Abstract:
An enhanced encryption keypad ( 100 ) capable of preventing illegal disassembly for an automated teller machine comprises a key panel ( 101 ) and a main control board ( 102 ). A removal detection protection circuit is disposed inside a main chip of the main control board ( 102 ), and at least one pin of the removal detection protection circuit is guided out from a surface ( 1021 ) of a side of the main control board ( 102 ) near the key panel to form a removal detection point ( 1022 ). The removal detection point ( 1022 ) has two opened signal contact points. The two opened signal contact points are conducted by a conductive adhesive ( 103 ) to activate the removal detection protection circuit. A conductive protection ring ( 1023 ) isolated from the removal detection point is disposed at the periphery of the removal detection point. The conductive protection ring ( 1023 ) is connected to the removal detection protection circuit inside the main control chip. A protection circle ( 1024 ) is disposed at the periphery of the conductive protection ring and the corresponding conductive adhesive. The present application effectively protects the encryption keypad from illegal attacks on the removal detection point from the side.

Description:
[0001]    The present application claims the benefit of priority to Chinese patent application No. 201010269434.3 titled “ENCRYPTION KEYPAD CAPABLE OF PREVENTING ILLEGAL DISASSEMBLY”, filed with the Chinese State Intellectual Property Office on Aug. 27, 2010. The entire disclosures thereof are incorporated herein by reference. 
       TECHNICAL FIELD OF THE INVENTION 
       [0002]    The present invention relates to an encryption keyboard, and in particular to an encryption keyboard for preventing illegal disassembly used for automatic teller machines. 
       BACKGROUND OF THE INVENTION 
       [0003]    The hard encryption keyboard of a bank self-service equipment bears works of inputting and encrypting a bank password of a user, and thus a working key and a master key of the bank are stored in a core processing part of the keyboard. For an unspeakable purpose, some criminals usually jimmy or poke the keyboard to steal the user password and even to decrypt the working key and master key of the bank in order to steal bank information, which threatens the security of information and money of the user and the bank directly. 
         [0004]    The existing ATM encryption keyboard includes a keyboard panel and a main control board. A removal detection and protection circuit is provided in a main chip in the main control board, and a plurality of lead pins of the removal detection and protection circuit are led out from the main control board to form removal detection points. Each removal detection point is provided with two disconnected signal contacts which are connected to the removal detection and protection circuit of the main chip via inner wirings of the main control board. Conductive adhesive is provided on a surface, which contacts with the main control board, of the keyboard panel at positions corresponding to the removal detection points of the main control board. When the keyboard is mounted on the mounting panel of the ATM, the keyboard panel presses the conductive adhesive, so that the conductive adhesive contacts with and connects with the disconnected removal detection points on the main control board to form a closed circuit. When the keyboard is being disassembled illegally, the conductive adhesive runs away from the signal contacts to break the circuit, which can be sensed. As a result, the removal detection and protection circuit is triggered to delete sensitive information from the keyboard main chip and to disable relevant functions, thereby preventing the criminal from stealing bank information. 
         [0005]    In the prior art, one layer of water-proof silicone rubber is generally provided between the keyboard panel and the main control board in order to enable the encryption keyboard to have a certain water-proof function, and the conductive adhesive is provided between the water-proof silicone rubber and the main control board. This technology has some disadvantages. Since the water-proof silicone rubber is made of elastic material, before disassembling the keyboard the criminal can insert a hard object through the clearance between the conductive adhesive and the panel and thus keep the object to press the conductive adhesive, so as to maintain the continuous connection between the conductive adhesive and the removal detection and protection circuit, and thus the keyboard may be disassembled without being sensed; or the criminal can insert a metal sheet through the clearance between the conductive adhesive and the removal detection points to maintain the continuous connection of the removal detection and protection circuit; or the criminal can fill with conductive glue through the clearance between the conductive adhesive and the removal detection points to maintain the continuous connection of the removal detection and protection circuit. In this way, in the case of being illegally disassembled, the encryption keyboard cannot be self-destructed and the user&#39;s password is illegally stolen, even the working key and main key of the bank are decrypted so as to steal the bank information, which threatens the security of information and money of users and bank directly. 
       SUMMARY OF THE INVENTION 
       [0006]    The object of the present invention is to provide an encryption keyboard for preventing illegal disassembly, which may improve the security of the encryption keyboard by providing a guard member at a removal detection point. 
         [0007]    In order to achieve the object of the present invention, the present invention provides the following technical solutions. 
         [0008]    The encryption keyboard according to the present invention includes a keystroke panel and a main control board. A removal detection and protection circuit is provided in a main chip of the main control board, and at least one lead pin of the removal detection and protection circuit is led out from a surface of the main control board adjacent to the keystroke panel so as to form a removal detection point. The removal detection point is provided with two disconnected signal contacts which are connected by conductive adhesive to activate the removal detection and protection circuit. A conductive protection ring is provided outside the removal detection point and is isolated from the removal detection point. The conductive protection ring is connected to the removal detection and protection circuit in the main chip. A guard member is provided at the outside of the conductive protection ring and of the conductive adhesive. 
         [0009]    Optionally, the guard member is provided with at least two hooks, and each of the hooks inserts into a semi-blind hole in a surface of the main control board adjacent to the keystroke panel. The guard member is fixed with the main control board by welding. 
         [0010]    Further, the guard member is a conductive metal ring which is electrically connected to the removal detection and protection circuit in the main control board. 
         [0011]    Optionally, the guard member is fixedly disposed on a surface, which is adjacent to the main control board, of the keystroke panel at the outside of a position corresponding to the conductive protection ring. 
         [0012]    Optionally, the guard member is formed by vertically folding edges of the keystroke panel towards the main control board so as to fully enclose edges of the main control board when being assembled. 
         [0013]    Optionally, a bottom board is provided at a side of the main control board away from the keystroke panel. The guard member is fixedly disposed on a surface, which is adjacent to the main control board, of the bottom board at the outside of a position corresponding to the conductive protection ring. The main control board is provided with a groove at a position corresponding to the guard member. 
         [0014]    Optionally, a bottom board is provided at a side of the main control board away from the keystroke panel. The guard member is formed by vertically folding edges of the bottom board towards the main control board so as to fully enclose edges of the main control board when being assembled. 
         [0015]    Preferably, a water-proof silicone rubber layer is provided between the keystroke panel and the main control board. The water-proof silicone rubber layer is provided with a conductive adhesive recess at a position corresponding to the conductive adhesive. 
         [0016]    Further, a groove or a hole for receiving the guard member is provided in the water-proof silicone rubber layer at a position corresponding to the guard member. 
         [0017]    Compared with the prior art, the technical solutions of the present invention has following advantages. 
         [0018]    First, the guard member is fixedly installed at the outside of the conductive protection ring, which effectively prevents the attack that the criminal inserts a hard object through the clearance between the conductive adhesive and the panel. 
         [0019]    Second, such a design may effectively prevent the attack that the criminal inserts a metal sheet through a clearance between the conductive adhesive and the removal detection point to keep the continuous connection of the removal detection and protection circuit. 
         [0020]    Third, the conductive protection ring and the metal guard member are electrically connected to the removal detection and protection circuit in the main control board respectively, which may effectively prevent the attack that the criminal fills with conductive silicone glue through the clearance between the conductive adhesive and the removal detection point. 
         [0021]    Fourth, the guard member is made of metal material, which may effectively prevent the attack that the criminal heat to melt the guard member. 
     
    
     
       BRIEF DESCRIPTION OF DRAWINGS 
         [0022]      FIG. 1  is an exploded schematic view of an encryption keyboard for preventing illegal disassembly according to a first embodiment of the present invention; 
           [0023]      FIG. 2  is a partially enlarged view of part A in  FIG. 1 ; 
           [0024]      FIG. 3  is an exploded schematic view of an encryption keyboard for preventing illegal disassembly according to a second embodiment of the present invention; 
           [0025]      FIG. 4  is an exploded schematic view of an encryption keyboard for preventing illegal disassembly according to a third embodiment of the present invention; 
           [0026]      FIG. 5  is an exploded schematic view of an encryption keyboard for preventing illegal disassembly according to a fourth embodiment of the present invention; and 
           [0027]      FIG. 6  is an exploded schematic view of an encryption keyboard for preventing illegal disassembly according to a fifth embodiment of the present invention. 
       
    
    
     DETAILED DESCRIPTION OF THE INVENTION 
       [0028]    Hereinafter, the technical solutions in embodiments of the present invention will be described clearly and completely in conjunction with drawings in the embodiments of the present invention. Apparently, the described embodiments are only preferred embodiments, not all of the embodiments of the present invention. Based on the embodiments of the present invention, all of other embodiments made by the person skilled in the art without inventive effort are deemed to fall into the protection scope of the present invention. 
         [0029]    Referring to  FIGS. 1 and 2 ,  FIG. 1  is an exploded schematic view of an encryption keyboard for preventing illegal disassembly according to a first embodiment of the present invention, and  FIG. 2  is a partially enlarged view of part A in  FIG. 1 . An encryption keyboard  100  according to the present invention includes a keystroke panel  101  and a main control board  102 . A removal detection and protection circuit (not shown) is provided in a main chip of the main control board  102 . At least one lead pin of the removal detection and protection circuit is led out from two opposite edges of the surface  1021 , which is adjacent to the keystroke panel  101 , of the main control board  102  to form a removal detection point  1022 . The removal detection point  1022  is provided with two disconnected signal contacts which are connected by conductive adhesive  103  to activate the removal detection and protection circuit. A conductive protection ring  1023  is provided outside the removal detection point  1022  and is isolated from the removal detection point  1022 . The conductive protection ring  1023  is connected to the removal detection and protection circuit in the main chip. A guard member is provided at the outside of the conductive protection ring and of the conductive adhesive. 
         [0030]    In the encryption keyboard according to the present embodiment, a water-proof silicone rubber layer  104  is provided between the keystroke panel  101  and the main control board  102  in order to enable the encryption keyboard to have a certain water-proof function. A recess for receiving the conductive adhesive  103  is provided in the water-proof silicone rubber layer  104  at the position corresponding to the conductive adhesive  103 . 
         [0031]    A hard metal guard member  1024  with a semi-enclosure structure is fixedly installed at the outside of the conductive protection ring  1023  on the main control board  102  by welding. The semi-enclosure guard member  1024  is open towards the center of the main control board, and has four hooks (taking four hooks as an example in this embodiment, at least two hooks are provided, but it is not limited to this). The hooks are inserted into semi-blind holes in the surface  1021 , which is adjacent to the keystroke panel, of the main control board  102 , and are electrically connected to the removal detection and protection circuit in the main control board. A groove  1041  is provided outside the recess of the water-proof silicone rubber layer  104  for receiving the conductive adhesive  103 , and has a shape matched with the guard member  1024 . 
         [0032]    The thickness of the hard metal guard member  1024  is substantially equal to the thickness of the water-proof silicone rubber layer  104 . When the keyboard is fixedly assembled together via stud bolts  1011  on the keystroke panel  101 , the water-proof silicone rubber layer  104  and the hard metal guard member  1024  are pressed between the keystroke panel  101  and the main control board  102 , and are fixed together tightly. Thus, there is no clearance between the hard metal guard member  1024  and the main control board  102 , as well as between the hard metal guard member  1024  and the keystroke panel  101 , which can ensure that the removal detection point  1022  is not being attacked by poking from the outside, and can effectively prevent the side surfaces of the encryption keyboard from being attacked by the criminal inserting a hard object through a clearance between the conductive adhesive and the panel. 
         [0033]    In addition, such a design may effectively prevent the attack that the criminal inserts a metal sheet through a clearance between the conductive adhesive  103  and the removal detection point  1022  to keep continuous connection of the removal detection and protection circuit. Since both the conductive protection ring  1023  and the metal guard member  1024  are electrically connected to the removal detection and protection circuit in the main control board respectively, when either of the conductive protection wing  1023  and the metal guard member  1024  is connected to the removal detection point, the circuit may be changed, which may be sensed by the main control chip. Thus, the ability of the encryption keyboard for preventing the criminal from filling with conductive silicone glue through the clearance between the conductive adhesive and the removal detection point is increased. 
         [0034]    Referring to  FIG. 3 , an exploded schematic view of an encryption keyboard for preventing illegal disassembly according to a second embodiment of the present invention is shown. An encryption keyboard  200  includes a keystroke panel  201 , a main control board  202  and a bottom board  205 . A removal detection and protection circuit (not shown) is provided in a main chip of the main control board  202 , and two lead pins of the removal detection and protection circuit are led out from two opposite edges of the surface  2021 , which is adjacent to the keystroke panel  201 , of the main control board  202  to form removal detection points  2022 . The removal detection point  2022  is provided with two disconnected signal contacts which are connected by conductive adhesive  203  to activate the removal detection and protection circuit. A conductive protection ring  2023  is provided outside each removal detection point  2022  and is isolated from the removal detection point  2022 . The conductive protection rings  2023  are connected to the removal detection and protection circuit in the main chip. In the encryption keyboard according to this embodiment, a water-proof silicone rubber layer  204  is provided between the keystroke panel  201  and the main control board  202  in order to enable the encryption keyboard to have a certain water-proof function. Recesses for receiving the conductive adhesive  203  are provided in the water-proof silicone rubber layer  204  at the positions corresponding to the conductive adhesive  203 . 
         [0035]    The bottom board  205  is attached to the rear surface of the main control board  202 , and is provided with guard members  2051  at the outside of the positions corresponding to the conductive protection rings  2023  of the main control board  202 . The guard member  2051  may be welded on the bottom board  205 , or may be cast with the bottom board  205  integrally. The guard member  2051  is open towards the center of the main control board  202 . Grooves  2024  are respectively provided outside the conductive protection rings  2023  of the main control board  202 , and grooves  2041  are provided outside the recesses of the water-proof silicone rubber  204  for receiving the conductive adhesive  203 . The grooves  2024  and grooves  2041  have a shape matched with the guard member  2051  so as to partially enclose the conductive adhesive  203  and conductive protection ring  2023 . The thickness of the guard member  2051  is equal to the sum of the thickness of the water-proof silicone rubber  204  and the thickness of the main control board  202 . When the keyboard is fixedly assembled together via stud bolts  2011  on the keystroke panel  201 , the water-proof silicone rubber layer  204  and the main control board  202  are pressed between the key panel  201  and the bottom board  205  and are fixed together tightly. The guard member  2051  partially encloses the removal detection point  2022  around three side surfaces, and closely contacts with the keystroke panel  201 , which ensures that the removal detection points  2022  are not being attacked by poking from the outside, and effectively prevents the side surfaces of the encryption keyboard from being attacked by the criminal inserting a hard object through a clearance between the conductive adhesive and the panel. 
         [0036]    Referring to  FIG. 4 , an exploded schematic view of an encryption keyboard for preventing illegal disassembly according to a third embodiment of the present invention is shown. An encryption keyboard  300  includes a keystroke panel  301 , a main control board  302  and a bottom board  305 . A removal detection and protection circuit (not shown) is provided in a main chip of the main control board  302 , and two lead pins of the removal detection and protection circuit are led out from two opposite edges of the surface  3021 , which is adjacent to the keystroke panel  301 , of the main control board  302  to form removal detection points  3022 . The removal detection point  3022  is provided with two disconnected signal contacts which are connected by conductive adhesive  303  to activate the removal detection and protection circuit. A conductive protection ring  3023  is provided outside each removal detection point  3022 , and is isolated from the removal detection point  3022 . The conductive protection ring  3023  is connected to the removal detection and protection circuit in the main chip. In the encryption keyboard according to this embodiment, a water-proof silicone rubber layer  304  is provided between the keystroke panel  301  and the main control board  302  in order to enable the encryption keyboard to have a certain water-proof function, and recesses for receiving the conductive adhesive  303  are provided in the water-proof silicone rubber layer  304  at positions corresponding to the conductive adhesive  303 . 
         [0037]    The bottom board  305  is attached to the rear surface of the main control board  302 , with its four edges being folded vertically so as to constitute a guard member  3051 . The guard member  3051  has a thickness equal to a sum of the thickness of the water-proof silicone rubber layer  304  and the thickness of the main control board  302 . When the keyboard is fixedly assembled together via stud bolts  3011  on the keystroke panel  301 , the water-proof silicone rubber layer  304  and the main control board  302  are pressed between the keystroke panel  301  and the bottom board  305 . The guard member  3051  fully encloses edges of the water-proof silicone rubber layer  304  and of the main control board  302 , and is tightly fixed with the keystroke panel. The guard member  3051  surrounds the main control board  302  on all sides, and closely contacts with the keystroke panel  201 , which ensures that the removal detection points  3022  are not being attacked by poking from the outside, and effectively prevents the side surfaces of the encryption keyboard from being attacked by the criminal inserting a hard object through a clearance between the conductive adhesive and the panel. 
         [0038]    Referring to  FIG. 5 , an exploded schematic view of an encryption keyboard for preventing illegal disassembly according to a fourth embodiment of the present invention is shown. An encryption keyboard  400  according to the present invention includes a keystroke panel  401 , a water-proof silicone rubber layer  404  and a main control board  402 . A removal detection and protection circuit (not shown) is provided in a main chip of the main control board  402 , and two lead pins of the removal detection and protection circuit are led out from two opposite edges of the surface, which is adjacent to the keystroke panel  401 , of the main control board  402  to form removal detection points  4022 . The removal detection point  4022  is provided with two disconnected signal contacts which are connected by conductive adhesive  403  to activate the removal detection and protection circuit. A conductive protection ring  4023  is provided outside each removal detection point  4022 , and is isolated from the removal detection point  4022 . The conductive protection ring  4023  is connected to the removal detection and protection circuit in the main chip. The conductive adhesive  403  is received in recesses provided in the surface of the water-proof silicone rubber layer  404  adjacent to the main control board. 
         [0039]    Hard metal guard members  4012  with a semi-enclosure structure are fixedly provided on the keystroke panel  401  at the outside of the positions corresponding to the conductive protection rings  4022 . The semi-enclosure guard member  4012  is open towards the center of the main control board. The semi-enclosure guard member  4012  is fixedly connected with the keystroke panel  401  by welding or integral forming. 
         [0040]    The thickness of the hard metal guard member  4012  is substantially equal to the thickness of the water-proof silicone rubber layer  404 . When the keyboard is fixedly assembled together via stud bolts  4011  on the keystroke panel  401 , the water-proof silicone rubber layer  404  and the hard metal guard member  4012  are pressed between the key panel  401  and the main control board  402  and fixed together tightly. Thus, there is no clearance between the hard metal guard member  4012  and the main control board  402 , as well as between the hard metal guard member  4012  and the keystroke panel  401 , which can ensure that the removal detection points  4022  are not being attacked by poking from the outside, and can effectively prevent the side surfaces of the encryption keyboard from being attacked by the criminal inserting a hard object through a clearance between the conductive adhesive and the panel. 
         [0041]    Referring to  FIG. 6 , an exploded schematic view of an encryption keyboard for preventing illegal disassembly according to a fifth embodiment of the present invention is shown. An encryption keyboard  500  according to the present invention includes a keystroke panel  501 , a water-proof silicone rubber layer  504 , and a main control board  502 . A removal detection and protection circuit (not shown) is provided in a main chip of the main control board  502 , and two lead pins of the removal detection and protection circuit are led out from two opposite edges of the surface, which is adjacent to the keystroke panel  501 , of the main control board  502  to form removal detection points  5022 . The removal detection point  5022  is provided with two disconnected signal contacts which are connected by conductive adhesive  503  to activate the removal detection and protection circuit. A conductive protection ring  5023  is provided outside each removal detection point  5022 , and is isolated from the removal detection point  5022 . The conductive protection rings  5023  are connected to the removal detection and protection circuit in the main chip. The conductive adhesive  503  is received in recesses provided in a surface of the water-proof silicone rubber layer  504  adjacent to the main control board. 
         [0042]    Four edges of the keystroke panel  501  are folded vertically to constitute a guard member  5012 . The guard member  5012  has a thickness equal to a sum of the thickness of the water-proof silicone rubber layer  504  and the thickness of the main control board  502 . When the keyboard is fixedly assembled together via stud bolts  5011  on the keystroke panel  501 , the water-proof silicone rubber layer  504  is pressed between the keystroke panel  501  and the main control board  502 . The guard member  5012  fully encloses edges of the water proof silicone rubber layer  504  and of the main control board  502 , and is tightly fixed with the keystroke panel. The guard member  5012  surrounds edges of the main control board  502  on all sides, and closely contacts with the main control board  502 , which ensures that the removal detection points  5022  are not being attacked by poking from the outside, and effectively prevents the side surfaces of the encryption keyboard from being attacked by the criminal inserting a hard object through a clearance between the conductive adhesive and the panel. 
         [0043]    The above embodiments are only preferred embodiments. In order to improve the security of the encryption keyboard, more protection layers may be provided for the encryption keyboard if desired. Many modifications and improvements may be made based on the prior art by the person skilled in the art without departing from the principle of the present invention, and these modifications and improvements should be deemed to fall into the protection scope of the present invention.