You have travelled back in time to November 1605, there's been a failed assassination attempt against King James I and one John Johnson, Servant to Mr. Thomas Percy, was there apprehended; who had placed Thirty-six Barrels of Gunpowder in the Vault under the House, with a Purpose to blow King, and the whole Company, when they should there assemble.
Although the government had an inklings of a plot, the first clear intelligence came with the anonymous warning given to a Catholic nobleman, Lord Monteagle, that he should not attend the opening of Parliament on 5 November. It read as follows:
My loRd, OUT of the LovE i bEar tO SomE OF YoUr friEnds, i haVe a CAre Of yOur PreserVATion. THeRefORE I WoulD aDVIse YOU, As YOU tEndEr yoUr life, TO DEvIsE soME exCUSe To shIft YoUR aTteNDANcE aT ThIS PaRliAMENt; FoR gOD anD man HatH ConCURREd To puNiSh THE wIcKedNess OF ThIs tIME. aNd tHInk NOT slIghTly oF THiS adVErtisemenT, but rETiRE YoUrselF inTO YouR CoUNtrY whERE YoU may ExpeCt the eVenT In SAFeTy. foR ThoUgH ThErE be NO apPEArANCe oF Any stir, yEt i SaY ThEy sHALL reCeiVe a tErriBlE Blow THiS paRliAmENT; and YET tHEy SHAlL nOt SEe Who hUrTs them. THis cOUNSel IS NOt To Be cONdeMNEd BECauSE it may do You GoOD aNd CaN Do yOu no hARm; FOr tHE dANGeR iS paSsed AS SoOn as you hAVe BurnT THE lEtteR. AnD i HopE God wILl Give YoU the grAcE To mAkE gooD usE of It, TO WHOSE HOLY PROTECTION I COMMEND YOU.
But as you may notice, something seems strange about the font. As a keen computer scientist, you are aware of the Baconian cipher, a method of steganographic message encoding devised by Francis Bacon in 1605, could this message have been encoded with this technique? If we can decode this message we may find out more information about this John Johnson and his co-conspirators.
For your convenience, the message has also been saved in message.txt.
To encode a message, each letter of the plaintext is replaced by a group of five of the letters 'A' or 'B'. This replacement is a 5-bit binary encoding and is done according to the alphabet of the Baconian cipher (from the Latin Alphabet).
In the first version I and J, U and V are each grouped together, but a second version of Bacon's cipher uses a unique code for each letter. In other words, I, J, U and V each have their own pattern in this variant.
The Baconian alphabet may optionally be extended to add a few punctuation characters such as the space, which has been added as the next character bbaba aka 11010, no other punctuation is used in the secret message.
Letter Code Binary
A aaaaa 00000
B aaaab 00001
C aaaba 00010
D aaabb 00011
E aabaa 00100
F aabab 00101
G aabba 00110
H aabbb 00111
I abaaa 01000
J abaab 01001
K ababa 01010
L ababb 01011
M abbaa 01100
N abbab 01101
O abbba 01110
P abbbb 01111
Q baaaa 10000
R baaab 10001
S baaba 10010
T baabb 10011
U babaa 10100
V babab 10101
W babba 10110
X babbb 10111
Y bbaaa 11000
Z bbaab 11001
` ` bbaba 11010
An obfuscated function which can encode has been made available as encode.g(message, carrier).
For example:
>>> encode.g('HELLO WORLD', 'The quick brown fox jumps over the lazy dogs, gamboling in the fields where the shepherds keep watch')
'thE QUicK broWn FOx JuMPs OVEr THe LaZy DOgs, GAMbOlinG iN tHE fieLDS WHERE THE SHEPHERDS KEEP WATCH'
>>> encode.g('steganography', "To encode a message each letter of the plaintext is replaced by a group of five of the letters 'A' or 'B'.")
"To eNcOde A MesSage eACh letter OF tHe PLAintEXt Is rePlaced bY A GRouP OF FIve oF THE LETTERS 'A' OR 'B'."
>>> encode.g('imperceptibility', 'The quick brown fox jumps over the lazy dogs, gamboling in the fields where the shepherds keep watch')
'tHe quiCK broWN FOx jUmpS oveR the Lazy Dogs, GAMBOliNG iN the fielDs Where ThE ShEpheRds KEEP watCH'
>>> encode.g('telecommunication', 'The quick brown fox jumps over the lazy dogs, gamboling in the fields where the shepherds keep watch')
ValueError: message is too long for the carrierNote: when the message is shorter than the carrier, the latter groups are all uppercase, so outside of the alphabet and are assumed not to form part of the message.