Abstract: Embodiments of the invention provide for authenticating users of web-based applications by presenting a previously acquired signed digital signature. Examples establish secure user sessions between a client and a user in response to a verification of an identification of the user by the client, the client creating a unique username for the user and unlocking access by the user to a client digital signature for use with a request for service from a third party web server. A secure facilitator session is established between the client and a third party web server, wherein messages exchanged with the unique username and a unique session identification indicia of the secure facilitator session signed by the unlocked digital signature result in executed processes requested by the service identifier data if the messages are validated without the client requiring the user to verify user identification for any message until a secure facilitator session ends.

Abstract: Embodiments of the invention provide for authenticating users of web-based applications by presenting a previously acquired signed digital signature. Examples establish secure user sessions between a client and a user in response to a verification of an identification of the user by the client, the client creating a unique username for the user and unlocking access by the user to a client digital signature for use with a request for service from a third party web server. A secure facilitator session is established between the client and a third party web server, wherein messages exchanged with the unique username and a unique session identification indicia of the secure facilitator session signed by the unlocked digital signature result in executed processes requested by the service identifier data if the messages are validated without the client requiring the user to verify user identification for any message until a secure facilitator session ends.

Abstract: A signer uses an undeniable signature scheme to sign his public key to thereby create an “undeniable certificate” which can be used to verify the signer's digital signature on any message signed using the signer's corresponding private key. Hence, once the undeniable certificate is received by the recipient, the recipient and the signer engage one time in a confirmation protocol or denial protocol to the satisfaction of the recipient that the undeniable certificate has in fact been signed by the signer thus certifying signer's public key. Thereafter, the recipient can use the certified public key to verify any documents signed by the signer with no further interaction with the signer. However, third parties are precluded from verifying the signer's signature since they do not possess the confirmed undeniable certificate and corresponding public key.

Abstract: A solution to the general problem of Secure Storage and Retrieval of Information (SSRI) guarantees that also the process of storing the information is correct even when some processors fail. A user interacts with the storage system by depositing a file and receiving a proof that the deposit was correctly executed. The user interacts with a single distinguished processor called the gateway. The mechanism enables storage in the presence of both inactive and maliciously active faults, while maintaining (asymptotical) space optimailty. This mechanism is enhanced with the added requirement of confidentiality of information; i.e., that a collusion of processors should not be able to learn anything about the information. Also, in this case space optimality is preserved.

Abstract: A method for providing a digital signature, "chameleon signatures", which provide the signer of a digital signature exclusive control to disclose the contents of the signed information to third parties. The signatures are closely related to "undeniable signatures", but allow for simpler and more efficient realizations. The method is essentially non-interactive requiring no communication between sender and receiver and do not involve the design and complexity of zero knowledge proofs on which traditional undeniable signatures are based. The method employs a combination of standard digital signing methods with a unique hash functions. These hash functions are characterized by the non-standard property of being collision resistant for the signer but collision tractable for the recipient.

Abstract: A solution to the general problem of Secure Storage and Retrieval of Information (SSRI) guarantees that also the process of storing the information is correct even when some processors fail. A user interacts with the storage system by depositing a file and receiving a proof that the deposit was correctly executed. The user interacts with a single distinguished processor called the gateway. The mechanism enables storage in the presence of both inactive and maliciously active faults, while maintaining (asymptotical) space optimailty. This mechanism is enhanced with the added requirement of confidentiality of information; i.e., that a collusion of processors should not be able to learn anything about the information. Also, in this case space optimality is preserved.