(Swift) Encrypt a File to a PKCS7 (CMS) Message

Shows how to encrypt a file into a PKCS7 encrypted message using the recipient's certificate. Public-key encryption requires no private key. However, the recipient's private key is necessary for decryption.

Chilkat Downloads for the Swift Programming Language MAC OS X (Cocoa) Objective-C/Swift Libs iOS Objective-C/Swift Libs

func chilkatTest() {
    // This example requires the Chilkat API to have been previously unlocked.
    // See Global Unlock Sample for sample code.

    let crypt = CkoCrypt2()!

    // Load the recipient's digital certificate. 
    // We don't need the private key for encryption.
    // Only the public key is needed (which is included in a certificate).
    let cert1 = CkoCert()!
    var success: Bool = cert1.load(fromFile: "qa_data/user1/cert_user1.pem")
    // Assume success for the example, but make sure your application checks for success/failure...
    crypt.setEncryptCert(cert1)

    // Indicate that we want PKI encryption (i.e. public-key infrastructure)
    // to produce a CMS message (Cryptographic Message Syntax/PKCS7),
    // that is be created with RSAES-OAEP padding, SHA256, and AES-256 for the
    // bulk encryption.
    crypt.cryptAlgorithm = "pki"
    crypt.pkcs7CryptAlg = "aes"
    crypt.keyLength = 256
    crypt.oaepHash = "sha256"
    crypt.oaepPadding = true

    // Load the file to be encrypted...
    let fileData = CkoBinData()!
    success = fileData.loadFile("qa_data/jpg/penguins.jpg")
    // Your app should check for success/failure..

    // Encrypt the data.  The contents of the fileData object are replaced with the PKCS7 encrypted message.
    success = crypt.encryptBd(fileData)
    if success != true {
        print("\(crypt.lastErrorText!)")
        return
    }

    // Save the PKCS7 encrypted message to a file..
    success = fileData.writeFile("qa_output/pkcs7_encrypted.p7")

    print("OK.")

}