Java

Select the S/MIME Encryption Algorithm

Demonstrates the Chilkat Email.Pkcs7CryptAlg property, which selects the underlying symmetric encryption algorithm used when an email is sent encrypted with PKCS#7 public-key (S/MIME) encryption. Possible values are aes, aes-gcm, des, 3des, and rc2; the default is aes. This example selects AES and pairs it with a 256-bit key length.

Background: S/MIME encryption is hybrid. The message body is encrypted with a fast symmetric algorithm (the one this property chooses, such as AES) using a randomly generated one-time key; then that one-time key is itself encrypted with each recipient's public key. This gives the speed of symmetric encryption with the key-distribution convenience of public-key cryptography. Modern choices like aes are strongly preferred — older options such as des and rc2 are considered weak.

Chilkat Java Downloads

Download Chilkat for Java

Chilkat2 Java

import com.chilkatsoft.chilkat2.Email;

public class ChilkatExample {

    public static void main(String[] args) {
        // Demonstrates the Email.Pkcs7CryptAlg property, which selects the symmetric encryption
        // algorithm used when an email is sent encrypted with PKCS#7 (S/MIME) public-key
        // encryption.  Possible values: aes, aes-gcm, des, 3des, rc2.  The default is aes.

        Email email = new Email();
        email.setSubject("Encrypted email");
        email.setBody("This message will be S/MIME encrypted when sent.");

        // Select AES with a 256-bit key for the symmetric encryption.
        email.setPkcs7CryptAlg("aes");
        email.setPkcs7KeyLength(256);

        System.out.println("Pkcs7CryptAlg = " + email.getPkcs7CryptAlg());
        System.out.println("Pkcs7KeyLength = " + email.getPkcs7KeyLength());
    }
}