Initial data commit

Task/Substitution-cipher/Java/substitution-cipher.java

@@ -0,0 +1,38 @@
+public class SubstitutionCipher {
+
+    final static String key = "]kYV}(!7P$n5_0i R:?jOWtF/=-pe'AD&@r6%ZXs\"v*N"
+            + "[#wSl9zq2^+g;LoB`aGh{3.HIu4fbK)mU8|dMET><,Qc\\C1yxJ";
+
+    static String text = "Here we have to do is there will be a input/source "
+            + "file in which we are going to Encrypt the file by replacing every "
+            + "upper/lower case alphabets of the source file with another "
+            + "predetermined upper/lower case alphabets or symbols and save "
+            + "it into another output/encrypted file and then again convert "
+            + "that output/encrypted file into original/decrypted file. This "
+            + "type of Encryption/Decryption scheme is often called a "
+            + "Substitution Cipher.";
+
+    public static void main(String[] args) {
+        String enc = encode(text);
+        System.out.println("Encoded: " + enc);
+        System.out.println("\nDecoded: " + decode(enc));
+    }
+
+    static String encode(String s) {
+        StringBuilder sb = new StringBuilder(s.length());
+
+        for (char c : s.toCharArray())
+            sb.append(key.charAt((int) c - 32));
+
+        return sb.toString();
+    }
+
+    static String decode(String s) {
+        StringBuilder sb = new StringBuilder(s.length());
+
+        for (char c : s.toCharArray())
+            sb.append((char) (key.indexOf((int) c) + 32));
+
+        return sb.toString();
+    }
+}