(Node.js) Encrypt File to PKCS7 .p7m

Node.js example to public-key encrypt a file creating a PKCS#7 .p7m file as output. Also demonstrates how to decrypt the .p7m to recover the original file.

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();

    // Indicate the public-key encryption is to be used.
    // Do this by setting the encryption algorithm equal 
    // to "PKI" (an acroynm for public-key infrastructure).
    crypt.CryptAlgorithm = "PKI";

    // Indicate the inner symmetric encryption algorithm to be used.
    // possible values are "aes", "des", "3des", and "rc2".
    // For this example, we'll use 256-bit AES encryption.
    crypt.Pkcs7CryptAlg = "aes";
    crypt.KeyLength = 256;

    // To encrypt, only a certificate w/ public key is needed.
    // (The certificate w/ private key is required for decryption.)

    // The LoadFromFile method can load virtually any certificate format:
    // 1. DER encoded binary X.509 (.CER)
    // 2. Base-64 encoded X.509 (.CER)
    // 3. Cryptographic Message Syntax Standard - PKCS #7 Certificates (.P7B)
    // 4. PEM format
    var encryptCert = new chilkat.Cert();
    var success = encryptCert.LoadFromFile("/Users/chilkat/testData/cer/acme.cer");
    if (success !== true) {
        console.log(encryptCert.LastErrorText);
        return;
    }

    // Tell the crypt object to use the certificate for encrypting:
    crypt.AddEncryptCert(encryptCert);

    // Encrypt a file, producing a .p7m as output.
    // The input file is unchanged, the output .p7m contains the encrypted
    // contents of the input file.
    var inFile = "/Users/chilkat/testData/pdf/sample.pdf";
    var outFile = "/Users/chilkat/testData/p7m/sample.pdf.p7m";
    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();

    // To decrypt, the certificate w/ private key is required.  A PFX (also known
    // as PKCS#12) is a common secure container for certs and private keys.
    var pfxFilename = "/Users/chilkat/testData/pfx/acme.pfx";
    var pfxPassword = "secret";

    // Tell the component to look in the PFX file for certs and private keys.
    success = decrypt.AddPfxSourceFile(pfxFilename,pfxPassword);
    if (success !== true) {
        console.log(decrypt.LastErrorText);
        return;
    }

    // Tell the decrypt object that PKI (public key encryption) is to be used
    // for decryptiong.
    decrypt.CryptAlgorithm = "PKI";
    // There is no need to set the Pkcs7Alg or KeyLength because this information
    // is contained within the .p7m

    // Decrypt the .p7m
    inFile = "/Users/chilkat/testData/p7m/sample.pdf.p7m";
    outFile = "/Users/chilkat/testData/pdf/recovered.pdf";
    success = decrypt.CkDecryptFile(inFile,outFile);
    if (success == false) {
        console.log(decrypt.LastErrorText);
        return;
    }

    console.log("Success!");

}

chilkatExample();