Java

AES Encrypt and Decrypt a File

_LANGUAGE_ demonstrates how to AES encrypt a file of any size, and then decrypt. Chilkat2 Java

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

public class ChilkatExample {

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

        Crypt2 crypt = new Crypt2();

        crypt.setCryptAlgorithm("aes");

        // CipherMode may be "ecb" or "cbc"
        crypt.setCipherMode("cbc");

        // KeyLength may be 128, 192, 256
        crypt.setKeyLength(256);

        // The padding scheme determines the contents of the bytes
        // that are added to pad the result to a multiple of the
        // encryption algorithm's block size.  AES has a block
        // size of 16 bytes, so encrypted output is always
        // a multiple of 16.
        crypt.setPaddingScheme(0);

        // An initialization vector is required if using CBC mode.
        // ECB mode does not use an IV.
        // The length of the IV is equal to the algorithm's block size.
        // It is NOT equal to the length of the key.
        String ivHex = "000102030405060708090A0B0C0D0E0F";
        crypt.setEncodedIV(ivHex, "hex");

        // The secret key must equal the size of the key.  For
        // 256-bit encryption, the binary secret key is 32 bytes.
        // For 128-bit encryption, the binary secret key is 16 bytes.
        String keyHex = "000102030405060708090A0B0C0D0E0F101112131415161718191A1B1C1D1E1F";
        crypt.setEncodedKey(keyHex, "hex");

        // Encrypt a file, producing the .aes as output.
        // The input file is unchanged, the output .aes contains the encrypted
        // contents of the input file.

        // Note: The .aes output file has no file format.  It is simply a stream
        // of bytes that resembles random binary data.
        String inFile = "/Users/chilkat/testData/pdf/sample.pdf";
        String outFile = "/Users/chilkat/testData/p7m/sample.pdf.aes";
        try {
            crypt.ckEncryptFile(inFile, outFile);
        } catch (ChilkatException e) {
            System.out.println(e.getLastErrorText());
            return;
        }

        // For demonstration purposes, a different instance of the object will be used
        // for decryption.
        Crypt2 decrypt = new Crypt2();

        // All settings must match to be able to decrypt:
        decrypt.setCryptAlgorithm("aes");
        decrypt.setCipherMode("cbc");
        decrypt.setKeyLength(256);
        decrypt.setPaddingScheme(0);
        decrypt.setEncodedIV(ivHex, "hex");
        decrypt.setEncodedKey(keyHex, "hex");

        // Decrypt the .aes
        inFile = "/Users/chilkat/testData/p7m/sample.pdf.aes";
        outFile = "/Users/chilkat/testData/pdf/recovered.pdf";
        try {
            decrypt.ckDecryptFile(inFile, outFile);
        } catch (ChilkatException e) {
            System.out.println(e.getLastErrorText());
            return;
        }

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