Add a function to decrypt a message with the gamma cipher.

src/cipher_analytical_machine/analyzers/analyzers.clj

@@ -36,3 +36,22 @@
             0
             letter-counts)))
 
+(defn sort-map-by-count
+  "Return a list of pairs from a map of pairs where a pair is a character and its count. The order is descending."
+  [count-map]
+  (->> count-map
+       (reduce (fn [acc [char count]] (conj acc [char count])) [])
+       (sort-by #(- (second %)))))
+
+(defn table-to-string
+  "Return the string from a frequency table."
+  [table]
+  (->> (map first table)
+       (apply str)))
+
+(defn symbol-frequency-table
+  "Return a table where pairs is a symbol from a cipher text and its value which is a symbol from frequency table."
+  [cipher-table frequency-table]
+  (zipmap (table-to-string (sort-map-by-count cipher-table))
+          (table-to-string (sort-map-by-count frequency-table))))
+

src/cipher_analytical_machine/ciphers/gamma.clj

@@ -0,0 +1,78 @@
+(ns cipher-analytical-machine.ciphers.gamma
+  (:require
+   [clojure.set :as set]
+   [clojure.string :as cs]
+   [cipher-analytical-machine.ciphers.simple-substitution :as ss])
+  (:gen-class))
+
+(defn add-mod
+  [f s module]
+  (-> (+ f s)
+      (mod module)))
+
+(defn generate-seq
+  "Generate a lazy sequence for a key (a b c)."
+  [a b c module]
+  ((fn build-seq [a b c]
+     (lazy-seq (cons a (build-seq b c (add-mod a c module))))) a b c))
+
+(defn generate-gamma-seq
+  "Generate the gamma seq from a sequence."
+  [acc seq module]
+  (if (= (second seq) nil) acc
+    (generate-gamma-seq
+     (conj acc (add-mod (first seq) (second seq) module))
+     (rest seq)
+     module)))
+
+(defn generate-gamma
+  "Generate the gamma from a key (a b c)."
+  [a b c module size]
+  (generate-gamma-seq []
+                      (->> (generate-seq a b c module)
+                           (take (inc size)))
+                      module))
+
+(defn encrypt-array
+  "Encrypt an array using the gamma cipher. The function is case-insensitive. The key is an array of three elements [a b c]. The array contains integer in range [0, module)."
+  [key module array]
+  (let [size (count array)
+        gamma (->> (apply conj [key module size])
+                   (apply generate-gamma))]
+    (->> gamma
+         (map vector array)
+         (map (fn [[a g]] (add-mod a g module))))))
+
+(defn encrypt-message
+  "Encrypt a message using the gamma cipher. The function is case-insensitive. The key is an array of three elements [a b c]. The array contains integer in range [0, module)."
+  [key symbols message]
+  (let [module (count symbols)
+        table (ss/generate-sorted-substitution-table symbols)]
+    (->> message
+         (ss/decrypt-by-table (set/map-invert table))
+         (encrypt-array key module)
+         (ss/decrypt-by-table table)
+         (cs/join))))
+
+(defn decrypt-array
+  "Decrypt an array using the gamma cipher. The function is case-insensitive. The key is an array of three elements [a b c]. The array contains integer in range [0, module)."
+  [key module array]
+  (let [size (count array)
+        gamma (->> (apply conj [key module size])
+                   (apply generate-gamma))]
+    (->> gamma
+         (map -)
+         (map vector array)
+         (map (fn [[a g]] (add-mod a g module))))))
+
+(defn decrypt-message
+  "Decrypt a message using the gamma cipher. The function is case-insensitive. The key is an array of three elements [a b c]. The array contains integer in range [0, module)."
+  [key symbols message]
+  (let [module (count symbols)
+        table (ss/generate-sorted-substitution-table symbols)]
+    (->> message
+         (ss/decrypt-by-table (set/map-invert table))
+         (decrypt-array key module)
+         (ss/decrypt-by-table table)
+         (cs/join))))
+

src/cipher_analytical_machine/ciphers/simple_substitution.clj

@@ -29,11 +29,16 @@
   [char substitution-table]
   (get substitution-table char))
 
+(defn decrypt-by-table
+  "Decrypt a message by the substitution-table"
+  [substitution-table message]
+  (map (fn [char] (find-value-in-table char substitution-table)) message))
+
 (defn encrypt-message
   "Encrypt a message using the simple substitution cipher. The function is case-insensitive. If a symbol isn't in the symbols list, then it will be removed."
   [message substitution-table]
   (->> message
-       (map (fn [char] (find-value-in-table char substitution-table)))
+       (decrypt-by-table substitution-table)
        (remove nil?)
        (cs/join \,)))
 
@@ -44,15 +49,21 @@
       (caesar/encrypt-message key symbols)
       (encrypt-message substitution-table)))
 
+(defn decrypt-message-by-symbol-table
+  "Decrypt a message using the simple substitution cipher. The function is case-insensitive. The substitution-table must be (symbols, symbols)."
+  [substitution-table message]
+  (->> message
+       (decrypt-by-table substitution-table)
+       (remove nil?)
+       (cs/join)))
+
 (defn decrypt-message
-  "Decrypt a message using the simple substitution cipher. The function is case-insensitive. The substitution-table must be "
+  "Decrypt a message using the simple substitution cipher. The function is case-insensitive. The substitution-table must be (int, symbols)."
   [message substitution-table]
   (let [message (cs/split message #",")]
     (->> message
          (map #(Integer/parseInt %))
-         (map (fn [char] (find-value-in-table char substitution-table)))
-         (remove nil?)
-         (cs/join))))
+         (decrypt-message-by-symbol-table substitution-table))))
 
 (defn decrypt-message-with-caesar
   "Decrypt a message using the simple substitution cipher and the Caesar cipher. The function is case-insensitive."

src/cipher_analytical_machine/cli/actions/cryptography.clj

@@ -1,6 +1,9 @@
 (ns cipher-analytical-machine.cli.actions.cryptography
   (:require
-   [cipher-analytical-machine.ciphers.caesar :as caesar])
+   [cipher-analytical-machine.ciphers.caesar :as caesar]
+   [cipher-analytical-machine.ciphers.simple-substitution :as ss]
+   [cipher-analytical-machine.parsers.parsers :as ps]
+   [cipher-analytical-machine.parsers.simple-substitution :as pss])
   (:gen-class))
 
 (defn caesar-actions
@@ -15,10 +18,33 @@
       (= action-type :decrypt)
       (caesar/decrypt-message message key symbols))))
 
+(defn simple-substitution-with-caesar-actions
+  [options arguments action-type]
+  (let [message (:message options)
+        key (:key options)
+        symbols (:symbols options)]
+    (cond
+      (= action-type :encrypt)
+      (let [data (pss/generate-table-or-decode-json key symbols)
+            key (ps/parse-unsigned-int (get data "key"))
+            substitution-table (get data "table")]
+        (println (pss/encode-key-and-substitution-table-to-json key substitution-table))
+        (ss/encrypt-message-with-caesar message key substitution-table symbols))
+
+      (= action-type :decrypt)
+      (let [data (-> (pss/decode-key-and-substitution-table-from-json key)
+                     (pss/invert-table-in-map))
+            key (get data "key")
+            substitution-table (get data "table")]
+        (ss/decrypt-message-with-caesar message key substitution-table symbols)))))
+
 (defn cryptography-actions
   [options arguments action-type]
   (let [cipher (:cipher options)]
     (cond
       (= cipher "Caesar")
-      (caesar-actions options arguments action-type))))
+      (caesar-actions options arguments action-type)
+
+      (= cipher "Simple substitution and Caesar")
+      (simple-substitution-with-caesar-actions options arguments action-type))))
 

src/cipher_analytical_machine/cli/cli.clj

@@ -160,3 +160,10 @@
 
      (show-and-save-output options))))
 
+(defn cli-main
+  [args]
+  (let [{:keys [options arguments action-type exit-message ok?]} (validate-args args)]
+    (if exit-message
+      (exit exit-message ok?)
+      (actions options arguments action-type))))
+

src/cipher_analytical_machine/cli/options.clj

@@ -22,7 +22,7 @@
     (option-values-as-list option values)))
 
 (def cipher-options
-  #{"Caesar"})
+  #{"Caesar" "Simple substitution and Caesar"})
 
 (def default-cipher "Caesar")
 

src/cipher_analytical_machine/core.clj

@@ -5,8 +5,5 @@
 
 (defn -main
   [& args]
-  (let [{:keys [options arguments action-type exit-message ok?]} (cli/validate-args args)]
-    (if exit-message
-      (cli/exit exit-message ok?)
-      (cli/actions options arguments action-type))))
+  (cli/cli-main args))
 

src/cipher_analytical_machine/parsers/parsers.clj

@@ -3,7 +3,21 @@
   (:gen-class))
 
 (defn unsigned-int?
+  "Return true if the string is an unsigned integer."
   [str]
   (if (re-matches #"\d+" str)
     true false))
 
+(defn parse-unsigned-int
+  "Return an integer if the argument is an integer."
+  [str-or-int]
+  (cond
+    (int? str-or-int)
+    str-or-int
+
+    (unsigned-int? str-or-int)
+    (Integer/parseInt str-or-int)
+
+    :else
+    nil))
+

src/cipher_analytical_machine/parsers/simple_substitution.clj

@@ -2,6 +2,7 @@
   (:require
    [cipher-analytical-machine.ciphers.simple-substitution :as ss]
    [cipher-analytical-machine.parsers.parsers :as ps]
+   [clojure.set :as set]
    [cheshire.core :as cc])
   (:gen-class))
 
@@ -42,3 +43,12 @@
         (assoc "table" (ss/generate-substitution-table symbols)))
     (decode-key-and-substitution-table-from-json key-or-json)))
 
+(defn invert-table-in-map
+  "Invert the table in a decoded json (key, table)"
+  [decoded-json]
+  (->>
+   (-> decoded-json
+       (get "table")
+       (set/map-invert))
+   (assoc decoded-json "table")))
+

test/cipher_analytical_machine/analyzers/analyzers_test.clj

@@ -0,0 +1,40 @@
+(ns cipher-analytical-machine.analyzers.analyzers-test
+  (:require
+   [clojure.test :refer :all]
+   [cipher-analytical-machine.analyzers.analyzers :refer :all]))
+
+(deftest count-characters-test
+  (testing "Count two dublicates and one uniq character from a string."
+    (is (= {\a 2 \b 1}
+           (count-characters "aba")))))
+
+(deftest chi-squared-letter-statistic-test
+  (testing "If the frequence of A is 0.1, the text length is 100 and contains 20 times, then the chi-squared is 10."
+    (is (= 10.0
+           (chi-squared-letter-statistic 20 0.1 100))))
+
+  (testing "If the frequence of A is 0.1, the text length is 10 and contains 5 times, then the chi-squared is 16.0."
+    (is (= 16.0
+           (chi-squared-letter-statistic 5 0.1 10)))))
+
+(deftest chi-squared-statistic-test
+  (let [text "aaaaabbbbb"]
+  (testing "If the frequencies of a and b is 0.1, the text length is 10 and contains them 5 times, then score is 32."
+    (is (= 32.0
+           (chi-squared-statistic text {\a 0.1 \b 0.1}))))))
+
+(deftest sort-map-by-count-test
+  (testing "Test the sort in descending order."
+    (is (= [[\b 3] [\a 2] [\c 1]]
+           (sort-map-by-count {\a 2 \b 3 \c 1} )))))
+
+(deftest table-to-string-test
+  (testing "Test the sort in descending order."
+    (is (= "bac"
+           (table-to-string [[\b 3] [\a 2] [\c 1]])))))
+
+(deftest symbol-frequency-table-test
+  (testing "Test the sort in descending order."
+    (is (= {\d \b, \e \a, \f \c}
+           (symbol-frequency-table {\d 3 \e 2 \f 1} {\b 3 \a 2 \c 1})))))
+

test/cipher_analytical_machine/ciphers/gamma_test.clj

@@ -0,0 +1,62 @@
+(ns cipher-analytical-machine.ciphers.gamma-test
+  (:require
+   [clojure.test :refer :all]
+   [cipher-analytical-machine.ciphers.gamma :refer :all]))
+
+(deftest add-mod-test
+  (testing "The remainder must be as expected."
+    (are [a b module expected]
+        (= expected (add-mod a b module))
+      5 2 4 3
+      1 2 3 0
+      2 2 3 1)))
+
+(deftest generate-seq-test
+  (testing "Checking that the next element of a sequence is calculated by (e[i-1] + e[i-3] % mod)."
+    (are [a b c module size expected]
+        (= expected (take size (generate-seq a b c module)))
+      4 32 15 33 10 [4 32 15 19 18 0 19 4 4 23]
+      1 2  3  3  9  [1 2 3 1 0 0 1 1 1])))
+
+(deftest generate-gamma-seq-test
+  (testing "Checking that the next element of a sequence is calculated by (s[i] + s[i+1] % mod)."
+    (are [acc seq module expected]
+        (= expected (generate-gamma-seq acc seq module))
+      [] [4 32 15 19 18 0 19 4 4 23] 33 [3 14 1 4 18 19 23 8 27]
+      [] [1 2 3 1 0 0 1 1 1]         3  [0 2 1 1 0 1 2 2])))
+
+(deftest generate-gamma-test
+  (testing "Checking that the gamma is generated as expected."
+    (are [a b c module size expected]
+        (= expected (generate-gamma a b c module size))
+      4 32 15 33 10 [3 14 1 4 18 19 23 8 27 17]
+      1 2  3  3  9  [0 2 1 1 0 1 2 2 0])))
+
+(deftest encrypt-array-test
+  (testing "Checking that the message is encrypted as expected: (msg+gamma)%module."
+    (are [key module array expected]
+        (= expected (encrypt-array key module array))
+      [4 32 15] 33 [3 14 1 4 18 19 23 8 27 17] [6 28 2 8 3 5 13 16 21 1]
+      [1 2  3 ] 3  [0 2 1 1 0 1 2 2 0]         [0 1 2 2 0 2 1 1 0])))
+
+(deftest encrypt-message-test
+  (testing "Checking that the message is encrypted as expected"
+    (are [key symbols message expected]
+        (= expected (encrypt-message key symbols message))
+      [4 32 15] "абвгґдеєжзиіїйклмнопрстуфхцчшщьюя" "гкбґопужчн" "ешвжгдймсб"
+      [1 2  3 ] "абв"  "авббабвва"  "абввавбба")))
+
+(deftest decrypt-array-test
+  (testing "Checking that the message is decrypted as expected."
+    (are [key module array expected]
+        (= expected (decrypt-array key module array))
+      [4 32 15] 33 [6 28 2 8 3 5 13 16 21 1] [3 14 1 4 18 19 23 8 27 17]
+      [1 2  3 ] 3  [0 1 2 2 0 2 1 1 0]       [0 2 1 1 0 1 2 2 0])))
+
+(deftest decrypt-message-test
+  (testing "Checking that the message is decrypted as expected"
+    (are [key symbols message expected]
+        (= expected (decrypt-message key symbols message))
+      [4 32 15] "абвгґдеєжзиіїйклмнопрстуфхцчшщьюя" "ешвжгдймсб" "гкбґопужчн"
+      [1 2  3 ] "абв" "абввавбба" "авббабвва")))
+

test/cipher_analytical_machine/ciphers/simple_substitution_test.clj

@@ -48,6 +48,23 @@
         "abc" 1 "2,3,1"
         "aDbdc" 0 "1,2,3"))))
 
+(deftest decrypt-by-table-test
+  (let [table {\d \a \e \b \f \c}]
+    (testing "The function must decrypt the message by the table."
+      (are [message expected]
+          (= expected (decrypt-by-table table message))
+        "def" '(\a \b \c)
+        "abf" '(nil nil \c)
+        "fed" '(\c \b \a)))))
+
+(deftest decrypt-message-by-symbol-table-test
+  (let [table {\d \a \e \b \f \c}]
+    (testing "The function must decrypt the message and remove unknown numbers."
+      (are [message expected]
+          (= expected (decrypt-message-by-symbol-table table message))
+        "def" "abc"
+        "daef" "abc"))))
+
 (deftest decrypt-message-test
   (let [table {1 \a 2 \b 3 \c}]
     (testing "The function must decrypt the message and remove unknown numbers."

test/cipher_analytical_machine/parsers/parsers_test.clj

@@ -4,7 +4,7 @@
    [cipher-analytical-machine.parsers.parsers :refer :all]))
 
 (deftest unsigned-int?-test
-  (testing ""
+  (testing "The function return true only for an unsingned integer as a string."
     (are [str expected]
         (= expected
            (unsigned-int? str))
@@ -13,3 +13,13 @@
       "-10" false
       "abc" false)))
 
+(deftest parse-unsigned-int-test
+  (testing "The function parse the integer if the string is an integer."
+    (are [str-or-int expected]
+        (= expected
+           (parse-unsigned-int str-or-int))
+      "9"   9
+      9     9
+      "10"  10
+      "-10" nil
+      "abc" nil)))

test/cipher_analytical_machine/parsers/simple_substitution_test.clj

@@ -39,3 +39,11 @@
         "1" {"key" 1 "table" {0 \a 1 \b 2 \c}}
         "2" {"key" 2 "table" {\a 0 \b 1 \c 2}}))))
 
+(deftest invert-table-in-map-test
+  (testing "The function invert the table in a decoded json."
+    (are [decoded-json expected-data]
+        (= expected-data
+           (invert-table-in-map decoded-json))
+      {"key" 1 "table" {0 \a 1 \b 2 \c}} {"key" 1 "table" {\a 0 \b 1 \c 2}}
+      {"key" 2 "table" {\a 0 \b 1 \c 2}} {"key" 2 "table" {0 \a 1 \b 2 \c}})))
+