class SingleByteXorCipher

crypto :: SingleByteXorCipher

Simple XOR cipher where the whole plaintext is XORed with a single byte.

Introduced properties

fun find_key

crypto :: SingleByteXorCipher :: find_key

Tries to find key using frequency analysis on all possible plaintexts.
fun key: Int

crypto :: SingleByteXorCipher :: key

Cryptographic key used in encryption and decryption.
protected fun key=(key: Int)

crypto :: SingleByteXorCipher :: key=

Cryptographic key used in encryption and decryption.

Redefined properties

redef type SELF: SingleByteXorCipher

crypto $ SingleByteXorCipher :: SELF

Type of this instance, automatically specialized in every class
redef fun decrypt

crypto $ SingleByteXorCipher :: decrypt

Decrypt ciphertext and populate self.plaintext
redef fun encrypt

crypto $ SingleByteXorCipher :: encrypt

Encrypt plaintext and populate self.ciphertext

All properties

fun !=(other: nullable Object): Bool

core :: Object :: !=

Have self and other different values?
fun ==(other: nullable Object): Bool

core :: Object :: ==

Have self and other the same value?
type CLASS: Class[SELF]

core :: Object :: CLASS

The type of the class of self.
type SELF: Object

core :: Object :: SELF

Type of this instance, automatically specialized in every class
fun ciphertext: Bytes

crypto :: Cipher :: ciphertext

Encrypted data
fun ciphertext=(ciphertext: Bytes)

crypto :: Cipher :: ciphertext=

Encrypted data
protected fun class_factory(name: String): CLASS

core :: Object :: class_factory

Implementation used by get_class to create the specific class.
fun class_name: String

core :: Object :: class_name

The class name of the object.
abstract fun decrypt

crypto :: Cipher :: decrypt

Decrypt ciphertext and populate self.plaintext
abstract fun encrypt

crypto :: Cipher :: encrypt

Encrypt plaintext and populate self.ciphertext
fun find_key

crypto :: SingleByteXorCipher :: find_key

Tries to find key using frequency analysis on all possible plaintexts.
fun get_class: CLASS

core :: Object :: get_class

The meta-object representing the dynamic type of self.
fun hash: Int

core :: Object :: hash

The hash code of the object.
init init

core :: Object :: init

fun inspect: String

core :: Object :: inspect

Developer readable representation of self.
protected fun inspect_head: String

core :: Object :: inspect_head

Return "CLASSNAME:#OBJECTID".
intern fun is_same_instance(other: nullable Object): Bool

core :: Object :: is_same_instance

Return true if self and other are the same instance (i.e. same identity).
fun is_same_serialized(other: nullable Object): Bool

core :: Object :: is_same_serialized

Is self the same as other in a serialization context?
intern fun is_same_type(other: Object): Bool

core :: Object :: is_same_type

Return true if self and other have the same dynamic type.
fun key: Int

crypto :: SingleByteXorCipher :: key

Cryptographic key used in encryption and decryption.
protected fun key=(key: Int)

crypto :: SingleByteXorCipher :: key=

Cryptographic key used in encryption and decryption.
intern fun object_id: Int

core :: Object :: object_id

An internal hash code for the object based on its identity.
fun output

core :: Object :: output

Display self on stdout (debug only).
intern fun output_class_name

core :: Object :: output_class_name

Display class name on stdout (debug only).
fun plaintext: Bytes

crypto :: Cipher :: plaintext

Unencrypted data
fun plaintext=(plaintext: Bytes)

crypto :: Cipher :: plaintext=

Unencrypted data
fun serialization_hash: Int

core :: Object :: serialization_hash

Hash value use for serialization
intern fun sys: Sys

core :: Object :: sys

Return the global sys object, the only instance of the Sys class.
abstract fun to_jvalue(env: JniEnv): JValue

core :: Object :: to_jvalue

fun to_s: String

core :: Object :: to_s

User readable representation of self.
package_diagram crypto::SingleByteXorCipher SingleByteXorCipher crypto::Cipher Cipher crypto::SingleByteXorCipher->crypto::Cipher core::Object Object crypto::Cipher->core::Object ...core::Object ... ...core::Object->core::Object

Ancestors

interface Object

core :: Object

The root of the class hierarchy.

Parents

abstract class Cipher

crypto :: Cipher

Base class to modelize cryptographic ciphers

Class definitions

crypto $ SingleByteXorCipher 
# Simple XOR cipher where the whole plaintext is XORed with a single byte.
class SingleByteXorCipher
	super Cipher

	# Cryptographic key used in encryption and decryption.
	var key: Int = 0

	redef fun encrypt do
		var key_bytes = new Bytes.with_capacity(1)
		key_bytes.add(key)
		ciphertext = plaintext.xorcipher(key_bytes)
	end

	redef fun decrypt do
		var key_bytes = new Bytes.with_capacity(1)
		key_bytes.add(key)
		plaintext = ciphertext.xorcipher(key_bytes)
	end
end
lib/crypto/xor_ciphers.nit:67,1--85,3

crapto :: xor $ SingleByteXorCipher 
redef class SingleByteXorCipher
	# Tries to find key using frequency analysis on all possible plaintexts.
	# Populates `self.key`
	fun find_key do

		# Accumulate best result
		var max = 0.0
		var best = 0

		# Iterate on possible values for a byte
		var xor_b = new Bytes.with_capacity(1)
		for b in [0 .. 255] do
			# Need `Bytes` to pass to xor
			xor_b[0] = b

			# Xor and evaluate result
			var xored = ciphertext.xorcipher(xor_b)
			var result = xored.to_s.english_scoring
			if result > max then
				max = result
				best = b
			end
		end

		self.key = best

	end
end
lib/crapto/xor.nit:22,1--49,3
Nit standard library. Version v0.8-3595-g3f58b4f.