(Swift) Working with PEM Encrypted Private Keys

Demonstrates how to load and save PEM encrypted private keys.

Note: This example requires Chilkat v11.0.0 or greater.

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func chilkatTest() {
    var success: Bool = false

    // This example assumes the Chilkat API to have been previously unlocked.
    // See Global Unlock Sample for sample code.

    success = false

    let pem = CkoPem()!

    var pemPassword: String? = "secret"

    // To load a PEM file containing encrypted private keys, simply
    // provide the password.
    success = pem.loadFile("/Users/chilkat/testData/pem/pemContainingEncryptedPrivateKeys.pem", password: pemPassword)
    if success == false {
        print("\(pem.lastErrorText!)")
        return
    }

    let fac = CkoFileAccess()!
    var pemText: String? = fac.readEntireTextFile("/Users/chilkat/testData/pem/pemContainingEncryptedPrivateKeys.pem", charset: pemPassword)

    // To load a PEM from a string, call LoadPem instead of LoadPemFile:
    success = pem.load(pemText)
    if success == false {
        print("\(pem.lastErrorText!)")
        return
    }

    // A few notes:
    // The PEM may contain both private keys and certificates (or anything else).
    // The password is utilized for whatever content in the PEM is encrypted.  
    // It is OK to have both encrypted and non-encrypted content within a given PEM.

    // PEM private keys can be encrypted in different formats.  The LoadPem and LoadPemFile
    // methods automatically handle the different formats.
    // One format is PKCS8 and is indicated by this delimiter within the PEM:

    // -----BEGIN ENCRYPTED PRIVATE KEY-----
    // MIICoTAbBgkqhkiG9w0BBQMwDgQIfdD0zv24lgkCAggABIICgE0PdHJmRbNs6cBX
    // ...

    // Another format, we'll call "passphrase" looks like this in the PEM:
    // -----BEGIN RSA PRIVATE KEY-----
    // Proc-Type: 4,ENCRYPTED
    // DEK-Info: DES-EDE3-CBC,A4215544D11C5D0C
    // 
    // paqy9XRexcSjurHfG0xhCaUD0HrvIdhuC0CbRxxxeMlkLaV6+uT80rBxt2AaibWG
    // ...

    // Show the bit length of each private key:
    var i: Int
    var numPrivateKeys: Int = pem.numPrivateKeys.intValue
    if numPrivateKeys == 0 {
        print("\(("Error: Expected the PEM to contain private keys.")!)")
        return
    }

    let privKey = CkoPrivateKey()!
    for i = 1; i <= numPrivateKeys; i++ {
        pem.privateKey(at: i - 1, privKey: privKey)
        print("\(i): \(privKey.bitLength.intValue) bits")
    }


}