Asymmetric encryption in Python using RSA from PyCrypto library

	# Inspired from http://coding4streetcred.com/blog/post/Asymmetric-Encryption-Revisited-(in-PyCrypto)
	# PyCrypto docs available at https://www.dlitz.net/software/pycrypto/api/2.6/
	from Crypto import Random
	from Crypto.PublicKey import RSA
	import base64
	def generate_keys():
	# RSA modulus length must be a multiple of 256 and >= 1024
	modulus_length = 256*4 # use larger value in production
	privatekey = RSA.generate(modulus_length, Random.new().read)
	publickey = privatekey.publickey()
	return privatekey, publickey
	def encrypt_message(a_message , publickey):
	encrypted_msg = publickey.encrypt(a_message, 32)[0]
	encoded_encrypted_msg = base64.b64encode(encrypted_msg) # base64 encoded strings are database friendly
	return encoded_encrypted_msg
	def decrypt_message(encoded_encrypted_msg, privatekey):
	decoded_encrypted_msg = base64.b64decode(encoded_encrypted_msg)
	decoded_decrypted_msg = privatekey.decrypt(decoded_encrypted_msg)
	return decoded_decrypted_msg
	########## BEGIN ##########
	a_message = "The quick brown fox jumped over the lazy dog"
	privatekey , publickey = generate_keys()
	encrypted_msg = encrypt_message(a_message , publickey)
	decrypted_msg = decrypt_message(encrypted_msg, privatekey)
	print "%s - (%d)" % (privatekey.exportKey() , len(privatekey.exportKey()))
	print "%s - (%d)" % (publickey.exportKey() , len(publickey.exportKey()))
	print " Original content: %s - (%d)" % (a_message, len(a_message))
	print "Encrypted message: %s - (%d)" % (encrypted_msg, len(encrypted_msg))
	print "Decrypted message: %s - (%d)" % (decrypted_msg, len(decrypted_msg))

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Symmetric encryption in python using AES from PyCrypto library

	# Inspired from https://pythonprogramming.net/encryption-and-decryption-in-python-code-example-with-explanation/
	# PyCrypto docs available at https://www.dlitz.net/software/pycrypto/api/2.6/
	from Crypto.Cipher import AES
	import base64, os
	def generate_secret_key_for_AES_cipher():
	# AES key length must be either 16, 24, or 32 bytes long
	AES_key_length = 16 # use larger value in production
	# generate a random secret key with the decided key length
	# this secret key will be used to create AES cipher for encryption/decryption
	secret_key = os.urandom(AES_key_length)
	# encode this secret key for storing safely in database
	encoded_secret_key = base64.b64encode(secret_key)
	return encoded_secret_key
	def encrypt_message(private_msg, encoded_secret_key, padding_character):
	# decode the encoded secret key
	secret_key = base64.b64decode(encoded_secret_key)
	# use the decoded secret key to create a AES cipher
	cipher = AES.new(secret_key)
	# pad the private_msg
	# because AES encryption requires the length of the msg to be a multiple of 16
	padded_private_msg = private_msg + (padding_character * ((16-len(private_msg)) % 16))
	# use the cipher to encrypt the padded message
	encrypted_msg = cipher.encrypt(padded_private_msg)
	# encode the encrypted msg for storing safely in the database
	encoded_encrypted_msg = base64.b64encode(encrypted_msg)
	# return encoded encrypted message
	return encoded_encrypted_msg
	def decrypt_message(encoded_encrypted_msg, encoded_secret_key, padding_character):
	# decode the encoded encrypted message and encoded secret key
	secret_key = base64.b64decode(encoded_secret_key)
	encrypted_msg = base64.b64decode(encoded_encrypted_msg)
	# use the decoded secret key to create a AES cipher
	cipher = AES.new(secret_key)
	# use the cipher to decrypt the encrypted message
	decrypted_msg = cipher.decrypt(encrypted_msg)
	# unpad the encrypted message
	unpadded_private_msg = decrypted_msg.rstrip(padding_character)
	# return a decrypted original private message
	return unpadded_private_msg
	####### BEGIN HERE #######
	private_msg = """
	Lorem ipsum dolor sit amet, malis recteque posidonium ea sit, te vis meliore verterem. Duis movet comprehensam eam ex, te mea possim luptatum gloriatur. Modus summo epicuri eu nec. Ex placerat complectitur eos.
	"""
	padding_character = "{"
	secret_key = generate_secret_key_for_AES_cipher()
	encrypted_msg = encrypt_message(private_msg, secret_key, padding_character)
	decrypted_msg = decrypt_message(encrypted_msg, secret_key, padding_character)
	print " Secret Key: %s - (%d)" % (secret_key, len(secret_key))
	print "Encrypted Msg: %s - (%d)" % (encrypted_msg, len(encrypted_msg))
	print "Decrypted Msg: %s - (%d)" % (decrypted_msg, len(decrypted_msg))

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