(Swift 3,4,5...) Duplicate openssl dgst -sha256 -sign private.pem -out sha256.sig in.dat

Demonstrates how to duplicate this OpenSSL command:

openssl dgst -sha256 -sign private.pem -out sha256.sig in.dat

1. Creates a SHA256 digest of the contents of the input file
2. Signs the SHA256 digest using the private key.

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 pkey = CkoPrivateKey()!

    // Load the private key from an PEM file:
    var success: Bool = pkey.loadPemFile("private.pem")
    if success != true {
        print("\(pkey.lastErrorText!)")
        return
    }

    let rsa = CkoRsa()!

    // Import the private key into the RSA component:
    success = rsa.importPrivateKeyObj(pkey)
    if success != true {
        print("\(rsa.lastErrorText!)")
        return
    }

    // OpenSSL uses big-endian.
    rsa.littleEndian = false

    // Load the file to be signed.
    let bdFileData = CkoBinData()!
    success = bdFileData.loadFile("in.dat")

    let bdSig = CkoBinData()!
    success = rsa.signBd(bdFileData, hashAlgorithm: "sha256", bdSig: bdSig)
    if success != true {
        print("\(rsa.lastErrorText!)")
        return
    }

    // Save the binary signature to a file.
    success = bdSig.writeFile("signature.sig")
    if success != true {
        print("Failed to write signature.sig.")
        return
    }

    print("Success.")

}