How to decode and what is the use?(Math!) • page 3/5 • Off-Topic Discussion • lichess.org

If you use a book to encrypt the message, breaking it should be possible (look at #16, the paragraph starting with "Moreover..."). Now I wholly agree, if you use a sequence of the Pi digits from a given position, to the best of my knowledge the sole method of breaking the cipher should be breaking its user, i. e. by bribing him in order to get that position.

@tromeus If you use a book to encrypt the message, breaking it should be possible (look at #16, the paragraph starting with "Moreover..."). Now I wholly agree, if you use a sequence of the Pi digits from a given position, to the best of my knowledge the sole method of breaking the cipher should be breaking its user, i. e. by bribing him in order to get that position.

tromeus edited

#22

@Otienimous Your #16 example paragraph has nothing to do with the "Running key ciphers" https://en.wikipedia.org/wiki/Running_key_cipher of my example, but in any case I was addressing "One-time pads" https://en.wikipedia.org/wiki/One-time_pad here ( one-time used running key only. )

Sorry for not making clear at the beginning.

@Otienimous Your #16 example paragraph has nothing to do with the "Running key ciphers" https://en.wikipedia.org/wiki/Running_key_cipher of my example, but in any case I was addressing "One-time pads" https://en.wikipedia.org/wiki/One-time_pad here ( one-time used running key only. ) Sorry for not making clear at the beginning.

Otienimous

#23

@tromeus

Nothing to be sorry for. Anyway, notice that in the linked article about running key ciphers it is explicitly written: "However, if (as usual) the running key is a block of text in a natural language, security actually becomes fairly poor, since that text will have non-random characteristics which can be used to aid cryptanalysis. As a result, the entropy per character of both plaintext and running key is low, and the combining operation is easily inverted". It is exactly what I tried to show in #16 message - using the fact that both the key and the message are in natural language in order to invert the encrypting operation.

In the linked article about one-time pad it is also claimed at the very beginning: "The resulting ciphertext will be impossible to decrypt or break if the following four conditions are met: 1) The key must be truly random". Of course, any book cannot be truly random. A sequence of Pi number digits (beginning from a given position) should behave as random, so it seems safe to use it, indeed. I hope that now I finally managed to write everything clearly - sorry for some maybe clumsy expressions, but English isn't my first language.

@tromeus Nothing to be sorry for. Anyway, notice that in the linked article about running key ciphers it is explicitly written: "However, if (as usual) the running key is a block of text in a natural language, security actually becomes fairly poor, since that text will have non-random characteristics which can be used to aid cryptanalysis. As a result, the entropy per character of both plaintext and running key is low, and the combining operation is easily inverted". It is exactly what I tried to show in #16 message - using the fact that both the key and the message are in natural language in order to invert the encrypting operation. In the linked article about one-time pad it is also claimed at the very beginning: "The resulting ciphertext will be impossible to decrypt or break if the following four conditions are met: 1) The key must be truly random". Of course, any book cannot be truly random. A sequence of Pi number digits (beginning from a given position) should behave as random, so it seems safe to use it, indeed. I hope that now I finally managed to write everything clearly - sorry for some maybe clumsy expressions, but English isn't my first language.

tromeus

#24

@Otienimous

You are quite welcome. Thank you for the beautiful conversation.

@Otienimous You are quite welcome. Thank you for the beautiful conversation.

hisokaxhunter

#25

Look for patent, words r repeatedly use would be vocals and others should be consonants, I hopes

tpr

#26

2048 bit RSA keys lie inside the range NSA can crack
https://en.wikipedia.org/wiki/Key_size

2048 bit RSA keys lie inside the range NSA can crack https://en.wikipedia.org/wiki/Key_size

Otienimous

#27

Generating a longer key (by writing an appropriate program) is perfectly possible.

aayushchess

#28

@BossOfBosses Dude do you guys learn decoding as well?! We guys just have calculus and trigo in maths XD

Yep

But in my syllabus, I guess not a lot