Sync

Task/Vigen-re-cipher/D/vigen-re-cipher-1.d

@@ -0,0 +1,29 @@
+import std.stdio, std.string;
+
+string encrypt(in string txt, in string key) pure
+in {
+    assert(key.removechars("^A-Z") == key);
+} body {
+    string res;
+    foreach (immutable i, immutable c; toUpper(txt).removechars("^A-Z"))
+        res ~= (c + key[i % $] - 2 * 'A') % 26 + 'A';
+    return res;
+}
+
+string decrypt(in string txt, in string key) pure
+in {
+    assert(key.removechars("^A-Z") == key);
+} body {
+    string res;
+    foreach (immutable i, immutable c; toUpper(txt).removechars("^A-Z"))
+       res ~= (c - key[i % $] + 26) % 26 + 'A';
+    return res;
+}
+
+void main() {
+    immutable key = "VIGENERECIPHER";
+    immutable original = "Beware the Jabberwock, my son!" ~
+                         " The jaws that bite, the claws that catch!";
+    immutable encoded = original.encrypt(key);
+    writeln(encoded, "\n", encoded.decrypt(key));
+}

Task/Vigen-re-cipher/D/vigen-re-cipher-2.d

@@ -0,0 +1,25 @@
+import std.stdio, std.range, std.ascii, std.string, std.algorithm,
+       std.conv;
+
+enum mod = (in int m, in int n) pure nothrow => ((m % n) + n) % n;
+
+enum _s2v = (in string s) pure /*nothrow*/ =>
+    s.toUpper.removechars("^A-Z").map!q{ a - 'A' };
+
+string _v2s(R)(R v) pure /*nothrow*/ {
+    return v.map!(x => uppercase[x.mod(26)]).text;
+}
+
+enum encrypt = (in string txt, in string key) pure /*nothrow*/ =>
+    txt._s2v.zip(key._s2v.cycle).map!q{ a[0] + a[1] }._v2s;
+
+enum decrypt = (in string txt, in string key) pure /*nothrow*/ =>
+    txt._s2v.zip(key._s2v.cycle).map!q{ a[0] - a[1] }._v2s;
+
+void main() {
+    immutable key = "Vigenere Cipher!!!";
+    immutable original = "Beware the Jabberwock, my son!" ~
+                         " The jaws that bite, the claws that catch!";
+    immutable encoded = original.encrypt(key);
+    writeln(encoded, "\n", encoded.decrypt(key));
+}

Task/Vigen-re-cipher/Pascal/vigen-re-cipher.pascal

@@ -0,0 +1,103 @@
+// The Vigenere cipher in reasonably standard Pascal
+// <no library functions: all conversions hand-coded>
+PROGRAM Vigenere;
+
+// get a letter's alphabetic position (A=0)
+FUNCTION letternum(letter: CHAR): BYTE;
+	BEGIN
+		letternum := (ord(letter)-ord('A'));
+	END;
+
+// convert a character to uppercase
+FUNCTION uch(ch: CHAR): CHAR;
+	BEGIN
+		uch := ch;
+		IF ch IN ['a'..'z'] THEN
+			uch := chr(ord(ch) AND $5F);
+	END;
+	
+// convert a string to uppercase
+FUNCTION ucase(str: STRING): STRING;
+	VAR i: BYTE;
+	BEGIN
+		ucase := '';
+		FOR i := 1 TO Length(str) DO
+			ucase := ucase + uch(str[i]);
+	END;
+	
+// construct a Vigenere-compatible string:
+// uppercase; no spaces or punctuation.
+FUNCTION vstr(pt: STRING): STRING;
+	VAR c: Cardinal;
+		s: STRING;
+	BEGIN
+		vstr:= '';
+		s 	:= ucase(pt);
+		FOR c := 1 TO Length(s) DO BEGIN
+			IF s[c] IN ['A'..'Z'] THEN
+				vstr += s[c];
+		END;
+	END;
+	
+// construct a repeating Vigenere key
+FUNCTION vkey(pt, key: STRING): STRING;
+	VAR c,n: Cardinal;
+		k  : STRING;
+	BEGIN
+		k    := vstr(key);
+		vkey := '';
+		FOR c := 1 TO Length(pt) DO BEGIN
+			n := c mod Length(k);
+			IF n>0 THEN vkey += k[n] ELSE vkey += k[Length(k)];
+		END;
+	END;
+	
+// Vigenere encipher	
+FUNCTION enVig(pt,key:STRING): STRING;
+	VAR ct: STRING;
+		c,n	 : Cardinal;
+	BEGIN
+		ct := pt;
+		FOR c := 1 TO Length(pt) DO BEGIN
+			n := letternum(pt[c])+letternum(key[c]);
+			n := n mod 26;
+			ct[c]:=chr(ord('A')+n);
+		END;
+		enVig := ct;
+	END;
+	
+// Vigenere decipher
+FUNCTION deVig(ct,key:STRING): STRING;
+	VAR pt	: STRING;
+		c,n	: INTEGER;
+	BEGIN
+		pt := ct;
+		FOR c := 1 TO Length(ct) DO BEGIN
+			n := letternum(ct[c])-letternum(key[c]);
+			IF n<0 THEN n:=26+n;
+			pt[c]:=chr(ord('A')+n);
+		END;
+		deVig := pt;
+	END;	
+
+	
+VAR 	key: STRING = 'Vigenere cipher';
+		msg: STRING = 'Beware the Jabberwock! The jaws that bite, the claws that catch!';
+		vtx: STRING = '';
+		ctx: STRING = '';
+		ptx: STRING = '';
+
+BEGIN
+	// make Vigenere-compatible
+	vtx := vstr(msg);
+	key := vkey(vtx,key);
+	// Vigenere encipher / decipher
+	ctx := enVig(vtx,key);
+	ptx := deVig(ctx,key);
+	// display results
+	Writeln('Message      : ',msg);
+	Writeln('Plaintext    : ',vtx);
+	Writeln('Key          : ',key);
+	Writeln('Ciphertext   : ',ctx);
+	Writeln('Plaintext    : ',ptx);
+END.

Task/Vigen-re-cipher/Racket/vigen-re-cipher-1.rkt

@@ -0,0 +1,21 @@
+#lang racket
+(define chr integer->char)
+(define ord char->integer)
+
+(define (encrypt msg key)
+  (define cleaned
+    (list->string
+     (for/list ([c (string-upcase msg)]
+                #:when (char-alphabetic? c)) c)))
+  (list->string
+   (for/list ([c cleaned] [k (in-cycle key)])
+     (chr (+ (modulo (+ (ord c) (ord k)) 26) (ord #\A))))))
+
+(define (decrypt msg key)
+  (list->string
+   (for/list ([c msg] [k (in-cycle key)])
+     (chr (+ (modulo (- (ord c) (ord k)) 26) (ord #\A))))))
+
+(decrypt (encrypt "Beware the Jabberwock, my son! The jaws that bite, the claws that catch!"
+                  "VIGENERECIPHER")
+         "VIGENERECIPHER")

Task/Vigen-re-cipher/Racket/vigen-re-cipher-2.rkt

@@ -0,0 +1 @@
+"BEWARETHEJABBERWOCKMYSONTHEJAWSTHATBITETHECLAWSTHATCATCH"