How do I progress with cracking this monoalphabetic substitution cipher that ignores natural word divisions?

Matt

1/12/23, 10:21 PM

Having some trouble cracking this cipher (this is part of a homework assignment for a cryptology class) I've looked at letter frequencies but I'm not sure what else there is to help me.

Given the encrypted string, TNFOS FOZSW PZLOC GQAOZ WAGQR PJZPN ABCZP QDOGR AMTHA RAXTB AGZJO GMTHA RAVAP ZW, the word LIBERTY is encrypted somewhere in the ciphertext.

From that, I find A and Z line up almost perfectly to E and T given a frequency chart and based off of that, I can pinpoint possible locations of the word LIBERTY (blue text). But after that, I don't really see anything to do to further decrypt it. With no spacing I cant really make out any words

0 + 0

substitution-cipher

decryption

fgrieu

1/13/23, 6:03 AM

Hints: How many _positions_ of `LIBERTY` relative to the start of the plaintext are possible for a 67-character plaintext? Can you exclude some of these given the particular ciphertext and knowing it's monoalphabetic substitution)? Would your eye+brain be enough to find the plaintext among what remains, if you wrote a program that displays the candidate plaintexts with `.` for characters where there's a remaining ambiguity? For short plaintext that approach has lower probability to miis than pure frequency distribution.

Daniel S

1/13/23, 6:27 AM

HInt: you might like to think of famous quotes involving the word "liberty"and compare them to the two possibilities.

fgrieu

1/13/23, 11:51 AM

Also: after a guess of the position of liberty, it's likely that S stands for one of the characters among the most frequent that remain. A program could also show that guess.

Elon Musk

I sit in a Tesla and translated this thread with Ai:

EN: How do I progress with cracking this monoalphabetic substitution cipher that ignores natural word divisions?

TH: ฉันจะก้าวหน้าไปกับการแคร็กรหัสตัวเลขแทนตัวอักษรเดี่ยวที่ละเว้นการแบ่งคำตามธรรมชาติได้อย่างไร

RO: Cum progresez cu spargerea acestui cifr de substituție monoalfabetică care ignoră diviziunile naturale ale cuvintelor?

RU: Как мне продвинуться во взломе этого моноалфавитного шифра замены, который игнорирует естественное разделение слов?

VI: Làm cách nào để tôi tiến bộ với việc bẻ khóa mật mã thay thế một bảng chữ cái này mà bỏ qua các phân chia từ tự nhiên?

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