(Node.js) Extract PKCS7 from MIME and Decrypt

Extracts the base64-encoded PKCS7 body of a MIME message to a file, and then decrypts using Chilkat Crypt2.

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

var os = require('os');
if (os.platform() == 'win32') {  
  var chilkat = require('@chilkat/ck-node23-win64'); 
} else if (os.platform() == 'linux') {
    if (os.arch() == 'arm') {
        var chilkat = require('@chilkat/ck-node23-linux-arm');
    } else if (os.arch() == 'arm64') {
        var chilkat = require('@chilkat/ck-node23-linux-arm64');
    } else {
        var chilkat = require('@chilkat/ck-node23-linux-x64');
    }
} else if (os.platform() == 'darwin') {
  var chilkat = require('@chilkat/ck-node23-mac-universal');
}

function chilkatExample() {

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

    var mime = new chilkat.Mime();

    var success = mime.LoadMimeFile("c:/aaworkarea/EmailInBytes.txt");
    if (success !== true) {
        console.log(mime.LastErrorText);
        return;
    }

    success = mime.SaveBody("c:/aaworkarea/smime.p7m");
    if (success !== true) {
        console.log(mime.LastErrorText);
        return;
    }

    var crypt = new chilkat.Crypt2();

    success = crypt.AddPfxSourceFile("c:/aaworkarea/my.pfx","pfxPassword");
    if (success == false) {
        console.log(crypt.LastErrorText);
        return;
    }

    // Indicate the public-key (PKCS7) encryption/decryption should be used:
    crypt.CryptAlgorithm = "pki";

    var inPath = "c:/aaworkarea/smime.p7m";
    var outPath = "c:/aaworkarea/decrypted.dat";

    success = crypt.CkDecryptFile(inPath,outPath);
    if (success == false) {
        console.log(crypt.LastErrorText);
        return;
    }

    console.log("Success.");

}

chilkatExample();