Bacon cipher: Difference between revisions
Added Java
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decrypt encrypt 'this is a test'
THISISATEST</lang>
=={{header|Java}}==
{{trans|Kotlin}}
{{works with|Java|9}}
<lang Java>import java.util.HashMap;
import java.util.Map;
import java.util.Objects;
public class BaconCipher {
private static final Map<Character, String> codes;
static {
codes = new HashMap<>();
codes.putAll(Map.of(
'a', "AAAAA", 'b', "AAAAB", 'c', "AAABA", 'd', "AAABB", 'e', "AABAA",
'f', "AABAB", 'g', "AABBA", 'h', "AABBB", 'i', "ABAAA", 'j', "ABAAB"
));
codes.putAll(Map.of(
'k', "ABABA", 'l', "ABABB", 'm', "ABBAA", 'n', "ABBAB", 'o', "ABBBA",
'p', "ABBBB", 'q', "BAAAA", 'r', "BAAAB", 's', "BAABA", 't', "BAABB"
));
codes.putAll(Map.of(
'u', "BABAA", 'v', "BABAB", 'w', "BABBA", 'x', "BABBB", 'y', "BBAAA",
'z', "BBAAB", ' ', "BBBAA" // use ' ' to denote any non-letter
));
}
private static String encode(String plainText, String message) {
String pt = plainText.toLowerCase();
StringBuilder sb = new StringBuilder();
for (char c : pt.toCharArray()) {
if ('a' <= c && c <= 'z') sb.append(codes.get(c));
else sb.append(codes.get(' '));
}
String et = sb.toString();
String mg = message.toLowerCase(); // 'A's to be in lower case, 'B's in upper case
sb.setLength(0);
int count = 0;
for (char c : mg.toCharArray()) {
if ('a' <= c && c <= 'z') {
if (et.charAt(count) == 'A') sb.append(c);
else sb.append(((char) (c - 32))); // upper case equivalent
count++;
if (count == et.length()) break;
} else sb.append(c);
}
return sb.toString();
}
private static String decode(String message) {
StringBuilder sb = new StringBuilder();
for (char c : message.toCharArray()) {
if ('a' <= c && c <= 'z') sb.append('A');
if ('A' <= c && c <= 'Z') sb.append('B');
}
String et = sb.toString();
sb.setLength(0);
for (int i = 0; i < et.length(); i += 5) {
String quintet = et.substring(i, i + 5);
Character key = codes.entrySet().stream().filter(a -> Objects.equals(a.getValue(), quintet)).findFirst().map(Map.Entry::getKey).orElse(null);
sb.append(key);
}
return sb.toString();
}
public static void main(String[] args) {
String plainText = "the quick brown fox jumps over the lazy dog";
String message = "bacon's cipher is a method of steganography created by francis bacon. " +
"this task is to implement a program for encryption and decryption of " +
"plaintext using the simple alphabet of the baconian cipher or some " +
"other kind of representation of this alphabet (make anything signify anything). " +
"the baconian alphabet may optionally be extended to encode all lower " +
"case characters individually and/or adding a few punctuation characters " +
"such as the space.";
String cipherText = encode(plainText, message);
System.out.printf("Cipher text ->\n\n%s\n", cipherText);
String decodedText = decode(cipherText);
System.out.printf("\nHidden text ->\n\n%s\n", decodedText);
}
}</lang>
{{out}}
<pre>Cipher text ->
BacON's cIPHer Is a METhoD of stEgAnogRaphy crEatEd By FRAncis baCOn. thIs TASk Is TO imPLeMENT a proGrAm FOR eNcRYPTIOn anD deCRyPtioN Of plAINTExt UsING the SIMpLe AlPhaBet Of thE BAConIan CIphER Or sOme OTHer kInD Of reprESenTATion OF This alPHaBET (makE An
Hidden text ->
the quick brown fox jumps over the lazy dog
</pre>
=={{header|Kotlin}}==
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