Data commit

Task/Vigen-re-cipher-Cryptanalysis/11l/vigen-re-cipher-cryptanalysis.11l

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+-V ascii_uppercase = Array(‘A’..‘Z’)
+
+F vigenere_decrypt(target_freqs, input)
+   V nchars = :ascii_uppercase.len
+   V ordA = ‘A’.code
+   V sorted_targets = sorted(target_freqs)
+
+   F frequency(input)
+      V result = :ascii_uppercase.map(c -> (c, 0.0))
+      L(c) input
+         result[c - @ordA][1]++
+      R result
+
+   F correlation(input)
+      V result = 0.0
+      V freq = sorted(@frequency(input), key' a -> a[1])
+
+      L(f) freq
+         result += f[1] * @sorted_targets[L.index]
+      R result
+
+   V cleaned = input.uppercase().filter(c -> c.is_uppercase()).map(c -> c.code)
+   V best_len = 0
+   V best_corr = -100.0
+
+   L(i) 2 .< cleaned.len I/ 20
+      V pieces = [[Int]()] * i
+      L(c) cleaned
+         pieces[L.index % i].append(c)
+      V corr = -0.5 * i + sum(pieces.map(p -> @correlation(p)))
+
+      I corr > best_corr
+         best_len = i
+         best_corr = corr
+
+   I best_len == 0
+      R (‘Text is too short to analyze’, ‘’)
+
+   V pieces = [[Int]()] * best_len
+   L(c) cleaned
+      pieces[L.index % best_len].append(c)
+
+   V freqs = pieces.map(p -> @frequency(p))
+
+   V key = ‘’
+   L(fr_) freqs
+      V fr = sorted(fr_, key' a -> a[1], reverse' 1B)
+      V m = 0
+      V max_corr = 0.0
+      L(j) 0 .< nchars
+         V corr = 0.0
+         V c = ordA + j
+         L(frc) fr
+            V d = (frc[0].code - c + nchars) % nchars
+            corr += frc[1] * target_freqs[d]
+
+         I corr > max_corr
+            m = j
+            max_corr = corr
+
+      key ‘’= Char(code' m + ordA)
+
+   V r = (enumerate(cleaned).map((i, c) -> Char(code' (c - @key[i % @best_len].code + @nchars) % @nchars + @ordA)))
+   R (key, r.join(‘’))
+
+V encoded = ‘
+    MOMUD EKAPV TQEFM OEVHP AJMII CDCTI FGYAG JSPXY ALUYM NSMYH
+    VUXJE LEPXJ FXGCM JHKDZ RYICU HYPUS PGIGM OIYHF WHTCQ KMLRD
+    ITLXZ LJFVQ GHOLW CUHLO MDSOE KTALU VYLNZ RFGBX PHVGA LWQIS
+    FGRPH JOOFW GUBYI LAPLA LCAFA AMKLG CETDW VOELJ IKGJB XPHVG
+    ALWQC SNWBU BYHCU HKOCE XJEYK BQKVY KIIEH GRLGH XEOLW AWFOJ
+    ILOVV RHPKD WIHKN ATUHN VRYAQ DIVHX FHRZV QWMWV LGSHN NLVZS
+    JLAKI FHXUF XJLXM TBLQV RXXHR FZXGV LRAJI EXPRV OSMNP KEPDT
+    LPRWM JAZPK LQUZA ALGZX GVLKL GJTUI ITDSU REZXJ ERXZS HMPST
+    MTEOE PAPJH SMFNB YVQUZ AALGA YDNMP AQOWT UHDBV TSMUE UIMVH
+    QGVRW AEFSP EMPVE PKXZY WLKJA GWALT VYYOB YIXOK IHPDS EVLEV
+    RVSGB JOGYW FHKBL GLXYA MVKIS KIEHY IMAPX UOISK PVAGN MZHPW
+    TTZPV XFCCD TUHJH WLAPF YULTB UXJLN SIJVV YOVDJ SOLXG TGRVO
+    SFRII CTMKO JFCQF KTINQ BWVHG TENLH HOGCS PSFPV GJOKM SIFPR
+    ZPAAS ATPTZ FTPPD PORRF TAXZP KALQA WMIUD BWNCT LEFKO ZQDLX
+    BUXJL ASIMR PNMBF ZCYLV WAPVF QRHZV ZGZEF KBYIO OFXYE VOWGB
+    BXVCB XBAWG LQKCM ICRRX MACUO IKHQU AJEGL OIJHH XPVZW JEWBA
+    FWAML ZZRXJ EKAHV FASMU LVVUT TGK’
+
+V english_frequences = [
+   0.08167, 0.01492, 0.02782, 0.04253, 0.12702, 0.02228, 0.02015,
+   0.06094, 0.06966, 0.00153, 0.00772, 0.04025, 0.02406, 0.06749,
+   0.07507, 0.01929, 0.00095, 0.05987, 0.06327, 0.09056, 0.02758,
+   0.00978, 0.02360, 0.00150, 0.01974, 0.00074]
+
+V (key, decoded) = vigenere_decrypt(english_frequences, encoded)
+print(‘Key: ’key)
+print("\nText: "decoded)