chart illustrating the operation of the method for protecting digital information according to one embodiment of the invention; and  
         [0017]    [0017]FIG. 3 is a flow chart illustrating the operation of the method for protecting digital information according to another embodiment of the invention. 
     
    
     DETAILED DESCRIPTION  
       [0018]    [0018]FIG. 1 illustrates the parties of a transaction performed in accordance with one embodiment of the invention. The main parties to the transaction are the purchaser  102 , the seller,  104  and a trusted third party  106  such as a bank or a credit card company. Each of the parties has a computer system  103 ,  105  and  107 , respectively. The purchaser&#39;s computer system may be any number of electronic devices with processing capabilities for processing digital information, such as a personal computer, personal digital assistant, television, music system, etc. The purchaser&#39;s computer system  103  also has a smart card reader  112  either built into the system or attached thereto.  
         [0019]    A method for protecting digital information from illegal copying according to one embodiment of the invention will now be described with reference to FIG. 2. The invention uses asymmetric keys in the transaction. Asymmetric keys comprise a public key and a private key, wherein information encrypted with a public key can only be decrypted by the private key and vice versa. In this embodiment of the invention, a purchaser  102  obtains a smart card  108  from the trusted third party  106  in step  202 . The smart card  108  can be a credit card, debit card, identification card, etc. Prior to giving the smart card  108  to the purchaser  102 , the trusted third party (or someone hired by the trusted third party)  106  selects an asymmetric pair of keys for the purchaser and stores the private key on the smart card  108 . The private key is stored on the smart card  108  in such a manner that the private key can be used by the purchaser  102  but is not known by the purchaser  102  or at least makes it difficult for the purchaser to discover the private key. The public key is then given to the purchaser and/or placed in a public database  110 . The purchaser then selects an activation code such as a personal identification code (PIN) or some biometric identification code which is also stored on the smart card  108 .  
         [0020]    In step  204 , when the purchaser  102  wants to buy digital information, e.g., computer software, music, literature, audio and/or video information, etc., the purchaser contacts the seller  104 , for example over the Internet or via telephone but the invention is not limited thereto. Once the seller  104  and the purchaser  102  have agreed to the sale of the digital information, the seller  104  retrieves the purchaser&#39;s public key from either the purchaser  102  or the database  110 . The seller then encrypts the digital information using the purchaser&#39;s public key on the seller&#39;s computer system  105  in step  206 . The seller then sends the encoded digital information to the purchaser by uploading/downloading the encoded digital information to the purchaser&#39;s computer system  103 , mailing the encoded digital information on a CD to the purchaser, or the like. The purchaser  102  then pays the trusted third party  106  for the digital information and the trusted third party pays the seller  104 .  
         [0021]    Each time the purchaser wants to use the encoded digital information, the purchaser  102  is prompted, in step  208 , by whatever electronic device is trying to use the encoded digital information, such as the computer system  103 , to enter the private key so that the encoded digital information can be decoded. The purchaser  102  then inserts the smart card  108  into the smart card reader  112  in step  210 . However, before the computer system  103  can access the private key stored on the smart card  108 , the purchaser must first activate the smart card by entering the correct activation code or biometric identification code so as to authenticate that the purchaser is the proper user of the smart card  108  in step  212 . The biometric identification code can be entered using a biometric scanner (not illustrated) or the like connected to the computer system  103 . Once the smart card has been properly activated, the computer system  103  (or a processing device connected to the computer system  103 ) can access the private key and then use the private key to decrypt the encoded digital information in step  214 . Alternatively, a processor in the smart card  108  can be used to decrypt the encoded digital information. By performing the decryption in the smart card, the private key never leaves the smart card which makes it very difficult for someone to steal the private key.  
         [0022]    In this embodiment of the invention, the purchaser  102  gives the seller  104  some personal information, i.e., the public key, but the seller cannot fraudulent use the information since the seller does not know the private key and activation code. Thus, the purchaser  102  is protected from fraudulent actions by the seller  104 . In addition, the purchaser&#39;s smart card and activation code are needed whenever someone wants to use the digital information. Since most people will not want to give control of their smart card and activation code to friends or strangers, the digital information is protected from illegal copying.  
         [0023]    One drawback with the above-described embodiment of the invention is that the trusted third party  106  may know all of the personal information (public key, private key, activation code) of the purchaser  102 . In order to provide an extra layer of security for the purchaser  102 , at least a second set of asymmetric keys can be used in the transaction as illustrated in FIG. 3. In this embodiment of the invention, a purchaser  102  obtains a smart card  108  from the trusted third party  106  in step  302 . Prior to giving the smart card  108  to the purchaser  102 , the trusted third party (or someone hired by the trusted third party)  106  selects a first asymmetric pair of keys for the purchaser and stores the first private key on the smart card  108 . The first private key is stored on the smart card  108  in such a manner that the first private key can be used by the purchaser  102  but is not known by the purchaser  102  or at least makes it difficult for the purchaser to discover the first private key. The first public key is then given to the purchaser and/or placed in a public database  110 . The purchaser then selects an activation code such as a personal identification code (PIN) or some biometric identification code which is also stored on the smart card  108  which is used to authenticate the identity of the user.  
         [0024]    Once the purchaser has received the smart card  108 , the purchaser selects at least a second pair of asymmetric keys in step  304 . While the rest of this illustrative description will discuss just a second pair of asymmetric keys, it will be understood by one skilled in the art that multiple pairs of asymmetric keys could also be selected and used by the purchaser. The purchaser  102  then stores the second private key on the smart card  108  in step  306  and either keeps and/or sends the second public key to the public database  110 . The purchaser  102  may use a machine at the offices of the trusted third party, the Internet or a variety of other means, such as an enhanced smart card reader/burner, for selecting and storing the second pair of asymmetric keys. As a result, only the purchaser  102  knows the second private key stored on the smart card  108 .  
         [0025]    In step  308 , when the purchaser  102  wants to buy digital information, e.g., computer software, music, literature, audio and/or video information, etc., the purchaser contacts the seller  104 , for example over the Internet or via telephone but the invention is not limited thereto. Once the seller  104  and the purchaser  102  have agreed to the sale of the digital information, the seller  104  retrieves the purchaser&#39;s first and second public keys from either the purchaser  102  or the database  110 . The seller then encrypts the digital information using the purchaser&#39;s first and second public key on the seller&#39;s computer system  105  in step  310 . The seller then sends the encoded digital information to the purchaser by uploading/downloading the encoded digital information to the purchaser&#39;s computer system  103 , mailing the encoded digital information on a CD to the purchaser, or the like. The purchaser  102  then pays the trusted third party  106  for the digital information and the trusted third party pays the seller  104 .  
         [0026]    Each time the purchaser wants to use the encoded digital information, the purchaser  102  is prompted, in step  312 , by whatever electronic device is trying to use the encoded digital information, such as the computer system  103 , to enter the first and second private keys so that the encoded digital information can be decoded. The purchaser  102  then inserts the smart card  108  into the smart card reader  112  in step  314 . However, before the computer system  103  can access the private keys stored on the smart card  108 , the purchaser must first activate the smart card by entering the correct activation code or biometric identification code so as to authenticate that the purchaser is the proper user of the smart card  108  in step  316 . Once the smart card has been properly activated, the computer system  103  (or a processing device connected to the computer system) can access the first and second private keys and then use the first and second private keys to decrypt the encoded digital information in step  318 . Alternatively, a processor in the smart card  108  can be used to decrypt the encoded digital information.  
         [0027]    In this embodiment of the invention, since the seller  104  and the trusted third party  106  do not know the second private key, the purchaser  102  is protected from the fraudulent use of the personal information by the seller  104  and the trusted third party  106 . At the same time, the digital information is protected from illegal copying by the financial risk the purchaser would be exposed to if the purchaser gives his/her smart card and activation code to other people.  
         [0028]    The above-described embodiments of the invention provide an improved method for protecting digital information from illegal copying while also providing a method of transacting a sale in which all of the parties take no additional risks than are normally present in a transaction. It will be understood that the different embodiments of the invention are not limited to the exact order of the above-described steps as the timing of some steps can be interchanged without affecting the overall operation of the invention. Furthermore, the term “comprising” does not exclude other elements or steps, the terms “a” and “an” do not exclude a plurality and a single processor or other unit may fulfill the functions of several of the units or circuits recited in the claims.