# US 6,560,339 B1 · Electronic watermarking method, digital information distribution system using such method, and storage medium storing program of such method > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 6,560,339 B1 - Document ID: US6560339B1 - Status: Granted - Kind: B1 - Application number: 09/248,975 - Filed: 1999-02-12 - Granted: 2003-05-06 - Earliest claimed: 1998-02-17 - Assignees: Canon Kabushiki Kaisha - Inventors: Keiichi Iwamura - Web page: https://patentgrep.com/patent/US6560339B1 ## CPC - H04N 21/63775: {for uploading keys, e.g. for a client to communicate its public key to the server (key management H04L9/08; network support of key management H04L63/06)} - H04N 7/1675: {Providing digital key or authorisation information for generation or regeneration of the scrambling sequence (pseudo-random number generators in general G06F7/58)} - H04N 21/2347: involving video stream encryption - H04N 21/25875: {involving end-user authentication (restricting access to computer systems by authenticating users using a predetermined code G06F21/33; arrangements for secret or secure communication including means for verifying the identity or authority of a user of the system H04L9/32; networks authentication protocols H04L63/08; authentication in wireless network security H04W12/06)} - H04N 21/8358: involving watermark {(protecting executable software by watermarking G06F21/16; image watermarking in general G06T1/0021; watermarks inserted in still images for transmission purposes H04N1/32144; inserting watermarks during video coding H04N19/467)} - H04N: PICTORIAL COMMUNICATION, e.g. TELEVISION ## Abstract An electronic watermarking method includes the steps of generating a plurality piece of information with different electronic watermark information, generating a plurality piece of encrypted information through encryption of the plurality piece of information with each independent encryption key, generating a plurality of encrypted encryption keys through encryption of each independent encryption key with each different encryption key, transmitting the plurality piece of encrypted information and the plurality of encrypted encryption keys to a user, the first to fourth steps being executed by a server, and selecting each pair of a piece of the plurality of encrypted information and a corresponding encrypted encryption key, the fifth step being executed by the user, wherein only some of the encryption keys are multiplied by random numbers. ## Claims ### Claim 1 An information processing method comprising: a first step of dividing digital data into a plurality of pieces and generating a plurality of pieces of encrypted digital data by encrypting each of the plurality of pieces of digital data using each respective one of a provider's encryption keys; a second step of generating a first set of encrypted provider encryption keys by multiplying at least one of the provider's encryption keys by a random number and encrypting the result; a third step of generating a second set of encrypted provider encryption keys by encrypting at least one of the provider's encryption keys, the first to third steps being executed by a provider apparatus; a fourth step of selecting at least one pair comprising a member of the second set of encrypted provider encryption key and a corresponding a piece of encrypted digital data; and a fifth step of generating a first set of double encrypted encryption keys by respectively encrypting each member of the first set of encrypted provider encryption keys and a second set of double encrypted encryption keys by respectively encrypting each member of the second set of encrypted provider encryption keys selected in the fourth step, the fourth and fifth steps being executed by a user apparatus, wherein the first set of double encrypted provider encryption keys and the second set of double encrypted provider encryption keys are decrypted and used to generate a third encrypted encryption key and a fourth encrypted encryption key by said provider apparatus. ### Claim 2 (depends on 1) An information processing method according to claim 1, further comprising: a sixth step of giving a digital signature on the basis of an encrypted random number to the first set of double encrypted encryption keys and the second set of double encrypted encryption keys, the sixth step being executed by said user apparatus. ### Claim 3 (depends on 2) An information processing method according to claim 2, further comprising: a seventh step of verifying the digital signature by using an anonymous public key with a certificate issued by a certification facility, the seventh step being executed by said provider apparatus, wherein the sixth step is executed in accordance with a public key cryptosystem. ### Claim 4 (depends on 2) An information processing method according to claim 2, further comprising: a step of adding electronic watermark information to each the plurality of pieces of encrypted digital data, this step being executed by said provider apparatus. ### Claim 5 (depends on 1) An information processing method according to claim 1, wherein the fourth step comprises selecting at least one pair comprising a member of the first set of encrypted provider encryption keys and a corresponding piece of encrypted digital data, and wherein the fifth step comprises generating the first set of double encrypted encryption keys by respectively encrypting each member of the first set of encrypted provider encryption keys selected in the fourth step. ### Claim 6 An information processing method comprising a plurality of steps being executed by a provider apparatus, said method comprising the steps of: dividing digital data into a plurality of pieces and generating a plurality of pieces of encrypted digital data by encrypting each of the plurality of pieces of digital data using each respective one of a provider's encryption keys; generating a first set of encrypted provider encryption keys by multiplying at least one of the provider's encryption keys by a random number and encrypting the result; generating a second set of encrypted provider encryption keys by encrypting at least one of the provider's encryption keys; and generating a third encrypted encryption key and a fourth encrypted encryption key on the basis of a first double encrypted encryption key and a second double encrypted encryption key; respectively, wherein the first double encrypted encryption key and the second double encrypted encryption key are respectively generated by encrypting a member of the first set of encrypted provider encryption keys and a member of the second set of encrypted provider encryption keys with a user's encryption key. ### Claim 7 A computer-readable program comprising program code for an information processing method comprising a plurality of steps being executed by a provider apparatus, said steps of: dividing digital data into a plurality of pieces and generating a plurality of pieces of encrypted digital data by encrypting each of the plurality of pieces of digital data using each respective one of the provider's encryption keys; generating a first set of encrypted provider encryption keys by multiplying at least one of the provider's encryption keys by a random number and encrypting the result; generating a second set of encrypted provider encryption keys by encrypting at least one of the provider's encryption keys; and generating a third encrypted encryption key and a fourth encrypted encryption key respectively on the basis of a first double encrypted encryption key and a second double encrypted encryption key; wherein the first double encrypted encryption key and the second double encrypted encryption key are respectively generated by encrypting a member of the first set of encrypted provider encryption keys and a member of the second set of encrypted provider encryption keys with a user's encryption key. ### Claim 8 A computer-readable medium containing program code for an information processing method comprising a plurality of steps being executed by a provider apparatus, said steps of: dividing digital data into a plurality of pieces and generating a plurality of pieces of encrypted digital data by encrypting each of the plurality of pieces of digital data using each respective one of the provider's encryption keys; generating a first set of encrypted provider encryption keys by multiplying at least one of the provider s encryption keys by a random number and encrypting the result; generating a second set of encrypted provider encryption keys by encrypting at least one of the provider's encryption keys; and generating a third encrypted encryption key and a fourth encrypted encryption key respectively on the basis of a first double encrypted encryption key and a second double encrypted encryption key, wherein the first double encrypted encryption key and the second double encrypted encryption key are respectively generated by encrypting a member of the first set of encrypted provider encryption keys and a member of the second set of encrypted provider encryption keys with a user's encryption key. ### Claim 9 An information processing method comprising a plurality of steps being executed by a user apparatus, said method comprising the steps of: receiving a first encrypted provider encryption key and a second encrypted provider encryption key from a provider apparatus, wherein the first encrypted provider encryption key is generated by multiplying a server's encryption key by a random number and encrypting the result, and the second encrypted provider encryption key is generated by encrypting the server's encryption key; selecting at least one pair comprising a second encrypted provider encryption key and a corresponding piece of encrypted digital data; and generating a first double encrypted encryption key and a second double encrypted encryption key by respectively encrypting the first encrypted provider encryption key and the second encrypted provider encryption key selected in selecting step. ### Claim 10 A computer-readable program comprising program codes for an information processing method comprising a plurality of steps being executed by a user apparatus, said method comprising the steps of: receiving a first encrypted provider encryption key and a second encrypted provider encryption key from a provider apparatus, wherein the first encrypted provider encryption key is generated by multiplying a server's encryption key by a random number and encrypting the result, and the second encrypted provider encryption key is generated by encrypting the server's encryption key; selecting at least one pair comprising a second encrypted provider encryption key and a corresponding piece of encrypted digital data; and generating a first double encrypted encryption key and a second double encrypted encryption key by respectively encrypting the first encrypted provider encryption key and the second encrypted provider encryption key selected in selecting step. ### Claim 11 A computer-readable medium containing program codes for an information processing method comprising a plurality of steps being executed by a user apparatus, said steps of: receiving first encrypted provider s encryption key and second server s encryption key from a provider apparatus, wherein said first encrypted provider s encryption key is generated by encrypting a result of multiplying server s encryption key by random number, and said second server s encryption key is generated by encrypting said server encryption key; selecting at least a pair of a second encrypted provider s encryption key and a corresponding a piece of encrypted digital data; and generating first double encrypted encryption keys and second double encrypted encryption keys through encrypting respectively first encrypted provider s encryption key and second encrypted provider s encryption key selected in selecting step.