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Creating Secure Passwords with Two Pieces of Paper

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By: ProgrammerE

November 9, 2016

pixa-access-data-436712_640This is a simple method to produce a completely secure password without having to memorize it:
  1. Open Excel.
  2. Copy this formula into cell A1 - T20: "=IF(ROUND(RAND(),0)=0,CHAR(RANDBETWEEN(65, 90)),CHAR(RANDBETWEEN(97, 122)))" (Without the quotes) *This puts either a lower case or upper case letter in the cell, allowing for 26 * 2 = 52 different possible letters per Cell, for all 400 cells.
  3. Print this out and place it in easy to reach locations. This is your public key. Feel free to post it online, or stick it on your laptop.
  4. Open another Tab on this worksheet.
  5. Copy this formula into A1-A20: "=CHAR(RANDBETWEEN(65,84)) & RANDBETWEEN(1, 20)"
  6. Overlay a blank piece of paper on top of your public key.
  7. For each Row/Column combination as per step 5, outline the box with a pencil on your new sheet of paper.
  8. Cut out each of these boxes with scissors.
  9.  Overlay the Paper. You should only see the 20 (or less, if two of the values in the second workbook were the same) values. This will be your password. The second piece of paper is your private key. Keep it secret.
  10. Repeat this for all the keys you need.
  11. For good security, replace private keys every 60 days (or every 30 if you want airtight security)
ExampleFor my example, I will use a 5 x 5 public key and a 5 length private keyPublic Key
Column/Row combination chosen:
Resulting Password: IspvmThree great things about this password1) Once you use the password a couple of times, you'll memorize the locations on the public key, and the physical private key will become unnecessary. Furthermore replacing your public key will not interfere with this memorization.2) Absolutely no memorization is needed. With sentence passwords, remembering the phrasing of the sentence can prove difficult, e.g. "Colonel Mustard in the Library with the Candlestick" (CMitLwtC) vs "Colonel Mustard with the Knife in the Observatory" (CMwtKitO)3) Multiple private keys (passwords) can be created using the same private key, and when the public key changes, it forces you to update all of your private keys, something most people neglect to do Hope this helps.
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