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115-467: The term first referred to groups who had reverse engineered the system of tones used to route long-distance calls . By re-creating the signaling tones, phreaks could switch calls from the phone handset while avoiding long-distance calling charges which were common then. These fees could be significant, depending on the time, duration and destination of the call. To ease the creation of the routing tones, electronic tone generators known as blue boxes became

230-510: A breach of contract as well as any other relevant laws. That is because most end-user license agreements specifically prohibit it, and US courts have ruled that if such terms are present, they override the copyright law that expressly permits it (see Bowers v. Baystate Technologies ). According to Section 103(f) of the Digital Millennium Copyright Act ( 17 U.S.C. § 1201 (f) ), a person in legal possession of

345-523: A recorder he owned could also play the tone at 2600 Hz with the same effect. John Draper discovered through his friendship with Engressia that the free whistles given out in Cap'n Crunch cereal boxes also produced a 2600 Hz tone when blown (providing his nickname, "Captain Crunch"). This allows control of phone systems that work on single frequency (SF) controls. One can sound a long whistle to reset

460-439: A 16- digit keypad to input the next portion of the destination telephone number in order to contact the next downstream long-distance telephone operator. This semi-automated signaling and switching proved successful in both speed and cost effectiveness. Based on this prior success with using MF by specialists to establish long-distance telephone calls, dual-tone multi-frequency signaling was developed for end-user signaling without

575-456: A 3D model. The physical object can be measured using 3D scanning technologies like CMMs , laser scanners , structured light digitizers , or industrial CT scanning (computed tomography). The measured data alone, usually represented as a point cloud , lacks topological information and design intent. The former may be recovered by converting the point cloud to a triangular-faced mesh . Reverse engineering aims to go beyond producing such

690-420: A 6-digit card and once every 1000 tries for a 7-digit card. While this is almost easy enough for people to do manually, computers made the task far easier. "Code hack" programs were developed for computers with modems. The modems would dial the long-distance access number, enter a random calling card number (of the proper number of digits), and attempt to complete a call to a computer bulletin board system (BBS). If

805-408: A SEM is stitching the images together, which is necessary because each layer cannot be captured by a single shot. A SEM needs to sweep across the area of the circuit and take several hundred images to cover the entire layer. Image stitching takes as input several hundred pictures and outputs a single properly-overlapped picture of the complete layer. Next, the stitched layers need to be aligned because

920-409: A call, the companies kept the calling card numbers short – usually 6 or 7 digits. This opened up a huge vulnerability to phone phreaks with a computer. 6-digit calling card numbers only offer 1 million combinations. 7-digit numbers offer just 10 million. If a company had 10,000 customers, a person attempting to "guess" a card number would have a good chance of doing so correctly once every 100 tries for

1035-507: A combination of geometric and freeform surfaces can provide a powerful method of 3D modeling . Areas of freeform data can be combined with exact geometric surfaces to create a hybrid model. A typical example of this would be the reverse engineering of a cylinder head, which includes freeform cast features, such as water jackets and high-tolerance machined areas. Reverse engineering is also used by businesses to bring existing physical geometry into digital product development environments, to make

1150-414: A competitor's product was built. That process is commonly used for "cracking" software and media to remove their copy protection , or to create a possibly-improved copy or even a knockoff , which is usually the goal of a competitor or a hacker. Malware developers often use reverse engineering techniques to find vulnerabilities in an operating system to build a computer virus that can exploit

1265-502: A digital 3D record of their own products, or to assess competitors' products. It is used to analyze how a product works, what it does, what components it has; estimate costs; identify potential patent infringement; etc. Value engineering , a related activity that is also used by businesses, involves deconstructing and analyzing products. However, the objective is to find opportunities for cost-cutting. Reverse engineering of printed circuit boards involves recreating fabrication data for

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1380-570: A function that is performed in the United States by Bell 202 modulated frequency-shift keying (FSK) signaling. DTMF was originally decoded by tuned filter banks . By the end of the 20th century, digital signal processing became the predominant technology for decoding. DTMF decoding algorithms typically use the Goertzel algorithm although application of MUSIC (algorithm) to DTMF decoding has been shown to outperform Goertzel and being

1495-400: A group of phreaks, known as "Group Bell". Bernay initiated a similar group named the "Mark Bernay Society". Both Bernay and Evan received fame amongst today's phone phreakers for internet publications of their collection of telephone exploration recordings. These recordings, conducted in the 1960s, 1970s, and early 1980s are available at Mark's website Phone Trips . In October 1971, phreaking

1610-508: A key sends a combination of the row and column frequencies. For example, the 1 key produces a superimposition of a 697 Hz low tone and a 1209 Hz high tone. Initial pushbutton designs employed levers, enabling each button to activate one row and one column contact. The tones are decoded by the switching center to determine the keys pressed by the user. Engineers had envisioned telephones being used to access computers and automated response systems. They consulted with companies to determine

1725-604: A line. Placing calls over longer distances required either operator assistance or provision of special subscriber trunk dialing equipment. Operators used an earlier type of multi-frequency signaling. Multi-frequency signaling ( MF ) is a group of signaling methods that use a mixture of two pure tone (pure sine wave ) sounds. Various MF signaling protocols were devised by the Bell System and CCITT . The earliest of these were for in-band signaling between switching centers, where long-distance telephone operators used

1840-682: A lot in common with reverse engineering. The tester usually has the API but has the goals to find bugs and undocumented features by bashing the product from outside. Other purposes of reverse engineering include security auditing, removal of copy protection (" cracking "), circumvention of access restrictions often present in consumer electronics , customization of embedded systems (such as engine management systems), in-house repairs or retrofits, enabling of additional features on low-cost "crippled" hardware (such as some graphics card chip-sets), or even mere satisfaction of curiosity. Binary reverse engineering

1955-449: A mesh and to recover the design intent in terms of simple analytical surfaces where appropriate ( planes , cylinders , etc.) as well as possibly NURBS surfaces to produce a boundary-representation CAD model. Recovery of such a model allows a design to be modified to meet new requirements, a manufacturing plan to be generated, etc. Hybrid modeling is a commonly used term when NURBS and parametric modeling are implemented together. Using

2070-677: A number is a priority call. Present-day uses of the signals A, B, C and D are rare in telephone networks, and are exclusive to network control. For example, A is used in some networks for cycling through a list of carriers. The signals are used in radio phone patch and repeater operations to allow, among other uses, control of the repeater while connected to an active telephone line. The signals *, #, A, B, C and D are still widely used worldwide by amateur radio operators and commercial two-way radio systems for equipment control, repeater control, remote-base operations and some telephone communications systems. DTMF signaling tones may also be heard at

2185-470: A part of signaling protocols, as long as both endpoints agree on a common approach to adopt. The DTMF telephone keypad is laid out as a matrix of push buttons in which each row represents the low frequency component and each column represents the high frequency component of the DTMF signal. The commonly used keypad has four rows and three columns, but a fourth column is present for some applications. Pressing

2300-500: A particular circuit board. This is done primarily to identify a design, and learn the functional and structural characteristics of a design. It also allows for the discovery of the design principles behind a product, especially if this design information is not easily available. Outdated PCBs are often subject to reverse engineering, especially when they perform highly critical functions such as powering machinery, or other electronic components. Reverse engineering these old parts can allow

2415-480: A process or artifact in which the manner of its construction, use, or internal processes has not been made clear by its creator. Patented items do not of themselves have to be reverse-engineered to be studied, for the essence of a patent is that inventors provide a detailed public disclosure themselves, and in return receive legal protection of the invention that is involved. However, an item produced under one or more patents could also include other technology that

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2530-416: A program may reverse-engineer and circumvent its protection if that is necessary to achieve "interoperability", a term that broadly covers other devices and programs that can interact with it, make use of it, and to use and transfer data to and from it in useful ways. A limited exemption exists that allows the knowledge thus gained to be shared and used for interoperability purposes. EU Directive 2009/24 on

2645-402: A reproduction of the code and translation of its form are indispensable to obtain the necessary information to achieve the interoperability of an independently created program with other programs. It has therefore to be considered that, in these limited circumstances only, performance of the acts of reproduction and translation by or on behalf of a person having a right to use a copy of the program

2760-441: A safe phone number for phreaks to give out to one another as home phone numbers and personal cellular numbers would allow the phreak's identity (and home address) to be discovered. This is especially important given that phone phreaks are breaking the law. Phreakers also use "bridges" to communicate live with one another. The term "bridge" originally referred to a group of telephone company test lines that were bridged together giving

2875-444: A staple of the phreaker community. This community included future Apple Inc. co-founders Steve Jobs and Steve Wozniak . The blue box era came to an end with the ever-increasing use of digital telephone networks which allowed telecommunication companies to discontinue the use of in-band signaling for call routing purposes. Instead, telecom companies began employing common-channel signaling (CCS), through which dialing information

2990-484: A subculture saw a brief dispersion in fear of criminal prosecution in the 1990s, before the popularity of the internet initiated a reemergence of phreaking as a subculture in the US and spread phreaking to international levels. The 1984 AT&T breakup gave rise to many small companies intent on competing in the long-distance market. These included the then-fledgling Sprint and MCI , both of whom had only recently entered

3105-464: A very short parts list that could be used to construct one. AT&T forced Ramparts to pull all copies from shelves, but not before numerous copies were sold and many regular subscribers received them. In the 1980s, the revolution of the personal computer and the popularity of computer bulletin board systems (BBSes) (accessed via modem ) created an influx of tech-savvy users. These BBSes became popular for computer hackers and others interested in

3220-485: Is a process or method through which one attempts to understand through deductive reasoning how a previously made device, process, system, or piece of software accomplishes a task with very little (if any) insight into exactly how it does so. Depending on the system under consideration and the technologies employed, the knowledge gained during reverse engineering can help with repurposing obsolete objects, doing security analysis, or learning how something works. Although

3335-423: Is a tone of 2600 Hz which causes a telephone switch to think the call had ended, leaving an open carrier line, which can be exploited to provide free long-distance, and international calls. At that time, long-distance calls were more expensive than local calls. The tone was discovered in approximately 1957, by Joe Engressia , a blind seven-year-old boy. Engressia had perfect pitch , and discovered that whistling

3450-417: Is an invasive and destructive form of analyzing a smart card . The attacker uses chemicals to etch away layer after layer of the smart card and takes pictures with a scanning electron microscope (SEM). That technique can reveal the complete hardware and software part of the smart card. The major problem for the attacker is to bring everything into the right order to find out how everything works. The makers of

3565-494: Is being used mostly for long and thorough reverse engineering tasks (complete analysis of a complex algorithm or big piece of software). In general, statistical classification is considered to be a hard problem, which is also true for software classification, and so few solutions/tools that handle this task well. A number of UML tools refer to the process of importing and analysing source code to generate UML diagrams as "reverse engineering". See List of UML tools . Although UML

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3680-473: Is generally available only to large chip manufacturers. Furthermore, the payoff from this attack is low since other security techniques are often used such as shadow accounts. It is still uncertain whether attacks against chip-and-PIN cards to replicate encryption data and then to crack PINs would provide a cost-effective attack on multifactor authentication. Full reverse engineering proceeds in several major steps. The first step after images have been taken with

3795-493: Is known to be NP-complete , but online learning can be done in polynomial time. An automatic offline approach has been demonstrated by Comparetti et al. and an online approach by Cho et al. Other components of typical protocols, like encryption and hash functions, can be reverse-engineered automatically as well. Typically, the automatic approaches trace the execution of protocol implementations and try to detect buffers in memory holding unencrypted packets. Reverse engineering

3910-400: Is legitimate and compatible with fair practice and must therefore be deemed not to require the authorisation of the rightholder. An objective of this exception is to make it possible to connect all components of a computer system, including those of different manufacturers, so that they can work together. Such an exception to the author's exclusive rights may not be used in a way which prejudices

4025-467: Is not patented and not disclosed. Indeed, one common motivation of reverse engineering is to determine whether a competitor's product contains patent infringement or copyright infringement . In the United States, even if an artifact or process is protected by trade secrets , reverse-engineering the artifact or process is often lawful if it has been legitimately obtained. Reverse engineering of computer software often falls under both contract law as

4140-557: Is one approach in providing "reverse engineering" more recent advances in international standards activities have resulted in the development of the Knowledge Discovery Metamodel (KDM). The standard delivers an ontology for the intermediate (or abstracted) representation of programming language constructs and their interrelationships. An Object Management Group standard (on its way to becoming an ISO standard as well), KDM has started to take hold in industry with

4255-604: Is performed if source code for a software is unavailable. This process is sometimes termed reverse code engineering , or RCE. For example, decompilation of binaries for the Java platform can be accomplished by using Jad. One famous case of reverse engineering was the first non- IBM implementation of the PC BIOS , which launched the historic IBM PC compatible industry that has been the overwhelmingly-dominant computer hardware platform for many years. Reverse engineering of software

4370-487: Is protected in the US by the fair use exception in copyright law . The Samba software , which allows systems that do not run Microsoft Windows systems to share files with systems that run it, is a classic example of software reverse engineering since the Samba project had to reverse-engineer unpublished information about how Windows file sharing worked so that non-Windows computers could emulate it. The Wine project does

4485-404: Is reverse-engineered back to the analysis phase, in an inversion of the traditional waterfall model . Another term for this technique is program comprehension . The Working Conference on Reverse Engineering (WCRE) has been held yearly to explore and expand the techniques of reverse engineering. Computer-aided software engineering (CASE) and automated code generation have contributed greatly in

4600-455: Is tested by genetic perturbation experiments followed by dynamic modelling, based on the principle that removing one network node has predictable effects on the functioning of the remaining nodes of the network. Applications of the reverse engineering of gene networks range from understanding mechanisms of plant physiology to the highlighting of new targets for anticancer therapy. Reverse engineering applies primarily to gaining understanding of

4715-418: Is the creation of new representation of the computer code so that it is easier to understand. Meanwhile, design recovery is the use of deduction or reasoning from general knowledge or personal experience of the product to understand the product's functionality fully. It can also be seen as "going backwards through the development cycle". In this model, the output of the implementation phase (in source code form)

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4830-420: Is the process of identifying similarities between different software binaries (such as two different versions of the same binary) used to detect code relations between software samples. The task was traditionally done manually for several reasons (such as patch analysis for vulnerability detection and copyright infringement ), but it can now be done somewhat automatically for large numbers of samples. This method

4945-559: The Bell System published the information in the Bell System Technical Journal in an article describing the methods and frequencies used for inter-office signalling. The journal was intended for the company's engineers; however, it found its way to various college campuses across the United States. With this one article, the Bell System accidentally gave away the "keys to the kingdom", and the intricacies of

5060-446: The fourth E above middle C (a frequency of 2637.02 Hz) would stop a dialed phone recording. Unaware of what he had done, Engressia called the phone company and asked why the recordings had stopped. Joe Engressia is considered to be the father of phreaking. Other early phreaks, such as "Bill from New York" (William "Bill" Acker 1953-2015), began to develop a rudimentary understanding of how phone networks worked. Bill discovered that

5175-445: The rotary dial as it spins back to its rest position after having been rotated to each desired number. The exchange equipment responds to the dial pulses either directly by operating relays or by storing the number in a digit register that records the dialed number. The physical distance for which this type of dialing was possible was restricted by electrical distortions and was possible only on direct metallic links between end points of

5290-467: The "subject system" is the end product of software development. Reverse engineering is a process of examination only, and the software system under consideration is not modified, which would otherwise be re-engineering or restructuring. Reverse engineering can be performed from any stage of the product cycle, not necessarily from the functional end product. There are two components in reverse engineering: redocumentation and design recovery. Redocumentation

5405-581: The 1960s when it was discovered that certain whistles could replicate the 2600 Hz pitch used in phone signalling systems in the United States. Phone phreaks experimented with dialing around the telephone network to understand how the phone system worked, engaging in activities such as listening to the pattern of tones to figure out how calls were routed, reading obscure telephone company technical journals (often obtained through dumpster diving ), social engineering , building electronic devices called blue boxes , black boxes , and red boxes to help them explore

5520-678: The UK, it is also known as MF4. Other vendors of compatible telephone equipment called the Touch-Tone feature tone dialing or DTMF . Automatic Electric (GTE) referred to it as "Touch-calling" in their marketing. Other trade names such as Digitone were used by the Northern Electric Company in Canada. As a method of in-band signaling , DTMF signals were also used by cable television broadcasters as cue tones to indicate

5635-456: The US, as the monopoly of AT&T Corporation was forced into divestiture. During this time, exploration of telephone networks diminished, and phreaking focused more on toll fraud. Computer hackers began to use phreaking methods to find the telephone numbers for modems belonging to businesses, which they could exploit later. Groups then formed around the BBS hacker/phreaking (H/P) community such as

5750-558: The United States and Canada to suppress caller ID . Public payphones that accept credit cards use these additional codes to send the information from the magnetic strip . The AUTOVON telephone system of the United States Armed Forces used signals A, B, C, and D to assert certain privilege and priority levels when placing telephone calls. Precedence is still a feature of military telephone networks, but using number combinations. For example, entering 93 before

5865-506: The United States as of 2020. It is rare to find a diverter solely used for Answering Service forwarding anymore, but the many other types such as phone-company test numbers and remote PBX DISAs are still used as diverters. Before the BBS era of the 1980s phone phreaking was more of a solitary venture as it was difficult for phreaks to connect with one another. In addition to communicating over BBSs phone phreaks discover voice mail boxes and party lines as ways to network and keep in touch over

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5980-518: The United States, and became known under the trademark Touch-Tone for use in push-button telephones supplied to telephone customers, starting in 1963. DTMF is standardized as ITU-T Recommendation Q.23. It is also known in the UK as MF4 . Touch-tone dialing with a telephone keypad gradually replaced the use of rotary dials and has become the industry standard in telephony to control automated equipment and signal user intent. Other multi-frequency systems are also used for signaling on trunks in

6095-519: The advent of VoIP, the use of telephone company-owned bridges has decreased slightly in favor of phreaker-owned conferences. The end of multi-frequency (MF) phreaking in the lower 48 United States occurred on June 15, 2006, when the last exchange in the contiguous United States to use a "phreakable" MF-signalled trunk replaced the aging (yet still well kept) N2 carrier with a T1 carrier . This exchange, located in Wawina Township, Minnesota ,

6210-404: The analysis of hardware for commercial or military advantage. However, the reverse engineering process may not always be concerned with creating a copy or changing the artifact in some way. It may be used as part of an analysis to deduce design features from products with little or no additional knowledge about the procedures involved in their original production. In some cases, the goal of

6325-479: The assistance of operators. The DTMF system uses a set of eight audio frequencies transmitted in pairs to represent 16 signals, represented by the ten digits, the letters A to D, and the symbols # and * . As the signals are audible tones in the voice frequency range, they can be transmitted through electrical repeaters and amplifiers, and over radio and microwave links, thus eliminating the need for intermediate operators on long-distance circuits. AT&T described

6440-423: The beginnings of YIPL ( Youth International Party Line ), a publication started by Abbie Hoffman and Al Bell to provide information to Yippies on how to "beat the man ", mostly involving telephones. In the first issue of YIPL , writers included a "shout-out" to all of the phreakers who provided technological information for the newsletter: "We at YIPL would like to offer thanks to all you phreaks out there." In

6555-437: The bill for the long-distance calls, as it was their own private equipment (not phone company security flaws) that allowed such fraud to occur. By 1993, call forwarding was offered to nearly every business line subscriber, making these diverters obsolete. As a result, hackers stopped searching for the few remaining ones, and this method of toll fraud died. Many (different type) of diverters still exist and are actively "phreaked" in

6670-409: The broad language set as well as evolution. KDM is compatible with UML, BPMN, RDF, and other standards enabling migration into other environments and thus leverage system knowledge for efforts such as software system transformation and enterprise business layer analysis. Protocols are sets of rules that describe message formats and how messages are exchanged: the protocol state machine . Accordingly,

6785-404: The card try to hide keys and operations by mixing up memory positions, such as by bus scrambling. In some cases, it is even possible to attach a probe to measure voltages while the smart card is still operational. The makers of the card employ sensors to detect and prevent that attack. That attack is not very common because it requires both a large investment in effort and special equipment that

6900-469: The computer connected successfully to the BBS, it proved that it had found a working card number, and it saved that number to disk. If it did not connect to the BBS in a specified amount of time (usually 30 or 60 seconds), it would hang up and try a different code. Using this method, code hacking programs would turn up hundreds (or in some cases thousands) of working calling card numbers per day. These would subsequently be shared amongst fellow phreakers. There

7015-427: The correlation of the various layers of system knowledge for either detailed analysis (such as root cause, impact) or derived analysis (such as business process extraction). Although efforts to represent language constructs can be never-ending because of the number of languages, the continuous evolution of software languages, and the development of new languages, the standard does allow for the use of extensions to support

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7130-415: The development of tools and analysis environments that can deliver the extraction and analysis of source, binary, and byte code. For source code analysis, KDM's granular standards' architecture enables the extraction of software system flows (data, control, and call maps), architectures, and business layer knowledge (rules, terms, and process). The standard enables the use of a common data format (XMI) enabling

7245-476: The effect of a party-line. Eventually, all party-lines, whether bridges or not, came to be known as bridges if primarily populated by hackers and/or phreakers. The popularity of the Internet in the mid-1990s, along with the better awareness of voice mail by business and cell phone owners, made the practice of stealing voice mailboxes less popular. To this day bridges are still very popular with phreakers yet, with

7360-484: The exchange does not support DTMF, the key lock can be circumvented by switch-hooking, and the tone dialer can be then used to operate automated DTMF controlled services that can not be used with rotary dial. The origins of phone phreaking trace back at least to AT&T 's implementation of fully automatic switches . These switches used tone dialing , a form of in-band signaling , and included some tones which were for internal telephone company use. One internal-use tone

7475-519: The famous Masters of Deception ( Phiber Optik ) and Legion of Doom ( Erik Bloodaxe ) groups. In 1985, an underground e-zine called Phrack (a combination of the words phreak and hack) began circulation among BBSes, and focused on hacking, phreaking, and other related technological subjects. In the early 1990s, groups like Masters of Deception and Legion of Doom were shut down by the US Secret Service 's Operation Sundevil . Phreaking as

7590-464: The field of reverse engineering. Software anti-tamper technology like obfuscation is used to deter both reverse engineering and re-engineering of proprietary software and software-powered systems. In practice, two main types of reverse engineering emerge. In the first case, source code is already available for the software, but higher-level aspects of the program, which are perhaps poorly documented or documented but no longer valid, are discovered. In

7705-692: The fields or by intelligence operations. It was often used during the Second World War and the Cold War . Here are well-known examples from the Second World War and later: Reverse engineering concepts have been applied to biology as well, specifically to the task of understanding the structure and function of gene regulatory networks . They regulate almost every aspect of biological behavior and allow cells to carry out physiological processes and responses to perturbations. Understanding

7820-520: The first phreaking methods was switch-hooking, which allows placing calls from a phone where the rotary dial or keypad has been disabled by a key lock or other means to prevent unauthorized calls from that phone. It is done by rapidly pressing and releasing the switch hook to open and close the subscriber circuit, simulating the pulses generated by the rotary dial. Even most current telephone exchanges support this method, as they need to be backward compatible with old subscriber hardware. By rapidly clicking

7935-654: The full contents of a Windows system's live memory including a binary-level, graphical reverse engineering of all running processes. Another classic, if not well-known, example is that in 1987 Bell Laboratories reverse-engineered the Mac OS System 4.1, originally running on the Apple Macintosh SE , so that it could run it on RISC machines of their own. Reverse engineering of software can be accomplished by various methods. The three main groups of software reverse engineering are Software classification

8050-425: The hook for a variable number of times at roughly 5 to 10 clicks per second, separated by intervals of roughly one second, the caller can dial numbers as if they were using the rotary dial. The pulse counter in the exchange counts the pulses or clicks and interprets them in two possible ways. Depending on continent and country, one click with a following interval can be either "one" or "zero" and subsequent clicks before

8165-418: The important circuitry and separates it from the uninteresting background and insulating materials. Finally, the wires can be traced from one layer to the next, and the netlist of the circuit, which contains all of the circuit's information, can be reconstructed. Reverse engineering is often used by people to copy other nations' technologies, devices, or information that have been obtained by regular troops in

8280-491: The initial. Then, the schematics for the circuit are finally generated using an appropriate tool. In 1990, the Institute of Electrical and Electronics Engineers (IEEE) defined (software) reverse engineering (SRE) as "the process of analyzing a subject system to identify the system's components and their interrelationships and to create representations of the system in another form or at a higher level of abstraction" in which

8395-428: The interval are additively counted. This renders ten consecutive clicks being either "zero" or "nine", respectively. Some exchanges allow using additional clicks for special controls, but numbers 0-9 now fall in one of these two standards. One special code, "flash", is a very short single click, possible but hard to simulate. Back in the day of rotary dial, technically identical phone sets were marketed in multiple areas of

8510-507: The last issue, YIPL stated: YIPL believes that education alone cannot affect the System, but education can be an invaluable tool for those willing to use it. Specifically, YIPL will show you why something must be done immediately in regard, of course, to the improper control of the communication in this country by none other than bell telephone company. In 1973, Al Bell would move YIPL over and start TAP (Technological American Party). Al Bell

8625-606: The late 1970s. TAP ended publication in 1984 due mostly to a break-in and arson at Tom Edison's residence in 1983. Cheshire Catalyst then took over running the magazine for its final (1984) year. A controversially suppressed article "Regulating the Phone Company In Your Home" in Ramparts magazine (June 1972) increased interest in phreaking. This article published simple schematic plans of a " black box " used to make free long-distance phone calls, and included

8740-483: The legal protection of computer programs, which superseded an earlier (1991) directive, governs reverse engineering in the European Union . The unauthorised reproduction, translation, adaptation or transformation of the form of the code in which a copy of a computer program has been made available constitutes an infringement of the exclusive rights of the author. Nevertheless, circumstances may exist when such

8855-402: The legitimate interests of the rightholder or which conflicts with a normal exploitation of the program. DTMF Dual-tone multi-frequency signaling ( DTMF ) is a telecommunication signaling system using the voice-frequency band over telephone lines between telephone equipment and other communications devices and switching centers . DTMF was first developed in the Bell System in

8970-409: The line, followed by groups of whistles (a short tone for a "1", two for a "2", etc.) to dial numbers. While single-frequency worked on certain phone routes, the most common signaling on the then long-distance network was multi-frequency (MF) controls. The slang term for these tones and their use was "Marty Freeman". The specific frequencies required were unknown to the general public until 1954, when

9085-400: The marketplace. At the time, there was no way to switch a phone line to have calls automatically carried by non-AT&T companies. Customers of these small long-distance operations would be required to dial a local access number, enter their calling card number, and finally enter the area code and phone number they wish to call. Because of the relatively lengthy process for customers to complete

9200-476: The network and make free phone calls, hanging out on early conference call circuits and "loop arounds" to communicate with one another and writing their own newsletters to spread information. Phreaking was especially prevalent in universities, where it began spreading much like computer hacking would in the following decades. Before 1984, long-distance telephone calls were a premium item in the United States, with strict regulations. In some locations, calling across

9315-460: The new PCB. The quality of these images that is necessary for suitable reverse engineering is proportional to the complexity of the PCB itself. More complicated PCBs require well lighted photos on dark backgrounds, while fairly simple PCBs can be recreated simply with just basic dimensioning. Each layer of the PCB is carefully recreated in the software with the intent of producing a final design as close to

9430-436: The new object or system. Review is the testing of the model to ensure the validity of the chosen abstract. Reverse engineering is applicable in the fields of computer engineering , mechanical engineering , design , electronic engineering , software engineering , chemical engineering , and systems biology . There are many reasons for performing reverse engineering in various fields. Reverse engineering has its origins in

9545-458: The only possibility in cases when number of available samples is limited. As DTMF signaling is often transmitted in-band with voice or other audio signals present simultaneously, the DTMF signal definition includes strict limits for timing (minimum duration and interdigit spacing), frequency deviations, harmonics, and amplitude relation of the two components with respect to each other ( twist ). National telephone systems define other tones, outside

9660-519: The opportunity this provided, and they would spend hours manually dialing businesses after hours, attempting to identify faulty diverters. Once a phreaker had access to one of these lines, they could use it for one of many purposes. In addition to completing phone calls anywhere in the world at the businesses' expense, they could also dial 1-900 phone sex/entertainment numbers, as well as use the line to harass their enemies without fear of being traced. Victimized small businesses were usually required to foot

9775-515: The phone system were at the disposal of people with a knowledge of electronics. The second generation of phreaks arose at this time, including New Yorkers "Evan Doorbell", "Ben Decibel" and Neil R. Bell and Californians Mark Bernay, Chris Bernay, and "Alan from Canada". Each conducted their own independent exploration and experimentation of the telephone network, initially on an individual basis, and later within groups as they discovered each other in their travels. "Evan Doorbell", "Ben" and "Neil" formed

9890-500: The problem of protocol reverse-engineering can be partitioned into two subproblems: message format and state-machine reverse-engineering. The message formats have traditionally been reverse-engineered by a tedious manual process, which involved analysis of how protocol implementations process messages, but recent research proposed a number of automatic solutions. Typically, the automatic approaches group observe messages into clusters by using various clustering analyses , or they emulate

10005-416: The process is specific to the object on which it is being performed, all reverse engineering processes consist of three basic steps: information extraction, modeling, and review. Information extraction is the practice of gathering all relevant information for performing the operation. Modeling is the practice of combining the gathered information into an abstract model, which can be used as a guide for designing

10120-496: The product as "a method for pushbutton signaling from customer stations using the voice transmission path". In order to prevent consumer telephones from interfering with the MF-based routing and switching between telephone switching centers, DTMF frequencies differ from all of the pre-existing MF signaling protocols between switching centers: MF/R1, R2 , CCS4, CCS5, and others that were later replaced by SS7 digital signaling. DTMF

10235-582: The protocol implementation tracing the message processing. There has been less work on reverse-engineering of state-machines of protocols. In general, the protocol state-machines can be learned either through a process of offline learning , which passively observes communication and attempts to build the most general state-machine accepting all observed sequences of messages, and online learning , which allows interactive generation of probing sequences of messages and listening to responses to those probing sequences. In general, offline learning of small state-machines

10350-423: The reconstruction of the PCB if it performs some crucial task, as well as finding alternatives which provide the same function, or in upgrading the old PCB. Reverse engineering PCBs largely follow the same series of steps. First, images are created by drawing, scanning, or taking photographs of the PCB. Then, these images are ported to suitable reverse engineering software in order to create a rudimentary design for

10465-461: The requirements. This led to the addition of the number sign (#, ''pound'' or "diamond" in this context, "hash", "square" or "gate" in the UK, and " octothorpe '' by the original engineers) and asterisk or "star" (*) keys as well as a group of keys for menu selection: A, B, C and D. In the end, the lettered keys were dropped from most keypads and it was many years before the two symbol keys became widely used for vertical service codes such as *67 in

10580-583: The reverse engineering process can simply be a redocumentation of legacy systems . Even when the reverse-engineered product is that of a competitor, the goal may not be to copy it but to perform competitor analysis . Reverse engineering may also be used to create interoperable products and despite some narrowly-tailored United States and European Union legislation, the legality of using specific reverse engineering techniques for that purpose has been hotly contested in courts worldwide for more than two decades. Software reverse engineering can help to improve

10695-652: The same thing for the Windows API , and OpenOffice.org is one party doing that for the Microsoft Office file formats. The ReactOS project is even more ambitious in its goals by striving to provide binary (ABI and API) compatibility with the current Windows operating systems of the NT branch, which allows software and drivers written for Windows to run on a clean-room reverse-engineered free software ( GPL ) counterpart. WindowsSCOPE allows for reverse-engineering

10810-452: The sample, after etching, cannot be put into the exact same position relative to the SEM each time. Therefore, the stitched versions will not overlap in the correct fashion, as on the real circuit. Usually, three corresponding points are selected, and a transformation applied on the basis of that. To extract the circuit structure, the aligned, stitched images need to be segmented, which highlights

10925-431: The second case, there is no source code available for the software, and any efforts towards discovering one possible source code for the software are regarded as reverse engineering. The second usage of the term is more familiar to most people. Reverse engineering of software can make use of the clean room design technique to avoid copyright infringement. On a related note, black box testing in software engineering has

11040-528: The start and stop times of local commercial insertion points during station breaks for the benefit of cable companies. Until out-of-band signaling equipment was developed in the 1990s, fast, unacknowledged DTMF tone sequences could be heard during the commercial breaks of cable channels in the United States and elsewhere. Previously, terrestrial television stations used DTMF tones to control remote transmitters. In IP telephony , DTMF signals can also be delivered as either in-band or out-of-band tones, or even as

11155-415: The start and/or end of some prerecorded VHS videocassettes. Information on the master version of the video tape is encoded in the DTMF tones. The encoded tones provide information to automatic duplication machines, such as format, duration and volume levels in order to replicate the original video as closely as possible. DTMF tones are used in some caller ID systems to transfer the caller ID information,

11270-408: The street counted as long distance. To report that a phone call was long-distance meant an elevated importance because the calling party is paying by the minute to speak to the called party. Some phreaking consists of techniques to evade long-distance charges, which is criminalized as " toll fraud". In 1990, the pager cloning technique arose and was used by law enforcement . In the UK the situation

11385-430: The structure and the dynamic behavior of gene networks is therefore one of the paramount challenges of systems biology, with immediate practical repercussions in several applications that are beyond basic research. There are several methods for reverse engineering gene regulatory networks by using molecular biology and data science methods. They have been generally divided into six classes: Often, gene network reliability

11500-555: The system vulnerabilities. Reverse engineering is also being used in cryptanalysis to find vulnerabilities in substitution cipher , symmetric-key algorithm or public-key cryptography . There are other uses to reverse engineering: As computer-aided design (CAD) has become more popular, reverse engineering has become a viable method to create a 3D virtual model of an existing physical part for use in 3D CAD , CAM , CAE , or other software . The reverse-engineering process involves measuring an object and then reconstructing it as

11615-433: The technology, and served as a medium for previously scattered independent phone phreaks to share their discoveries and experiments. This not only led to unprecedented collaboration between phone phreaks, but also spread the notion of phreaking to others who took it upon themselves to study, experiment with, or exploit the telephone system. This was also at a time when the telephone company was a popular subject of discussion in

11730-409: The telephone network. Before the development of DTMF, telephone numbers were dialed by users with a loop-disconnect (LD) signaling, more commonly known as pulse dialing (dial pulse, DP) in the United States. It functions by interrupting the current in the local loop between the telephone exchange and the calling party 's telephone at a precise rate with a switch in the telephone that is operated by

11845-429: The telephone. They usually appropriate unused boxes that are part of business or cellular phone systems. Once a vulnerable mailbox system is discovered, word would spread around the phreak community, and scores of them would take residence on the system. They use these systems as a "home base" for communication with one another until the rightful owners discover the intrusion and wipe them off. Voice mailboxes also provide

11960-439: The time required to understand the source code, thus reducing the overall cost of the software development. Reverse engineering can also help to detect and to eliminate a malicious code written to the software with better code detectors. Reversing a source code can be used to find alternate uses of the source code, such as detecting the unauthorized replication of the source code where it was not intended to be used, or revealing how

12075-413: The two lines together. This gave the appearance to the caller that they were directly forwarded to the company's answering service. The switching equipment would typically reset the line after the call had hung up and timed out back to dial tone, so the caller could simply wait after the answering service had disconnected, and would eventually get a usable dial tone from the second line. Phreakers recognized

12190-567: The understanding of the underlying source code for the maintenance and improvement of the software, relevant information can be extracted to make a decision for software development and graphical representations of the code can provide alternate views regarding the source code, which can help to detect and fix a software bug or vulnerability. Frequently, as some software develops, its design information and improvements are often lost over time, but that lost information can usually be recovered with reverse engineering. The process can also help to cut down

12305-480: The use of an access number. Another method of obtaining free phone calls involves the use of "diverters". Call forwarding was not an available feature for many business phone lines in the late 1980s and early 1990s, so they were forced to buy equipment that could do the job manually between two phone lines. When the business would close, they would program the call diverting equipment to answer all calls, pick up another phone line, call their answering service, and bridge

12420-401: The world, only with plugs matched by country and the dials being bezeled with the local standard numbers. Such key-locked telephones, if wired to a modern DTMF capable exchange, can also be exploited by a tone dialer that generates the DTMF tones used by modern keypad units. These signals are now very uniformly standardized worldwide. It is notable that the two methods can be combined: Even if

12535-409: Was denied opening a bank account under the name of Technological American Party , since he was not a political party , so he changed the name to Technological Assistance Program to get a bank account. TAP developed into a major source for subversive technical information among phreaks and hackers all over the world. TAP ran from 1973 to 1984, with Al Bell handing over the magazine to "Tom Edison" in

12650-465: Was introduced to the masses when Esquire magazine published a story called "Secrets of the Little Blue Box" by Ron Rosenbaum . This article featured Engressia and John Draper prominently, synonymising their names with phreaking. The article also attracted the interest of other soon-to-be phreaks, such as Steve Wozniak and Steve Jobs , who went on to found Apple Computer . 1971 also saw

12765-423: Was known throughout the Bell System by the trademark Touch-Tone . The term was first used by AT&T in commerce on July 5, 1960, and was introduced to the public on November 18, 1963, when the first push-button telephone was made available to the public. As a parent company of Bell Systems, AT&T held the trademark from September 4, 1962, to March 13, 1984. It is standardized by ITU-T Recommendation Q.23. In

12880-486: Was no way for these small phone companies to identify the culprits of these hacks. They had no access to local phone company records of calls into their access numbers, and even if they had access, obtaining such records would be prohibitively expensive and time-consuming. While there was some advancement in tracking down these code hackers in the early 1990s, the problem did not completely disappear until most long-distance companies were able to offer standard 1+ dialing without

12995-515: Was rather different due to the difference in technology between the American and British systems, the main difference being the absence of tone dialing and signaling , particularly in the 1950s and 1960s. The tone system in the United States has been almost entirely replaced, but in some countries, in addition to new systems, the tone system is still available, for example in Italy. Possibly one of

13110-685: Was run by the Northern Telephone Company of Minnesota. Recent notable instances of phreaking involve hacking of VOIP systems. In 2011, the government of the Philippines and the FBI arrested four hackers for phone phreaking through PBX hacking. In 2015, Pakistani officials arrested a prominent phreaker who had amassed more than $ 50 million from PBX hacking activities. Reverse engineering Reverse engineering (also known as backwards engineering or back engineering )

13225-472: Was sent on a separate channel that was inaccessible to the telecom customer. By the 1980s, most of the public switched telephone network (PSTN) in the US and Western Europe had adopted the SS7 system which uses out-of-band signaling for call control (and which is still in use to this day), therefore rendering blue boxes obsolete. Phreaking has since become closely linked with computer hacking . Phreaking began in

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