Python3 examples¶

Creating an instance¶

First you need to create an instance of the cipher you want to use. If you target 256 bit level, use this:

from drysponge.drygascon import DryGascon
cipher128 = DryGascon.DryGascon128().instance()

If you target 256 bit level, use that:

from drysponge.drygascon import DryGascon
cipher256 = DryGascon.DryGascon256().instance()

Hash¶

import binascii
digest = cipher128.hash("abc".encode('utf-8'))
print(binascii.hexlify(digest))

b'8883ff9cf556714116390fda08768463cf82b12021d4697250d959d53aaa87cf'

Encrypt¶

ciphertext = cipher128.encrypt(
        key=binascii.unhexlify(b'000102030405060708090A0B0C0D0E0F'),
        nonce=binascii.unhexlify(b'F0F1F2F3F4F5F6F7F8F9FAFBFCFDFEFF'),
        message="message".encode('utf-8'),
        associated_data="associated data".encode('utf-8'))
print(binascii.hexlify(ciphertext))

b'8c49773e01cf469eb668ae9908201262d8f14682800d52'

Decrypt¶

message = cipher128.decrypt(
        key=binascii.unhexlify(b'000102030405060708090A0B0C0D0E0F'),
        nonce=binascii.unhexlify(b'F0F1F2F3F4F5F6F7F8F9FAFBFCFDFEFF'),
        ciphertext=ciphertext,
        associated_data="associated data".encode('utf-8'))
print(message)

bytearray(b'message')

Getting instance’s parameter¶

print("'small' profile key size:\t", cipher128.key_size())
print("'fast' profile key size:\t", cipher128.fastkey_size())
print("'full' profile key size:\t", cipher128.fullkey_size())
print("nonce size:\t", cipher128.nonce_size())
print("block size:\t", cipher128.block_size())
print("tag size:\t", cipher128.tag_size())

'small' profile key size:    16
'fast' profile key size:     32
'full' profile key size:     56
nonce size:  16
block size:  16
tag size:    16

Using the SPY¶

Each instance as an independant verbosity level. By default operations are silent, that’s usually what you want if you use the cipher in an application. If you wish to see the internal values, you can set the verbosity level to one of the following values:

cipher128.SPY_ALG_IO: operation inputs/outputs (min verbosity bar none)
cipher128.SPY_F_IO: F function’s inputs/outputs level
cipher128.SPY_ROUND_IO: GASCON function’s inputs/outputs level
cipher128.SPY_FULL: all intermediate values (max verbosity)

cipher128.Verbose(cipher128.SPY_ALG_IO)
cipher128.encrypt(
        key=binascii.unhexlify(b'000102030405060708090A0B0C0D0E0F'),
        nonce=binascii.unhexlify(b'F0F1F2F3F4F5F6F7F8F9FAFBFCFDFEFF'),
        message="message".encode('utf-8'),
        associated_data="associated data".encode('utf-8'))

Encrypting 7 bytes message with 15 bytes of associated data and 0 bytes of static data
Key size: 16 bytes
   Key:             000102030405060708090A0B0C0D0E0F
   Nonce:           F0F1F2F3F4F5F6F7F8F9FAFBFCFDFEFF
   Associated data: 6173736F6369617465642064617461
   Message:         6D657373616765
   Padded A. data:  6173736F636961746564206461746101
   Padded Message:  6D657373616765010000000000000000
   CipherText:      8C49773E01CF46
   Tag:             9EB668AE9908201262D8F14682800D52