Reading PKCS12 with Swift in Foundation

PKCS12.swift

// xcode 7.3

import Foundation

/**
 Struct representing values returned by `SecPKCS12Import` from the Security framework.
 
 This is what Cocoa and CocoaTouch can tell you about a PKCS12 file.
 
 */
public class PKCS12 {
  let label:String?
  let keyID:NSData?
  let trust:SecTrustRef?
  let certChain:[SecTrustRef]?
  let identity:SecIdentityRef?

  public init(PKCS12Data:NSData,password:String)
  {
    let importPasswordOption:NSDictionary = [kSecImportExportPassphrase as NSString:password]
    var items : CFArray?
    let secError:OSStatus = SecPKCS12Import(PKCS12Data, importPasswordOption, &items)
    
    guard secError == errSecSuccess else {
      if secError == errSecAuthFailed {
        NSLog("ERROR: SecPKCS12Import returned errSecAuthFailed. Incorrect password?")
      }
      fatalError("SecPKCS12Import returned an error trying to import PKCS12 data")
    }
    
    guard let theItemsCFArray = items else { fatalError()  }
    let theItemsNSArray:NSArray = theItemsCFArray as NSArray
    guard let dictArray = theItemsNSArray as? [[String:AnyObject]] else { fatalError() }
    
    func f<T>(key:CFString) -> T? {
      for d in dictArray {
        if let v = d[key as String] as? T {
          return v
        }
      }
      return nil
    }
    
    self.label = f(kSecImportItemLabel)
    self.keyID = f(kSecImportItemKeyID)
    self.trust = f(kSecImportItemTrust)
    self.certChain = f(kSecImportItemCertChain)
    self.identity =  f(kSecImportItemIdentity)
  }
}

extension NSURLCredential {
  public convenience init?(PKCS12 thePKCS12:PKCS12) {
    if let identity = thePKCS12.identity {
      self.init(
        identity: identity,
        certificates: thePKCS12.certChain,
        persistence: NSURLCredentialPersistence.ForSession)
    }
    else { return nil }
  }
}