Node.js

AES Encrypt and Decrypt a File

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

NODEJS_PRELUDE

function chilkatExample() {

    var success = false;

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

    var crypt = new chilkat.Crypt2();

    crypt.CryptAlgorithm = "aes";

    //  CipherMode may be "ecb" or "cbc"
    crypt.CipherMode = "cbc";

    //  KeyLength may be 128, 192, 256
    crypt.KeyLength = 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.PaddingScheme = 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.
    var 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.
    var 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.
    var inFile = "/Users/chilkat/testData/pdf/sample.pdf";
    var outFile = "/Users/chilkat/testData/p7m/sample.pdf.aes";
    success = crypt.CkEncryptFile(inFile,outFile);
    if (success !== true) {
        console.log(crypt.LastErrorText);
        return;
    }

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

    //  All settings must match to be able to decrypt:
    decrypt.CryptAlgorithm = "aes";
    decrypt.CipherMode = "cbc";
    decrypt.KeyLength = 256;
    decrypt.PaddingScheme = 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";
    success = decrypt.CkDecryptFile(inFile,outFile);
    if (success == false) {
        console.log(decrypt.LastErrorText);
        return;
    }

    console.log("Success!");

}

chilkatExample();