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@@ -0,0 +1,14 @@
+= Linear Feedback Shift Register =
+
+A LFSR is set of rules to alter a set of bits. They are useful to psudeo random
+number generators, and as key generators for stream ciphers.
+
+All LFSRs are cyclical in nature, and after a set amount of time will repeat
+back into themselves. THe initial state of the bits in the LFSR is called the
+seed.
+
+The maximum period for a _n_ bit shift register is 
+
+2^n - 1
+
+A *tap* is where a bit is read and fed back into itself.
diff --git a/tech/security.wiki b/tech/security.wiki
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@@ -11,6 +11,10 @@ Hiding information
 * [[substitution|Substitution]] 
 * [[Affine]]
 
+=== Misc ===
+
+* [[LFSR|Linear Feedback Shift Registers]]
+
 === Math for Crypto ===
 
 * [[../math/congruences]]