CA1286401C

CA1286401C - Security system for protecting information

Info

Publication number: CA1286401C
Application number: CA000540480A
Authority: CA
Inventors: Andre Novickis; George F. Denehy; James H. Lauffenburger
Original assignee: MEDIA SECURITY Inc AND ASSOCIATES
Current assignee: MEDIA SECURITY Inc AND ASSOCIATES
Priority date: 1986-06-25
Filing date: 1987-06-25
Publication date: 1991-07-16
Anticipated expiration: 2008-07-16
Also published as: EP0251210A1; DE3773545D1; US4794470A; EP0251210B1

Abstract

ABSTRACT

A system for providing a security capability for an electronic information reproducing device mounted within a housing, such as a floppy disk mounted in a jacket or a tape in a 3480 tape cartridge, by attaching an electronic sur-velliance tag to an inner surface of the housing during its manufacture so that the electronic surveillance tag cannot be easily removed from within the floppy disk or 3480 tape cartridge without destroying it and is not visible from outside of the housing and an electronic drive means having an electronic circuit for detecting the presence or absence of an electric surveillance tag and generating a signal in response to such presence or absence.

Description

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A 8ECURITY SYST~M FOR PROTEC~ING INFORMA~ION

Field o~ tha Invention Thi~ invention relatea generally to a eecurity 6ystem 05 o~ ths type that U88e an eleatronia surveillance tag / at i~
attach2d to an article wherain the pre~ence o~ the electronlc eurvaillance tag iB readily det~cted by an electronic aircuit to generate an el~ctric 3ignal and more particularly to such a ~y~tem whereln the electronic eur-velllance tag le incorporated withln an electronic in~orm~-tion reproducing device at the point o~ manu~acturQ ~o that the electronl~ ~urveillanae tag i8 not readily vi3ible or eaeily removed and th~ electronic survelllance tag al30 ~unctione to prevent normal operation o~ an eleatronic in~ormation reproducing device not prov~ded with an elec-- -- tronic surv~illance tag and to produce a . elgnal to alert eecurlty pereonnelO

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sackqround o~ the Invention With the proliferation of the personal computer (PC) ln the workplace, control of the security of computer software and the data contained in the so~tware floppy disk~ has 05 become a problem of major proportions. Attempts at encryp-tion of the data or use of password systems to prevent unauthorized access to the data contained in the floppy disk~ has to date proven to be ineffective. Information has continued to be pirated and bootlegged by breaking the encryption codes through the use of yet another aomputer program. Non-encrypted data has simply been copied and removed from the premises to be exploited or released by the perpetrator. These losses of information have also been aggravated by the outright theft of the floppy dis~s them-selves. Thus the control of the release of information aswell as the actual theft of ths floppy disk upon which the information is stored ha~ presented a continuou~ problem to lnformation and data security managers. To date no suitable solution has been found which would provide real-time/hands-on control of the data filled floppy disk. Due to the hlghtransportability and easy aoncealment of the ~loppy disk, the ~ob of control and detection of the presence of the floppy di~k i~ virtually impos~ible without extraordinary mea~ure~ ~uch a~ detailed body and briefcase searches by security per~onnel. Suah activitie~ within the office working environment are not well received and create ma~or problems.
These problems are also present in relation to the 3480 tape cartrldge~, marketed by numerous media manufacturers ;' '. '' , ' ` "'' ' '' ' , ~2~40~

such as IBM, which are presently being introduced as a replaaement for the conventional 2400 foot one half inch reel to reel tapes for large mainframe computers. A feature of the 3480 tape cartridge i9 that it can contain ten times os the information normally contained on one 2400 foot reel of conventional tape~ The large storage capacity of this tape cartridge i8 a major a6sst of this product as well as a major deficiency. Due to its small size, high transport ability and voluminouç capacity for ~toragel it is a major information security liability.
~,j.., Brief Description of the Invention -~ his invention provide~ a security system for protecting information contained in an electronic informa-tion reproduclny device such as a floppy disk or a 3480 tapecartridge. In one embodiment, the invention provides a security sy6tem for a floppy disk wherein an electronic surveillance tag is mounted in~ide the jacXet in which the floppy disk is enclosed so that no portion of the electronic surveillance tag i6 visible. In another embodiment, an electronic surveillance tag is mounted inside a 3480 tape cartridge so that no portion of the electronic surveillance tag i5 vislble. The eleatronia surveillance tag comprises an electronic IC clrcuit. Al60, this invention provides an electronic cirauit within the drive mean~ for enabling or disabling the use of the electronic informatlon reprodu~ing device in the electronic drive mèans depending on the presence or ab~ence of the electronic surveillance tag therein.

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3a In its method aspect the invention relates to a method for providing security system using an electronic surveillance tag which is readily detected by an electronic circuit for an electronic information reproducing device.
The method comprises: providing an electronic information reproducing device located within a housing; attaching an electronic survPillance tag capable of producing a detectable electric signal to an inner surface of the housing during the manufacture of the electronic information reproducing device; sealing the housing after the attachment of the electronic surveillance tag so that the housing may not be opened without detection; locating the electronic surveillance tag so that the electronic surveillance tag is not visible from outside the housing; providing an electronic drive means for obtaining information from the electronic information reproducing device; providing the electronic drive means with an electronic circuit to detect the presence or absence of the electronic surveillance tag;
inserting the housing into the electronic drive means; the electronic circuit being responsive to the presence or absence of the electronic surveillance tag; and generating a signal to enable or disable the use of the electronic information reproducing device in the electronic drive means depending on the presence or absence of the electronic surveillance tag.

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, ~L2~36'~01 In one embodiment of the invention, a ~acket blank for holding a floppy diek comprises a generally rectangular ~lat sheet of ~acketing material having a plurality of integral flaps extending outwardly from portions thereof. A
05 generally rectangular liner having a low aoefficient of friction i~ supsrposed over the rectangular portion of the sheet of ~acketing material. A plurality of cut-outs ara made in the sheet of jacketing material and the superposed liner to provide for access to a floppy disk. An electronic surveillance tag iB mounted between a portion of the sheet of ~acketing ma-terial and a portion of the superposed liner.
The ~heet of ~acketlng material and the superposed liner are folded in half and then two of the flaps are folded over and sealed to the sheet of ~acketing material. A floppy disk is inserted into the ~aaket between portions of the liner and the remaining flap is folded over and sealed to the ~acket-ing material BO that the diskette is enclosed within tha ~acket and no portion of the electronic surveillance tag is visible. The ~acketed floppy disk is inserted into a drive mean~ which has an electronio aircuit to detect the presence or ab~nce of the electronia surveillance tag. If no elec-tronic ~urveillance tag is detected, the electronic circuit can control acoess to BpeCifiC portlon~ of the computer to ~`
prevent operation thereof and produce a signal which can alert security per~onnel.
In another embodlment o~ the lnvention, an electronic surveillance tag iB in~talled in~ide an electronic informa-tion reproducing device such a~ a 3480 tape cartridge at the point of manufacture. ~he electronic surveillance tag is located sq that it~ presence can not be detected by an ''~
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out6ide vi~ual inspection of the tape cartridge nor easily removed without the destruction of the cartridge case. The `~
electronic ~urveillance tag functlons in a normal mode of detecting any attempt to remove the tape aartridge ~rom a `;
05 given location. In normal use at a given location, a tape cartridge i5 inserted into a computer drive mechani6m which has an electronia circult to detect the presence or absence of the electronic surveillance tag. If no electronic surveillance tag is detected, the electronic circuit can 10 control access to prevent the normal use o~ the tape car- -tridge and produce a signal which can alert ~ecurity person-nel of the attempted use of a tape cartridge without the electronic surveillance tag.
It ls an ob~ect of this invention to provide a covert sy~tem for the protection of information contalned on electronic information reproducing devices.
It is another ob;ect of this inventlon to provide a ~:
security ~ystem to prevent the misappropriation of the ~loppy disk itself and/or the information it contains.
It is a further ob~ect of this invention to provide a ~ecurity ~y~tem to prevent the misappropriation of the 3~80 ;
tape cartridge ltself and/or the information it contains.
Additional oh~eat~, advantages, and novel features of the invention are set forth in part in the description which follows which will be understood by those ~killed in the art upon examination of the following or may be learned by ,i`
practice of the lnvention. The ob~ects and advantages o~ ;
the invention may be realized and obtained by means of the instrumentalities and combinations particularly pointed out in the ap~ended claims.
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8rief Descrlptlon of the Drawinq Fig. 1 is n top plan view of a ~acket blank of thl~
inventiont ' `,-Fig. 2 1~ a top plan vlew of a clo~ed -~acket of thls 05 invention having a 10ppy di6k located ~hexeln;
- Flg. 3 1~ a pictorial vlew of a floppy dlsk drive ~-means;
Fig. 4 is a graphic representation of a profile of AGC ,-voltages generated by the clrcuits of the present lnventlon;
Fig. 5 is a graphic representation of the operatlon of the integrated Pilter actlon and resulting control;
- Fig. 6 are block diagram representations of the cir-cuit~ used in the pre~ent lnvention;
Fig. 7 iB an outside plan view o~ one portion of a 3480 lS tape cartrldge;
Fig. B is an inside plan view o~ Fig. 7; ~ ' Fig. 9 iB an outside plan view o~ the other portion of a 3480 tape cartridge; and -Fig. 10 i6 an inside plan view of Fig. 9. ;

Detailed DescriPtion o~ the Invention In Fig. 1, there is illustrated a ~acket blank 2 o~ one modification o~ the invention. The -~acket blank 2 has a flat sheet 4 o~,~acketiny material having a yenerally 25 rectanyular portion 6 and three inteyral flaps 8, 10 and 12 extendiny outwardly from portions thereoP. A generally rectangular flat liner 14 o~ a material having a low coe~fi-cient o~ friction is ~uperposed over the generally reatanyu-lar portion 6 of the flat sheet 4 of ~acketing material.
30 The gener,ally reatangular flat liner 14 i~ eecured to the , ' ,~,, .,:
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flat sheQt 4 of ~acketing material by suitable means, ~uch a~ an adheslve.
An electronic surveillance tag 16 is po~itioned between a portion o~ the flat sheet 4 of ~acketing material and a 05 portion of the ganerally rectangular flat liner 14. The ~` electronic surveillance tag 16 i~ of a conventional nature - and may comprise an inductive-capacitive circuit such as that marketed by Check-Point Incorporated. In the modifica- i~
tion illustrated in Fig. 1, the electronic ~urveillance tag 16 is located in the upper central portion of the jacket blank 2. There are seven locations on the modification illustrated in Fig. 1 where the electronic surveillance tag 16 may be located such a~ the upper left 18 or right 20 locations, the middle left 22 or right 24 locations and the 15 lower left 26 or right 28 location~. The electronic sur- ;-veillance tag 16 may be secured to either the flat sheet 4 of ~acketing material or the generally rectangular flat llner or to both by suitable means, such as an adhesive.
Circular openings 30 and 32 are formed in the ~acket i;.
blank 2 to provide for the exposure of the central portion o~ a floppy disk as described below. Oblong openings 3~ and 36 are form~d in the ~aclcet blank 2 to provide for the `
exposure o~ the inEormation portion of a floppy disk as descrlbed. Information openings 3B and 40 and 42 and ~4 are also formed in the ~acket blank 2.
A closed ~acket 46 having a ~loppy disk 4B enclosed therain, illustrated in Fig. 2, is formed by first folding the ~acket blank 2 substantially in hal~ around the fold line 50. Flaps 8 and 12 are then folded over portions o~ ~ -the flat sheet 4 of ~acketing material and ~ecured thereto , . :
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by 3uitable mQans~ suah as an adhe~va, to form a ~aoket.
floppy disk 48 is insert~d into the ~acket between portions of tha generally rectangular liner 14. The flap 10 is then folded over portions of the flat sh2et ~ of jacketing material and secured thereto by suitable means, such as an adhesive. The floppy disk 48 has a central portion 52 exposed through the circular openings 30 and 32 and adapted to be grasped by the drive means described below. The floppy disk 48 also has information means 54 exposed through the oblong openings 34 and 36.
A conventional floppy disk drive means 56 is illustrated in Fiq. 3. The drive means 56 is generally box-like and has a rectangular opening 58 in an end wall 60 through which a closed ~acket 46 having a floppy disk 48 enclosed therain may be inserted. The drive means 56 has an electronic clrcuit, described below, mounted therein for detecting the presence or absence o~ an electronic surveil-lance tag 16.
The purpose of the electronic circuit contained in the disk drive mechanism ~shown in block diagram in Fig. 6) is to detect the special disk desaribed herein. A conventional floppy dlsk drive is modified ko oontain an alectronia circuit and a sense antenna which can detect the presence of the tag or circuit placed in the envelope for the magnetic disk media. The tag contains a resonant clrcuit which preferably is ~mall and lossy. In the embodiment described, the tag circuit i~ designed to be resonant at preferably about B MHz. ~he circuit contained in the disk driva ;
preferably contains an FM oscillator which is connected to an antenna ~Fig. 6) which acts as the inductor in a resonant :, ~, .
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tank circult. The other component of the tank circult is a voltage variable capacltor or varactor. By providing specific adjustment of the voltage on the capacitor of the tank circuit, the FM oscillator can be made to oscillate 05 preferably between 6 MHz and lO MHz. In the embodiment described, the clrcuit al~o contain~ a second oscillator which preferably is designed to generate a triangular wave form at a frequency of about 2 kHz. Thi~ signal is used to drive the varactor in the FM oscillator, as shown in Fig. 6.
As the triangle wave ramps up, a~ shown in Fig. 4, the FM
o~cillator frequency is increased and conversely the tank frequency decreases as the triangle wave ramp~ down. By this process, the frequency of the antenna varie~ directly and ~ynchronously with the triangle wave form, Bhown in Fig.
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~ he amplitude of the oscillatlons from the FM o~cilla-tor is controlled by an automatic gain control circuit (AGC). Using this design, a voltage proportional to the gain i5 periodically reached in the cirauit during opera-tion.
The tag on the floppy disk, when in proximity to theantenna inside the disk drive mechanism, and when scanned, places an addltional load on the FM oscillator which in turn increases gain and lncreases the voltage ~ignal.
This ~lgnal processiny de~ign provides ~or ~ynchronous rise~ in the AGC voltage whlch must be detected to verify the pre~ence of a tag. Normally, such designs would employ ~everal stages of differentiation in order to magnify the small voltage changes to detectable levels. Conventional ~;~
de~igns, hqwever, increase the the circuits' sensitivity to ~' "

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noise where the envlronment may produce incorrect signal responses. The present invention incorporates an ampli~ier 2 kHz wlth small gain. This first staya o~ di~ferentlation between signals and noi~e is extremely important where the .
~5 environment is characteristically noisy.
The next level of discrimination in the present inven- -tion takes advantage of the fact that the circuit can be designed to identify the time when the tag-blip is expected to appear. This should happen at the time the point in the triangular wave correspond~ to approximately the 8 MHz output of the F~ Oscillator. A comparator connected to the triangle wave generator produces a timing signal, designated as OSC Window +, that indicates where the so-called tag-blip ~ -should be. A peak detector connected to the comparator looks for the highest amplitude blip during the time of this window ~called peak A in Fig. 6~. A second peak detector measures the highest peak during the rest of the triangular :~
cycle~ this i5 called peak B (also in Fig. 6). If there is no tag-blip, then on the average, tha highest peak A ~hould be about the same as the hiyhest peak B. A fixed oEfset is added to peak B. Thus, for the condition of no tag-blip, --the ~inal peak B should be larger than peak A. These two levels are compared, and i~ B i~ larger, no tag is indicated (by a low on the detector line in Fig. 5).
I~ there is a tay-blip due to the presence o~ a disk~
ette containing the re~onant circuit in the ~ield o~ the antenna in the dlsk drive mechanism, it should add to the noise level during the appropriate time, and peak A ghould be larger. This will be senqed by the comparator and a tag is indlcat~d (a high on the detector lina in Fig. 5).

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- Since the noi~e in the circuit iB random with respect to the 2 k~z triangular wave, any noi~e will appear with equal probability as a ~ignal in or out of the peak A wlndow (oSC Window +, Fig. 6). Most noise is of a much higher 05 frequency than 2 kHz, and will therefore be: 1) effectively filtered out of the resultant 6ignal by the low bandwidth of the amplifier; or is 2), present in both the peak A window -and the peak B window. I~ it is present in both windows, it ls effectively cancslled out by the peak dat~ctors.
Noise present in the envlronment of the circuit may -~
cau6e a mis-triggering of the comparator between peak A and peak B. Thus, on a random ba~i~, the detector line in Fig.
5 will will not show a signal a 6mall percentage of the time. The gain and offset of peak A and peak B ~hould bs 6uch that thi~ happens at an infrequent rate. This rate may be as mall a~ one in one hundred ~ampl06.
To correct for even thi~ ~ituatlon, further discrlmina-tion i6 provided by an ~ntegrating Filter, ~hown in the block dlagram in Flg.6. This filter i8 designed such that approximately 10 correct sample~ are re~uired for the final fllp/flop to change ~tate. The detector llne would then ;
- have to report high for about 10 ayales of the 2 kHz trian- ~;
gular wave in order for the airauit to verify deteation of the pre~enae o-~ the resonant circuit in the tag. Once deteated,`the deteator line would have to be low for the 6ame amount of time in order for the airauit to ahange baak to a tag not detected 6tate. Thu~, this timed disarimina-tion effectively filter6 out infrequent noi6e-induced error~

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'........... ' ' ''" -' ' ~, - ' ' ' ~L2~il69L01 The final devlce in the circuit i~ the flip/flop circuit referred previously and designated a~ F/F in Fig. 6.
This circuit is designed to provide set or reset signals to indicate the presence or absence of the tag in the disk 05 drive according to the signals also previously described.
This circuit selectively drives an output transi~tor whose collector is connected in series to the ground side of the write-protect sensor which is present in any disk drive. If the ~lip/flop circuit is in the set mode, the transistor allows the write-protect sensor to work normally. If, on the other hand, a tag i~ not detected, then the flip/flop circult is retained in the reset mode by the transistor remaining in an high-impedance stata, and the floppy drive remains in a write-protected mode. This provlde~ protection against unauthorized entry into a proteated ey~tem which will frustrate copying, alteration or any other activities which have nor previou~ly been authorized. Other outputs can be provided which would alert ~scur~ty personnel that unauthorized entry has ~een attempted.
In Fig. 7, there iB illustrated the outer ~urfacs configuration 62 of one portion of a conventional 3480 tape cartridge and in Fig. 8, there i5 illustrated the inner ~urface configuration 64 of the same one portion. A plural-ity of curved inner partitions 66 provide means for properly loaating the tape ~not shown). ~ central opening 68 having a beveled ~ldewall 70 i~ provided in the one portion.
Conventional means 72 are provided for cooperation with the tape in a conventional manner.
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In Fig. 9, there is illustrated the outer surface configura~tion 74 of the other portion of the conventional .
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3480 tape cartrldge. Ithe outer surfaae aonfiguration 74 has a recessed area 76 in which i5 secured, by suitable means such as adhesive, an opaque indicia bearing labsl 78 aon-taining information relating to the tape cartridge. In Fig.
o~ 10, there ls illustjrated the inner surface con~iguration 80 of the other portion of the tape cartridge. A plurality of curved inner portions 82 and a center stud ~4 provide means ;~
for locating the tape. Also, conventlonal means 86 are provided for cooperating with the conventional mean3 72 in a `,~
10 conventional manner.
An electronic surveillance tag 16, as described above, is secured to ths inner ~urface configuration 80 of the , other portion. The electronic surveillance tag 16 i~
located within the borders of the opaque lndicia bearing 15 label 78 so that the electronic eurvelllance tag 16 ls not visiblra when looking at the outer surf'ace conflguratlon 74.
Al~o, the electronlc surveillance tag 16 ls withln the ~
border deflned by the curved lnner portlons 66 and 82 so ~ ' that the tape ~not shown) prevQnts observance of the elea-20 tronlc surveillance tag 16 when looklng at the outer surface 62. The electronic surveillance tag 16 is applled durlng the manufacture of the tape cartridge ~o that the electronic ~, surveillance tag 16 is covertly secured in the 34B0 tape ~,, cartridge as it is in the floppy diek. In the manufacturing ~ . .
25 process, an eleatronic surveillance tag 16 i3 seaured on the ~;
inner surface conflguration by suitable means, such ae an adhesive, at a location a~ indicated in Fig. 10. A tape is inserted within the border defined by the curved inner `~
portions ~2. The one portion is then positioned over the other por~ion eo that the inner eurface configuration 64 and '.

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80 are in a facing relatlonshlp. The one portlon 1R then permanently ~ecured to the other portion by suitable means, such a~ an adhesive, so that the tape cartrldge may not be opened without detection. Although the inventlon is de-o~ scribed above ln relation to floppy disXs and 3480 tapecartridges, it is within the spirit of the invention to protect in a covert fashion other types of electronic - information reproducing devlces.
An electronic circuit, such as that de~cribed above, in relation to Figs. 4 - 6, wlll be provided in the computer drive mechanism used with the tape cartridge to detect the presence or absence of the electronic ~urveillance tag 16.
If no electronic surveillance taq 16 is detected, the electronic circuit will prevent operation of the computer drive mechanism and produce a signal to alert security personnel.
It is contemplated that the inventive concepts herein described may be variously otherwise embodied and it i5 intended that the appended claims be construed to include alternative embodiments of the invention except insofar as limited by the prior art.
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Claims

1. A security system using an electronic surveillance tag which is readily detected by an electronic circuit for preventing unauthorized use or removal of an electronic information reproducing device comprising:
a housing;
an electronic information reproducing device contained within said housing;
an electronic surveillance tag capable of producing a detectable electric signal secured within said housing prior to the sealing thereof so that no portion of said electronic surveillance tag is visible from outside said housing;
sealing means for sealing said housing after said electronic information reproducing device and said electronic surveillance tag have been placed therein to prevent access into said housing;
electronic drive means for obtaining information from said electronic information reproducing device;
and said drive means having an electronic circuit for detecting the presence or absence of said electronic surveillance tag for enabling or disabling the use of said electronic information reproducing device.

2. Apparatus as in claim 1 wherein said housing and said electronic information reproducing device comprises:
a tape cartridge.

3. Apparatus as in claim 2 wherein said tape car-tridge comprises:
a 3480 tape cartridge.

4. Apparatus as in claim 2 wherein said electronic surveillance tag comprises:
an inductive-capacitive circuit.

5. Apparatus as in claim 1 wherein said housing and said electronic information reproducing device comprises:
a floppy disk mounted in a jacket.

6. Apparatus as in claim 1 wherein said housing and said electronic information reproducing device comprises:
a 3480 tape cartridge.

7. Apparatus as in claim 6 wherein said electronic surveillance tag comprises:
an inductive-capacitive circuit.

8. A security system using an electronic surveillance tag which is readily detected by an electronic circuit for enabling an electronic drive means to differentiate between electronic information reproducing devices inserted into such electronic drive means with or without the electronic surveillance tag and to enable or disable the use of such electronic information reproducing devices comprising:
an electronic surveillance circuit means including resonant circuit means capable of acting as the induc-tor in a resonant tank circuit;

said electronic surveillance circuit means being associated with an electronic information reproducing device to be secured;
electronic circuit means for reading the proximity and presence of said electronic surveillance circuit means, said electronic circuit means including:
frequency modulated oscillator means for producing an output comprising a range of frequen-cies which include the resonant frequency of said electronic surveillance circuit means;
antenna means connected to said frequency modulated oscillator means responsive to the presence of said electronic circuit means to increase the voltage output of said frequency modulated oscillator means at said resonant frequency;
automatic gain control means for producing a signal indicative of the voltage from said fre-quency modulated oscillator means;
a fixed frequency triangular wave generator, whose frequency is selected to be outside the range of frequencies produced by said frequency modulated oscillator means, connected to the input of said frequency modulated oscillator means and to a comparator circuit means;
said comparator circuit means produces a signal to a first peak detector means at the time when said antenna will be responding to the presence of said electronic surveillance circuit means so that said first peak detector means receives a signal from said automatic gain control means;
said first peak detector means producing an output signal indicative of the highest peak received from said automatic gain control means;
said comparator circuit means produces a signal to a second peak detector means at a time when said electronic surveillance circuit means cannot resonate said antenna means so that said second peak detector receives a signal from said automatic gain control means;
said second peak detector means producing an output signal indicative of the highest peak received from said automatic gain control means;
comparator means for comparing the output signals from said first and second peak detectors and generating a signal depending on the presence or absence of said electronic circuit means in proximity to said antenna means; and control circuit means connected to the output of said comparator means for enabling or disabling the use of said electronic information reproducing device in said electronic drive means depending on the presence or absence of said electronic sur-veillance circuit means, in proximity to said antenna means.

9. The security system of claim 8 wherein:
said control circuit contains integrating filter means for sampling more than one triangular wave comparison in order to verify the presence of a valid signal from the presence of an electronic surveillance circuit in proximity to said antenna means of said electronic circuit means.

10. The security system of claim 9 wherein:
said electronic surveillance circuit means is resonant as an inductor at about 8 MHz.

11. The security system of claim 10 wherein:
the frequency modulated oscillator means produces a range of frequencies from about 2 MHz to 10 MHz.

12. The security system of claim 11 wherein:
said triangular wave generator is operated at about 2 kHz.

13. A method for providing security system using an electronic surveillance tag which is readily detected by an electronic circuit for an electronic information reproducing device comprising:
providing an electronic information reproducing device located within a housing;
attaching an electronic surveillance tag capable of producing a detectable electric signal to an inner surface of said housing during the manufacture of said electronic information reproducing device;
sealing said housing after said attachment of said electronic surveillance tag so that said housing may not be opened without detection;

locating said electronic surveillance tag so that said electronic surveillance tag is not visible from outside said housing;
providing an electronic drive means for obtaining information from said electronic information reproducing device;
providing said electronic drive means with an electronic circuit to detect the presence or absence of said electronic surveillance tag;
inserting said housing into said electronic drive means;
said electronic circuit being responsive to the presence or absence of said electronic surveillance tag; and generating a signal to enable or disable the use of said electronic information reproducing device in said electronic drive means depending on the presence or absence of said electronic surveillance tag.