| ==Phrack Inc.== |
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| Volume Two, Issue Eleven, Phile #5 of 12 |
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| {Simple Data Encryption} |
| <or digital electronics 101> |
| By:{The Leftist} |
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| Prologue: |
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| Well, it's been awhile since I've done one of my activities files. This time |
| I've switched from chemistry to electronics. Hopefully, I will be writing |
| more files similar to this one. Also, I have devised a more sophisticated |
| encryption device, which I may release in the future |
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| Do you run a BBS, living in fear that the "feds" are gonna log on, and fool |
| you into giving them a password? Do you wish that you could limit exactly WHO |
| logs onto your board? Well, this file is just for you.. |
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| Parts: |
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| 1:9 volt battery |
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| 1: 74hc/hct04 cmos hex inverter <about .50 cents> |
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| Some basic knowledge of electronics might help, and some wire would be helpful |
| too. If you want to be fancy you can even splurge and get a 9 volt connector. |
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| Note: Although it is not required that you put this on an etched PC board, you |
| can do this quite easily, and it makes for a much cleaner job. |
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| Ok, the basic idea behind this scheme is this: |
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| Data coming to and going from your modem is translated as 1's and 0's. This |
| represents highs and lows, which translate out to code which your computer |
| recognizes as valid data. Now, if you could switch all those 1's to 0's, and |
| 0's to 1's, then you would have a simple way of encrypting your data. That's |
| exactly what the hex inverter does. If it sees a 0, it makes it a 1. If it |
| sees a 1, it makes it a 0. So, what you want to do is have an inverter on your |
| send line, and an inverter on your receive line. The computer you are |
| connected to must also have inverters on its send and receive, or all you will |
| see will be garbage! I tried to be as non-technical as possible in this for |
| all you non-technical types out there. |
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| Connections: |
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| Hold the chip, and look at it. There should be a little notch in one end. Hold |
| it as illustrated in the schematic: |
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| (80 columns) |
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| ______________________________ |
| | | |
| 14 13 11 12 10 9 8 | |
| | | | | | | | | |
| __________________ | |
| | | |_ to positive on battery |
| \ 74hc/hct04 | |
| / | |
| |__________________| to negative on battery |
| | | | | | | | | |
| 1 2 3 4 5 6 7______________| |
| | | | | |
| | | | |_________________________________to computer port |
| | | |_______________________________from modem |
| | |________________________________________________to modem conn. |
| |________________________________________________ from computer port |
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| <all other pins are not connected> |
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| Ok, hook the + 9volts up to pin 14, and the negative up to pin 7. |
| There are 6 inverters on this chip. For this, we will be using only 2 of them. |
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| Find the wire coming from your computer to the send data line on your modem. |
| Sever this wire, and hook one side of it to pin 1. Hook the other end of it to |
| pin 2. Next, find the receive data line, and sever it. Hook one end of it to |
| pin 3, the other end to pin 4. That's about it.. if you want to use the other |
| inverters on the chip, here's the complete pinouts. |
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| Pin# Name and function |
| ---- ----------------- |
| 1,3,5,9,11,13 Data inputs |
| --------------------------------- |
| 2,4,6,8,10,12 Data outputs |
| --------------------------------- |
| 7 Ground |
| --------------------------------- |
| 14 VCC |
| --------------------------------- |
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| Remember, that your BBS modem must have one of these devices on it, as well as |
| the user calling. I have tested this on Smartmodems, and it does work. If you |
| have an internal modem, this may be a little difficult for you. |
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|
