readms

Cryptography/README.md

@@ -1,6 +1,11 @@
 # Cryptography
 
-* Often data is just encoded in base64 or hex. Other thimes it's just compressed (gzip).
+* Often data is just encoded in base64 or hex. Other times it's just compressed (gzip):
+	- text 32 characters long --> md5 hash.
+	- 40 characters long --> SHA1 hash.
+	- equal signs spread --> base64 encoded string.
+	- text only letters, without numbers or special characters --> Caesar, Vigenere, or other type of cipher.
+	- hints about keys and signing --> likely RSA.
 
 
 
@@ -9,6 +14,8 @@
 
 - The MD5 hashing algorithm always returns 128 bit values, so the chance that two randomly chosen objects have the same hash is 1:2**128.
 
+
+
 ### Scripts
 
 - Hash length extension attack
@@ -29,8 +36,10 @@ $ echo -n password | md5sum
 
 - Use Python's md5.md5().digest()
 
-- md5 hashes: [here](http://hash-killer.com/) and [here](http://www.md5this.com/)
+- md5 hashes: [here](http://hash-killer.com/), [here](http://www.md5this.com/), [here](http://www.hashkiller.co.uk/).
 
+- [md5sum](http://linux.about.com/library/cmd/blcmdl1_md5sum.htm)
+- [md5 creator](http://www.md5-creator.com/)
 
 ------
 
@@ -38,6 +47,8 @@ $ echo -n password | md5sum
 
 - SHA-1 has output size of 160 bits, so chances of collisions are 2**160.
 
+- [Hash maker](http://ratfactor.com/sha1).
+
 ### Scripts
 - SHA-256 brute force
 
@@ -73,6 +84,10 @@ for a, b, c, d, e, f in itertools.product(ch, ch, ch, ch, ch, ch):
 
 - Frequency analysis: [here](http://www.simonsingh.net/The_Black_Chamber/hintsandtips.html) and [here](http://www.xarg.org/tools/caesar-cipher)
 
+- [Cesar Cipher decryption](http://www.xarg.org/tools/caesar-cipher/) and [here](http://tools.zenverse.net/caesar-cipher/).
+
+- [Vigenere Cipher breaker](http://www.mygeocachingprofile.com/codebreaker.vigenerecipher.aspx) and [here](http://smurfoncrack.com/pygenere/index.php).
+
 ### In the command line
 
 ```sh
@@ -88,6 +103,20 @@ In Python [we can use decoding](https://docs.python.org/2/library/codecs.html#co
 ```python
 "YRIRY GJB CNFFJBEQ EBGGRA".decode(encoding="ROT13")
 ```
+
+### Readings:
+
+- [How Viginere works](http://sharkysoft.com/vigenere/).
+
+---
+
+## RSA
+
+* Public-key cryptosystem which uses a public-private key pair to encrypt and decrypt information securely
+
+* [RSA Python](https://pypi.python.org/pypi/rsa)
+
+
 ----
 
 ## Pailier Cryptosystem
@@ -99,6 +128,7 @@ In Python [we can use decoding](https://docs.python.org/2/library/codecs.html#co
 
 ---
 
+
 ## Tools
 
 ### Scripts

Cryptography/Rotation-Ciphers/caesarCipher_from_net.py

@@ -0,0 +1,27 @@
+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