Java

AES and CHACHA20 Encrypt/Decrypt Text

See more Encryption Examples

Demonstrates the use of the new EncryptSb and DecryptSb methods introduced in Chilkat v9.5.0.67 to encrypt/decrypt the contents of StringBuilder objects.

Note: This example requires Chilkat v9.5.0.67 or greater.

Chilkat2 Java

import com.chilkatsoft.chilkat2.BinData;
import com.chilkatsoft.chilkat2.ChilkatException;
import com.chilkatsoft.chilkat2.Crypt2;
import com.chilkatsoft.chilkat2.StringBuilder;

public class ChilkatExample {

    public static void main(String[] args) {
        // This example assumes the Chilkat API to have been previously unlocked.
        // See Global Unlock Sample for sample code.

        // First build a string to be encrypted
        StringBuilder sb = new StringBuilder();
        int i = 1;
        while (i < 10) {
            sb.appendInt(i);
            sb.append(" the quick brown fox jumped over the lazy dog.\r\n");
            i = i + 1;
        }

        System.out.println(sb.getAsString());

        // The string to be encrypted looks like this:

        // 1 the quick brown fox jumped over the lazy dog.
        // 2 the quick brown fox jumped over the lazy dog.
        // 3 the quick brown fox jumped over the lazy dog.
        // 4 the quick brown fox jumped over the lazy dog.
        // 5 the quick brown fox jumped over the lazy dog.
        // 6 the quick brown fox jumped over the lazy dog.
        // ...

        Crypt2 crypt = new Crypt2();

        // Specify the encryption to be used.
        // First we'll do AES-128 CBC
        crypt.setCryptAlgorithm("aes");
        crypt.setCipherMode("cbc");
        crypt.setKeyLength(128);

        String ivHex = "000102030405060708090A0B0C0D0E0F";
        crypt.setEncodedIV(ivHex, "hex");

        String keyHex = "000102030405060708090A0B0C0D0E0F101112131415161718191A1B1C1D1E1F";
        crypt.setEncodedKey(keyHex, "hex");

        // When EncryptSb is called, the contents of the source (sb)
        // remains unmodified.  The encrypted bytes are written into bdEncrypted.
        // If bdEncrypted already contained data, it is replaced with the encrypted bytes.
        BinData bdEncrypted = new BinData();
        try {
            crypt.encryptSb(sb, bdEncrypted);
        } catch (ChilkatException e) {
            System.out.println(e.getLastErrorText());
            return;
        }

        // Examine the encrypted bytes:
        System.out.println(bdEncrypted.getEncoded("base64_mime"));

        // Sample encrypted data:

        // 0DdNZ22ckMMJBiaKhAu3wUEfh16XW356NIUsDmNs/xwbHe/p1201OmpfzwXwKktkAefu2pckrBgC
        // df+1w8lRo+KAy5n5wlAgMGM/UrsVJsp0BmDPk1vaxKrmrGpSXOVCQs1n2+0atIs5YLiOG+Va3+Mi
        // EQNb4YK7bNMmvt0++irBxTiGnkx/RncfKwgkbBUpl2x7yV13MW6lapDT6Md0DKAMsTXFJYGeIdEf
        // g2uxDDQzI5gUOUHTMrXQ8paD/K76KKB9Jpp/kAM9z8g/d8KUmuphA7KI64d38xsgOmcITlbhlCQ2
        // PDkcU6RRzX0FUTUSMgQukhy0jkLZEjHX9poKJD+iJTOkcQUC3OqR9hKhSrvIgJN4lxdR71MheOoQ
        // 2wmvRdq+agTWWh333Vmb6J6yDV79aSpnqEDrA8Ks7Xzciol0gve91+JtVJlJKjWwEzWEU8GxF7Q8
        // eaWI70lsC5nTLGcbqgKu6gzkzHlHyHaE2FAQA/d5I2dvfsAYUQCza0Zdyw8mmTtHhlP2Tfxj1uPv
        // H4Q7BGuKnx3SWT2CnpbX4091w7KzLAztrbFBo/Tf9w8ZpgTK9k1ryfW9/xnk6rW6iQ==

        // Decrypt to restore back to the original:
        StringBuilder sbOriginal = new StringBuilder();
        try {
            crypt.decryptSb(bdEncrypted, sbOriginal);
        } catch (ChilkatException e) {
            System.out.println(e.getLastErrorText());
            return;
        }

        // Examine the original data:
        System.out.println(sbOriginal.getAsString());

        // ----------------------------------------------------------------------------------
        // To do chacha20 encryption, just change the settings:

        crypt.setCryptAlgorithm("chacha20");
        crypt.setKeyLength(256);
        // The initial count is the initial block counter for the chacha20 algorithm.
        // It can be any integer, but must be set to the same when decrypting.
        crypt.setInitialCount(22);

        // EncryptSb completely replaces the contents of bdEncrypted.
        crypt.encryptSb(sb, bdEncrypted);

        // However.. DecryptSb appends the decrypted text to whatever may
        // have already existed within sbOriginal.
        crypt.decryptSb(bdEncrypted, sbOriginal);

        System.out.println("----");
        System.out.println("The original data should be here twice.  Once from the AES decrypt, and again from the chacha20 decrypt.");
        System.out.println(sbOriginal.getAsString());
        System.out.println("Success.");
    }
}