Abstract: A method and apparatus for tracing of computer documents is disclosed. A computer processor stores a processor identifier that is unique to the particular processor. Documents created by a computer system are tagged with an identification tag that is a value which results from performing a cryptographic function on the hash of the document and the unique processor identifier. Processor associators are stored in a secure database, with each of the processor associators being associated with one of the unique processor identifiers. In a first embodiment, the processor associators are the same as the processor identifiers. In a second embodiment, the processor identifiers are a function of their related processor associator. Documents may be traced by a third party possessing a document (including an attached identification tag) and a database of processor associators and user identification data associated with each of the processor associators.

Abstract: Cryptography-based methods and apparatus for secure information processing are disclosed that are particularly efficient in terms of the computational resources required, and thus implementable in mobile telephones, personal digital assistants (PDAs) or other lightweight processing devices. A setup procedure is performed to permit interactions of a designated type, e.g., secure mobile gaming interactions, to be carried out between participants, e.g., one or more players and a casino. A given participant initiates a particular interaction with another participant by sending to that participant initiation information based at least in part on one or more results of the setup procedure. The other participant in turn sends response information back to the given participant, and the interaction then continues with one or more rounds each involving one or more decisions committed to by each participant.

Abstract: A method and apparatus for tracing of computer documents is disclosed. A computer processor stores a processor identifier that is unique to the particular processor. Documents created by a computer system are tagged with an identification tag that is a value which results from performing a cryptographic function on the hash of the document and the unique processor identifier. Processor associators are stored in a secure database, with each of the processor associators being associated with one of the unique processor identifiers. In a first embodiment, the processor associators are the same as the processor identifiers. In a second embodiment, the processor identifiers are a function of their related processor associator. Documents may be traced by a third party possessing a document (including an attached identification tag) and a database of processor associators and user identification data associated with each of the processor associators.

Abstract: A method is provided for digital signature infrastructure that provides public keys which are effective only for verifying digital signatures, and are not effective for encrypting information in a way that is unrecoverable by law-enforcement entities. The method can be implemented in software, thus avoiding the need for tamper-proof hardware. The method has the property that signing private keys are not escrowed, since the corresponding public keys cannot be used effectively for criminal communications. As a result no one can impersonate the user; alternatively users can prove impersonations. Furthermore, the system is shadow public key resistant. A shadow public key is a public key which is not escrowed and which can be used for untappable communications. Therefore, the method presented here cannot be used to publish public keys which are not escrowed. All information displayed by the certificate authorities, and even the digital signatures of users, are shadow public key resistant.

Abstract: Cryptography-based methods and apparatus for secure information processing are disclosed that are particularly efficient in terms of the computational resources required, and thus implementable in mobile telephones, personal digital assistants (PDAs) or other lightweight processing devices. A setup procedure is performed to permit interactions of a designated type, e.g., secure mobile gaming interactions, to be carried out between participants, e.g., one or more players and a casino. A given participant initiates a particular interaction with another participant by sending to that participant initiation information based at least in part on one or more results of the setup procedure. The other participant in turn sends response information back to the given participant, and the interaction then continues with one or more rounds each involving one or more decisions committed to by each participant.

Abstract: A method is provided for an escrow cryptosystem that is essentially overhead-free, does not require a cryptographic tamper-proof hardware implementation (i.e., can be done in software), is publicly verifiable, and cannot be used subliminally to enable a shadow public key system. The keys generated are based on composite numbers (like RSA keys). A shadow public key system is an unescrowed public key system that is publicly displayed in a covert fashion. The keys generated by the method are auto-recoverable and auto-certifiable (abbrev. ARC). The ARC Cryptosystem is based on a key generation mechanism that outputs a public/private key pair, and a certificate of proof that the key is recoverable by the escrow authorities. Each generated public/private key pair can be verified efficiently to be escrowed properly by anyone. The verification procedure does not use the private key.

Abstract: A method is provided for an escrow cryptosystem that is essentially overhead-free, does not require a cryptographic tamper-proof hardware implementation (i.e., can be done in software), is publicly verifiable, and cannot be used subliminally to enable a shadow public key system. A shadow public key system is an unescrowed public key system that is publicly displayed in a covert fashion. The keys generated by the method are auto-recoverable and auto-certifiable (abbrev. ARC). The ARC Cryptosystem is based on a key generation mechanism that outputs a public/private key pair, and a certificate of proof that the key is recoverable by the escrow authorities. Each generated public/private key pair can be verified efficiently to be escrowed properly by anyone. The verification procedure does not use the private key.

Abstract: A method is provided for an escrow cryptosystem that is overhead-free, does not require a cryptographic tamper-proof hardware implementation (i.e., can be done in software), is publicly verifiable, and cannot be used subliminally to enable a shadow public key system. A shadow public key system is an unescrowed public key system that is publicly displayed in a covert fashion. The keys generated by the method are auto-recoverable and auto-certifiable (abbrev. ARC). The ARC Cryptosystem is based on a key generation mechanism that outputs a public/private key pair, and a certificate of proof that the key was generated according to the algorithm. Each generated public/private key pair can be verified efficiently to be escrowed properly by anyone. The verification procedure does not use the private key. Hence, the general public has an efficient way of making sure that any given individual's private key is escrowed properly, and the trusted authorities will be able to access the private key if needed.

Abstract: A method is provided for an escrow cryptosystem that is overhead-free, does not require a cryptographic tamper-proof hardware implementation (i.e., can be done in software), is publicly verifiable, and cannot be used subliminally to enable a shadow public key system. A shadow public key system is an unescrowed public key system that is publicly displayed in a covert fashion. The key generated by the method are auto-recoverable and auto-certifiable (abbrev. ARC). The ARC Cryptosystem is based on a key generation mechanism that outputs a public/private key pair, and a certificate of proof that the key was generated according to the algorithm. Each generated public/private key pair can be verified efficiently to be escrowed properly by anyone. The verification procedure does not use the private key. Hence, the general public has an efficient way of making sure that any given individual's private key is escrowed properly, and the trusted authorities will be able to access the private key if needed.

Abstract: A method is provided for an escrow cryptosystem combined with an unescrowed digital signature scheme that uses a single public key per user. This system is overhead-free, does not require a cryptographic tamper-proof hardware implementation (i.e., can be done in software), and is publicly verifiable. The system cannot be used subliminally to enable a shadow public key system. Namely, an unescrowed public key system that is publicly displayed in a covert fashion. The cryptosystem contains a key generation mechanism that outputs a key triplet, and a certificate of proof that the keys were generated according to the algorithm. The key triplet consists of a public key, a private decryption key, and a private signing key. Using the public key and the certificate, the triplet can be verified efficiently by anyone to have the following properties: (1) the private signing key is known to the user, and (2) the private decryption key is recoverable by the escrow authorities.