Dead simple keychain access

Keychain.swift

import Security

public class Keychain
{
  public class func set(key: String, value: String) -> Bool
  {
    if let data = value.dataUsingEncoding(NSUTF8StringEncoding)
    {
      return set(key, value: data)
    }
    
    return false
  }
  
  public class func set(key: String, value: NSData) -> Bool
  {
    let query = [
      (kSecClass as! String)       : kSecClassGenericPassword,
      (kSecAttrAccount as! String) : key,
      (kSecValueData as! String)   : value
    ]
    
    SecItemDelete(query as CFDictionaryRef)
    
    return SecItemAdd(query as CFDictionaryRef, nil) == noErr
  }
  
  public class func get(key: String) -> NSString?
  {
    if let data = getData(key)
    {
      return NSString(data: data, encoding: NSUTF8StringEncoding)
    }
    
    return nil
  }
  
  public class func getData(key: String) -> NSData?
  {
    let query = [
      (kSecClass as! String)       : kSecClassGenericPassword,
      (kSecAttrAccount as! String) : key,
      (kSecReturnData as! String)  : kCFBooleanTrue,
      (kSecMatchLimit as! String)  : kSecMatchLimitOne
    ]
    
    var dataTypeRef: Unmanaged<AnyObject>?
    let status = SecItemCopyMatching(query, &dataTypeRef)
    
    if status == noErr && dataTypeRef != nil
    {
      return dataTypeRef!.takeRetainedValue() as? NSData
    }
    
    return nil
  }
  
  public class func delete(key: String) -> Bool
  {
    let query = [
      (kSecClass as! String)       : kSecClassGenericPassword,
      (kSecAttrAccount as! String) : key
    ]
    
    return SecItemDelete(query as CFDictionaryRef) == noErr
  }
  
  public class func clear() -> Bool
  {
    let query = [
      (kSecClass as String): kSecClassGenericPassword
    ]
    
    return SecItemDelete(query as CFDictionaryRef) == noErr
  }
}

Can you post a license for this? I'd love to use a somewhat altered version in my app but am hesitant without a clear license! Thanks for putting this out here, the keychain API is certainly not a joy to work with :)

I forked your code and fixed some changes to make it work with Swift 2.2 and Xcode 7.3.1
You can find the adapted code there:
https://github.com/kanedo/Keychain