Codebusters C

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waterlubber
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Re: Codebusters C

Post by waterlubber »

Anyone know about "ideal" calculators? Basically, the most digits (and with a memory, hopefully) that you can cram into a four-function. RSA is...calculationally demanding, to say the least.
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Re: Codebusters C

Post by UTF-8 U+6211 U+662F »

waterlubber wrote:Anyone know about "ideal" calculators? Basically, the most digits (and with a memory, hopefully) that you can cram into a four-function. RSA is...calculationally demanding, to say the least.
I don't do this event but what part of the RSA are you using your calculator most for? It seems like given small primes, it shouldn't be that bad
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Re: Codebusters C

Post by jimmy-bond »

On a practice test, I had the question "Encode DREW BREES using the keyword VEAR." It displayed VEAR as a 2x2 matrix, so this is clearly a Hill cipher problem. I tried encrypting it as I would a normal Hill cipher but got a different answer than the answer key. I'm pretty sure I did it wrong, so can someone explain to me how to do this problem and the solution you get? Thanks.
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Re: Codebusters C

Post by Anonymous15 »

Thank you all for your answers to my questions from before!
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Re: Codebusters C

Post by dragonfruit35 »

jimmy-bond wrote:On a practice test, I had the question "Encode DREW BREES using the keyword VEAR." It displayed VEAR as a 2x2 matrix, so this is clearly a Hill cipher problem. I tried encrypting it as I would a normal Hill cipher but got a different answer than the answer key. I'm pretty sure I did it wrong, so can someone explain to me how to do this problem and the solution you get? Thanks.
Which way did you write the DREW BREES matrix? With the letters readable horizontally or vertically?
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Re: Codebusters C

Post by jimmy-bond »

dragonfruit35 wrote:Which way did you write the DREW BREES matrix? With the letters readable horizontally or vertically?
Idk how to put a matrix but I did

D R
E W
B R
E E
S
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Re: Codebusters C

Post by Longivitis »

jimmy-bond wrote:
dragonfruit35 wrote:Which way did you write the DREW BREES matrix? With the letters readable horizontally or vertically?
Idk how to put a matrix but I did

D R
E W
B R
E E
S
It's supposed to be
D
R
E
W
B
R
E
E
S
(Z)

and then multiply by the 2x2 matrix keyword
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Re: Codebusters C

Post by UTF-8 U+6211 U+662F »

Longivitis wrote:
jimmy-bond wrote:
dragonfruit35 wrote:Which way did you write the DREW BREES matrix? With the letters readable horizontally or vertically?
Idk how to put a matrix but I did

D R
E W
B R
E E
S
It's supposed to be
D
R
E
W
B
R
E
E
S
(Z)

and then multiply by the 2x2 matrix keyword
You can't multiply those two matrices. They don't line up. It's supposed to be
the VEAR matrix multiplied by
and then the VEAR matrix multiplied by
etc., etc., I believe.

Although annoyingly, it's not evenly split into chunks of 2 so you'd have to insert an extra letter at the end.
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Re: Codebusters C

Post by Longivitis »

UTF-8 U+6211 U+662F wrote:
Longivitis wrote:
jimmy-bond wrote: Idk how to put a matrix but I did

D R
E W
B R
E E
S
It's supposed to be
D
R
E
W
B
R
E
E
S
(Z)

and then multiply by the 2x2 matrix keyword
You can't multiply those two matrices. They don't line up. It's supposed to be
the VEAR matrix multiplied by
and then the VEAR matrix multiplied by
etc., etc., I believe.

Although annoyingly, it's not evenly split into chunks of 2 so you'd have to insert an extra letter at the end.
Yeah, that's what I meant guess I really wasn't clear enough.
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Re: Codebusters C

Post by dragonfruit35 »

Longivitis wrote:
UTF-8 U+6211 U+662F wrote:
Longivitis wrote:
It's supposed to be
D
R
E
W
B
R
E
E
S
(Z)

and then multiply by the 2x2 matrix keyword
You can't multiply those two matrices. They don't line up. It's supposed to be
the VEAR matrix multiplied by
and then the VEAR matrix multiplied by
etc., etc., I believe.

Although annoyingly, it's not evenly split into chunks of 2 so you'd have to insert an extra letter at the end.
Yeah, that's what I meant guess I really wasn't clear enough.
Yeah, UTF is right, it should be multiplied by the encryption key, in whichever orientation they gave it to you, to be clear.
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