def new(key, mode=MODE_ECB, IV=None, counter=None, segment_size=None):
"""Create a new cipher object
DES using pycrypto for algo and pycryptoplus for ciphermode
key = raw string containing the 2/3 keys
- DES-EDE2: supply 2 keys as 1 single concatenated 16byte key= key1|key2
- DES-EDE3: supply 3 keys as 1 single concatenated 24byte key= key1|key2|key3
mode = python_AES.MODE_ECB/CBC/CFB/OFB/CTR/CMAC, default is ECB
IV = IV as a raw string, default is "all zero" IV
-> only needed for CBC mode
counter = counter object (CryptoPlus.Util.util.Counter)
-> only needed for CTR mode
segment_size = amount of bits to use from the keystream in each chain part
-> supported values: multiple of 8 between 8 and the blocksize
of the cipher (only per byte access possible), default is 8
-> only needed for CFB mode
EXAMPLES:
**********
IMPORTING:
-----------
>>> import codecs
>>> from CryptoPlus.Cipher import DES3
CBC TDES-EDE3 EXAMPLE: (using test vectors from http://csrc.nist.gov/groups/STM/cavp/documents/des/DESMMT.pdf)
------------
>>> key = codecs.decode('37ae5ebf46dff2dc0754b94f31cbb3855e7fd36dc870bfae', 'hex')
>>> IV = codecs.decode('3d1de3cc132e3b65', 'hex')
>>> cipher = DES3.new(key, DES3.MODE_CBC, IV)
>>> ciphertext = cipher.encrypt(codecs.decode('84401f78fe6c10876d8ea23094ea5309', 'hex'))
>>> codecs.encode(ciphertext, 'hex')
b'7b1f7c7e3b1c948ebd04a75ffba7d2f5'
>>> decipher = DES3.new(key, DES3.MODE_CBC, IV)
>>> plaintext = decipher.decrypt(ciphertext)
>>> codecs.encode(plaintext, 'hex')
b'84401f78fe6c10876d8ea23094ea5309'
CMAC TDES-EDE3 EXAMPLE: (http://csrc.nist.gov/publications/nistpubs/800-38B/Updated_CMAC_Examples.pdf)
-------------
>>> key = codecs.decode('8aa83bf8cbda10620bc1bf19fbb6cd58bc313d4a371ca8b5', 'hex')
>>> plaintext = codecs.decode('6bc1bee22e409f96e93d7e117393172aae2d8a57', 'hex')
>>> cipher = DES3.new(key, DES3.MODE_CMAC)
>>> codecs.encode(cipher.encrypt(plaintext), 'hex')
b'743ddbe0ce2dc2ed'
CMAC TDES-EDE2 EXAMPLE:
-----------------------
testvector: http://csrc.nist.gov/groups/STM/cavp/documents/mac/cmactestvectors.zip
>>> key1 = codecs.decode("5104f2c76180c1d3", 'hex')
>>> key2 = codecs.decode("b9df763e31ada716", 'hex')
>>> key = key1 + key2
>>> plaintext = codecs.decode('a6866be2fa6678f264a19c4474968e3f4eec24f5086d', 'hex')
>>> cipher = DES3.new(key, DES3.MODE_CMAC)
>>> codecs.encode(cipher.encrypt(plaintext), 'hex')
b'32e7758f3f614dbf'
"""
return DES3(key, mode, IV, counter, segment_size)
