SubstitutionBreaker.py

import collections
from contextlib import contextmanager
import sys

cypherText = '''HSCDIYCDXWSCWIYGYCHCWLRCOXGSC
BHKYACLCMLSCWIXCRLHBYACDXCRYLC
LSACIYCDXBACFRCXTCIHRCBHTYC
HSCDIYCBLSACXTCRFOMLGHSYR
'''

# C has to be separate because of trailing space culling
subsitutions = 'C ' + '''
HI
LA
DT
IH
YE
XO
OB
GR
RS
WW
BL
AD
TF'''
# KV
# MM
# FU
#SN'''

sub = { k:v for k,v in subsitutions.split('\n') }
assert len(sub) == len(set(sub.values())), 'not a 1-1 mapping'

p = sys.stdout.write # shorthand for print (without spacing)

@contextmanager
def printcolour(colour):
    p('\033[{0}m'.format(colour))
    yield
    p('\033[m')


for c in cypherText:
    if c in sub:
        with printcolour(93):
            p(sub[c])
    else:
        p(c)