Java

Streaming Encryption by Encrypting in Chunks

See more Encryption Examples

Encrypt data in chunks. Java

import com.chilkatsoft.*;

public class ChilkatExample {

  static {
    try {
        System.loadLibrary("chilkat");
    } catch (UnsatisfiedLinkError e) {
      System.err.println("Native code library failed to load.\n" + e);
      System.exit(1);
    }
  }

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

    CkCrypt2 crypt = new CkCrypt2();

    crypt.put_CryptAlgorithm("aes");
    crypt.put_CipherMode("cbc");
    crypt.put_KeyLength(128);

    crypt.SetEncodedKey("000102030405060708090A0B0C0D0E0F","hex");
    crypt.SetEncodedIV("000102030405060708090A0B0C0D0E0F","hex");

    crypt.put_EncodingMode("hex");
    String txt1 = "The quick brown fox jumped over the lazy dog.\r\n";
    String txt2 = "-\r\n";
    String txt3 = "Done.\r\n";

    CkStringBuilder sbEncrypted = new CkStringBuilder();

    // Encrypt the 1st chunk:
    // (don't worry about feeding the data to the encryptor in 
    // exact multiples of the encryption algorithm's block size.
    // Chilkat will buffer the data.)
    crypt.put_FirstChunk(true);
    crypt.put_LastChunk(false);
    sbEncrypted.Append(crypt.encryptStringENC(txt1));

    // Encrypt the 2nd chunk
    crypt.put_FirstChunk(false);
    crypt.put_LastChunk(false);
    sbEncrypted.Append(crypt.encryptStringENC(txt2));

    // Now encrypt N more chunks...
    // Remember -- we're doing this in CBC mode, so each call
    // to the encrypt method depends on the state from previous
    // calls...
    crypt.put_FirstChunk(false);
    crypt.put_LastChunk(false);
    int i;
    for (i = 0; i <= 4; i++) {
        sbEncrypted.Append(crypt.encryptStringENC(txt1));
        sbEncrypted.Append(crypt.encryptStringENC(txt2));
        }

    // Now encrypt the last chunk:
    crypt.put_FirstChunk(false);
    crypt.put_LastChunk(true);
    sbEncrypted.Append(crypt.encryptStringENC(txt3));

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

    // Now decrypt in one call.
    // (The data we're decrypting is both the first AND last chunk.)  
    crypt.put_FirstChunk(true);
    crypt.put_LastChunk(true);
    String decryptedText = crypt.decryptStringENC(sbEncrypted.getAsString());

    System.out.println(decryptedText);

    // Note: You may decrypt in N chunks by setting the FirstChunk
    // and LastChunk properties prior to calling the Decrypt* methods
  }
}