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65 lines
2.5 KiB
65 lines
2.5 KiB
(ns cipher-analytical-machine.analyzers.caesar
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(:require [cipher-analytical-machine.ciphers.caesar :as caesar]
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[clojure.string :as cs]
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[cipher-analytical-machine.analyzers.language :as language]
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[cipher-analytical-machine.analyzers.analyzers :as ca])
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(:import [cipher_analytical_machine.ciphers.caesar Decrypted]
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[cipher_analytical_machine.analyzers.caesar IsNonsense]
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[cipher_analytical_machine.analyzers.caesar FrequencyAnalyzer])
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(:gen-class))
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(defn get-all-texts
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"Return a list of pairs which have a key and a second posible plaintext."
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[ciphertext symbols]
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(let [keys (range (count symbols))]
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(reduce
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(fn [acc key]
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(conj acc [key (caesar/decrypt-message ciphertext key symbols)]))
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'() keys)))
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(defn get-all-scores
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"For pairs (key, plaintext) finds scores and return list of pairs [key, score]."
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[letter-frequencies pairs]
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(map (fn [[key text]]
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[key (ca/chi-squared-statistic text letter-frequencies)])
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pairs))
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(defn get-min-score-pair
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"For pairs (key, plaintext) finds scores and return list of pairs [key, score]."
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[pairs]
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(reduce
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(fn [[key value] [new-key new-value]]
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(if (> value new-value) [new-key new-value]
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[key value]))
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[0 Double/MAX_VALUE]
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pairs))
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(defn get-key
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"To find the key with frequencies of letters."
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[ciphertext symbols letter-frequencies]
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(->> (get-all-texts ciphertext symbols)
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(get-all-scores letter-frequencies)
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(get-min-score-pair)
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(first)))
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(defn get-plaintext
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"Return the plaintext from a ciphertext. The function is case-insensitive."
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[ciphertext symbols letter-frequencies]
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(let [ciphertext (cs/lower-case ciphertext)]
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(caesar/decrypt-message ciphertext
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(get-key ciphertext symbols letter-frequencies)
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symbols)))
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(defn frequency-analizer-get-plaintext
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"Return the plaintext from a ciphertext using simple analizer. The function is case-insensitive."
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[ciphertext symbols letter-frequencies-string language-code]
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(let [decrypt (reify Decrypted
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(decrypt [this message key symbols]
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(caesar/decrypt-message message key symbols)))
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is-nonsense (reify IsNonsense
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(isNonsense [this message]
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(language/is-nonsense? message language-code)))]
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(-> (new FrequencyAnalyzer ciphertext symbols letter-frequencies-string decrypt is-nonsense)
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.crack)))
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