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Vigenere.java
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Vigenere.java
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package cryptography.ciphers.vigenere;
import cryptography.Mode;
public class Vigenere {
public static void main(String[] args) {
}
public static String vigenere(String input, String key, Mode mode) {
String output = null;
input = input.toUpperCase();
if (mode == Mode.ENCRYPT) {
StringBuilder res = new StringBuilder();
for (int i = 0, j = 0; i < input.length(); i++) {
char c = input.charAt(i);
if (c < 'A' || c > 'Z')
continue;
res.append((char) ((c + key.charAt(j) - 2 * 'A') % 26 + 'A'));
j = ++j % key.length();
}
output = res.toString();
}
if (mode == Mode.DECRYPT) {
StringBuilder res = new StringBuilder();
for (int i = 0, j = 0; i < input.length(); i++) {
char c = input.charAt(i);
if (c < 'A' || c > 'Z')
continue;
res.append((char) ((c - key.charAt(j) + 26) % 26 + 'A'));
j = ++j % key.length();
}
output = res.toString();
}
return output;
}
}