Swift

Yubikey RSA Encrypt/Decrypt

See more RSA Examples

Demonstrates how to do RSA decryption using a private key stored on a Yubikey (or other USB token or smartcard).

Note: RSA encryption uses the public key, which is freely exportable and does not need to occur on the token/smartcard.

Swift

func chilkatTest() {
    var success: Bool = false

    // This example assumes you have a certificate with private key on the Yubikey token.
    // When doing simple RSA encryption/decryption, we don't actually need the certificate,
    // but we'll be using the private key associated with the certificate.
    // 
    // The sensitive/secret material that needs to be kept private is the private key.
    // The certificate itself and the public key can be freely shared.
    // 

    // We're going to encrypt and decrypt 32-bytes of data.
    let bd = CkoBinData()!
    success = bd.appendEncoded(encData: "000102030405060708090A0B0C0D0E0F", encoding: "hex")
    success = bd.appendEncoded(encData: "000102030405060708090A0B0C0D0E0F", encoding: "hex")

    // Let's get the desired cert.
    // For this example, a self-signed certificate with a 2048-bit RSA key was generated in slot 9A.
    let cert = CkoCert()!

    // Force Chilkat to use PKCS11 over ScMinidriver (if on Windows) and Apple Keychain (if on MacOS)
    cert.uncommonOptions = "NoScMinidriver,NoAppleKeychain"

    cert.smartCardPin = "123456"

    success = cert.load(fromSmartcard: "cn=chilkat_test_2048")
    if success == false {
        print("\(cert.lastErrorText!)")
        return
    }

    // RSA encrypt using the public key.
    let rsa = CkoRsa()!

    // Provide the RSA object with the certificate on the Yubkey.
    success = rsa.setX509Cert(cert: cert, usePrivateKey: true)
    if success == false {
        print("\(rsa.lastErrorText!)")
        return
    }

    // RSA encrypt using the public key.
    var usePrivateKey: Bool = false
    success = rsa.encryptBd(bd: bd, usePrivateKey: usePrivateKey)
    if success == false {
        print("\(rsa.lastErrorText!)")
        return
    }

    print("RSA Encrypted Output in Hex:")
    print("\(bd.getEncoded(encoding: "hex")!)")

    // Now let's decrypt, using the private key on the Yubikey.
    usePrivateKey = true
    success = rsa.decryptBd(bd: bd, usePrivateKey: usePrivateKey)
    if success == false {
        print("\(rsa.lastErrorText!)")
        return
    }

    print("RSA Decrypted Output in Hex:")
    print("\(bd.getEncoded(encoding: "hex")!)")

}