MIME S/MIME Encryption Algorithm Properties

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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.

<?php

use Chilkat2\Cert;
use Chilkat2\Mime;

$mime = new Mime();
try {
    $mime->SetBodyFromPlainText('This message will be encrypted.');

    // 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).
    $cert = new Cert();
    $cert->LoadFromFile('qa_data/recipient.cer');

    // Encrypt using the algorithm settings configured above.
    $mime->Encrypt($cert);
} catch (\Chilkat2\Exception $e) {
    echo $e->getMessage(), "\n";
    exit;
}

echo 'Encrypted with ', $mime->Pkcs7CryptAlg, ' ', $mime->Pkcs7KeyLength, "-bit key.\n";