JavaScript

MIME S/MIME Encryption Algorithm Properties

Demonstrates the properties that control S/MIME encryption: Pkcs7CryptAlg (the symmetric content-encryption algorithm), Pkcs7KeyLength (the content-encryption key length in bits), OaepPadding (whether RSAES-OAEP key transport is used instead of RSAES-PKCS1-v1_5), and the OAEP hash settings OaepHash and OaepMgfHash. The properties are configured before calling Encrypt.

Background. CMS/PKCS #7 encryption uses a symmetric algorithm to protect the content and an RSA key-transport scheme to protect the symmetric key. The defaults (aes, 128-bit, PKCS1-v1_5 padding) work broadly; these properties tune the algorithms and padding.

Note

This example is intended for running within a Chilkat.Js embedded JavaScript engine. All Chilkat JavaScript examples require Chilkat v11.4.0 or greater.

JavaScript

var success = false;

var mime = new CkMime();
success = mime.SetBodyFromPlainText("This message will be encrypted.");
if (success == false) {
    console.log(mime.LastErrorText);
    return;
}

//  Pkcs7CryptAlg is the symmetric content-encryption algorithm.  Supported values are aes, aes-gcm,
//  des, 3des, and rc2.  The default is aes.
mime.Pkcs7CryptAlg = "aes";

//  Pkcs7KeyLength is the content-encryption key length in bits.  The default is 128.
mime.Pkcs7KeyLength = 256;

//  OaepPadding selects the RSA key-transport padding.  The default is false (RSAES-PKCS1-v1_5).
//  Set true to use RSAES-OAEP, in which case the OAEP hash settings apply.
mime.OaepPadding = true;
mime.OaepHash = "sha256";
mime.OaepMgfHash = "sha256";

//  Load the recipient certificate (public key is sufficient for encrypting).
var cert = new CkCert();
success = cert.LoadFromFile("qa_data/recipient.cer");
if (success == false) {
    console.log(cert.LastErrorText);
    return;
}

//  Encrypt using the algorithm settings configured above.
success = mime.Encrypt(cert);
if (success == false) {
    console.log(mime.LastErrorText);
    return;
}

console.log("Encrypted with " + mime.Pkcs7CryptAlg + " " + mime.Pkcs7KeyLength + "-bit key.");