(Swift) RSA Sign using a Private Key on a USB Token or Smartcard

See more Apple Keychain Examples

Create an RSA signature using a private key stored on a USB token or smartcard.

Note: On MacOS and iOS, this example requires Chilkat v10.1.2 or later when the Apple Keychain is used as the underlying means to do the signing.

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func chilkatTest() {
    // Assuming the smartcard/USB token is installed with the correct drivers from the manufacturer,
    // this code can work on multiple platforms including Windows, MacOS, Linux, and iOS.

    // Chilkat automatically detects and determines the way in which the HSM is used,
    // which can be by PKCS11, Apple Keychain, Microsoft CNG / Crypto API, or ScMinidriver.

    let cert = CkoCert()!

    // Set the token/smartcard PIN prior to loading.
    cert.smartCardPin = "123456"

    // Specify the certificate by its common name.
    var success: Bool = cert.load(fromSmartcard: "cn=chilkat-rsa-2048")
    if success == false {
        print("\(cert.lastErrorText!)")
        return
    }

    print("Signing with cert: \(cert.subjectCN!)")

    // Create data to be hashed and signed.
    let bd = CkoBinData()!
    var i: Int
    for i = 0; i <= 100; i++ {
        bd.appendEncoded("000102030405060708090A0B0C0D0E0F", encoding: "hex")
    }

    let rsa = CkoRsa()!

    // Use the certificate's private key for signing.
    success = rsa.setX509Cert(cert, usePrivateKey: true)
    if success == false {
        print("\(rsa.lastErrorText!)")
        return
    }

    // Sign the SHA-256 hash of the contents of bd.
    let bdSig = CkoBinData()!
    success = rsa.signBd(bd, hashAlgorithm: "sha256", bdSig: bdSig)
    if success == false {
        print("\(rsa.lastErrorText!)")
        return
    }

    // The RSA signature is equal in length to the size of the RSA key.
    print("Output signature size in bits = \(bdSig.numBytes.intValue * 8)")

    // We can save the signature for later verification..
    bdSig.writeFile("rsaSignatures/test1.sig")

    // See the example to verify the RSA signature:
    // Verfies an RSA Signature

}