diff --git a/3_digital_signatures b/3_digital_signatures.py
similarity index 100%
rename from 3_digital_signatures
rename to 3_digital_signatures.py
diff --git a/4_hashing b/4_hashing
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+++ b/4_hashing
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+###    HASHING    ###
+
+from helpers import mainnet,testnet
+from pprint import pprint
+
+# Hash functions takes data and gives you a fingerprint.You CANT reverse it
+
+# This is a built in library in python
+# To get more information on hashlib: help(hashlib)
+import hashlib
+
+# hashlib onjects return a hash obj
+msg = b'hello, i am efe'
+hash1 = hashlib.sha256(msg)
+print(hash1,'\n')
+
+# with digest we get the data in that hash object
+hash2 = hashlib.sha256(msg).digest()
+print(hash2,'\n')
+
+# with hexdigest we get the hexadecimal data in that hash object
+# Hexadecimal(means 16) characters: 0123456789ABCDEF
+hash3 = hashlib.sha256(msg).hexdigest()
+print(hash3,'\n')
+
+# Example
+# Get a string, turn it into bytes and hash it.
+msg2 = input('Enter a string:')
+print(msg2.encode()) #turns into byte
+
+#You must change msg to the bytes with encode befre hashing
+#hash5 = hashlib.sha256(msg2).hexdigest() #fail. 
+#print(hash5)
+
+hash4 = hashlib.sha256(msg2.encode()).hexdigest() #get the hash with encoded string
+print(hash4)
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