diff --git a/content/notes/05-crypography.md b/content/notes/05-crypography.md
index d93f8a9c1..85b70a43b 100644
--- a/content/notes/05-crypography.md
+++ b/content/notes/05-crypography.md
@@ -63,4 +63,25 @@ digital crypto schemes normally work on the binary data (images, .docs, .txt, mp
 # Randomness
 - a lack of predicability
 - no patterns
-- 
+- stochastic (can be analysed but not predcted) vs deterministic
+
+used for
+- one time pad
+- generating key-pairs
+- generating salts for password hashing
+- seeding pesudo random number generators
+
+humans are not good at randomness
+- e.g., see patterns when there are none
+- e.g., random dot pattern
+- shuffle algorithm
+- gambers fallacy
+
+computers have the same problem: they are deterministic
+- cannot really produce true random numbers
+- CSPRNGS crypto secure pseudo random number generators
+- hardware entropy generator
+
+entropy pool
+- modern OSs implement an entropy pool that processes can draw on when the need random data
+	- some systems provide blocking and non-blocking random sourc