摘要:
The invention is directed to a method for distinguishing reachable objects and non-reachable objects in an object-based application in a system with a volatile memory and a non-volatile memory. The object-based application operates in the non-volatile memory on the objects, whereof at least one is a root object. Each root object is processed by writing for each object that is reachable from the root object, a positive reachability information into the volatile memory and marking those objects in the non-volatile memory as reusable memory, for which no positive reachability information is present in the volatile memory.
摘要:
A space-efficient and flexible mechanism for implementing a virtual machine in a resource-constrained environment such as a smartcard is proposed. The virtual machine is designed for interpreting or carrying out instructions which are identified by an instruction code, also called opcode. Both, the addresses, respectively identifiers, of the functions implementing the instruction codes, respectively opcodes, which the virtual machine interprets, as well as parameters to those functions are kept within lookup tables.
摘要:
Provides a data processing system comprising a processor and encrypted information in a first persistent memory whose level of information leakage is higher than that of a second persistent memory. The second persistent memory stores a cryptographic key for decrypting the encrypted information, generating therefrom unencrypted information that is usable by the processor for executing an operation. The cryptographic key may be used for encrypting the unencrypted information, generating the encrypted information. Also provided is a method of processing such a data-processing system with an operating system, comprising writing unencrypted information into the first persistent memory, encrypting the unencrypted information under use of the first cryptographic key, creating therefrom encrypted information in the first persistent memory, and setting the data-processing system to a state in which writing into the first persistent memory is controlled by the operating system.
摘要:
A method for providing a user device with a set of access codes comprises, in the user device, storing an encryption key and an identification code, and sending a message containing the identification code to a server via a communications network. In the server, an encryption key is stored corresponding to the key stored in the user device, allocating the set of access codes on receipt of the identification code from the user device. A look up function is performed based on the identification code received in the message to retrieve the key from storage. The set of access codes is encrypted using the retrieved key to produce an encrypted set. A message containing the encrypted set is sent to the user device via the network. In the user device, the encrypted set received from the server is decrypted using the key in storage, and storing the decrypted set of access codes for use by a user of the user device.
摘要:
A method for creating an object in a non-persistent memory is proposed. From an instruction code sequence, a first instruction code is read out which effects the execution of a first function which effects the choice of a non-persistent memory as the location for the next object to be created. This object creation is effected by the execution of a second function which is effected by reading out a second instruction code. Furthermore it is proposed to store a pointer to a transient object in the stack memory and to provide a mechanism for writing this pointer to and reading it from a persistent memory.
摘要:
A method for transactional writing of data into a data space in a persistent memory. The data space has a data space header which signals that the data space is free. A data header is generated when there is a writing transaction in the data space. After successful completion of the transactional writing, the data header signals that the data space is occupied by the written data. The data is written directly to the persistent memory, and in the case the transactional writing is not successfully completed, the data space header is valid for the data space. If the transactional writing is successfully completed, the data header is valid for the written data in the data space. A persistent buffer serves for storing validity information for ensuring the validity of the data header or the data space header as appropriate.
摘要:
A method for providing a user device with a set of access codes comprises, in the user device, storing an encryption key and an identification code, and sending a message containing the identification code to a server via a communications network. In the server, an encryption key is stored corresponding to the key stored in the user device, allocating the set of access codes on receipt of the identification code from the user device. A look up function is performed based on the identification code received in the message to retrieve the key from storage. The set of access codes is encrypted using the retrieved key to produce an encrypted set. A message containing the encrypted set is sent to the user device via the network. In the user device, the encrypted set received from the server is decrypted using the key in storage, and storing the decrypted set of access codes for use by a user of the user device.
摘要:
The invention is directed to a data-processing system comprising a processor and first encrypted information in a first persistent memory whose level of information leakage is higher than that of a second persistent memory. In the second persistent memory is stored a first cryptographic key for decrypting the first encrypted information, thereby generating therefrom first unencrypted information that is usable by the processor for executing an operation. The same cryptographic key may also be used for encrypting the first unencrypted information, thereby generating the first encrypted information. It is also directed to a method of processing such a data-processing system with an operating system, comprising a writing step for writing first unencrypted information into the first persistent memory, an encryption step for encrypting the first unencrypted information under use of the first cryptographic key, creating therefrom first encrypted information in the first persistent memory, and an access-limitation step for setting the data-processing system to a state in which writing into the first persistent memory is controlled by the operating system. It also relates to a method of executing an operation on such a data-processing system comprising a decryption step for decrypting the first encrypted information under use of the first cryptographic key, thereby generating therefrom first unencrypted information and an execution step for executing an operation by the processor, using the first unencrypted information.
摘要:
Scheme for the distinguishing of reachable objects and non-reachable objects used by an object-based application in a system with volatile memory of limited size. The object-based application operates on n objects whereby Z objects thereof are root objects. The following steps are carried out for each root object: (a) traversing from said root object to any other object that can be reached from said root object; (b) marking all objects that were reached from said root object and storing, while marking, in said volatile memory a description of the path from said root object to the currently visited object; if the marking phase reaches an object and the respective path does not fit into said volatile memory, then this object is not marked but identified as an object which has to be processed later; and continuing the marking phase until all root objects identified as objects which have to be processed later are processed.
摘要:
A method for providing a user device with a set of access codes comprises, in the user device, storing an encryption key a an identification code, and sending a message containing the identification code to a server via a communications network. In the server, an encryption key is stored corresponding to the key stored in the user device, allocating the set of access codes on receipt of the identification code from the user device. A look up function is performed based on the identification code received in the message to retrieve the key from storage. The set of access codes is encrypted using the retrieved key to produce an encrypted set. A message containing the encrypted set is sent to the user device via the network. In the user device, the encrypted set received from the server is decrypted using the key in storage, and storing the decrypted set of access codes for use by a user of the user device.