Java

Compress and Encrypt a Large File (Low and Constant Memory Footprint)

See more Compression Examples

Demonstrates how to compress and encrypt a large file such that the memory footprint remains low and constant.

Note: This example requires Chilkat v9.5.0.99 or greater.

Chilkat2 Java

import com.chilkatsoft.chilkat2.ChilkatException;
import com.chilkatsoft.chilkat2.Compression;
import com.chilkatsoft.chilkat2.Crypt2;
import com.chilkatsoft.chilkat2.JsonObject;

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.

        Compression compress = new Compression();
        compress.setAlgorithm("deflate");

        // Set encryption params.
        // The possible values are the same as for the corresponding properties in the Chilkat Crypt2 class/object.
        // The encoded IV and Key must be specified as hex.
        JsonObject json = new JsonObject();
        json.updateString("cryptAlgorithm", "aes");
        json.updateString("cipherMode", "cbc");
        json.updateInt("keyLength", 128);
        json.updateInt("paddingScheme", 0);
        json.updateString("encodedIV", "000102030405060708090A0B0C0D0E0F");
        json.updateString("encodedKey", "000102030405060708090A0B0C0D0E0F");

        // Do file-to-file compression+encryption in a single call.
        String inPath = "qa_data/largeFile.dat";
        String outPath = "c:/temp/qa_output/compressed_encrypted.dat";
        try {
            compress.compressEncryptFile(json, inPath, outPath);
        } catch (ChilkatException e) {
            System.out.println(e.getLastErrorText());
            return;
        }

        // We can do file-to-file decrypt/decompress like this:
        String inPath2 = outPath;
        String outPath2 = "c:/temp/qa_output/restored.dat";
        try {
            compress.decryptDecompressFile(json, inPath2, outPath2);
        } catch (ChilkatException e) {
            System.out.println(e.getLastErrorText());
            return;
        }

        // Note: The above decrypt + decompress is the equivalent of doing the same in these two steps:
        Crypt2 crypt = new Crypt2();
        crypt.setCryptAlgorithm("aes");
        crypt.setCipherMode("cbc");
        crypt.setKeyLength(128);
        crypt.setPaddingScheme(0);
        crypt.setEncodedIV("000102030405060708090A0B0C0D0E0F", "hex");
        crypt.setEncodedKey("000102030405060708090A0B0C0D0E0F", "hex");

        String decryptedPath = "c:/temp/qa_output/decrypted.dat";
        try {
            crypt.ckDecryptFile(inPath2, decryptedPath);
        } catch (ChilkatException e) {
            System.out.println(e.getLastErrorText());
            return;
        }

        String outPath3 = "c:/temp/qa_output/restored_in_two_steps.dat";
        try {
            compress.decompressFile(decryptedPath, outPath3);
        } catch (ChilkatException e) {
            System.out.println(e.getLastErrorText());
            return;
        }

        System.out.println("Success.");
    }
}