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Cryptography/Rotation-Ciphers/caesarCipher_from_net.py

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+def caesar(plaintext,shift):
+
+	alphabet=["a","b","c","d","e","f","g","h","i","j","k","l",
+	"m","n","o","p","q","r","s","t","u","v","w","x","y","z"]
+
+	#Create our substitution dictionary
+	dic={}
+	for i in range(0,len(alphabet)):
+		dic[alphabet[i]]=alphabet[(i+shift)%len(alphabet)]
+
+	#Convert each letter of plaintext to the corrsponding
+	#encrypted letter in our dictionary creating the cryptext
+	ciphertext=""
+	for l in plaintext.lower():
+		if l in dic:
+			l=dic[l]
+		ciphertext+=l
+
+	return ciphertext
+
+#Example useage
+plaintext="the cat sat on the mat"
+print "Plaintext:", plaintext
+print "Cipertext:",caesar(plaintext,3)
+#This will result in:
+#Plaintext: the cat sat on the mat
+#Cipertext: wkh fdw vdw rq wkh pdw