Kriptografi Vernam Cipher Menggunakan Java

public class mVC {

public static void main(String[]args){
String plain="Lembaga Peduli Pendidikan Masyarakat Aray";
String key="lp2maray";
mVC x=new mVC();
String chipper=x.enkripsi(plain,key);
String decrypt=x.dekripsi(chipper,key);

System.out.println("Plain Text:\t"+plain);
System.out.println("Key Text:\t"+key);
System.out.println("Chipper Text:\t"+chipper);
System.out.println("Decrypt Text:\t"+decrypt);

}

String enkripsi(String p,String k){
//String l="ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz0123456789!@#&%*()-_=:,.'?/$^ ";
String l="0123456789 ";

int pms=l.length();
int pln=p.length();
int ky=k.length();

String y =k;
int m = pln%ky;
for( int i=1; i<pln/ky ; i++){k=k+y;}
k=k+k.substring(0,m);
System.out.println("Key2 Text:\t"+k);
System.out.println("=============================================");

String c="";
for (int j=0; j<pln; j++ ){
char hsl=l.charAt((l.indexOf(k.charAt(j)) + l.indexOf(p.charAt(j)))%pms);
c=c + l.charAt((l.indexOf(k.charAt(j)) + l.indexOf(p.charAt(j)))%pms);
}
return c;
}

//==================================================================================
String dekripsi(String p,String k){
String l="ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz0123456789!@#&%*()-_=:,.'?/$^ ";
int pms=l.length();
int cpr=p.length();
int ky=k.length();

String y =k;
int m = cpr%ky;
for( int i=1; i<cpr/ky ; i++){k=k+y;}
k=k+k.substring(0,m);
String pl = "";
for (int j=0; j<cpr; j++ ){
char hsl=l.charAt(((l.indexOf(p.charAt(j)) - l.indexOf(k.charAt(j))) +pms )%pms);
pl=pl + hsl;
}
return pl;
}
}