Abstract:
Disclosed is a tamper resistant PIN entry apparatus for input of a key and for encryption of a password in a cash transaction machine. The PIN entry apparatus supplies the electric power to a memory of an electric circuit section, in such a manner that a first rod and a second rod of a rear case connect contacts of a key scan board, wherein the first rod is protruded on the rear of a key module including a button provided substantially on the front of the key module and the second rod of the rear case is coupled with the rear of the key module. At this time, in case that the rear case is removed from the key module or damaged, thereby changing the location of any one of the first and the second rods at the contact, the electric circuit section detects the event and destroys the memory itself physically. Otherwise, the electric circuit section makes information stored in the memory physically or softwarely unreadable, thereby preventing the leakage of the information.

Description:
CROSS REFERENCE TO RELATED APPLICATION 
   This application claims priority under 35 USC § 119 to Korean Patent Application No. 2004-92464 filed on Nov. 12, 2004, the contents of which are incorporated herein by reference in its entireties. 
   BACKGROUND OF THE INVENTION 
   1. Field of the Invention 
   The present invention relates to an apparatus for entering a Personal Identification Number (hereinafter, PIN) in a cash transaction machine. More particularly, the present invention relates to a PIN entry apparatus for protecting a PIN and encrypting a user&#39;s valuable information in a cash transaction machine (terminal), and relates to a tamper resistant PIN entry apparatus in which the apparatus, in case that the PIN entry apparatus is disassembled to hack into a password, detects the event, makes the password or key data unreadable, and in case that a key pad is to be partially incised, prevents hacking of the password by disabling the incision. 
   2. Description of the Related Art 
   Generally, a device such as a financial terminal that prevents illegal access of another person for personal purpose, grants a password per user so as to authenticate financial transactions. In addition, the device like above lets the user input the password before performing financial transactions, and allows the next step to be performed only when the input password is confirmed to be identical to the pre-registered password. 
   Like above, a financial terminal requires the maximum security, and an encryptor for encrypting inputted data is coupled with a key pad for input of a password. As for the encryptor like above, there is being widely used an encryption PIN pad module that adopts DES (Data Encryption Standard) algorithm. 
   The DES PIN pad module is a module for processing encryption with respect to a user&#39;s password or a key. Therefore, the DES PIN pad module comprises number buttons for inputting a password, a plurality of selection buttons for performing all kinds of functions, and SRAM storing an encryption key. At this time, the SRAM is included in an electric circuit embedded inside the device, so as to disable the external random manipulation. On the other hand, the number buttons, the selection buttons, and the like are exposed on a position where a user can manipulate easily. 
   However, in case that a user with unjust intentions disassembles the DES PIN pad module embedded in a financial terminal and connects a separate hacking equipment to a key input unit, there is a problem that passwords might remain in a memory might be leaked. 
   The prior art to solve the aforementioned problem is the U.S. Pat. No. 6,512,454, and said United States Patent relates to technology which destroys information stored in a memory so as to maintain information stored in an electronic device, in case that a third person tries to access thereto. 
   For this, said United States Patent comprises an enclosure for protecting the electronic device and an electrical assembly adopting the enclosure. 
     FIG. 1  is a perspective view illustrating the conventional PIN pad module. 
   Briefly describing a technical configuration referred to said United States Patent, as shown in  FIG. 1 , an electronic device  10  is enclosed by first and second covers  20  and  30 , and a fixing component  40  (e.g., a screw) passes through the first cover  20 , so as to bind the covers  20  and  30  to each other, and passes through the electronic device  10 , so as to form a part of an electric circuit. 
   In a normal state, fixing components  40  according to said United States Patent enable an electric current to pass to a part of circuit stably. However, in a state where any one of fixing components  40  is partially removed by an intruder or the like, the electric current circulating the fixing components  40  is cut off and a detector detects the event. 
   That is, although said United States Patent relates to technology for detecting external intrusion with respect to the electronic device  10 , it is apparent that a detecting method is mainly concentrated on the fixing components  40  such as screws or the like. At this time, the fixing component  40  should form a part of circuit, not a simple fixing means, and separation thereof  40  or partial removal thereof  40  is required to detect an intruder&#39;s intrusion. The detector should detect the event directly through control of relevant circuits. 
   However, according to the conventional technology for protecting the electronic device, such as said United States Patent, in case that the intruder cuts off any one of the first and the second covers  20  and  30  of the electronic device  10 , without touching the fixing component  40 , thereby maintaining an electric current in a normal state, the electronic device  10  does not detect the external intrusion. Thus, there is a problem that information stored in the memory of the electronic device  10  might be leaked by hacking equipment. 
   Furthermore, only in case that the fixing component  40  such as a screw is completely removed from the electronic device  10 , the flow of electric current is blocked and the detector detects the event. Therefore, in case that an intruder unscrews and cuts off the fixing component  40  by predetermined length, so as to maintain the flow of electric current of the electronic device  10  as it is, the first and the second covers  20  and  30  that enclose the electronic device  10  are opened to each other, and the electronic device  10  enclosed thereby  20  and  30  is completely exposed. Thus, there is a problem that the intruder may obtain useful information from the memory of the electron device  10  by using hacking equipments. 
   SUMMARY OF THE INVENTION 
   The present invention enables to protect a PIN entry apparatus having important information in a cash transaction machine or ATM (Automated Teller Machine). That is, in case that an intruder accesses a memory by disassembling or cutting the PIN pad module while maintaining the fixing structure thereof, an apparatus of the present invention enable to protect the PIN pad module from hacking of passwords. For one example, an apparatus of the present invention may comprise protecting functions of deleting inside data of SRAM, and of losing inside data thereof by cutting off the electronic power supplied to the SRAM, and the SRAM is a memory storing an encryption key and the like. 
   An apparatus for protecting a PIN pad module according to the present invention comprises a key module, a key scan board, a rear case and an electric circuit section. The key module includes a button for key input provided substantially on the front of the key module and a first rod formed substantially on the rear of the key module. The key scan board includes a first contact for the button, a second contact for the first rod and a third contact, wherein the first and the second contacts are formed substantially on the front of the key scan board and the third contact is formed substantially on the rear of the key scan board. The rear case is coupled with the key module and includes the second rod for the third contact. The electric circuit section might make stored information unreadable in accordance with a change of an electric current or voltage at the second contact or the third contact, the change caused by reduction or absence of pressing force by the first rod or the second rod. 
   At this time, that the electric circuit section makes stored information unreadable includes both physical protection and software protection which prevents leakage of important information in all kinds of information storage media which input/output information at any time, such as for example a RAM, a flash memory, an optical disk, a magnetic disk, etc. 
   For example, the electric circuit section may include an analog control module that delivers high voltage or a lot of electric current to a storage medium, so as to destroy the storage medium storing information. In addition, the electric circuit section may produce a control module easily by using a microcontroller, and damage the storage medium by enabling the control module to control a power generator that generates the voltage or electric current. In case that the storage medium is a random access memory that maintains information only when electric power is supplied, such as SRAM, the electric circuit section may delete information by cutting off electricity. 
   Furthermore, the electric circuit section may include a control module having a program in which orders of remembering information included in the storage medium may be disordered or partially lost and information stored in the storage medium may be replaced for dummy information or completely deleted. 
   Preferably, the electric circuit section may include a memory such as SRAM storing information. When the electric circuit section detects the change of voltage or electric current with respect to any one of the second and the third contacts, the electric circuit section may prevent leakage of information by making the stored information unreadable, just like cutting the power supply thereto. 
   Furthermore, a metal plate is mounted adjacent to the key module or the rear case to physically protect the key scan board against a tampering attempt. 
   The first rod or the second rod may include a tube portion and a rubber member, wherein the tube portion is protruded on the key module or the rear case toward the second contact or the third contact, and the rubber member is positioned at the end of the tube portion to elastically press the second or the third contact, respectively. 
   A circuit connector may be formed on the electric circuit section and a board connector may be formed on the key scan board in accordance with the circuit connector, such that the board connector may be electrically connected to the circuit connector to transmit the states of connection at the first, the second and the third contacts to the electric circuit. 
   Here, the board connector and the circuit connector may be positioned between the key scan board and the rear case, so the connecting portion of the connectors may be easily exposed to an intruder when separating the rear case from the key module. Also, the circuit and the board connector may be electrically connected using a plurality of metal pins and pin holes having a terminal in general and the intruder may use a conduction liquid to electrically connect the metal pin and the terminal of the pin hole. In order to protect the apparatus from a tamper attempt using a conduction liquid, ink, etc., the metal pins and the pin holes may be arranged perpendicularly across the third contacts. 
   For example, in case that two of the third contacts are positioned vertically, the metal pins and the pin holes of the connectors are arranged horizontally between the third contacts. At this time, the first reason why the board connector is positioned substantially on a vertical line passing between the third contacts is to prevent general accesses to the third contact and prevent the third contact from being applied by electric conduction liquid (electric conduction ink). Thus, in case that the rear case is to be removed from the key module, the electric circuit section detects the event immediately. The second reason is to hide the connecting portion of the circuit connector and the board connector with the second rod, so that the intruder may have many difficulties to flow the conduction liquid for cheating connections. 
   Furthermore, at least one of the second and the third contacts may be positioned adjacent to a screw hole for a screw. When the screw is unscrewed or removed, the states of connection of the first and the second rods for the second and the third contacts change. The electric circuit section may detect the change of the voltage or electric current at one or more contacts of the second and the third contacts, and may make the memory unreadable, e.g. by destroying or erasing the stored information. 
   Moreover, the screw hole may be formed at the center portion of the key scan board, and the second contact may be positioned adjacent to the screw hole on the key scan board. At this time, a couple of screw holes are provided and the second contact is positioned therebetween. In case that the screw hole is unscrewed, the first rod for the second contact is separated. Thus, the electric circuit section may detect the event easily. 
   Preferably, the second contact or the third contact may include three terminals, such as a first terminal, a second terminal and third terminal. The first terminal and the second terminal may be electrically connected by the adjacent rod and the third terminal may be formed closely adjacent to the first and the second terminal to form a part of the electric circuit section. The electric circuit section may make the stored information unreadable when the first and the second terminal are electrically separated because of removing or separating the rod. Also, although an intruder may try to electrically connect the first and the second terminals with conduction liquid or ink, the electric circuit section may detect connection between the first and the third terminals or between the second and the third terminals to make the stored information unreadable. 
   Furthermore, the second and the third contacts may be formed using piezo electric elements to measure the pressing force. Therefore, in case that the pressing force by any one of the first and second rods changes and the electric voltage or current changes in accordance with the change of the pressing force, the electric circuit section may detect the event and make the stored information unreadable. 
   Furthermore, a front membrane may be interposed between the key module and the key scan board. The front membrane includes a first switching portion for electrically connecting or cutting off the first contact according to the button of the key module and a second switching portion for electrically connecting or cutting off the second contact according to the first rod. 
   A rear membrane may be interposed between the key scan board and the rear case, wherein the rear membrane includes a third switching portion for electrically connecting or cutting off the third contact according to the second rod. 
   The switching portion of the first or the second membrane is similar to a general membrane switch formed on a button in a mobile phone, and includes an elastic dome for elastically receiving the pressing force. The lower surface of the elastic dome is formed using an electric conductor such as a carbon and connects the terminal of contacts formed on the key scan board. 
   In addition, a back bracket is interposed between the key scan board and the electric circuit section to substantially support the key scan board and the electric circuit section for prevent them from being bent. At this time, the back bracket may be formed using a plurality of metal plates and the metal plates may have different thickness respectively. The back bracket is interposed between the key scan board and the electric circuit section, with filling the gap formed therebetween. 
   The key module further comprises a protection rubber attached on the rear of the button for water-proofing; a front bracket positioned substantially at the front of the button, having a button hole regularly arranged in the front bracket; a protection pad positioned substantially at the rear of the front bracket, wherein the protection rubber is stuck to the protection pad for water-proofing; a transmitting member positioned substantially at the rear of the protection pad, for transmitting the pressing force given to the button; a switching member positioned substantially at the rear of the transmitting member, for transmitting the pressing force given to the transmitting member; and a bezel base including a groove formed substantially on the front of the bezel base for receiving the transmitting member, a hole formed at the groove for passing the switching member and the first rod protruded backward at the rear of the bezel base to press the second contact. 
   At this time, in case that at least one of the first rod and the second rod for second and third switching portions of the membrane is removed from the bezel base of the key module and the pressing force or location thereof changes, and the voltage or electric current changes at least one of a plurality of second and third contacts for the second switching portion and the third switching portion, the electric circuit section detects the event and makes the stored information unreadable. 
   In addition, the protection pad is positioned substantially at the rear end of the button and prevents water from penetrating into the front bracket, thereby, forming the waterproof structure together with the protection rubber. 
   Moreover, the bezel base is formed by injecting plastic into an injection mold, and a plurality of first rods is positioned on the rear of the bezel base. One of the first rods is positioned on one side at the center of the bezel base and the other is positioned on the other side at the center thereof, spaced apart by a predetermined interval 
   At this time, the first rods are positioned on each of sides at the center and the bezel base is spaced apart from the rear case. Therefore, the location of the first rod changes and the voltage or the electric current of the second contact for the first rod also changes. The electric circuit selection detects the event and makes information stored in the memory unreadable immediately. 
   Furthermore, the key module may comprise a bezel base positioned at the front of the rubber pad, including a hole for exposing the button and a rubber pad including the button protruded forward substantially at the front of the rubber pad and the first rod protruded backward substantially at the rear of the rubber pad. 

   
     BRIEF DESCRIPTION OF THE DRAWINGS 
     The present invention will become more apparent to those of ordinary skill in the art be describing, in detail, exemplary embodiments thereof, with reference to the attached drawings, wherein like elements are represented by like reference numerals, which are given by way of illustration only and thus do not limit the exemplary embodiments of the present invention. 
       FIG. 1  is a perspective view illustrating the conventional PIN pad module. 
       FIG. 2  is a perspective view illustrating an apparatus for protecting a PIN pad module according to one embodiment of the present invention. 
       FIG. 3  is a plan view illustrating the rear of a bezel base according to one embodiment of the present invention. 
       FIG. 4  is a partial perspective view illustrating an apparatus for protecting a PIN pad module according to one embodiment of the present invention. 
       FIG. 5  is a sectional view illustrating an apparatus for protecting a PIN pad module according to one embodiment of the present invention. 
       FIG. 6  is a partially enlarged view illustrating a second rod and a third contact of  FIG. 5 . 
       FIG. 7  is a plan view illustrating the upper surface of a key scan board according to one embodiment of the present invention. 
       FIG. 8  is a bottom view illustrating the lower surface of a key scan board according to one embodiment of the present invention. 
       FIG. 9  is a schematic view illustrating a process of protecting a PIN pad module according to one embodiment of the present invention. 
       FIG. 10  is a perspective view illustrating an apparatus for protecting a PIN pad module according to one embodiment of the present invention. 
       FIG. 11  is a plan view illustrating the rear of a rubber pad including buttons according to one embodiment of the present invention. 
       FIG. 12  is a sectional view illustrating an apparatus for protecting a PIN pad module according to one embodiment of the present invention. 
       FIG. 13  is a partially enlarged view illustrating a second rod and a third contact of  FIG. 12 . 
       FIG. 14  is a plan view illustrating the upper surface of a key scan board according to one embodiment of the present invention. 
       FIG. 15  is a bottom view illustrating the lower surface of a key scan board according to one embodiment of the present invention. 
       FIG. 16  is a schematic view illustrating a process of protecting a PIN pad module according to one embodiment of the present invention. 
   

   DESCRIPTION OF THE INVENTION 
   Hereinafter, exemplary embodiments of the present invention will be more fully described with reference to the accompanying drawings. This invention may, however, be embodied in many different forms and should not be construed as limited to the embodiments set forth herein; rather, these embodiments are provided so that this disclosure will be thorough and complete, and will fully convey the scope of the invention to those skilled in the art. Like reference numerals refer to similar or identical elements throughout. 
     FIG. 2  is a perspective view illustrating an apparatus for protecting a PIN pad module according to one embodiment of the present invention;  FIG. 3  is a plan view illustrating the rear of a bezel base according to one embodiment of the present invention;  FIG. 4  is a partial perspective view illustrating an apparatus for protecting a PIN pad module according to one embodiment of the present invention;  FIG. 5  is a sectional view illustrating an apparatus for protecting a PIN pad module according to one embodiment of the present invention;  FIG. 6  is a partially enlarged view of  FIG. 5 ;  FIG. 7  is a view illustrating the upper surface of a key scan board according to one embodiment of the present invention;  FIG. 8  is a view illustrating the lower surface of a key scan board according to one embodiment of the present invention; and  FIG. 9  is a view illustrating a process of protecting a PIN pad module according to one embodiment of the present invention. 
   As illustrated, in order to achieve the above object, an apparatus for protecting a PIN pad module according to one embodiment of the present invention comprises a key module  100  including pluralities of buttons  111  and a bezel base  120  wherein the buttons  111  are provided substantially on the front of the key module  100  and pluralities of protruded first rods  122  are formed on the rear of the key module  100 ; a first switching portion  126  for the button  111  of the key module  100  and a second switching point  127  for the first rod  122  of the bezel base  120 ; and a front membrane  125  for transmitting the pressing force of the button  111  and the first rod  122  through the first switching portion  126  and the second switching portion  127 . 
   Furthermore, the button  111  provided substantially on the front of the key module  100  is inserted into a front bracket  114 , which has a button hole  115 , to be close to a protection rubber  113 , the rear of the button  111  passes through the rear of the front bracket  114  tightly, and the protection pad  116  is provided on the rear of the protection rubber  113 , wherein the front bracket  114  is formed into a lattice. At this time, the protection rubber  113  prevents water from penetrating through the space between the button  111  and the front bracket  114 , and the protection pad  116  prevents water from penetrating into the bezel base  120 . 
   Furthermore, a transmitting member  118  is positioned substantially at the rear of the protection pad  116  and at the front of the bezel base  120 , for transmitting the pressing force. A switching member  119  is positioned substantially at the rear of the transmitting member  118 , for transmitting the pressing force to the first switching portion  126  of the front membrane  125  through the bezel base  120 . 
   At this time, the button  111  and the front bracket  114  constituting the outer surface of the key module  100  are formed using metal plates, and form a protection wall against the external intrusion. Therefore, components provided inside of the key module may be protected. 
   Moreover, the bezel base  120  is formed by injecting plastic into an injection module, and one of pluralities of first rods  122  formed on the rear of the bezel base  120  is positioned on one side at the center of the bezel base  120  and another is positioned on the other side at the center thereof  120 , spaced apart by predetermined interval. 
   At this time, the bezel base  120 , which includes a groove  121  formed substantially on the front of the bezel base  120 , is positioned at the rear of the transmitting member  118 , and the rear of the button  111  passes through the protection pad  116 , thereby pressing a groove  124  formed on the front of the transmitting member  118 , and then passes through a hole formed on the bezel base  120 , and coupled with the switching member  119 , thereby pressing the first switching portion  126  of the front membrane  125 . 
   Furthermore, a key scan board  130  is positioned at the rear of the front membrane  125 , and pluralities of first contacts  132  for connecting the first switching portion  126  and pluralities of second contacts  133  for connecting the second switching portion  127  are positioned on the front of the key scan board  130 . And pluralities of third contacts  134  are further positioned on the rear of the key scan board  130 . 
   At this time, the first and the second switching portions  126  and  127  of the front membrane  125  are formed using a elastic dome, for elastically receiving the pressing force. An electric conductor such as a carbon board is applied on the lower surface of the elastic dome, and electrically connects the first and the second contacts  132  and  133  positioned on the key scan board  130 . 
   Furthermore, a plurality of second contacts  133  positioned on the front of the key scan board  130  are provided adjacent to a screw hole  136  for a screw for coupling the key module  100  and the rear case  180 . When the screw is removed, the pressing force of the first rod  122  for the second contact  133 , or the location thereof changes. 
   More particularly, a pair of screw holes  136  for a screw for coupling the key module  100  and the rear case  180  is formed on a vertical line passing the center portion. The second contact  133  is positioned between the screw holes  136 . Thus, in case that the screw is removed, the location or pressing force of the first rod  122  for the second contact  133  changes. The electric circuit section  170  detects the change of the voltage or electric current of the second contact  133  and makes information stored in the memory unreadable immediately. 
   Furthermore, a rear membrane  140  including a third switching portion  142  for connecting the third contact  134  is positioned at the rear of the key scan board  130 . An electric circuit section  170  including a memory is positioned at the rear of the rear membrane  140 , for performing logic calculation, wherein the memory first receives a value in accordance with connection of contacts of the key scan board  130  and later stores the same. The rear case  180  is positioned at the rear of the electric circuit section  170 , and the rear case  180  includes a second rod  182  for the third switching portion  142  included in the rear membrane  140  and is coupled with the bezel base  120  of the key module  100 . 
   Moreover, third contacts  134  positioned on the rear of the key scan board  130  are formed of a pair and positioned on a vertical line passing the center portion. The arrangement of the third contacts  134  like above is to detect that the rear case  180  is removed from the bezel base  120  with the minimum contacts. Accordingly, in case that the rear of the rear case  180  moves away from the rear of the bezel base  120 , even a little, the pressing force of the second rod  182  for the third switching portion  142  of the rear membrane changes and the electric current or the voltage changes at the third contact  134  connected to the third switching portion  142  of the rear membrane  140 . 
   Furthermore, a circuit connector  172  of the electric circuit section  170  is provided on a vertical line passing through the third contacts  134  and a board connector  135 , so that the board connector  135 , for transmitting the states of connections at contacts of the key scan board  130 , passes through the third contacts  134 . The arrangement of the board connector  135  like above is to prevent the board connector  135  from getting access to the third contacts  134  and prevent a hacker from applying electric conduction liquid (electric conduction ink) to the third contact to make it as same as the first state of connection thereof  134 . In case that the hacker attempts to put electric conduction liquid into the terminal of the circuit connector  172  in a state where the circuit connector  172  is coupled with the board connector  135 , the arrangement of the board connector  135  like above is to prevent an instrument including electric conduction liquid from getting access to the circuit connector  172  by the second rod  182  for the third contact  134 . 
   In addition, the third contact  134  includes a first terminal  134   a  and a second terminal  134   b , which are electrically connected by the second rod  182 , and the third contact  134  further includes a third terminal  134   c  which is formed closely adjacent to the first terminal  134   a  and the second terminal  134   b , and the electric circuit section  170  makes the stored information unreadable in accordance with the connection between the second and the third terminals  134   a  and  134   b . Furthermore, although it is not illustrated, the second contact  133  also includes a first terminal and a second terminal which are electrically connected by the first rod  122 , just like the third contact  134 , and may include a third terminal adjacent to the first terminal or the second terminal. 
   Meanwhile, the second rod  182  of the rear case  180  is formed to be protruded in the opposite direction from the first rod  122 , with the similar structure, and includes a tube portion  182   a  and a rubber member  182   b  for the third switching portion  142 . At this time, the second rods  182  are formed of a pair to correspond to the third contacts  134  and respectively positioned on the upper portion and the lower portion at the center portion of the rear case  180 . 
   Furthermore, a first back bracket  150  is positioned at the rear of the rear membrane  140  to support the rear membrane  140  and the key scan board  130 . A second bracket  160  is formed inside the rear case  180  for the electric circuit section  170 , and positioned at the rear of the first back bracket to support the electric circuit section  170 . At this time, it is preferable that the first back bracket  150  and the second back bracket  160  are stuck closely without gap. 
   In addition, the first and the second back brackets  150  and  160  are formed using steel to enhance their strength. Therefore, even in case that the rear case  180  is damaged, the first and the second back brackets  150  and  160  protect the electric circuit section  170  substantially. 
   Moreover, the external surface of the electric circuit section  170  is molded by epoxy  173  in a state where the electric circuit section  170  is formed inside the rear case  180 . Therefore, it is possible to prevent the external access to the electric circuit section  170 . 
   Hereinafter, the process for protecting the PIN pad module according to the present embodiment will be described. 
   In case that there is any tampering attempt to remove the bezel base  120  or the button  111  of the key module  100  for the purpose of hacking into a password through the electric circuit section  170  or the key scan board  130  of the PIN pad module, it is required to unscrew the screw of the bezel base  120  or remove the front bracket  114  on which the button  111  is positioned. At this time, the key module  100  protects the front of the PIN pad module. 
   In case that the screw for fixing the bezel base  120  to the rear case  180  is unscrewed, the pressing force or the location changes at any one of the first rod  122  and the second rod  182  for the second and the third switching portions  126  and  142  of the membrane. Furthermore, the voltage or the electric current changes at any one of the second and third contacts  133  and  134  for the second switching portion  126  and the third switching portion  142 . At this time, the electric circuit section  170  recognizes the change in the voltage or the electric current of the second and the third contacts  133  and  134 , as hacking for the PIN pad module, thereby making the stored information unreadable. 
     FIG. 10  is a perspective view illustrating an apparatus for protecting a PIN pad module according to one embodiment of the present invention;  FIG. 11  is a plan view illustrating the rear of a rubber pad including buttons according to one embodiment of the present invention;  FIG. 12  is a sectional view illustrating an apparatus for protecting a PIN pad module according to one embodiment of the present invention;  FIG. 13  is a partially enlarged view of  FIG. 12 ;  FIG. 14  is a view illustrating the upper surface of a key scan board according to one embodiment of the present invention;  FIG. 15  is a view illustrating the lower surface of a key scan board according to one embodiment of the present invention; and  FIG. 16  is a view illustrating a process of protecting a PIN pad module according to one embodiment of the present invention. 
   As illustrated, in order to achieve the above object, an apparatus for protecting a PIN pad module according to one embodiment of the present inventions comprises a key module  200  including a rubber pad  210  and a bezel base  220  wherein pluralities of buttons  211  are formed on the front of the rubber pad  210 , pluralities of protruded first rods  222  are formed on the rear thereof  210 , and the rubber pad  210  is inserted into the bezel base  220  including holes; and a front membrane  225  including a first switching portion  226  for the button  211  of the key module  200  and a second switching portion  227  for the first rod  222 , to transmit the pressing force of the button  211  and the first rod  222  to the rear through the first and the second switching portions  226  and  227 . 
   Furthermore, a key scan board  230  is positioned at the rear of the front membrane  225 , and includes pluralities of first contacts  232  for the first switching portions  226 , and pluralities of second contacts  233  for the second switching portions  227  on the front of the key scan board  230  and pluralities of third contacts  234  on the rear thereof  230 . In addition, a rear membrane  240  is positioned at the rear of the key scan board  230 , and includes a third switching portion  242  for the third contact  234 , and an electric circuit section  270  is positioned at the rear of the rear membrane  240  and includes a memory for receiving the states of connection of contacts of the key scan board  230  to perform logic calculation. A rear case  280  is positioned at the rear of the rear membrane  240 , includes a pair of second rods  282  for third contacts  242  and is coupled with the bezel base  220  of the key module  200  by screws. 
   At this time, the structure and materials of the front membrane  225  and the rear membrane  240  embodying the present embodiment are similar to those of the previous embodiment. The number of the contacts  226  of the front membrane  225  for the buttons  221  formed on the rubber pad  210  and the number of the first contacts  232  of the key scan board  230  is more than that of the previous embodiment. 
   Furthermore, a circuit connector  272  of the electric circuit section  270  is provided on a vertical line passing through the third contacts  234  and a board connector  235 , so that the board connector  235 , for transmitting the states of connection at contacts of the key scan board  230 , passes through the third contacts  234 . The arrangement of the board connector  235  like above is to prevent the board connector  235  from getting access to the third contacts  234  and prevent a hacker from applying electric conduction liquid (electric conduction ink) to the third contact to make it as same as the first state of connection thereof  234 . In case that the hacker attempts to put electric conduction liquid into the terminal of the circuit connector  272  in a state where the circuit connector  272  is coupled with the board connector  235 , the arrangement of the board connector  235  like above is to prevent an instrument including electric conduction liquid from getting access to the circuit connector  272  by a second rod  282  for the third contact  234 . 
   In addition, the third contact  234  includes a first terminal  234   a  and a second terminal  234   b , which are electrically connected by the first rod  282 , and the third contact  234  further includes a third terminal  234   c  which is formed closely adjacent to the first terminal  234   a  and the second terminal  234   b , and the electric circuit section  270  makes the stored information unreadable in accordance with the connection between the second and the third terminals  234   a  and  234   b . Furthermore, although it is not illustrated, the second contact  233  also includes a first terminal and a second terminal which are electrically connected by the first rod  222 , just like the third contact  234 , and may include a third terminal adjacent to the first terminal or the second terminal. 
   Meanwhile, the second rod  282  of the rear case  280  is formed to be protruded in the opposite direction from the first rod  222 , with the similar structure, and includes a tube portion  282   a  and a rubber member  282   b  for the third contact  242 . At this time, the second rods  282  are formed of a pair to correspond to the third contacts  234  and respectively positioned on the upper portion and the lower portion at the center portion of the rear case  280 . 
   Furthermore, a first back bracket  250  is positioned at the rear of the rear membrane  240  to support the rear membrane  240  and the key scan board  230 . A second bracket  250  is formed inside the rear case  280  for the electric circuit section  270 , and positioned at the rear of the first back bracket  250  to support the electric circuit section  270 . 
   In addition, the first and the second back brackets  250  and  260  are formed using steel to enhance their strength. Therefore, even in case that the rear case  280  is damaged, the first and the second back brackets  250  and  260  protect the electric circuit section  270  substantially. 
   Moreover, the external surface of the electric circuit section  270  is molded by epoxy in a state where the electric circuit section  270  is formed inside the rear case  280 . Therefore, it is possible to prevent the external access to the electric circuit section  270 . 
   The first, the second, and the third contacts  232 ,  233 , and  234  that are formed on the key scan board  230 , and a screw hole  236  are positioned similar to the previous embodiment. 
   Hereinafter, the process for protecting the PIN pad module according to one embodiment will be described. 
   In case that there is any tampering attempt to remove the bezel base  220  or the button  211  of the key module  200  for the purpose of hacking into a password through the electric circuit section  270  or the key scan board  230  of the PIN pad module, it is required to unscrew the screw of the bezel base  220  or remove the rubber pad  210  on which the button  111  is positioned. At this time, the key module  200  protects the front of the PIN pad module. 
   In case that the screw for fixing the bezel base  220  to the rear case  280  is unscrewed to remove the bezel base  220  from the rear case  280 , or the bezel base  220  is destroyed, thereby moving the rubber pad  210 , the pressing force or the location changes at any one of the first rod  222  and the second rod  282  for the second and the third switching portions  226  and  242  of the membrane. Furthermore, the voltage or the electric current changes at any one of the second and third contacts  233  and  234  for the second switching portion  226  and the third switching portion  242 . At this time, the electric circuit section  270  recognizes the change as hacking for the PIN pad module, thereby making the stored information unreadable. 
   As described above, in case that an apparatus for protecting a PIN pad module according to the present invention is adopted and there is any tampering attempt to physically disassemble the PIN pad module to install hacking equipments for the purpose of finding out a password, the pressing force or location changes at any one of the first and the second rods, wherein the PIN pad module is installed in a financial terminal or the like. In addition, the voltage or electric current changes at any one of the second and the third contacts of the key scan board and the electric circuit section detects the event and recognizes the event as hacking for the PIN pad module, thereby making the stored information unreadable. Therefore, the present invention can enhance the security of the PIN pad module. 
   Furthermore, the rear of the key scan board embodying the PIN pad module is protected by a plurality of metal brackets. Therefore, the present invention can prevent a hacker&#39;s intrusion, such as for example, cutting off the rear of the PIN pad module and accessing the key scan board. 
   Furthermore, a method of detecting hacking that is adopted by the apparatus for protecting the PIN pad module, does not electrically connect contacts by fixing components. The method uses contacts of the key scan board in which the electric circuit section detects the states of connection. Therefore, in case that an intruder cuts off around the fixing component or cuts off the fixing component, the pressing force or the location of the rod changes at contacts and the electrical change occurs at contacts. Thus, the present invention can detect the intrusion immediately through the electric circuit section.