(Swift 3,4,5...) RSA SHA256 Signature using Private Key from Java Keystore

Signs plaintext using RSA SHA256 using a key from a Java keystore.

Duplicatest this code:

KeyStore keystore; // key repository for keys containing signature certificate
String alias; // alias for the certificate in the key repository
String password; // password for the certificate's private key
String plaintext; // text being signed


Signature signature = Signature.getInstance("SHA256withRSA");
signature.initSign((PrivateKey) keystore.getKey(alias, password.toCharArray()));
signature.update(plaintext.getBytes("UTF-8"));
byte[] rsa_text= signature.sign();

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

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

    let jks = CkoJavaKeyStore()!

    var jksPassword: String? = "secret"

    // Load the Java keystore from a file.  The JKS file password is used
    // to verify the keyed digest that is found at the very end of the keystore.
    // It verifies that the keystore has not been modified.
    var success: Bool = jks.loadFile(jksPassword, path: "qa_data/jks/sample_secret.jks")
    if success != true {
        print("\(jks.lastErrorText!)")
        return
    }

    // Get the private key from the JKS.
    // The private key password may be different than the file password.
    var privKeyPassword: String? = "secret"
    var caseSensitive: Bool = false
    var privKey: CkoPrivateKey? = jks.findPrivateKey(privKeyPassword, alias: "some.alias", caseSensitive: caseSensitive)
    if jks.lastMethodSuccess != true {
        print("\(jks.lastErrorText!)")
        return
    }

    // Establish the RSA object and tell it to use the private key..
    let rsa = CkoRsa()!

    success = rsa.importPrivateKeyObj(privKey)
    privKey = nil
    if success != true {
        print("\(rsa.lastErrorText!)")
        return
    }

    // Indicate we'll be signing the utf-8 byte representation of the string..
    rsa.charset = "utf-8"

    // Sign some plaintext using RSA-SHA256
    var binarySignature: NSData
    var plaintext: String? = "this is the text to be signed"
    binarySignature = rsa.sign(plaintext, hashAlg: "SHA256")
    if rsa.lastMethodSuccess != true {
        print("\(rsa.lastErrorText!)")
        return
    }

    // Alternatively, if the signature is desired in some encoded string form,
    // such as base64, base64-url, hex, etc.
    rsa.encodingMode = "base64-url"
    var signatureStr: String? = rsa.signStringENC(plaintext, hashAlg: "SHA256")
    print("base64-url RSA signature: \(signatureStr!)")

}