Question

My affine cipher will not decode every 5th and 6th letter correctly.... Please help.

public class KeyGen {

public void encrypt(ArrayList plainText, ArrayList cipherText) {
for(int i = 0; i < plainText.size(); i++){
int ct = (int) plainText.get(i);
ct = ((((ct-97) *5) +8)%26)+97;
cipherText.add(ct);
System.out.print((char)(int)cipherText.get(i));

}
}

public void decrypt(ArrayList cipherText, ArrayList decodedText){
for(int i = 0; i < cipherText.size(); i++){
int ct = (int) cipherText.get(i);

Answer 1

public class KeyGen {

public void encrypt(ArrayList plainText, ArrayList cipherText) {
for(int i = 0; i < plainText.size(); i++){
int ct = (int) plainText.get(i);
ct = ((((ct-97) *5) +8)%26)+97;
cipherText.add(ct);
System.out.print((char)(int)cipherText.get(i));

}
}

public void decrypt(ArrayList cipherText, ArrayList decodedText){
for(int i = 0; i < cipherText.size(); i++){
int ct = (int) cipherText.get(i);
ct = ct-97;
ct = (abs((ct-8))*21 %26)+97;
decodedText.add(ct);

}
}