Abstract: A method, system, and article for compressing an input stream of uncompressed data. The input stream is divided into one or more data segments. A hash is applied to a first data segment, and an offset and length are associated with this first segment. This hash, together with the offset and length data for the first segment, is stored in a hash table. Thereafter, a subsequent segment within the input stream is evaluated and compared with all other hash entries in the hash table, and a reference is written to a prior hash for an identified duplicate segment. The reference includes a new offset location for the subsequent segment. Similarly, a new hash is applied to an identified non-duplicate segment, with the new hash and its corresponding offset stored in the hash table. A compressed output stream of data is created from the hash table retained on storage media.

Abstract: There is realized a data conversion device that performs generation of a hash value with improved analysis resistance and a high degree of safety. There are provided a stirring processing section performing a data stirring process on input data; and a compression processing section performing a data compression process on input data including data segments which are divisions of message data, the message data being a target of a data conversion. Part of multi-stage compression subsections is configured to perform a data compression process based on both of output of the stirring processing section and the data segments in the message data. There is provided such a configuration that the stirring process is executed at least on fixed timing of a compression processing round of plural rounds and thus, there is realized a data conversion device that performs generation of a hash value with improved analysis resistance and a high degree of safety.

Abstract: A system and method for validating software parts on an aircraft. A first hash value is calculated for a software part on the aircraft. A determination is made on the aircraft as to whether the first hash value matches a second hash value from a software integrity data structure stored on the aircraft. The software integrity data structure comprises the hash values that are not determined on the aircraft for the software parts used by the aircraft. A validation status is provided based on whether the first hash value matches the second hash value. An operation is performed on the software part on the aircraft only if the first hash value matches the second hash value.

Abstract: Techniques for managing data objects of a data storage system are described herein. According to one embodiment, a hash function is generated for a plurality of data objects by analyzing each of the data objects stored in the data storage system. For each of the data objects, a hash operation is performed on the data object using the hash function, generating a hash value. The hash value is associated with a predetermined attribute of the data object, such that the predetermined attribute of the data object is uniquely identified using the hash function subsequently in response to a request for accessing the predetermined attribute of the data object. The data object is then stored at a persistent storage location of the data storage system, wherein the persistent storage location is identifiable based on a hash value obtained from the hash function.

Abstract: A method and system is provided for copying data between two deduplicating storage systems. A list of unique fingerprints is compiled from the data which will be sent. This list is transmitted to the receiving system during a preliminary data exchange called the preamble. The receiving system replies with a second list which contains the unique fingerprints of the data which either needs to be sent or can be omitted. Which list depends on the size of the list where the smaller list is sent for efficiency and lower bandwidth consumption. A reference list of duplicate blocks being sent is retained on the receiving system until the copy operation is complete. This reference list is used to protect blocks on the receiving system by deferring deletions until the incoming hallow block can reference the duplicate block on the receiver to confirm that is on the target system and should not be deleted.

Abstract: Electronic circuitry includes an input/output (I/O) interface, memory which stores a set of database fingerprints generated from records of a database, and an analyzing circuit coupled to the I/O interface and the memory. The analyzing circuit is constructed and arranged to derive a set of sample tokens from electronic data under test (e.g., an email, an electronic document, etc.), and form a set of sample fingerprints from the set of sample tokens. Each sample fingerprint is based on a sample token of the set of sample tokens. The analyzing circuit is further constructed and arranged to output a result signal based on a comparison between the set of sample fingerprints and the set of database fingerprints. The result signal provides an indication of whether the electronic data under test includes particular information from the database.

Abstract: A replicated decentralized storage system comprises a plurality of servers that locally store disk images for locally running virtual machines as well as disk images, for failover purposes, for remotely running virtual machines. To ensure that disk images stored for failover purposes are properly replicated upon an update of the disk image on the server running the virtual machine, a hash of a unique value known only to the server running the virtual machine is used to verify the origin of update operations that have been transmitted by the server to the other servers storing replications of the disk image for failover purposes. If verified, the update operations are added to such failover disk images.

Abstract: An apparatus for authentication of fragments using hash trees may include a processor. The processor may be configured to provide one or more data fragments and a hash tree representing the one or more fragments, send at least one first fragment accompanied by any nodes of the hash tree necessary to authenticate the one or more first sent fragments, and send one or more subsequent fragments accompanied by only some, but not all, of the nodes of the hash tree necessary to authenticate the one or more subsequent fragments with the other nodes that are not sent but are necessary for authentication having been previously sent in conjunction with a prior fragment.

Abstract: In deduplicating data including objects, the system obtains information of the location of the objects and uses the information in calculating the hash value. The hash value calculation program divides data from the boundary location to chunks to match the boundary location of the objects subject to deduplication and the hash value is calculated from each chunk.

Abstract: A client device or other processing device comprises a file processing module, with the file processing module being operative to request proof from a file system that a file having a first format is stored by the file system in a second format different than the first format, to receive the proof from the file system, and to verify that the file is stored in the second format using the proof provided by the file system responsive to the request. The proof is based at least in part on application of a function to the file in the second format, and the function imposes a minimum resource requirement on generation of the proof. The file system may comprise one or more servers associated with a cloud storage provider. Advantageously, one or more illustrative embodiments allow a client device to verify that its files are stored by a cloud storage provider in encrypted form or with other appropriate protections.

Abstract: A system and method for protecting computing systems, and more particularly a system and method which a dedicated hardware component configured to communicate with a protection program. A computer hardware subsystem includes a memory comprising content. The content is at least a list of files which have been modified within a predetermined period of time. The list of files is a subset of files of a hard drive. A dedicated hardware component is configured to track the files which have been modified and provide a location of the files to the memory. A communication link between the dedicated hardware component and a protection program provides the protection program with the subset of files of the hard drive as referenced by the memory content.

Abstract: A two-level cache to facilitate resolving resource path expressions for a hierarchy of resources is described, which includes a system-wide shared cache and a session-level cache. The shared cache is organized as a hierarchy of hash tables that mirrors the structure of a repository hierarchy. A particular hash table in a shared cache includes information for the child resources of a particular resource. A database management system that manages a shared cache may control the amount of memory used by the cache by implementing a replacement policy for the cache based on one or more characteristics of the resources in the repository. The session-level cache is a single level cache in which information for target resources of resolved path expressions may be tracked. In the session-level cache, the resource information is associated with the entire path expression of the associated resource.

Abstract: In general, one aspect of the subject matter described in this specification can be embodied in a system that includes a network-based information server system; and a computer operable to interact with a user interface device and operable to perform operations including: receiving from the network-based information server system status information corresponding to software applications, the status information including black-list information and phoenix-list information; updating a local cache, retained by the computer, with the status information received from the network-based information server system; generating an identifier for a software application, using a digital certificate and a hash value, when the software application is launched on the computer; checking the identifier for the software application against the status information; and notifying a user of the computer when a match is found during the checking.

Abstract: Described embodiments provide coherent processing of hash operations of a network processor having a plurality of processing modules. A hash processor of the network processor receives hash operation requests from the plurality of processing modules. A hash table identifier and bucket index corresponding to the received hash operation request are determined. An active index list is maintained for active hash operations for each hash table identifier and bucket index. If the hash table identifier and bucket index of the received hash operation request are in the active index list, the received hash operation request is deferred until the hash table identifier and bucket index corresponding to the received hash operation request clear from the active index list. Otherwise, the active index list is updated with the hash table identifier and bucket index of the received hash operation request and the received hash operation request is processed.

Abstract: A system and method for “on-the-fly” de-duplication of data before storing the data in a storage system. A data de-duplication module illustratively cooperates with protocol servers and a file system of a storage operating system executing on the storage system to implement the novel de-duplication technique. The de-duplication module illustratively generates a block store, an index file and a hash table on storage space provided by the storage system. The hash table is utilized for tracking fingerprints and locations of blocks within the block store. The index file is utilized for storing directory information identifying the contents of data containers stored on the storage system, while the block store is utilized to store raw data blocks that comprise the data containers.

Abstract: Described embodiments provide a media controller that determines the size of a cache of data being transferred between a host device and one or more sectors of a storage device. The one or more sectors are segmented into a plurality of chunks, and each chunk corresponds to at least one sector. The contents of the cache are managed in a cache hash table. At startup of the media controller, a buffer layer module of the media controller initializes the cache in a buffer of the media controller. During operation of the media controller, the buffer layer module determines a number of chunks allocated to the cache. Based on the number of chunks allocated to the cache, the buffer layer module updates the size of the of the cache hash table.

Abstract: Example apparatus, methods, and computers are configured to consider multiple lookups when making decisions concerning whether a probabilistic data structure indicates that an item is or is not present. One example method includes receiving a first response from a probabilistic data structure, where the first response indicates whether a first element is a member of a set of stored elements. The example method also includes receiving a set of second responses from the probabilistic data structure, where the set of second responses indicate whether members of a corresponding set of second elements are members of the set of stored elements. The method then provides a present/absent signal concerning whether the first element is a member of the set of stored elements. The signal is computed as a function of the first response and the set of second responses rather than merely as a function of the first response.

Abstract: A method and system is provided by which unauthorized changes to the registry may be detected and that provides the capability to verify whether registry, or other system configuration data, changes that occur on a computer system are undesirable or related to possible malware attack before the changes become effective or are saved on the system. A method for verifying changes to system configuration data in a computer system includes generating an identifier representing an entry in the system configuration data, packaging the identifier, and sending the packaged identifier to a client for verification. The identifier may be generated by hashing the first portion of the entry and the second portion of the entry to generate the identifier, or by filtering the first portion of the entry and hashing the filtered first portion of the entry and the second portion of the entry to generate the identifier.

Abstract: A robust hashing method is applied to media data (e.g., video, image, and/or audio data), producing a hash output that is robust with respect to at least one attribute of the media data. A histogram is generated for the media data and the histogram is hashed using a weighted hashing procedure. The histogram can be derived from a plurality of randomized versions of the media file, each randomized version of the media file altered to a random extent with respect to the attribute. The histogram can also be derived from a plurality of feature descriptors computed for the media data that are coarsely encoded with respect to the attribute. The weighted hashing procedure includes assigning a weight to components of the histogram and applying a plurality of hash functions to a number of versions of each component, the number of versions based on the assigned weight.

Abstract: A system and method for distributing and accessing files in a distributed storage system uses an ordered list of the storage nodes in the system to determine the storage node on which a file is stored. The distributed storage system includes a cluster of storage nodes and may also include one or more client nodes that participate in the system as storage resources. Each node (client and storage) stores an ordered list of the storage nodes in the system, allowing any of the nodes to access the file. The list is updated whenever a new storage node is added to the system, an existing storage node is removed from the system, or a new storage node is swapped with an existing storage node. Each one of the nodes may independently compute a new mapping of files to the storage nodes when the ordered list is changed.

Abstract: Methods and corresponding systems in a mobile device for remotely modifying data stored in the mobile device include receiving a message in the mobile device. The message can be a short message service (SMS) message. The message is compared to a secret message, wherein the secret message is a hash value output by a hash function, wherein inputs to the hash function include a text string and a secret text string. The text string can be an e-mail address, and the secret text string can be a password of the mobile device. In response to the message matching the secret message, data stored in memory in the mobile device is modified to prevent unauthorized access. A secret message cancellation can be received in the mobile device to cancel a scheduled memory modification. Memory modification can include erasing data, replacing data, or encrypting data.

Abstract: A data management system respectively computes first hash values while sliding a window a prescribed amount at a time with respect to a prescribed range from a start location of a data block to a prescribed size. The system extracts, from among the first hash values, a first hash value, which is equivalent to a characteristic value, and partitions the data block into a first chunk of data at a location corresponding to this first hash value. The system determines coincidence between a first chunk of data and a stored second chunk of data, and prevents duplicate data from being stored twice.

Abstract: The technique introduced here includes a system and method for preprocessing a data set to improve deduplication, and more specifically for reducing latency. The technique illustratively utilizes one or more preprocessing steps, including a “skipping” step and a “folding” step, which can be applied to a data set prior to deduplication to reduce the time consumed by deduplication. The folding step is applied to segments of the data set to reduce the length of the segments. The skipping step can be applied to the data set prior to the folding step to remove particular segments of the data set, to further improve deduplication performance in certain circumstances. The overall effect of the skipping and folding steps of this technique is to produce a data set of reduced total length for consideration in identifying duplicate data, which aids in reducing the time required for deduplication.

Abstract: A distributed file system and a data block consistency managing method thereof are disclosed. The method comprises: a file location register generates the values of the counters corresponding to CHUNKs and the values of the counters are simultaneously stored in file access servers and a file location register; when writing data into a CHUNK, a file access client writes data into both the main and standby file access servers and revises the values of counters of CHUNKs in the file access servers into which data is written normally; the file location register takes the CHUNK whose counter has the maximal value as the normal and valid one according to the corresponding values of the counters of corresponding CHUNK reported by the main and standby file access servers.

Abstract: The present invention provides for a system and method for assuring integrity of deduplicated data objects stored within a storage system. A data object is copied to secondary storage media, and a digital signature such as a checksum is generated of the data object. Then, deduplication is performed upon the data object and the data object is split into chunks. The chunks are combined when the data object is subsequently accessed, and a signature is generated for the reassembled data object. The reassembled data object is provided if the newly generated signature is identical to the originally generated signature, and otherwise a backup copy of the data object is provided from secondary storage media.

Abstract: An method for creating a index of the data blocks is applicable in data de-duplication procedure, includes loading an index file, the index file includes a plurality of location blocks, each location block includes a plurality of storage fields, and each storage field records a primary Hash value corresponding to the data block; performing a first Hash procedure on a primary Hash value of the data block and calculating a block number; performing a second Hash procedure on the primary Hash value in the same data block and calculating a field number; loading a location conflict list; comparing the field number with the field number in the location conflict list to search whether the same field number is stored in the location conflict list; writing the primary Hash value into the corresponding block number and the field number if the field number does not exist in the location conflict list.

Abstract: A system and methods of managing entries in a cuckoo hash table that is subject to manipulation by a plurality of concurrent processors are provided. The cuckoo hash table is used to maintain a plurality of keys, along with their data items, in a plurality of entries. In accordance with an operating method, a first command for the cuckoo hash table is processed, and the first command is associated with a first processor of the plurality of concurrent processors. In addition, invalid conditions associated with concurrent processing of a second command for the cuckoo hash table are prevented or minimized. The second command is associated with a second processor of the plurality of concurrent processors. As one example, the operating method manages the situation where concurrent push commands create a race condition. As another example, the operating method manages the situation where a lookup or delete command from one processor competes with a push command from another processor.

Abstract: In deduplicating data including objects, the system obtains information of the location of the objects and uses the information in calculating the hash value. The hash value calculation program divides data from the boundary location to chunks to match the boundary location of the objects subject to deduplication and the hash value is calculated from each chunk.

Abstract: An algorithm (such as the MD5 hash function) is applied to a file to produce an intrinsic unique identifier (IUI) for the file (or message digest). The file is encrypted using its IUI as the key for the encryption algorithm. An algorithm is then applied to the encrypted file to produce an IUI for the encrypted file. The encrypted file is safely stored or transferred within a network and is uniquely identifiable by its IUI. The encrypted file is decrypted using the IUI of the plaintext file as the key. The IUI serves as both a key to decrypt the file and also as verification that the integrity of the plaintext file has not been compromised. IUIs for any number of such encrypted files may be assembled into a descriptor file that includes meta data for each file, the IUI of the plaintext file and the IUI of the encrypted file. An algorithm is applied to the descriptor file to produce an IUI for the descriptor file.

Abstract: A method for preventing a user from interpreting optional stored data information even when the user extracts the optional stored data, and an apparatus thereof. The apparatus for encrypting and processing data in a flash translation layer includes a flash memory and a controller. The flash translation layer searches at least one page of the flash memory storing the data when a write of optional data is requested from the controller, generates, corresponding to respective searched pages, a page key according to a predetermined encrypting function when the searched page supports an encryption, and encrypts and stores the data by the page key in the respective searched pages.

Abstract: A system, method, and computer program product for backing up data from a backup source to a central repository using deduplication, where the data comprises source data segments is disclosed. A fingerprint cache comprising fingerprints of data segments stored in the central repository is received, where the data segments were previously backed up from the backup source. Source data fingerprints comprising fingerprints (e.g., hash values) of the source data segments are generated. The source data fingerprints are compared to the fingerprints in the fingerprint cache. The source data segments corresponding to fingerprints not in the fingerprint cache may not be currently stored in the central repository. After further queries to the central repository, one or more of the source data segments are sent to the central repository for storage responsive to comparison.

Abstract: A database structure (400) stores data representing a plurality of resource identifiers (200) such as URLs in a computing system. The URLs (200) are each associated with a respective category code (310). Each of resource identifiers (200) is hashed to provide a hash value (300) which is divided into at least first and second hash portions (301, 302). The first hash portions (301) index a main hash array (410) to select a main data block (421) in a main data section (420) holding a set of the second hash portions (302) and the respective category codes (310). For security and compactness, optionally the hash value (300) is further divided to provide a third hash portion (303) which is discarded and is not used to access the database (400).

Abstract: Surrogate hashing is described, including running a hashing algorithm against a portion of a file to generate a hash value, determining whether the hash value is substantially similar to a stored hash value associated with another portion of another file, the portion and the another portion being standardized, and identifying a location of the another file if the hash value is substantially similar to the stored hash value associated with the another portion of the another file.

Abstract: Methods, systems and apparatus, including computer program products, for enhancing query performance through fixed length hashing of multidimensional data. According to one method, a fixed length hash of a multidimensional data record is created where the hash has respective fixed length sections for each data dimension of the record being hashed. The composite fixed length hash is stored with a reference to the original data record to which it corresponds. Query parameters are hashed and compared to a corresponding section of the fixed length hash to determine a set of candidate records.

Abstract: A computerized method of adjudicating text against a policy includes receiving one or more system policies, creating a system datastructure for each received system policy, receiving an input message comprising a text to be adjudicated, selecting a system policy from the one or more received system policies based on the input message, and processing the text to be adjudicated and the system datastructure corresponding to the selected system policy to determine if a prohibited word is present in the text to be adjudicated. The one or more system policies include one or more prohibited words and a first hit value corresponding to each prohibited word. The system datastructure includes a plurality of linked lists corresponding the letters of the alphabet and a head linked list operable to store one or more found prohibited words.

Abstract: A replicated decentralized storage system comprises a plurality of servers that locally store disk images for locally running virtual machines as well as disk images, for failover purposes, for remotely running virtual machines. To ensure that disk images stored for failover purposes are properly replicated upon an update of the disk image on the server running the virtual machine, a hash of a unique value known only to the server running the virtual machine is used to verify the origin of update operations that have been transmitted by the server to the other servers storing replications of the disk image for failover purposes. If verified, the update operations are added to such failover disk images. To enable the replicated decentralized system to recover from a failure of the primary server, the master secret is subdivided into parts and distributed to other servers in the cluster.

Abstract: A method for efficiently synchronizing configuration data within distributed computing systems may include: 1) maintaining a hash tree that is based on the hierarchical relationship of each object within a distributed computing system that is relevant to the computing device, 2) determining, during a reconciliation process with an additional computing device, that a hash of a top-level node of the hash tree differs from a hash of a corresponding node of the additional computing device's hash tree, 3) identifying, by iterating through the hash levels of the computing device's hash tree, at least one leaf node within the computing device's hash tree whose hash differs from a hash of a corresponding leaf node within the additional computing device's hash tree, 4) receiving the changed leaf node's value from the additional computing device, and then 5) updating the identified leaf node's value to match the changed leaf node's value.

Abstract: Defense-in Depth security defines a set of graduated security tasks, each of which performs a task that must complete before another task can complete. Only when these tasks complete successfully and in the order prescribed by Defense-in-Depth security criteria is a final process allowed to execute. Through such Defense-in-Depth security measures, vulnerable software, such as bytecode, can be verified as unaltered and executed in a secure environment that prohibits unsecured access to the underlying code.

Abstract: A data repository system and method are provided. A method in accordance with an embodiment includes an operation that can be used to port data from one or more existing database partitions to new database partitions according to a minimally progressive hash. The method can be used to increase the overall size of databases while a system runs hot, with little or no downtime.

Abstract: Data de-duplication schemes reduce the amount of storage necessary to store a data set by dividing the data into segments and storing a segment identifier on a storage medium in place of each data segment. Each unique data segment is stored in a repository, and duplicate data segments are not stored. Methods and apparatus are provided for distributing data segments across multiple repositories in a data storage system, thereby reducing the quantity of data stored at a particular repository. Segments are assigned to repositories based upon a characteristic of the segments. The characteristic may be the length of the segment or some other value produced by a repeatable, uniformly-distributed function of the segment. The characteristic may be stored on the storage medium along with the segment identifier. The original data may be regenerated by retrieving the segment identifiers and characteristics from the storage medium and retrieving each segment from the repository identified by the characteristic.

Abstract: A similarity measure system selects a first value and a first context related to the first value, divides the first value into a first set of substrings in an order preserving way, and processes each of these substrings through an obfuscation function to produce a first set of obfuscated substrings. The system selects a second value and a second context related to the second value, and processes the second value to produce a second set of obfuscated substrings. The system calculates a context similarity measure for the first context and the second context. The system determines a value similarity measure from the first and second set of order preserved obfuscated substrings. The system determines a closeness degree between the first value and the second value and a closeness degree based on the context similarity measure.

Abstract: An embodiment of the invention provides an apparatus and method for data verification by challenge. The apparatus and method perform acts including: sending a hash value of a data piece in a sender; if the hash value matches a stored hash value in a receiver, then sending a challenge from the receiver to the sender; sending a sample data set from the data piece in the sender, wherein the sample data set is determined by a window that is identified by the challenge; comparing the sample data set with a data set that is overlapped by the window for a stored data piece in the receiver; and performing a response based on the comparison of the sample data set and the stored data set that is overlapped by the window for the stored data piece.

Abstract: Various embodiments are provided for facilitating construction of a synthetic backup in a deduplication storage system. In one embodiment, a deduplication storage system enables new input data to be deduplicated with data of synthetic backups already constructed, and for this purpose efficiently calculates deduplication digests for synthetic backups being constructed, based on already existing digests of data referenced by the synthetic backups. For each input data segment of the plurality of input data segments of a synthetic backup being constructed, a plurality of deduplication digests of stored data segments, referenced by the input data segment, is retrieved from an index. Each input data segment is partitioned into each of a plurality of fixed-sized data sub-segments.

Abstract: A method comprising, sending an instruction from a validator member of a sysplex to a second member of a sysplex to prevent operations that alter a sysplex namespace, determining whether the validator member of the sysplex is communicative with the second member of the sysplex and whether the members of the sysplex retain current sysplex status information, sending an instruction from the validator member to the second member to send a first namespace attribute data associated with the second member to the validator member responsive to determining that the validator member of the sysplex is communicative with the second member of the sysplex and the members of the sysplex retain current sysplex status information, determining whether the first namespace attribute data associated with the second member is consistent with a second namespace attribute data, and sending an instruction to correct the first namespace attribute data.

Abstract: Example embodiments are directed to methods of hashing for networks and systems thereof. At least one example embodiment provides a method of processing elements in a system. The method includes receiving a first element, generating a first plurality of hash values based on the first element and a first plurality of hash functions, determining a first plurality of buckets in a table based on the first plurality of hash values, each of the first plurality of buckets associated with a different one of the hash values, selecting one of the first plurality of buckets, storing a first associated value in the selected bucket, the first associated value being associated with the first element, and encoding an identifier (ID) of the hash function generating the hash value associated with the selected bucket into a filter based on the hash value.

Abstract: One embodiment of the present invention provides a system that facilitates detecting data tampering within a table in a database. The system operates by hashing a row in the table to create a row-hash. The system then hashes a block of consecutive row-hashes to create a block-hash. Finally, the system signs the block-hash with an encryption key, so that tampering with data in the row will result in an invalid row-hash and an invalid block-hash.

Abstract: Surrogate hashing is described, including a database configured to store data associated with a first file and a second file, and a processor configured to run a first hashing algorithm against a first portion of a first file to generate a first hash value, and running a second hashing algorithm against the first portion of the first file to generate a second hash value, to determine whether the first hash value and the second hash value are substantially similar to one or more stored hash values associated with a second portion of a second file, wherein the second portion is identified by one or more attributes that are substantially similar to one or more corresponding attributes associated with the first portion, and to identify a location of the second file if the first hash value and the second hash value are substantially similar to the one or more stored hash values associated with the second portion of the second file.

Abstract: Surrogate hashing is described, including initializing one or more variables in a collection, evaluating an address associated with a host, comparing the address to the collection to determine if the address is stored in the collection, and processing the address to hash a file identified by the address if the address is not stored in the collection or determining if another address is indicated by the address if the address is stored in the collection.

Abstract: A computer-implemented method for seeding a fingerprint cache for data deduplication associated with a single-instance-storage computing subsystem may comprise: 1) maintaining server-side fingerprint usage data for a plurality of fingerprints associated with data stored in the single-instance-storage computing subsystem and 2) building, based at least in part on the fingerprint usage data, a server-side fingerprint cache for use in client-side data deduplication, the server-side fingerprint cache comprising at least a subset of the plurality of fingerprints. The method may further comprise: 1) receiving a request for the server-side fingerprint cache from a client-side data deduplication computing subsystem and 2) transmitting data representative of the server-side fingerprint cache to the client-side data deduplication computing subsystem for use in client-side data deduplication associated with the single-instance-storage computing subsystem.

Abstract: A system and method to implement a technique to compare a collection of files. A reference index is extracted from a reference version file. The reference index specifies contents of a reference directory at a binary level. A target index is extracted from a target version file. The target index specifies contents of a target directory at the binary level. The target index is compared against the reference index to determine whether the contents of the target directory match the contents of the reference directory.