eric6.Utilities.crypto.py3AES

Module implementing classes for encryption according Advanced Encryption Standard.

Global Attributes

None

Classes

AES	Class implementing the Advanced Encryption Standard algorithm.
AESModeOfOperation	Class implementing the different AES mode of operations.

Functions

append_PKCS7_padding	Function to pad the given data to a multiple of 16-bytes by PKCS7 padding.
decryptData	Module function to decrypt the given data with the given key.
encryptData	Module function to encrypt the given data with the given key.
strip_PKCS7_padding	Function to strip off PKCS7 padding.

AES

Class implementing the Advanced Encryption Standard algorithm.

Derived from

object

Class Attributes

KeySize

Rcon

rsbox

sbox

Class Methods

None

Methods

__addRoundKey	Private method to add (XORs) the round key to the state.
__aes_invMain	Private method to do the inverse AES encryption for one round.
__aes_invRound	Private method to apply the 4 operations of the inverse round in sequence.
__aes_main	Private method to do the AES encryption for one round.
__aes_round	Private method to apply the 4 operations of the forward round in sequence.
__core	Private method performing the key schedule core operation.
__createRoundKey	Private method to create a round key.
__expandKey	Private method performing Rijndael's key expansion.
__galois_multiplication	Private method to perform a Galois multiplication of 8 bit characters a and b.
__getRconValue	Private method to retrieve a given Rcon value.
__getSBoxInvert	Private method to retrieve a given Inverted S-Box value.
__getSBoxValue	Private method to retrieve a given S-Box value.
__mixColumn	Private method to perform a galois multiplication of 1 column the 4x4 matrix.
__mixColumns	Private method to perform a galois multiplication of the 4x4 matrix.
__rotate	Private method performing Rijndael's key schedule rotate operation.
__shiftRow	Private method to shift the bytes of a row to the left.
__shiftRows	Private method to iterate over the 4 rows and call __shiftRow() with that row.
__subBytes	Private method to substitute all the values from the state with the value in the SBox using the state value as index for the SBox.
decrypt	Public method to decrypt a 128 bit input block against the given key of size specified.
encrypt	Public method to encrypt a 128 bit input block against the given key of size specified.

Static Methods

None

AES.__addRoundKey

__addRoundKey(state, roundKey)

Private method to add (XORs) the round key to the state.

state: state to be changed (bytearray)
roundKey: key to be used for the modification (bytearray)

Returns:: modified state (bytearray)

AES.__aes_invMain

__aes_invMain(state, expandedKey, nbrRounds)

Private method to do the inverse AES encryption for one round.

Perform the initial operations, the standard round, and the final operations of the inverse AES, creating a round key for each round.

state: state to be worked on (bytearray)
expandedKey: expanded key to be used (bytearray)
nbrRounds: number of rounds to be done (integer)

Returns:: modified state (bytearray)

AES.__aes_invRound

__aes_invRound(state, roundKey)

Private method to apply the 4 operations of the inverse round in sequence.

state: state to be worked on (bytearray)
roundKey: round key to be used (bytearray)

Returns:: modified state (bytearray)

AES.__aes_main

__aes_main(state, expandedKey, nbrRounds)

Private method to do the AES encryption for one round.

Perform the initial operations, the standard round, and the final operations of the forward AES, creating a round key for each round.

state: state to be worked on (bytearray)
expandedKey: expanded key to be used (bytearray)
nbrRounds: number of rounds to be done (integer)

Returns:: modified state (bytearray)

AES.__aes_round

__aes_round(state, roundKey)

Private method to apply the 4 operations of the forward round in sequence.

state: state to be worked on (bytearray)
roundKey: round key to be used (bytearray)

Returns:: modified state (bytearray)

AES.__core

__core(data, iteration)

Private method performing the key schedule core operation.

data: data to operate on (bytearray)
iteration: iteration counter (integer)

Returns:: modified data (bytearray)

AES.__createRoundKey

__createRoundKey(expandedKey, roundKeyPointer)

Private method to create a round key.

expandedKey: expanded key to be used (bytearray)
roundKeyPointer: position within the expanded key (integer)

Returns:: round key (bytearray)

AES.__expandKey

__expandKey(key, size, expandedKeySize)

Private method performing Rijndael's key expansion.

Expands a 128, 192 or 256 bit key into a 176, 208 or 240 bit key.

key: key to be expanded (bytes or bytearray)
size: size of the key in bytes (16, 24 or 32)
expandedKeySize: size of the expanded key (integer)

Returns:: expanded key (bytearray)

AES.__galois_multiplication

__galois_multiplication(a, b)

Private method to perform a Galois multiplication of 8 bit characters a and b.

a: first factor (byte)
b: second factor (byte)

Returns:: result (byte)

AES.__getRconValue

__getRconValue(num)

Private method to retrieve a given Rcon value.

num: position of the value (integer)

Returns:: Rcon value (integer)

AES.__getSBoxInvert

__getSBoxInvert(num)

Private method to retrieve a given Inverted S-Box value.

num: position of the value (integer)

Returns:: value of the Inverted S-Box (integer)

AES.__getSBoxValue

__getSBoxValue(num)

Private method to retrieve a given S-Box value.

num: position of the value (integer)

Returns:: value of the S-Box (integer)

AES.__mixColumn

__mixColumn(column, isInv)

Private method to perform a galois multiplication of 1 column the 4x4 matrix.

column: column to be worked on (bytearray)
isInv: flag indicating an inverse operation (boolean)

Returns:: modified column (bytearray)

AES.__mixColumns

__mixColumns(state, isInv)

Private method to perform a galois multiplication of the 4x4 matrix.

state: state to be worked on (bytearray)
isInv: flag indicating an inverse operation (boolean)

Returns:: modified state (bytearray)

AES.__rotate

__rotate(data)

Private method performing Rijndael's key schedule rotate operation.

Rotate the data word eight bits to the left: eg, rotate(1d2c3a4f) == 2c3a4f1d.

data: data of size 4 (bytearray)

Returns:: rotated data (bytearray)

AES.__shiftRow

__shiftRow(state, statePointer, nbr, isInv)

Private method to shift the bytes of a row to the left.

state: state to be worked on (bytearray)
statePointer: index into the state (integer)
nbr: number of positions to shift (integer)
isInv: flag indicating an inverse operation (boolean)

Returns:: modified state (bytearray)

AES.__shiftRows

__shiftRows(state, isInv)

Private method to iterate over the 4 rows and call __shiftRow() with that row.

state: state to be worked on (bytearray)
isInv: flag indicating an inverse operation (boolean)

Returns:: modified state (bytearray)

AES.__subBytes

__subBytes(state, isInv)

Private method to substitute all the values from the state with the value in the SBox using the state value as index for the SBox.

state: state to be worked on (bytearray)
isInv: flag indicating an inverse operation (boolean)

Returns:: modified state (bytearray)

AES.decrypt

decrypt(iput, key, size)

Public method to decrypt a 128 bit input block against the given key of size specified.

iput: input data (bytearray)
key: key to be used (bytes or bytearray)
size: key size (16, 24 or 32)

Returns:: decrypted data (bytes)

Raises ValueError:: key size is invalid

AES.encrypt

encrypt(iput, key, size)

Public method to encrypt a 128 bit input block against the given key of size specified.

iput: input data (bytearray)
key: key to be used (bytes or bytearray)
size: key size (16, 24 or 32)

Returns:: encrypted data (bytes)

Raises ValueError:: key size is invalid

AESModeOfOperation

Class implementing the different AES mode of operations.

Derived from

object

Class Attributes

ModeOfOperation

aes

Class Methods

None

Methods

__extractBytes	Private method to extract a range of bytes from the input.
decrypt	Public method to perform the decryption operation.
encrypt	Public method to perform the encryption operation.

Static Methods

None

AESModeOfOperation.__extractBytes

__extractBytes(inputData, start, end, mode)

Private method to extract a range of bytes from the input.

inputData: input data (bytes)
start: start index (integer)
end: end index (integer)
mode: mode of operation (0, 1, 2)

Returns:: extracted bytes (bytearray)

AESModeOfOperation.decrypt

decrypt(cipherIn, originalsize, mode, key, size, IV)

Public method to perform the decryption operation.

cipherIn: data to be decrypted (bytes)
originalsize: unencrypted string length (required for CBC) (integer)
mode: mode of operation (0, 1 or 2)
key: key to be used (bytes)
size: length of the key (16, 24 or 32)
IV: initialisation vector (bytearray)

Returns:: decrypted data (bytes)

Raises ValueError:: key size is invalid or decrypted data is invalid

AESModeOfOperation.encrypt

encrypt(inputData, mode, key, size, IV)

Public method to perform the encryption operation.

inputData: data to be encrypted (bytes)
mode: mode of operation (0, 1 or 2)
key: key to be used (bytes)
size: length of the key (16, 24 or 32)
IV: initialisation vector (bytearray)

Returns:: tuple with mode of operation, length of the input data and the encrypted data (integer, integer, bytes)

Raises ValueError:: key size is invalid or decrypted data is invalid

append_PKCS7_padding

append_PKCS7_padding(b)

Function to pad the given data to a multiple of 16-bytes by PKCS7 padding.

b: data to be padded (bytes)

Returns:: padded data (bytes)

decryptData

decryptData(key, data, mode=AESModeOfOperation.ModeOfOperation["CBC"])

Module function to decrypt the given data with the given key.

key: key to be used for decryption (bytes)
data: data to be decrypted (with initialization vector prepended) (bytes)
mode: mode of operations (0, 1 or 2)

Returns:: decrypted data (bytes)

Raises ValueError:: raised to indicate an invalid key size

encryptData

encryptData(key, data, mode=AESModeOfOperation.ModeOfOperation["CBC"])

Module function to encrypt the given data with the given key.

key: key to be used for encryption (bytes)
data: data to be encrypted (bytes)
mode: mode of operations (0, 1 or 2)

Returns:: encrypted data prepended with the initialization vector (bytes)

Raises ValueError:: raised to indicate an invalid key size

strip_PKCS7_padding

strip_PKCS7_padding(b)

Function to strip off PKCS7 padding.

b: data to be stripped (bytes)

Returns:: stripped data (bytes)

Raises ValueError:: data padding is invalid

Home ⌂Doc Index ◂Up ▴