Swift Keychain class ( supported Xcode 6.0.1 )

import UIKit import Security

class Keychain {

class func save(key: String, data: NSData) -> Bool {
    let query = [
        kSecClass as String       : kSecClassGenericPassword as String,
        kSecAttrAccount as String : key,
        kSecValueData as String   : data ]
    
    SecItemDelete(query as CFDictionaryRef)
    
    let status: OSStatus = SecItemAdd(query as CFDictionaryRef, nil)
    
    return status == noErr
}

class func load(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: OSStatus = SecItemCopyMatching(query, &dataTypeRef)
    
    if status == noErr {
        return (dataTypeRef!.takeRetainedValue() as NSData)
    } else {
        return nil
    }
}

class func delete(key: String) -> Bool {
    let query = [
        kSecClass as String       : kSecClassGenericPassword,
        kSecAttrAccount as String : key ]
    
    let status: OSStatus = SecItemDelete(query as CFDictionaryRef)
    
    return status == noErr
}


class func clear() -> Bool {
    let query = [ kSecClass as String : kSecClassGenericPassword ]
    
    let status: OSStatus = SecItemDelete(query as CFDictionaryRef)
    
    return status == noErr
}

}