4136.sagews

original = (open(DATA+'text.txt')).read()
#original = "FACT IS STRONGER THAN FICTION" 
compressed = original

compressed = compressed.replace('a','')
compressed = compressed.replace('e','')
compressed = compressed.replace('i','')
compressed = compressed.replace('o','')
compressed = compressed.replace('u','')
compressed = compressed.replace('A','')
compressed = compressed.replace('E','')
compressed = compressed.replace('I','')
compressed = compressed.replace('O','')
compressed = compressed.replace('U','')
compressed = compressed.replace(' ','')


print original + "(" + str(len(original)) + ")"
print
print compressed + "(" + str(len(compressed)) + ")"
print
print "Compression Rate = " +"%1.2f" % (float(len(compressed))/float(len(original)))

The Code Book covers a diverse set of historical topics including the Man in the Iron Mask, Arabic cryptography, Charles Babbage, the mechanisation of cryptography, the Enigma Machine, and the decipherment of Linear B and other ancient writing systems. Later sections cover the development of public key cryptography and some of this material is based on interviews with the participants, including those who worked in secret at GCHQ. The book concludes with a discussion of PGP, quantum computing, and quantum cryptography. (530) ThCdBkcvrsdvrsstfhstrcltpcsncldngthMnnthrnMsk,rbccryptgrphy,ChrlsBbbg,thmchnstnfcryptgrphy,thngmMchn,ndthdcphrmntfLnrBndthrncntwrtngsystms.Ltrsctnscvrthdvlpmntfpblckycryptgrphyndsmfthsmtrlsbsdnntrvwswththprtcpnts,ncldngthswhwrkdnscrttGCHQ.ThbkcncldswthdscssnfPGP,qntmcmptng,ndqntmcryptgrphy. (297) Compression Rate = 0.56

alphabet = dict()
length = len(original)

for symbol in original:
    if symbol in alphabet:
        alphabet[symbol] += 1 / length
    else:
        alphabet[symbol] = 1 / length

entropy = 0

for symbol, fraction in alphabet.iteritems():
    entropy -= fraction * log(fraction, 2)
    #print symbol, float(fraction)
    
print "\nEntropy Original: " + str(float(entropy))#

alphabet = dict()
length = len(compressed)

for symbol in compressed:
    if symbol in alphabet:
        alphabet[symbol] += 1 / length
    else:
        alphabet[symbol] = 1 / length

entropy = 0

for symbol, fraction in alphabet.iteritems():
    entropy -= fraction * log(fraction, 2)
    #print symbol, float(fraction)
    
print "\nEntropy Compressed: " + str(float(entropy))#

Entropy Original: 4.49845624995 Entropy Compressed: 4.32942578129