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

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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.

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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 assumes the Chilkat API to have been previously unlocked.
    // See Global Unlock Sample for sample code.

    CkCompression compress = new CkCompression();
    compress.put_Algorithm("deflate");

    boolean success;

    // 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.
    CkJsonObject json = new CkJsonObject();
    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";
    success = compress.CompressEncryptFile(json,inPath,outPath);
    if (success == false) {
        System.out.println(compress.lastErrorText());
        return;
        }

    // We can do file-to-file decrypt/decompress like this:
    String inPath2 = outPath;
    String outPath2 = "c:/temp/qa_output/restored.dat";
    success = compress.DecryptDecompressFile(json,inPath2,outPath2);
    if (success == false) {
        System.out.println(compress.lastErrorText());
        return;
        }

    // Note: The above decrypt + decompress is the equivalent of doing the same in these two steps:
    CkCrypt2 crypt = new CkCrypt2();
    crypt.put_CryptAlgorithm("aes");
    crypt.put_CipherMode("cbc");
    crypt.put_KeyLength(128);
    crypt.put_PaddingScheme(0);
    crypt.SetEncodedIV("000102030405060708090A0B0C0D0E0F","hex");
    crypt.SetEncodedKey("000102030405060708090A0B0C0D0E0F","hex");

    String decryptedPath = "c:/temp/qa_output/decrypted.dat";
    success = crypt.CkDecryptFile(inPath2,decryptedPath);
    if (success == false) {
        System.out.println(crypt.lastErrorText());
        return;
        }

    String outPath3 = "c:/temp/qa_output/restored_in_two_steps.dat";
    success = compress.DecompressFile(decryptedPath,outPath3);
    if (success == false) {
        System.out.println(compress.lastErrorText());
        return;
        }

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