Abstract: Remote terminals are configured to generate ciphertexts from plaintext polynomials. Each ciphertext corresponds to a plaintext polynomial bound to a message space of a polynomial-based fully homomorphic cryptographic scheme. At least one server is configured to receive ciphertexts via a network from the plurality of remote terminals. The server performs a multiplication operation and an addition operation on the ciphertexts to obtain resultant ciphertexts. The multiplication operation includes performing a bitwise decomposition function on a ciphertext to obtain a bitwise decomposed ciphertext. The bitwise decomposition function maps a multi-bit data type to a sequence of bits. The multiplication operation further includes performing matrix multiplication on the bitwise decomposed ciphertext and a data element belonging to a set of data elements. Message filters, data search engines, and other applications are discussed.

Abstract: An avionic equipment unit, intended to be on board an aircraft, including a calculating module configured to calculate a signature associated with a data field, the calculated signature depending on the data field, and a transmission module configured to transmit a message to another avionic equipment unit on board the aircraft, the message including the data field and the associated calculated signature, the calculated signature being unique for each data field and for each respective message transmission.

Abstract: A media player may include a media reader to read media content from a recording medium inserted into the media reader. The media player may also include a media analysis component to identify one or more valid portions of the recording medium containing media content and one or more invalid portions of the recording medium without media content. In one embodiment, the media player includes an archival component to store the media content from the one or more valid portions in a storage medium and a playback component to play back the one or more valid portions of the media content from the storage medium concurrently with the identification of the one or more valid portions by the media analysis component and the storage of the media content by the archival component.

Abstract: An apparatus, system, and method for image processing are disclosed, each of which obtains a mark from image data, detects additional information in the mark, determines whether the mark is detected in the mark to generate a determination result, and controls processing performed by an image processing apparatus with respect to the image data based on the determination result.

Abstract: A test pattern containing plurality of patches recorded using small dot patterns and large dot patterns is printed. The dot sizes arranged in the patches are different between patches. Then the test patterns are read. The detection rate and average density of additional information embedded in each large dot pattern are obtained. A large dot pattern whose detection rate and average density fall within a reference range and are closest to ideal values is determined. The average density of each small dot pattern is obtained. A small dot pattern whose average density falls within a reference range and is closest to the average density of the determined large dot pattern is determined. A copy-forgery-inhibited pattern image is generated using these dot patterns and combined with a print target image.

Abstract: An image processing device, which includes: an original reception unit that receives an original image; a dot image generation unit that generates, on the basis of additive information to be added to the original image, a dot image in which a plurality of dots each formed by one or more pixels are arranged; a state alteration unit that, when any of the dots in the dot image is determined to be not extractable, alters a state of the non-extractable dot on the basis of a relationship between a position on the dot image generated by the dot image generation unit and a corresponding position on the original image; and a composite image generation unit that generates a composite image by superimposing, on the original image, the dot image having the state of the non-extractable dot altered by the state alteration unit.

Abstract: This disclosure describes methods for using embedded auxiliary signals in documents for copy detection and other applications. In on application, the auxiliary signal is formed as an array of elements selected from a set of print structures with properties that change differently in response to copy operations. These changes in properties of the print structures that carry the embedded auxiliary signal are automatically detectable. For example, the changes make the embedded auxiliary signal more or less detectable. The extent to which the auxiliary data is detected forms a detection metric used in combination with one or more other metrics to differentiate copies from originals. Examples of sets of properties of the print structures that change differently in response to copy operations include sets of colors (including different types of inks), sets of screens or dot structures that have varying dot gain, sets of structures with different aliasing effects, etc.

Abstract: A watermark information embedding apparatus generates a document image from electronic document data that has been input thereto, modifies the electronic document data based upon the document image and embeds information in the electronic document data. The apparatus includes a document image generator for generating a document image from the electronic document data; a document analyzer for detecting layout information of each constituent image in the generated document image; a normalization information calculation unit for calculating normalization information, which is for normalizing placement of each constituent image, based upon the detected layout information; a modification unit for modifying the electronic document data; and an embedding unit for embedding information in the modified electronic document data.

Abstract: In a computer system in which information represented by digital data is output to plural pages of recording medium, and then information on the plural pages of recording medium is read to use digital data representing the read information, authentication information is embedded in information of a start page selected by the computer system; a page number of the start page embedded the authentication information is notified to a user; information on the plural pages of recording medium is read, wherein the start page is positioned so as to be read first; digital data read from the plural pages of recording medium is authenticated based on the authentication information embedded in the start page; and a process for the digital data read from the plural pages of recording medium is controlled in accordance with a result of the authentication.

Abstract: The present invention provides methods and apparatus for embedding an identifying pattern of visible speckles into the digitized image of each page of a document. A speckle is a cluster of black or white pixels. Speckles are printed as black speckles on the white paper, or conversely, as areas of missing black removed from the black text characters, called white speckles. The collective pattern of all embedded black and white speckles on a single document page is called a specklemark. A specklemark can survive contrast manipulations on photocopiers and binary rasterization done by fax scanning prior to data transmission. The random pattern of the black and white speckles visible in the digitized image of a document page can be detected automatically, and by systematically matching the detected pattern with those known to have been embedded into marked copies of a document page, a specific document copy can be identified.

Abstract: Content reproduction apparatus, content recording apparatus, network system, and method of recording and reproducing content are provide.

Abstract: Methods and apparatus provide for: decrypting a first of a plurality of operating systems (OSs) within a first processor of a multiprocessing system using a private key thereof, the plurality of OSs having been encrypted by a trusted third party, other than a manufacturer of the multiprocessing system, using respective public keys, each paired with the private key; executing an authentication program using the first processor to verify that the first OS is valid; and executing the first OS on the first processor.

Abstract: Messages are encrypted/decrypted according to a modified triple wrap procedure in which the messages are encrypted/decrypted in three encryption/decryption operations and are processed in three additional operations using first, second, third, fourth, fifth, and sixth keys.

Abstract: Disclosed is a method of verifying the integrity of data acquired from a device emulating a hard disk to a host computer over a data transfer pathway. A storage medium containing known data is connected to the data transfer pathway, the storage medium capable of emulating a hard disk. The known data is transferred from the storage medium to the host computer over the data transfer pathway for storage on the host computer. A characteristic of the data stored on the host computer is compared with a corresponding characteristic of said known data to determine whether data corruption has occurred during data transfer over said data transfer pathway. The characteristic could be a hash code value, such as a Message-Digest 5 (MD5) or Secure Hash Algorithm (SHA) value.

Abstract: An authentication method for authenticating an article in a device includes the steps of (a) reading an identification number stored on the article, (b) reading an authentication number stored on the article, (c) determining an input number based at least in part on the identification number, (d) applying an authentication function to the input number to calculate an output number, (e) determining that the article is authentic only if the authentication number corresponds to the output number, and (f) permitting use of the article in the device if the article is authentic, and disabling use of the article in the device if the article is not authentic.

Abstract: A self-authenticating check authorization system and method includes a check that has standard bank and account information printed on the MICR line, as well as a one-way hash value that is computed based on the standard bank and account information as well as a personal identification code of a customer and a key. The scanned MICR line data is provided to a check verifier, which also receives the personal identification code from the customer. The check verifier performs a hashing algorithm on the received data, and compares the computed hash value to a hash value obtained from the scanned MICR line data. If there is a match, the check is verified; if not, the check is not verified.

Abstract: A device is provided that includes a monetary instrument having a surface, and a magnetic ink character recognition (MICR) line coupled to that surface. The MICR line includes an ABA number, a customer account number, and a one-way hash value. The one-way hash value is output from a hashing process using input including the ABA number, the customer account number, together with a personal identification code and a key that are not included on the MICR line. A method is also provided that authenticates a monetary instrument by comparing a computed one-way hash value with a one-way hash value that is located in the MICR line of the monetary instrument. At the point-of-sale, the MICR line data is scanned and the personal identification code obtained from the customer. The scanned data and the personal identification code are transmitted to a check verifier that provides a check verification status.

Abstract: An authentication method for authenticating an article in a device includes the steps of (a) reading an identification number stored on the article, (b) reading an authentication number stored on the article, (c) determining an input number based at least in part on the identification number, (d) applying an authentication function to the input number to calculate an output number, (e) determining that the article is authentic only if the authentication number corresponds to the output number, and (f) permitting use of the article in the device if the article is authentic, and disabling use of the article in the device if the article is not authentic.

Abstract: An encryption scheme for mass storage devices employing a tweakable encryption scheme to add variability to the encrypted data to resist attacks by traffic analysis. Explicit tweak and implicit tweak may be used to add variability to plaintext prior to encryption and eventual storage. The tweak information is either stored on the storage device along with the encrypted data as in the case of an explicit tweak, or it is derived from another source when needed as in the case of an implicit tweak. The ciphertext is decrypted using either the stored explicit tweak value or derive the implicit tweak value to “de-tweak” the decrypted data prior to usage. The data may be deleted by destroying the cipher key(s) to render the ciphertext useless. The tweak information alone is useless for decryption, as the ciphertext needs to be decrypted with the cipher key(s).

Abstract: An apparatus generates first shared information that is shared by the apparatus and a recording medium by performing a first bilateral authentication. The apparatus encrypts overwrite data that is used to erase key information item recorded in the recording medium using the first shared information. Encrypted overwrite data is transferred to the recording medium. Second shared information is generated and shared by the apparatus and the recording medium by performing a second bilateral authentication between them. The apparatus receives data that is encrypted using the second shared information and that has been used by the recording medium for erasing key information. Encrypted data is decrypted using second shared information item and key information recorded in the recording medium is erased when the decrypted data is identical to overwrite data.

Abstract: A system includes long-term storage (e.g., flash memory) for storing sensitive data and critical components of a consumer electronic (CE) device such as an operating system (OS) kernel, private cryptographic key values, security applications, and firmware configurations, for example. Security hardware/software designates and restricts access to secured portions of long-term storage that contain the critical components. Requests for access to these secured portions are addressed by the security hardware/software, which authenticates a cryptographic authorization code received with the request. Read-write access to the secured portions is allowed for download and installation of, for example, a software or firmware upgrade if the cryptographic authorization code is authenticated.

Abstract: A method, system and program are provided for enabling selective access to multiple users' encrypted data in a single storage cartridge. A unique, derived key is generated for each user's data by performing cryptographic operations on a combination of a common base key and metadata related to the data to be encrypted (e.g. its total block count). The base data key is wrapped with one or more encryption keys to form one or more encryption encapsulated data keys (EEDKs). The base key and the derived key are wrapped to create a session encrypted data key (SEDK), which along with the EEDKs, are conveyed to the tape drive, where the SEDK is decrypted. The EEDKs are then stored in one or more places on the storage cartridge. The base key and the derived key are used to encrypt a predetermined user's data, with the derived key stored on the cartridge with the encrypted data. The encrypted data may be subsequently decrypted by retrieving the EEDK and decrypting it with a decryption key to extract the base data key.

Abstract: An apparatus, system, and method are disclosed for self-describing, heterogeneous magnetic tape formatting. A detection module determines if data is to be encrypted when written to a magnetic tape in response to a host command and if the data is already encrypted. An encryption module encrypts the data if the data is to be encrypted and if the data is not already encrypted. A write module writes a reserved codeword followed by the data to the magnetic tape wherein the reserved codeword is configured as an encryption reserved codeword if the data is encrypted. If the data is not encrypted, the reserved codeword is configured as a clear reserved codeword. The encrypted and unencrypted data segments are intermixed on the magnetic tape.

Abstract: A data transmitting method, a data recording apparatus, a data record medium and a data reproducing apparatus are provided to disallow the encryption to be easily decoded and keep the secrecy of key information higher. The data transmitting apparatus includes an error correction coding process block. In the block, an input converting circuit operates to perform a logic operation with respect to the information data from an interface circuit 12 according to the key data. The converted information data is sent to an encoder 15 for generating parity data. This parity data is mixed with information data before conversion in a mixing circuit. The error correction coding block operates to send the resulting data to a modulating circuit 17 for modulating the data. The modulated data is recorded on a disk record medium.

Abstract: A scrambler that facilitates encryption of data to be recorded and a magnetic storage device using this are provided. The scrambler has a shift register of a plurality of stages and an exclusive OR circuit that finds the exclusive OR of the logic of the stages of the shift register that correspond to a single generating polynomial. The output of the exclusive OR circuit is arranged to be fed back to the initial stage of the shift register. At least this single generating polynomial is an arbitrary generating polynomial. The drive number, in binary form, that identifies the storage device, is set as the initial value of the shift register of a plurality of stages.

Abstract: A calculator system for performing duplication of contents does not necessarily perform screening, i.e., electronic watermark detection, rather, contents copy control information can be obtained otherwise. For example, in the event of copying a CD regarding which it is known beforehand that there is no electronic watermark inserted in the contents, the electronic watermark detection processing itself can be skipped as long as the CD can be confirmed to be such, thereby reducing the amount of time necessary for copying. Electronic watermark inspecting processing with heavy computation loads is performed vicariously for judging whether or not duplication of contents is permissible.

Abstract: Data is recorded in a first part PA1 in accordance with a signal format same as that of an existing CD at the lower limit (1.5 ?m) of an allowable value of a Wreck pitch and the lower limit (1.2 m/sec) of a linear velocity. As a result, the data for the maximum regeneration time (74.7 min) can be recorded in the first part PA1. An existing CD reproducing apparatus can reproduce the audio data recorded in the first part PA1 with no problem. Moreover, compressed and encrypted audio data is recorded in a second part PA2 at a single density or a double density. The single density represents a recording density same as that of an existing CD and the double density represents a density two time larger than the single density. Furthermore, the audio data recorded in the second part PA2 is charged when reproduced in order to protect copyrights. The format of the data recorded in the second part PA2 uses the format of a CD-ROM.

Abstract: A financial transaction network includes a customer network serviced by a host processor. The financial transaction network provides customers with a plurality of diverse and interchangeable financial products and financial services that customers may utilize to directly manage their financial assets. The host processor acts as a communications switch validating incoming transaction requests and routing them to specialized subsystems. The host processor maintains central records that can be accessed by network participants. The financial transaction network enables customers to continually interchange account values relating to any financial product, or financial service within the network. With its accessibility, speed and finality of settlement, the network permits these interchanges to be accomplished with maximum efficiency.

Abstract: A recording-medium cartridge including a recording-medium and a cartridge memory. In this recording-medium cartridge, the cartridge memory holds a unique cryptographic key in the condition that the rewrite of the cryptographic key is forbidden, and is detachably attached to the recording-medium cartridge. The recording-medium holds a CRC-code, which is generated based on the cryptographic key and data to be recorded on the recording-medium, and data in the condition that the CRC-code is correlated with the data.

Abstract: An apparatus generates first shared information that is shared by the apparatus and a recording medium by performing a first bilateral authentication. The apparatus encrypts overwrite data that is used to erase key information item recorded in the recording medium using the first shared information. Encrypted overwrite data is transferred to the recording medium. Second shared information is generated and shared by the apparatus and the recording medium by performing a second bilateral authentication between them. The apparatus receives data that is encrypted using the second shared information and that has been used by the recording medium for erasing key information. Encrypted data is decrypted using second shared information item and key information recorded in the recording medium is erased when the decrypted data is identical to overwrite data.

Abstract: In the optical disk apparatus, an arbitrary seed data for randomizing is added to an original data to be recorded on a disk. One-bit randomizing data is determined by operation using one-bit original data or seed data, and plural-bit past randomized data. At the time of descrambling, descrambling is performed without seed data.

Abstract: A device for and method of cryptographically wrapping information by first constructing information to be wrapped into an even multiple of y bits. Information to be wrapped is parsed into equal blocks P1, P2, . . . , Pn. Next, registers Ri are loaded with the blocks Pi. Next, an initialization vector IV is stored into a register A. Set j=0. Set i=1. Set t=(n×j)+i. Concatenate A and Ri. Encrypt the result of the last step to form 2y encrypted bits. Divide the encrypted bits into a first set of y bits and a second set of y bits. Set Ri equal to the first set. Combine the second set with t using a user-definable function. Set A equal to the combination. If i=n then increment j and reset i=1; otherwise, increment i. If j is equal to a user-definable number then return A, R1, R2, . . . , Rn as the cryptographically wrapped information and stop. Otherwise, return to the step where t is set.

Abstract: A self-authenticating check authorization system and method includes a check that has standard bank and account information printed on the MICR line, as well as a one-way hash value that is computed based on the standard bank and account information as well as a personal identification code of a customer. The scanned MICR line data is provided to a check verifier, which also receives the personal identification code from the customer. The check verifier performs a hashing algorithm on the received data, and compares the computed hash value to a hash value obtained from the scanned MICR line data. If there is a match, the check is verified; if not, the check is not verified.

Abstract: A financial transaction network includes a customer network serviced by a host processor. The financial transaction network provides customers with a plurality of diverse and interchangeable financial products and financial services that customers may utilize to directly manage their financial assets. The host processor acts as a communications switch validating incoming transaction requests and routing them to specialized subsystems. The host processor maintains central records that can be accessed by network participants. The financial transaction network enables customers to continually interchange account values relating to any financial product, or financial service within the network. With its accessibility, speed and finality of settlement, the network permits these interchanges to be accomplished with maximum efficiency.

Abstract: A recording type optical disk on which data is recordable includes a data recording and reproducing area for recording data therein and reproducing data therefrom, and a read-only disk identification information area for recording disk identification information for identifying the optical disk therein. In the optical disk, the disk identification information is formed by removing a reflection film that is formed on the optical disk in a strip shape. The disk identification information includes an inherent disk identifier for each optical disk, and the data recording and reproducing area includes an area for recording encrypted data therein. The encrypted data is encrypted by using information including the disk identification information for identifying the optical disk as a key.

Abstract: A method and system for protecting electronic files from unauthorized access. The drive on which the file is stored is provided with a hardware identification code, which is unique to the drive. An Operating System (OS) extension allows a user to provide a security code required to access a requested drive. OS device driver, working in conjunction with the extension of the OS checks the requested drive to determine if an access code is required, and the drive responds with the security code or a default code. The default code indicates that the drive is globally accessible to users on the system. When a security code is returned, the OS compares the security code to the access code provided and provides the user with access to the drive only when the access code matches the security code.

Abstract: Data containing important information are stored in DB cards separable from terminals. The terminals and mediums are placed in corresponding relationship. Multi-security measures are taken to prevent a third party not authorized to access one of the DB cards from accessing the card and its data due to loss and robbery of the DB card and the third party's malice to thereby prevent the information from leaking out from the DB card. To this end, when the terminal accesses the DB card, the terminal compares its own hardware identification number with that of the card to determine whether the terminal is authorized to access the DB card. When it is, the terminal 2 further compares its own software identification number with that of the card to determine whether the terminal is further authorized to access a mobile DB in the card.

Abstract: A printing device component having a memory tag with password protected data areas to control read and write access to the memory tag. The memory tag provides an encrypted authorization code to a printing device into which the component is installed. The printing device determines if the authorization code is valid and, if so, the printing device enables all printing device functions. Otherwise, limited functions are enabled. The memory tag utilizes encryption methods to allow only authorized user access to read from and write to selected data areas of the memory tag.

Abstract: Immersive environments for teleconferencing, collaborative shared spaces and entertainment require spatial audio. Such environments may have non-ideal sound reproduction conditions (loudspeaker positioning, listener placement or listening room geometry) where wavefront-synthesis techniques, such as ambisonics, will not give listeners the correct audio spatialization. A method disclosed for generating a sound field from a spatialized original audio signal, wherein the original signal is configured to produce an optimal sound percept at one predetermined ideal location. A plurality of output signal components are generated, each for reproduction by one of an array of loudspeakers. Antiphase output components are attenuated such that their contribution to the spatial sound percept is reduced for locations other than the predetermined ideal location.

Abstract: An electronic ticket system for virtually preventing forgery, copying and other unauthorized uses of electronic tickets; for proving to a third party the contents of an electronic ticket contested between a user and an issuing party; and for protecting users' anonymity upon ticket use. The system comprises a ticket creating and issuing device, a ticket proving device, and a ticket verification device. A ticket creating unit in the ticket creating and issuing device creates specifications of a ticket representing a predetermined service or product in response to a ticket creating request. A ticket issuing unit of the ticket creating and issuing device, in reply to a ticket issuing request, issues the corresponding ticket using as input a ticket identifier, a proving identifier, a ticket specification identifier, and ticket added information. The ticket proving device gets a ticket issued by the ticket issuing unit and communicates with the ticket verification device to prove the possession of the ticket.

Abstract: Provided is a method, system, and program for enabling access to data in a storage medium within one of a plurality of storage cartridges capable of being mounted into a interface device. An association is provided of at least one coding key to a plurality of storage cartridges. A determination is made of one coding key associated with one target storage cartridge, wherein the coding key is capable of being used to access data in the storage medium within the target storage cartridge. The determined coding key is encrypted. The coding key is subsequently decrypted to use to decode and code data stored in the storage medium.

Abstract: A confusion data generator for the generation of non-linear confusion data utilizes a plurality of arrays acting as non-linear state machines to generate a stream of confusion data of a certain width. Each non-linear state machine contributes equally to the overall width of the confusion data. The output bit stream from the confusion data generator is then used with a combiner such as an XOR combiner to generate secure text from plaintext. The confusion data generator can be used to securely store data on a storage medium or transmit data over a communication medium. The confusion data generator is computationally inexpensive, scalable and provides good security when used with a combiner, such as an XOR combiner, to generate secure text.

Abstract: A method and apparatus for the initialization of a class of non-linear confusion data generators is especially useful to enhance the security of non-linear confusion data generators that are restricted to short size secret keys or seeds. The initializer utilizes a user seed and a displacement distance to single or multiple secret key and cipher arrays to randomize confusion data generators such that their security is enhanced. The initializer provides the ability to design confusion data generators that are capable of securing large size data files as a collection of smaller size segments that can be independently decrypted for fast access and review. The initializer can be used to securely store data on a storage medium or transmit data over a communication medium.

Abstract: In the optical disk apparatus, an arbitrary seed data for randomizing is added to an original data to be recorded on a disk. One-bit randomizing data is determined by operation using one-bit original data or seed data, and plural-bit past randomized data. At the time of descrambling, descrambling is performed without seed data.

Abstract: A method and system for providing controlled access to information stored on a smartcard. The system includes a data processing center maintained by a trusted third party for storing a database of authorizations of various service providers to access information pertaining to individuals, and for responding to request by service providers for access from terminals which communicate with the data processing center and smartcards storing the individuals' information. The information is stored on the smartcard in encrypted form and the data processing center provides an access code, which includes a key for decrypting the information, only to service providers who are authorized to access the information. The service provider then sends the access code to the smartcard which verifies the access code and decrypts and outputs the requested information.

Abstract: An apparatus records and reproduces digital video signals on a tape such that recording by another digital VTR or another analog VTR can be blocked, both through a digital interface and an analog interface, to provide a copy protection through various techniques, such as AGC or color striping. The digital recording format includes a recording area for encoded video signals and a recording area for auxiliary information configured in packs. A disturbance signal generating flag is included in an auxiliary information pack and recorded in the auxiliary information recording area. Based on the status of the flag, a disturbance signal may be inserted as a copy protection signal that is reproduced from the encoded video signals into the analog video signal.

Abstract: Recording data is recorded on a CD-ROM so as to satisfy a relationship expressed as W.gtoreq.D and W>m where W is the data length of recording data recorded on the CD-ROM, D is the data length of effective data useful for being accessed (system area, file groups selected when data is edited and retrieval data such as volume descriptor, path table and directory) and m is the maximum recordable data length of a blank disk of a CD-ROM to which data recorded on the CD-ROM is copied. Then, when the relationship between the recording data length W and the effective data length D is expressed by W>D, said recording data contains randomly quasi-data useless for being accessed. Further, a part (e.g., path table) of the retrieval data is arranged at the end of the recording data upon recording. Thus, an illegal copy from the CD-ROM to a blank disk becomes substantially useless, thereby making it possible to effectively protect a copyright of the CD-ROM.

Abstract: A high-speed tape dubbing method and apparatus for dubbing a signal recorded on a master tape onto slave tapes running at a speed N (for example, 3) times a standard tape running speed, which is capable of inserting a copy guard signal without degradation of image quality, during a time period in which the signal is processed in digital form and a copy guard signal inserting apparatus for use in the tape dubbing apparatus are provided. The copy guard signal is inserted by digitally processing the signal by the copy guard signal inserting apparatus during a vertical blanking period of a digital luminance signal whose speed is made N times the standard speed by a signal arrangement converter/digital rate converter. The digital luminance signal to which the copy guard signal is inserted is converted into an analog signal by a D/A converter and recorded by respective slave recording apparatuses together with the chroma signal.

Abstract: A reproducible number limiting apparatus for a magnetic recording medium using a reproducible number limiting algorithm is disclosed including: scrambling means for scrambling an input bit stream using a scrambling key; encryption means for encrypting the scrambling key used in the scrambling means' scrambling and additional information, and outputting a ciphertext; a key storage for storing an encryption key required in encryption; recording/reproducing means for recording or reproducing the output of the scrambling means and encryption means; decryption means for updating the additional information for every playback from the ciphertext using an encryption key, and destroying the scrambling key when the additional information satisfies a specific condition; and descrambling means for descrambling a reproduced bit stream using the scrambling key from the decryption means.

Abstract: An emulation module (110) includes a pre-fetch queue (116) having an adjustable size (126) to eliminate any dependence of virus decryption routines on the size of the pre-fetch queue (116) when emulating executable files to test for the presence of virus infections. An executable file is tested by setting (210, 258) the size of the emulator's pre-fetch queue (116) and emulating (220) the file under the guidance of an emulation control module (130). Emulated instructions are monitored and a flag is set (230) when any instructions are modified (224) after being copied to the pre-fetch queue and subsequently executed (228). Emulation continues until the emulation control module (130) indicates (230) that the file should be scanned for virus signatures. If no virus signatures are detected (234) and the flag is set (244), the size of the pre-fetch queue is reduced (258) and the process is repeated.