(Node.js) AES Encrypt and Decrypt a File

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

Install Chilkat for Node.js and Electron using npm at Chilkat npm packages for Node.js Chilkat npm packages for Electron on Windows, Linux, MacOSX, and ARM

var os = require('os');
if (os.platform() == 'win32') {  
    if (os.arch() == 'ia32') {
        var chilkat = require('@chilkat/ck-node21-win-ia32');
    } else {
        var chilkat = require('@chilkat/ck-node21-win64'); 
    }
} else if (os.platform() == 'linux') {
    if (os.arch() == 'arm') {
        var chilkat = require('@chilkat/ck-node21-arm');
    } else if (os.arch() == 'x86') {
        var chilkat = require('@chilkat/ck-node21-linux32');
    } else {
        var chilkat = require('@chilkat/ck-node21-linux64');
    }
} else if (os.platform() == 'darwin') {
    if (os.arch() == 'arm64') {
        var chilkat = require('@chilkat/ck-node21-mac-m1');
    } else {
        var chilkat = require('@chilkat/ck-node21-macosx');
    }
}

function chilkatExample() {

    // 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";
    var 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();