this is the second video on how to

decrypt the Visionnaire cipher the first

video was about if you know the key in

this video I'm going to talk about what

happens when you do not know the key for

the Visionnaire cipher how do you crack

it in that case there are two steps one

find the key length you have to know how

long the key is if the key is three

numbers long or ten numbers long step

two is you have to find each number in

the key once you know how long it is you

have to figure out what the numbers are

in order to find the key length first

thing you have to do is write out your

ciphertext so this is my ciphertext that

I want to find out what it says what I'm

going to do is I'm going to literally

rewrite the ciphertext only one over

so our ciphertext is V the HQ etc so I'm

doing the same thing I'm just screwing

it over one place

so I just literally rewrote the exact

same thing ciphertext only one over and

in nice little lies

um I didn't write the last G right here

uh should be JG I just wrote the J

that's okay we can just go ahead and

stop at the end of the line what I'm

going to do is I'm going to write it

again and I'm going to scoot it over one

more time so I started here before and

now I'm going to start here

so again I just wrote the ciphertext out

only one place farther over now I'm

going to do it again

so at this point you're probably getting

the pattern I'm going to write it quite

a few times and just keep moving over

each time

so you can see I just kept going and

moved it over one space each time you

can stop when you've either got a lot of

rows you run out of letters or in my

case I ran out of colors so once we have

that what we want to look for is what we

call coincidences um so coincidence is

when you have the same thing in your top

row in the same place that you have it

in the next row for instance we have a V

here and we have a V right below it

that's a coincidence

let's look for any more we've got

another one here that's a coincidence oh

yeah that's it for that row so this row

has two coincidences the purple row has

two coincidences

alright now let's look at the green room

remember we're comparing the top one the

blue one with the green one not the

purple and the green the blue and the

green all right so let's look and see if

any of these match so let's look and see

if any in the blue and green rope match

hv you would be I go all the way down

and what I see is right here sampling at

this G and this G right here I don't

care about the purple bro right now but

the blue row in the green room both have

a G in the same place so this row has

one coincidence

all right let's compare the blue row in

the red row now this row does not have

anything in common with the blue row so

let's try the next one orange all right

so we have one in this case now let's

move on to the next row and I'm going to

go ahead and count all the rows

hopefully I don't make any mistakes

sorry if I do they're hard to catch but

I'm going to basically count C V and V

here I'm going to count coincidences for

every row I have okay now that I have

counted the number of coincidences what

I want to do is look for numbers that

are particularly large in this case our

ciphertext was really short this is

actually considered short normally need

a lot of text to be accurate about this

but you can see that

right here is a bigger number and right

here is a bigger number um we have twos

in both cases instead of ones and zeroes

it's a little better now what we want to

do is count how often big numbers occur

so right now we have here and then 1 2 3

4 so 4 places later another big number

occurs therefore we would conclude that

the key has a length of 4 now normally

you'd like I said you get bigger numbers

like if you had like C this is more like

what you want to see Oh like so you've

got a big number here and then 1 2 3 4

spots later you've got another big

number got 30 25 and then 1 2 3 4 spots

later you've got 40 those are all much

bigger than 0 1 5 6 even so that's a

little bit more what you want to be

looking for but in this example the

ciphertext was very short it would take

a very long time to write it all out

therefore we have smaller numbers

however you can sort of see a pattern

there so we would assume the lengths to

the key for this message is four digits

long or four numbers long

step to finding the actual numbers once

you know the length of the heat you have

to figure out what the numbers in the

key are but before I can show you how to

do that I have to convince you of a

mathematical concept and how it works

right so let's say you have the numbers

1 2 & 5

now you want to multiply each of these

numbers with 1 2 & 5

how do you get the largest possible

number if we want to add them up like I

could say if I did 1 x - 2 times 1 and 5

times 5 that could be an option 2 times

1 so that would be 2 + 2 + 25 alright so

we have 29 now let's try different

combinations let's try 5 & 1 2 & 5 1 2

alright so then we've got 2 plus 10 plus

5

and that will equal 17 now we can do a

whole lot of different options we can

mix them match them up lots of different

ways but the way we're going to get the

largest number is if we do the largest

with the largest that's 5 with 5 then

the next with the next 2 is 2 and then

the smallest with the smallest now let

me show you that would be 25 plus 4 plus

1 equals 30 so you'll notice that this

is greater than 17 and 29 it'll also be

greater than any of the other

combinations you try so you have to get

them in the right order aligned with

each other in the same order in order

for it to produce the largest number now

that you understand that you have to put

them in the same order and multiply them

to get the biggest possible number I can

explain to you how the video narrow side

for decryption works because it's based

very strongly on that friends

I'll come back to that math principle in

a bit but first we have to do something

with the message this is the encrypted

message that we are attempting to

decrypt now first what we have to do

let's just say this is just the very

beginning of a message because you would

need a very long message in order to

make this work

the length is for let's say we already

determine that in the previous step so

therefore we're going to take every

fourth letter 1 2 3 4 1 2 3 4 1 2 3 and

then it would keep going like that and

that is going to be used to find all the

letters that I would box in the fourth

letter all the way down to the very end

of the message assuming you had a very

long message we would um we're going to

use this to find the first number in the

key so we know that right now that the

key is 1 2 3 or 4 things that we don't

know that we have to fill in the blanks

for now there's one other thing we know

in this case we're using an alphabet

with 3 letters ABC for simplicity sake

and we know that the frequencies in this

language for these letters are 0.1 0.2

0.7 for a B and C respectively so that's

what we start out knowing about the

alphabet and this is what we knew from

the last step I started with 1 2 3

every fourth letter because it was

length 4 and what these are going to do

is fill this blank so what I would do is

I would pull down all these letters in

this case I have one of each but let's

say I went through and I counted them

let's say I went through an entire

message and I counted and I found that

there were 50 A's there were 200 B's

there were 25 seized okay so I went

through every fourth letter added them

all together how many I had of each when

counting it every fourth and ended up

with those numbers

like I said needs to be long which is

why I'm not counting that many letters

so what we have to do now is determine

the frequency of each of these letters

in the encrypted message so how we do

that obviously we add these up oops

let's that's not 200 let's say that's

125 so that the total is 200 all right

so we have 200 we want to find the

frequency BAE so 50 divided by 200 point

2 5 125 divided by 200 point 1 2 5 25 no

excuse me that goes here 1 2 5 125

divided by 200 will be 0.625 so those

are the frequencies of the letters that

we have now what we're going to do is

we're going to multiply these numbers

with these numbers in the correct order

in the order the alphabet goes in ok so

I just rewrote those numbers over here

we're going to do is we're going to

write down the alphabet frequencies of

the numbers or the letters in the

alphabet in order of the alphabet we are

using so at the English alphabet has

certain frequencies we would write that

down in order next we are going to write

them these in order underneath it in

order maybe C so what we're going to do

with that is we're going to multiply

these well by that that and that and

then we're going to add each of these

numbers up so when we add them up I'm

going to put it over here I know that's

weird okay so what I did

as I multiplied this times this Plus

this times this Plus this times this I

hope I did that math right but should be

point to for approximately so you can

see how I wrote a zero here that's

because I didn't shift this blue road it

was an order of a b c so say this was B

this was C of our cipher text next I'm

going to do is I'm going to shift the

whole thing this direction so I'm going

to take the C and I'm going to move it

over one place I'm going to take the B

I'm going to move it over one I'm going

to take the a and it gets bumped around

the beginning and then I'm going to do

the same thing where I multiply this

times this and then add this times this

and add this times this and let's see

whenever I get for that okay so assuming

I actually did my multiplication in

addition correctly um you should get a

point two six here and that was with a

shift of one next we're going to shift

it over again in the same direction

um so before we had C be a now we're

going to take the a move it over here

take our C move it over here take our B

and bump it around to the end and then

I'm going to repeat the process multiply

this times this this times this and this

times this and add those three numbers

together now once again assuming I did

my math correctly I got 0.50 for the son

for that one and that was with a shift

of two with C B and a so what we can see

here from these numbers is that this

number remember that math principle I

went over the beginning how you have to

align them to get the largest possible

value so this number would

we got the largest possible value is

where they are aligned where the true

frequencies these ones are aligned with

the correct frequencies for the own

shift so we can see that that occurred

with a shift of two therefore this

number the first key here or the first

number in the key here is two because

that's what kind of shift it took to get

it correctly aligned so we have the

first number for the key I know this

kind of long but the other numbers are

calculated the same way with the same

process only for the second one we start

at the second letter so we go this one

and then one two or after that and then

two three or after that and then we

would take all these letters all the way

down to the end of the message that I'm

encircling with a red box and we would

count how many eggs how many bees how

many C's and we would get a total some

number of total letters and then we

would calculate the frequencies like

point five point three and point two or

something like that and then we would

repeat the process using the true values

and remember multiplying it times the

correct order starting with ABC the

frequency of a the frequency of B the

frequency of C and then shift and then

shift again if you need to back up in

the video review that process it's the

exact same thing it's the exact same

thing all you're just counting the

letters that are every fourth letter

starting with the second one and then

you do that and you say let's let's say

for instance that a shift of one Oh

resulted in your largest some of your

largest value

then the shift would go here and then we

would do the process again for we would

count this one

these we do it again count them do the

process all over again fill in this box

based on back those letters then we

would finally count these letters same

exact process do the frequencies

multiply the frequencies see what makes

what shift makes the largest sum and

fill that in with the key there and

there for you once you have the key you

can go back to the video on how to

decrypt when you know the key and use

that to decrypt the message it's simple

from there