Abstract:
The invention provides a method and system for preserving trustworthiness of data, the method includes storing data on an untrusted system, and committing the data to a trusted computing base (TCB). The committing includes upon an end of a predetermined time interval, transmitting a constant size authentication data from the untrusted system to the TCB, and the TCB preserving trustworthiness of the authentication data based on performing a single hash operation of a first root and a second root of a general hash tree representing authenticated data.
Abstract:
A multiple level security system and method for encrypting data within documents is disclosed. The method includes one or more different encryption algorithms, and can employ the one or more different encryption algorithms to achieve the multiple levels of encryption. More particularly, a first encryption algorithm is based upon multiple rearrangements of bits representing data to obtain encoded data. A second encryption algorithm is based upon performing multiple XOR operations on bits representing data so that each data word is at least encoded with previous data words. Either encryption method or a combination of both encryption methods can be repeatedly applied to portions of data within a document to selectively encrypt each data portion within the document in accordance with the authorization level associated with the data portion.
Abstract:
A stream stretcher is provided for securely expanding a key stream to match the length of a data block to be encrypted and/or decrypted. A key stream is obtained having a length of L Z bits. A length LD corresponding to a data block to be encrypted/decrypted is obtained, where L D > L Z . L D -L Z new bits are recursively generated by combining at least two bits of the key stream. The L D -L Z new bits are appended to the key stream to generate a stretched key stream. The data block may then be encrypted/decrypted with the stretched key stream. The at least two bits are selected to have offsets that form a full positive difference set.
Abstract translation:提供流扩展器用于安全地扩展密钥流以匹配待加密和/或解密的数据块的长度。 获得长度为L Z sub>的密钥流。 获得对应于要加密/解密的数据块的长度LD,其中L →<子>ž子>。 通过组合密钥流的至少两个比特来递归地生成L_D_Z_Z新比特。 将L D sub> -L Z sub>新比特附加到密钥流以生成拉伸的密钥流。 然后可以用拉伸的密钥流对数据块进行加密/解密。 至少两位被选择为具有形成完整正差分集的偏移量。 p>
Abstract:
A system and a method for encrypting sections of a video with a sequence of encrypt keys and generating a plurality of sequences of decrypt keys of varying perfection are provided. The sequencing of the decrypt keys of varying perfection is key-coded to watermark the decrypted video so that the source of pirated copies of the video may be traced. Application of the system and method for the purposes of advance screening, digital cinema distribution, video service-network content distribution including broadcast services, on-demand services and pay-per-view services are also provided.
Abstract:
Embodiments of the present invention are directed to Web-Services- based data backup and data-archiving applications that provide remote data backup and data archiving to private individuals, small businesses, and other organizations that need reliable, secure, geographically remote, and cost-effective data backup, data archiving, and backed-up and archived-data retrieval. In one embodiment of the present invention, a private or small-business client contracts with a service provider for data-backup and data-archiving services. The service provider, in turn, contracts with a remote data-storage facility to provide secure, reliable data backup and data archiving to the personal or small-business client. A client-side application is downloaded to the client computer and configured to allow the client to store locally encrypted data at the remote, data-storage facilities. Neither the service provider nor the data-storage facility can decrypt or otherwise access the information stored by the client. In addition, the encryption key or encryption keys used by the client to encrypt the data for remote storage are securely stored at the remote, data-storage facility for subsequent recovery by the client, should the client suffer damage or loss to a local computer system. However, the client encryption key is stored in a doubly encrypted fashion, preventing access to the client's encryption key by either the service provider or the data-storage facility. Certain embodiments of the present invention also provide local indexing for remotely stored, encrypted data and efficient storage of updates to already remotely stored data.
Abstract:
La présente invention concerne un procédé et un système permettant de chiffrer ou de déchiffrer à la volée un flux d' information à haut débit. L' information se présente sous forme de blocs de bits (M 0 , M 1 ,..., M n-1 ), eux-mêmes regroupés en secteurs (S). L'invention met en œuvre un algorithme de chiffrement par blocs, par exemple l'AES (Advanced Encryption Standard), exécuté deux fois par secteur et servant à construire, pour chaque secteur, une clé secondaire (KS) utilisée par un algorithme plus rapide (par exemple masque XOR). Les clés secondaires dépendent du contenu du secteur et de sa place dans le flux. Une même information sera ainsi codée différemment selon son contexte. Lors du déchiffrement, la clé secondaire peut se recalculer à partir du secteur chiffré, à l'aide de l'algorithme de chiffrement par blocs. Le nombre de blocs par secteur sera ajusté pour réaliser le meilleur compromis entre rapidité de calcul et sécurité cryptographique.
Abstract:
A first communication device authenticates an approaching second communication device by an identifier and request an authentication station to authenticate the first communication device and the second communication device. If the authentication station authenticates that the both devices are authorized, the authentication station returns a release permission signal to the first communication device. After this, the first communication device acquires a piece of fingerprint information divided and stored in advance from the second communication device and request the authentication station to authentication the fingerprint information together with a piece stored in the first communication device. If the authentication station authenticates that the fingerprint information received is correct by searching its DB, it transmits an identification signal to the first communication device and a device to be controlled. After this, the device to be controlled performs a predetermined control according to a command from the first communication device.
Abstract:
Security and privacy of tag information in an RFID-based system can be achieved through the usage of pseudonyms generated based on one-way hash functions. A system based on binary one-way trees allows for the scalable generation and decoding of authentication keys to obtain access to tag identities. The apparatus and methods described can also be adapted to provide limited access for readers to tag information.
Abstract:
Authentication of elements (e.g. digital certificates 140) as possessing a pre-specified property (e.g. being valid) or not possessing the property is performed by (1) assigning a distinct integer p i to each element, and (2) accumulating the elements possessing the property or the elements not possessing the property using a P-th root u 1/P (mod n) of an integer u modulo a predefined composite integer n, where P is the product of the integers associated with the accumulated elements. Alternatively, authentication is performed without such accumulators but using witnesses associated with such accumulators. The witnesses are used to derive encryption and/or decryption keys for encrypting the data evidencing possession of the property for multiple periods of time. The encrypted data are distributed in advance. For each period of time, decryption keys are released which are associated with that period and with the elements to be authenticated in that period of time. Authentication can be performed by accumulating elements into data which are a function of each element but whose size does not depend on the number of elements, and transmitting the accumulator data over a network to a computer system which de-accumulates some elements as needed to re-transmit only data associated with elements needed by other computer systems. This technique is suitable to facilitate distribution of accumulator data in networks such as ad hoc networks.