Embodiments of the subject matter described herein relate generally to data security in the context of computer systems and networks. More particularly, embodiments of the subject matter described herein relate to methods of concealing data within computer files and/or data streams.
Steganography is the practice of concealing data. That is, while most branches of cryptography are focused on encrypting and decrypting messages that might be observed and analyzed by any number of individuals (i.e., not just the sender and recipient), steganography is focused on concealing even the existence of such messages.
In 16th-century France, for example, Girolamo Cardano devised a method for hiding messages within written correspondence by providing the recipient a separate sheet of paper including carefully positioned cut-outs or apertures. When properly aligned with a page of the correspondence, individual letters could be viewed through the apertures, thereby revealing the hidden message. This scheme is generally referred to as the “Cardan grille” method, owing to the grill-like appearance of the perforated sheet of paper.
In the digital era, however, steganography typically involves changing the contents of a file in a way that embeds the secret message (i.e., the “target data”) but is sufficiently subtle to avoid detection. For example, the least-significant bits of digital images or sound files may be manipulated, or imperceptible delays may be added to packets sent over a network. Steganography techniques such as these are unsatisfactory in a number of respects, however, because the source dataset (i.e., the original image or file) must be altered in some way to embed the target data. In some applications, the source data cannot be modified, or modification would provide a clue that the target data was encoded therein. Accordingly, there is a need for improved systems and methods for computer-implemented steganography.
A more complete understanding of the subject matter may be derived by referring to the detailed description and claims when considered in conjunction with the following figures, wherein like reference numbers refer to similar elements throughout the figures.
Embodiments of the subject matter described herein generally relate to systems and methods for concealing a target dataset (e.g., a password, a key, or a secret message) by applying computer-implemented digital steganography to a source dataset (e.g., a large text file or the like) while at the same time preserving the contents of the source dataset itself—i.e., without injecting data into the source dataset itself.
In the illustrated embodiment, user input device 102 generally represents the hardware and/or other components coupled to processing system 106 for providing a user interface to computing device 100. For example, the user input device 102 may be realize as a key pad, a keyboard, a touch panel, a touchscreen, or any other device capable of receiving input from a user. The communications interface 104 generally represents the hardware, software, firmware and/or combination thereof that are coupled to the processing system 106 and configured to transmit and/or receive data packets to and/or from the computing device 100 via a communications network, such as the Internet or another computer network. In this regard, the communications interface 104 may include one or more amplifiers, filters, modulators and/or demodulators, digital-to-analog converters (DACs), analog-to-digital converters (ADCs), antennas, or the like. In an exemplary embodiment, the display device 110 is realized as an electronic display device configured to graphically display information and/or content under control of the processing system 106.
In the computing device 100 of
As depicted in
Referring now to
In general, target dataset 320 is the key, password, secret message, or other digital object that needs to be concealed, and the source dataset 310 is the text or other digital object that is used to conceal the target dataset 320. Source dataset 310 and target dataset 320 each may be any form of computer-readable file now known or used in the future, such as a simple text file, a word-processing file, a digital image file (e.g., JPEG or GIF), a digital music file (e.g., MP3 or FLAC), a binary large object (BLOB) file, an executable file, or any other file capable of existing in binary form. As further described below, the predefined extraction method may require scanning through the source dataset 310 to find data elements (or bit sequences) that correspond to the data elements or bit sequences within target dataset 320. Accordingly, it is desirable that source dataset 310 be sufficiently large and diverse that it is capable of being used in conjunction with the expected length of target dataset 320. So, for example, a 10-byte source dataset would likely not be sufficient for encoding a 100-byte target dataset. At the same time, a 10 MB source dataset consisting of all null bytes would not be sufficient for encoding even a small target dataset.
Referring now to
The goal of scanning module 330, then, is to sequentially consider each target data element within target dataset 320 and then inspect source dataset 310 to find the next occurrence that matches that target data element. If there is no match (i.e., if the source dataset is not sufficiently large), then a default value may be used or an error code or exception may be generated. The indice of the matching element is then added to grille dataset 340. Thus, in this simple example, target data element t1 is found first at indice three (i.e., t1=s3), t2 corresponds to s5, t3 corresponds to s9, t4 corresponds to s12, and t5 corresponds to s16. The corresponding indices (of source dataset 310) is then the ordered set {3, 5, 9, 12, 16}. This set of indices can then be used to reconstruct target dataset 320, assuming that the extraction method is known.
As more concrete example, consider the case where the target dataset is the following character string:
HELLOWORLD
and the source dataset (with index reference numbers added for convenience) is:
an extraction method that identified the first occurrence of each letter relative to the leftmost character in the source dataset would then produce a grille dataset 340 of {2, 3, 30, 30, 11, 12, 30, 10, 30, 22}.
In another embodiment, the extraction method is performed on a bit-level rather than an element (or character) level. That is, predefined extraction method is configured to produce a grille dataset comprising, for each target data element, a corresponding indice indicating the position of a specific bit within a bitwise representation of the source dataset, irrespective of the position of the source data elements. In such a case, the string “HELLOWORLD” and the source dataset above are represented by ASCII or another bit-wise code. The extraction method can then consider a three, four, or any number of bits at a time, ignoring the bitwise position of each of the source data elements.
In the above examples, the position within the source dataset is referenced from the beginning of the dataset (i.e., the leftmost element); however, in other embodiments, the position of the next occurrence is determined based on a location that is not the beginning of the source dataset, for example, from the end or at an arbitrary position in the middle of the source dataset.
Further, in some examples the position within the source dataset is referenced from a position that changes from element to element. Thus, the first position (i.e., indice) may be referenced from the leftmost element, the second from the rightmost character, the third from the leftmost character, and so on. In general, the entire predetermined extraction method may change from character to character or at any other suitable interval.
A variety of predetermined extraction methods may used in addition to those described above. For example, the source data set could be considered a two dimensional array of data (with bounds selected by the designer), and the position to be x, y coordinates. Such an embodiment would more closely represent a physical Cardano grille. A transformation may be applied to the dataset (for example, a reproducible encryption) that would cause the dataset to become more random, and thus provide a richer information set. Further, the target dataset to be hidden using the source dataset could drive the choice of an extraction method. For instance, if the target data is an image to be hidden within a JPG digital image file, it may be desirable to decode the source dataset image before determining the extraction method, as an encoded JPG has been regularized to some extent. False indices could be placed into the extraction data to randomize it. In one implementation, particular bits of extraction data are randomly generated. The extraction method would then be responsible for determining which data is false and which has meaning.
In one embodiment, the scanning module 330 (
In another embodiment, the predefined extraction method is based in part on a key, PIN, or other information provided by a user. That is, while the examples above assume that the predefined extraction method is constant and known, in some embodiments the extraction method becomes “predefined” only after a key or other input is provided by the user creating the grille dataset 340.
In some embodiments, the grille dataset 340 is transmitted over a computer network (e.g., 202 in
In some embodiments, the predetermined extraction method may be sensitive to changes in the source dataset 310. In this way, the predetermined extraction method may be used as a form of cyclic-redundancy check to detect tampering of the source dataset 310. In one embodiment, the extraction method could be defined as a cyclic-redundancy check (CRC) or other Hash algorithm. In such an embodiment, the resulting grille dataset is a hash value that is extremely sensitive to any change in the source data. In another example, consider the case where the target dataset and source dataset are identical. In this case any change to the source would clearly affect the target. Since the target dataset is based upon the source dataset, this extraction method is inherently sensitive to changes in the source data it can function as a change detector whenever the target is known in advance.
In accordance with various embodiment, the systems and methods described above are used in the context of a multi-tenant database system. More particularly, referring to
As used herein, a “tenant” or an “organization” should be understood as referring to a group of one or more users that shares access to common subset of the data within the multi-tenant database 530. In this regard, each tenant includes one or more users associated with, assigned to, or otherwise belonging to that respective tenant. Tenants may represent customers, customer departments, business or legal organizations, and/or any other entities that maintain data for particular sets of users within the multi-tenant system 500. Although multiple tenants may share access to the server 502 and the database 530, the particular data and services provided from the server 502 to each tenant can be securely isolated from those provided to other tenants. The multi-tenant architecture therefore allows different sets of users to share functionality without necessarily sharing any of the data 532 belonging to or otherwise associated with other tenants.
The multi-tenant database 530 is any sort of repository or other data storage system capable of storing and managing the data 532 associated with any number of tenants. The database 530 may be implemented using any type of conventional database server hardware. In some embodiments, the database 530 shares processing hardware 504 with the server 502, while in other embodiments, the database 530 is implemented using separate physical and/or virtual database server hardware that communicates with the server 502 to perform the various functions described herein.
In practice, the data 532 may be organized and formatted in any manner to support the application platform 510. In various embodiments, the data 532 is suitably organized into a relatively small number of large data tables to maintain a semi-amorphous “heap”-type format. The data 532 can then be organized as needed for a particular virtual application 528. In various embodiments, conventional data relationships are established using any number of pivot tables 534 that establish indexing, uniqueness, relationships between entities, and/or other aspects of conventional database organization as desired. Further data manipulation and report formatting is generally performed at run-time using a variety of metadata constructs. Metadata within a universal data directory (UDD) 536, for example, can be used to describe any number of forms, reports, workflows, user access privileges, business logic and other constructs that are common to multiple tenants. Tenant-specific formatting, functions and other constructs may be maintained as tenant-specific metadata 538 for each tenant, as desired. Rather than forcing the data 532 into an inflexible global structure that is common to all tenants and applications, the database 530 is organized to be relatively amorphous, with the pivot tables 534 and the metadata 538 providing additional structure on an as-needed basis. To that end, the application platform 510 suitably uses the pivot tables 534 and/or the metadata 538 to generate “virtual” components of the virtual applications 528 to logically obtain, process, and present the relatively amorphous data 532 from the database 530.
The server 502 is implemented using one or more actual and/or virtual computing systems that collectively provide the dynamic application platform 510 for generating the virtual applications 528. For example, the server 502 may be implemented using a cluster of actual and/or virtual servers operating in conjunction with each other, typically in association with conventional network communications, cluster management, load balancing and other features as appropriate. The server 502 operates with any sort of conventional processing hardware 504, such as a processor 505, memory 506, input/output features 507 and the like. The input/output features 507 generally represent the interface(s) to networks (e.g., to the network 545, or any other local area, wide area or other network), mass storage, display devices, data entry devices and/or the like. The processor 505 may be implemented using any suitable processing system, such as one or more processors, controllers, microprocessors, microcontrollers, processing cores and/or other computing resources spread across any number of distributed or integrated systems, including any number of “cloud-based” or other virtual systems. The memory 506 represents any non-transitory short or long term storage or other computer-readable media capable of storing programming instructions for execution on the processor 505, including any sort of random access memory (RAM), read only memory (ROM), flash memory, magnetic or optical mass storage, and/or the like. The computer-executable programming instructions, when read and executed by the server 502 and/or processor 505, cause the server 502 and/or processor 505 to establish, generate, or otherwise facilitate the application platform 510 and/or virtual applications 528 and perform additional tasks, operations, functions, and processes herein. It should be noted that the memory 506 represents one suitable implementation of such computer-readable media, and alternatively or additionally, the server 502 could receive and cooperate with computer-readable media (not separately shown) that is realized as a portable or mobile component or platform, e.g., a portable hard drive, a USB flash drive, an optical disc, or the like.
The application platform 510 is any sort of software application or other data processing engine that generates the virtual applications 528 that provide data and/or services to the client devices 540. In a typical embodiment, the application platform 510 gains access to processing resources, communications interfaces and other features of the processing hardware 504 using any sort of conventional or proprietary operating system 508. The virtual applications 528 are typically generated at run-time in response to input received from the client devices 540. For the illustrated embodiment, the application platform 510 includes a bulk data processing engine 512, a query generator 514, a search engine 516 that provides text indexing and other search functionality, and a runtime application generator 520. Each of these features may be implemented as a separate process or other module, and many equivalent embodiments could include different and/or additional features, components or other modules as desired.
The runtime application generator 520 dynamically builds and executes the virtual applications 528 in response to specific requests received from the client devices 540. The virtual applications 528 are typically constructed in accordance with the tenant-specific metadata 538, which describes the particular tables, reports, interfaces and/or other features of the particular application 528. In various embodiments, each virtual application 528 generates dynamic web content that can be served to a browser or other client program 542 associated with its client device 540, as appropriate.
The runtime application generator 520 suitably interacts with the query generator 514 to efficiently obtain multi-tenant data 532 from the database 530 as needed in response to input queries initiated or otherwise provided by users of the client devices 540. In a typical embodiment, the query generator 514 considers the identity of the user requesting a particular function (along with the user's associated tenant), and then builds and executes queries to the database 530 using system-wide metadata 536, tenant specific metadata 538, pivot tables 534, and/or any other available resources. The query generator 514 in this example therefore maintains security of the common database 530 by ensuring that queries are consistent with access privileges granted to the user that initiated the request.
Still referring to
In operation, developers use the application platform 510 to create data-driven virtual applications 528 for the tenants that they support. Such virtual applications 528 may make use of interface features such as tenant-specific screens 524, universal screens 522 or the like. Any number of tenant-specific and/or universal objects 526 may also be available for integration into tenant-developed virtual applications 528. The data 532 associated with each virtual application 528 is provided to the database 530, as appropriate, and stored until it is requested or is otherwise needed, along with the metadata 538 that describes the particular features (e.g., reports, tables, functions, etc.) of that particular tenant-specific virtual application 528. For example, a virtual application 528 may include a number of objects 526 accessible to a tenant, wherein for each object 526 accessible to the tenant, information pertaining to its object type along with values for various fields associated with that respective object type are maintained as metadata 538 in the database 530. In this regard, the object type defines the structure (e.g., the formatting, functions and other constructs) of each respective object 526 and the various fields associated therewith.
Still referring to
For the sake of brevity, conventional techniques related to computer programming, computer networking, data processing, cryptography, and other functional aspects of the systems (and the individual operating components of the systems) may not be described in detail herein. In addition, those skilled in the art will appreciate that embodiments may be practiced in conjunction with any number of system and/or network architectures, data transmission protocols, and device configurations, and that the system described herein is merely one suitable example. Furthermore, certain terminology may be used herein for the purpose of reference only, and thus is not intended to be limiting. For example, the terms “first”, “second” and other such numerical terms do not imply a sequence or order unless clearly indicated by the context.
Embodiments of the subject matter may be described herein in terms of functional and/or logical block components, and with reference to symbolic representations of operations, processing tasks, and functions that may be performed by various computing components or devices. Such operations, tasks, and functions are sometimes referred to as being computer-executed, computerized, software-implemented, or computer-implemented. In this regard, it should be appreciated that the various block components and modules (e.g., modules 330 and 332) shown in the figures may be realized by any number of hardware, software, and/or firmware components configured to perform the specified functions. For example, an embodiment of a system or a component may employ various integrated circuit components, e.g., memory elements, digital signal processing elements, logic elements, look-up tables, or the like, which may carry out a variety of functions under the control of one or more microprocessors or other control devices.
The foregoing description is merely illustrative in nature and is not intended to limit the embodiments of the subject matter or the application and uses of such embodiments. Furthermore, there is no intention to be bound by any expressed or implied theory presented in the technical field, background, or the detailed description. As used herein, the word “exemplary” means “serving as an example, instance, or illustration.” Any implementation described herein as exemplary is not necessarily to be construed as preferred or advantageous over other implementations, and the exemplary embodiments described herein are not intended to limit the scope or applicability of the subject matter in any way.
While at least one exemplary embodiment has been presented in the foregoing detailed description, it should be appreciated that a vast number of variations exist. It should also be appreciated that the exemplary embodiment or embodiments described herein are not intended to limit the scope, applicability, or configuration of the claimed subject matter in any way. Rather, the foregoing detailed description will provide those skilled in the art with a convenient road map for implementing the described embodiment or embodiments. It should be understood that various changes can be made in the function and arrangement of elements without departing from the scope defined by the claims, which includes known equivalents and foreseeable equivalents at the time of filing this patent application.
This application is a continuation of U.S. application Ser. No. 13/467,557 filed May 9, 2012, which claims the benefit of U.S. provisional patent application Ser. No. 61/506,439 filed Jul. 11, 2011, the entire contents of which are incorporated by reference herein.
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Parent | 13467557 | May 2012 | US |
Child | 14672720 | US |