WWDC 2013已经闭幕，IOS7 Beta随即发布，界面之难看无以言表...,简直就是山寨Android。
更让IOS程序猿悲催的是，设备唯一标识的MAC Address在IOS7中也失效了。
IOS系统中，获取设备唯一标识的方法有很多：
一.UDID(Unique Device Identifier)
UDID的全称是Unique Device Identifier，顾名思义，它就是苹果IOS设备的唯一识别码，它由40个字符的字母和数字组成。
二.UUID(Universally Unique Identifier)
UUID是Universally Unique Identifier的缩写,中文意思是通用唯一识别码.
三.MAC Address
四.OPEN UDID
五.广告标示符（IDFA-identifierForIdentifier）
六.Vindor标示符 (IDFV-identifierForVendor)
Vendor是CFBundleIdentifier（反转DNS格式）的前两部分。来自同一个运营商的应用运行在同一个设备上，此属性的值是相同的；不同的运营商应用运行在同一个设备上值不同。
经测试，只要设备上有一个tencent的app，重新安装后的identifierForVendor值不变，如果tencent的app全部删除，重新安装后的identifierForVendor值改变。
但是很不幸，上面所有这些表示设备唯一号的标识，在IOS7中要么被禁止使用，要么重新安装程序后两次获取的标识符不一样。
由于IOS系统存储的数据都是在sandBox里面，一旦删除App，sandBox也不复存在。好在有一个例外，那就是keychain（钥匙串）。
通常情况下，IOS系统用NSUserDefaults存储数据信息，但是对于一些私密信息，比如密码、证书等等，就需要使用更为安全的keychain了。
keychain里保存的信息不会因App被删除而丢失。所以，可以利用这个keychain这个特点来保存设备唯一标识。
那么，如何在应用里使用使用keyChain呢，我们需要导入Security.framework ，keychain的操作接口声明在头文件SecItem.h里。
直接使用SecItem.h里方法操作keychain，需要写的代码较为复杂，我们可以使用已经封装好了的工具类KeychainItemWrapper来对keychain进行操作。
KeychainItemWrapper是apple官方例子“GenericKeychain”里一个访问keychain常用操作的封装类，在官网上下载了GenericKeychain项目后，
只需要把“KeychainItemWrapper.h”和“KeychainItemWrapper.m”拷贝到我们项目，并导入Security.framework 。KeychainItemWrapper的用法：
/** 初始化一个保存用户帐号的KeychainItemWrapper */
KeychainItemWrapper *wrapper = [[KeychainItemWrapper alloc] initWithIdentifier:@"Account Number"
accessGroup:@"YOUR_APP_ID_HERE.com.yourcompany.AppIdentifier"];
//保存数据
[wrapper setObject:@"<帐号>" forKey:(id)kSecAttrAccount];
[wrapper setObject:@"<帐号密码>" forKey:(id)kSecValueData];
//从keychain里取出帐号密码
NSString *password = [wrapper objectForKey:(id)kSecValueData];
//清空设置
[wrapper resetKeychainItem];
其中方法“- (void)setObject:(id)inObject forKey:(id)key;”里参数“forKey”的值应该是Security.framework 里头文件“SecItem.h”里定义好的key，用其他字符串做key程序会出错！
//
// SFHFKeychainUtils.h
//
// Created by Buzz Andersen on 10/20/08.
// Based partly on code by Jonathan Wight, Jon Crosby, and Mike Malone.
// Copyright 2008 Sci-Fi Hi-Fi. All rights reserved.
//
// Permission is hereby granted, free of charge, to any person
// obtaining a copy of this software and associated documentation
// files (the "Software"), to deal in the Software without
// restriction, including without limitation the rights to use,
// copy, modify, merge, publish, distribute, sublicense, and/or sell
// copies of the Software, and to permit persons to whom the
// Software is furnished to do so, subject to the following
// conditions:
//
// The above copyright notice and this permission notice shall be
// included in all copies or substantial portions of the Software.
//
// THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,
// EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES
// OF MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND
// NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT
// HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY,
// WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING
// FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR
// OTHER DEALINGS IN THE SOFTWARE.
//
#import <UIKit/UIKit.h>
@interface SFHFKeychainUtils : NSObject {
}
+ (NSString *) getPasswordForUsername: (NSString *) username andServiceName: (NSString *) serviceName error: (NSError **) error;
+ (BOOL) storeUsername: (NSString *) username andPassword: (NSString *) password forServiceName: (NSString *) serviceName updateExisting: (BOOL) updateExisting error: (NSError **) error;
+ (BOOL) deleteItemForUsername: (NSString *) username andServiceName: (NSString *) serviceName error: (NSError **) error;
@end//
// SFHFKeychainUtils.m
//
// Created by Buzz Andersen on 10/20/08.
// Based partly on code by Jonathan Wight, Jon Crosby, and Mike Malone.
// Copyright 2008 Sci-Fi Hi-Fi. All rights reserved.
//
// Permission is hereby granted, free of charge, to any person
// obtaining a copy of this software and associated documentation
// files (the "Software"), to deal in the Software without
// restriction, including without limitation the rights to use,
// copy, modify, merge, publish, distribute, sublicense, and/or sell
// copies of the Software, and to permit persons to whom the
// Software is furnished to do so, subject to the following
// conditions:
//
// The above copyright notice and this permission notice shall be
// included in all copies or substantial portions of the Software.
//
// THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,
// EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES
// OF MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND
// NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT
// HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY,
// WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING
// FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR
// OTHER DEALINGS IN THE SOFTWARE.
//
#import "SFHFKeychainUtils.h"
#import <Security/Security.h>
static NSString *SFHFKeychainUtilsErrorDomain = @"SFHFKeychainUtilsErrorDomain";
#if __IPHONE_OS_VERSION_MIN_REQUIRED < 30000 && TARGET_IPHONE_SIMULATOR
@interface SFHFKeychainUtils (PrivateMethods)
+ (SecKeychainItemRef) getKeychainItemReferenceForUsername: (NSString *) username andServiceName: (NSString *) serviceName error: (NSError **) error;
@end
#endif
@implementation SFHFKeychainUtils
#if __IPHONE_OS_VERSION_MIN_REQUIRED < 30000 && TARGET_IPHONE_SIMULATOR
+ (NSString *) getPasswordForUsername: (NSString *) username andServiceName: (NSString *) serviceName error: (NSError **) error {
if (!username || !serviceName) {
*error = [NSError errorWithDomain: SFHFKeychainUtilsErrorDomain code: -2000 userInfo: nil];
return nil;
}
SecKeychainItemRef item = [SFHFKeychainUtils getKeychainItemReferenceForUsername: username andServiceName: serviceName error: error];
if (*error || !item) {
return nil;
}
// from Advanced Mac OS X Programming, ch. 16
UInt32 length;
char *password;
SecKeychainAttribute attributes[8];
SecKeychainAttributeList list;
attributes[0].tag = kSecAccountItemAttr;
attributes[1].tag = kSecDescriptionItemAttr;
attributes[2].tag = kSecLabelItemAttr;
attributes[3].tag = kSecModDateItemAttr;
list.count = 4;
list.attr = attributes;
OSStatus status = SecKeychainItemCopyContent(item, NULL, &list, &length, (void **)&password);
if (status != noErr) {
*error = [NSError errorWithDomain: SFHFKeychainUtilsErrorDomain code: status userInfo: nil];
return nil;
}
NSString *passwordString = nil;
if (password != NULL) {
char passwordBuffer[1024];
if (length > 1023) {
length = 1023;
}
strncpy(passwordBuffer, password, length);
passwordBuffer[length] = '\0';
passwordString = [NSString stringWithCString:passwordBuffer];
}
SecKeychainItemFreeContent(&list, password);
// CFRelease(item);
return passwordString;
}
+ (void) storeUsername: (NSString *) username andPassword: (NSString *) password forServiceName: (NSString *) serviceName updateExisting: (BOOL) updateExisting error: (NSError **) error {
if (!username || !password || !serviceName) {
*error = [NSError errorWithDomain: SFHFKeychainUtilsErrorDomain code: -2000 userInfo: nil];
return;
}
OSStatus status = noErr;
SecKeychainItemRef item = [SFHFKeychainUtils getKeychainItemReferenceForUsername: username andServiceName: serviceName error: error];
if (*error && [*error code] != noErr) {
return;
}
*error = nil;
if (item) {
status = SecKeychainItemModifyAttributesAndData(item,
NULL,
strlen([password UTF8String]),
[password UTF8String]);
// CFRelease(item);
}
else {
status = SecKeychainAddGenericPassword(NULL,
strlen([serviceName UTF8String]),
[serviceName UTF8String],
strlen([username UTF8String]),
[username UTF8String],
strlen([password UTF8String]),
[password UTF8String],
NULL);
}
if (status != noErr) {
*error = [NSError errorWithDomain: SFHFKeychainUtilsErrorDomain code: status userInfo: nil];
}
}
+ (void) deleteItemForUsername: (NSString *) username andServiceName: (NSString *) serviceName error: (NSError **) error {
if (!username || !serviceName) {
*error = [NSError errorWithDomain: SFHFKeychainUtilsErrorDomain code: 2000 userInfo: nil];
return;
}
*error = nil;
SecKeychainItemRef item = [SFHFKeychainUtils getKeychainItemReferenceForUsername: username andServiceName: serviceName error: error];
if (*error && [*error code] != noErr) {
return;
}
OSStatus status;
if (item) {
status = SecKeychainItemDelete(item);
// CFRelease(item);
}
if (status != noErr) {
*error = [NSError errorWithDomain: SFHFKeychainUtilsErrorDomain code: status userInfo: nil];
}
}
+ (SecKeychainItemRef) getKeychainItemReferenceForUsername: (NSString *) username andServiceName: (NSString *) serviceName error: (NSError **) error {
if (!username || !serviceName) {
*error = [NSError errorWithDomain: SFHFKeychainUtilsErrorDomain code: -2000 userInfo: nil];
return nil;
}
*error = nil;
SecKeychainItemRef item;
OSStatus status = SecKeychainFindGenericPassword(NULL,
strlen([serviceName UTF8String]),
[serviceName UTF8String],
strlen([username UTF8String]),
[username UTF8String],
NULL,
NULL,
&item);
if (status != noErr) {
if (status != errSecItemNotFound) {
*error = [NSError errorWithDomain: SFHFKeychainUtilsErrorDomain code: status userInfo: nil];
}
return nil;
}
return item;
}
#else
+ (NSString *) getPasswordForUsername: (NSString *) username andServiceName: (NSString *) serviceName error: (NSError **) error {
if (!username || !serviceName) {
if (error != nil) {
*error = [NSError errorWithDomain: SFHFKeychainUtilsErrorDomain code: -2000 userInfo: nil];
}
return nil;
}
if (error != nil) {
*error = nil;
}
// Set up a query dictionary with the base query attributes: item type (generic), username, and service
NSArray *keys = [[NSArray alloc] initWithObjects: (NSString *) kSecClass, kSecAttrAccount, kSecAttrService, nil];
NSArray *objects = [[NSArray alloc] initWithObjects: (NSString *) kSecClassGenericPassword, username, serviceName, nil];
NSMutableDictionary *query = [[NSMutableDictionary alloc] initWithObjects: objects forKeys: keys];
// First do a query for attributes, in case we already have a Keychain item with no password data set.
// One likely way such an incorrect item could have come about is due to the previous (incorrect)
// version of this code (which set the password as a generic attribute instead of password data).
NSDictionary *attributeResult = NULL;
NSMutableDictionary *attributeQuery = [query mutableCopy];
[attributeQuery setObject: (id) kCFBooleanTrue forKey:(id) kSecReturnAttributes];
OSStatus status = SecItemCopyMatching((CFDictionaryRef) attributeQuery, (CFTypeRef *) &attributeResult);
// [attributeResult release];
// [attributeQuery release];
if (status != noErr) {
// No existing item found--simply return nil for the password
if (error != nil && status != errSecItemNotFound) {
//Only return an error if a real exception happened--not simply for "not found."
*error = [NSError errorWithDomain: SFHFKeychainUtilsErrorDomain code: status userInfo: nil];
}
return nil;
}
// We have an existing item, now query for the password data associated with it.
NSData *resultData = nil;
NSMutableDictionary *passwordQuery = [query mutableCopy];
[passwordQuery setObject: (id) kCFBooleanTrue forKey: (id) kSecReturnData];
status = SecItemCopyMatching((CFDictionaryRef) passwordQuery, (CFTypeRef *) &resultData);
if (status != noErr) {
if (status == errSecItemNotFound) {
// We found attributes for the item previously, but no password now, so return a special error.
// Users of this API will probably want to detect this error and prompt the user to
// re-enter their credentials. When you attempt to store the re-entered credentials
// using storeUsername:andPassword:forServiceName:updateExisting:error
// the old, incorrect entry will be deleted and a new one with a properly encrypted
// password will be added.
if (error != nil) {
*error = [NSError errorWithDomain: SFHFKeychainUtilsErrorDomain code: -1999 userInfo: nil];
}
}
else {
// Something else went wrong. Simply return the normal Keychain API error code.
if (error != nil) {
*error = [NSError errorWithDomain: SFHFKeychainUtilsErrorDomain code: status userInfo: nil];
}
}
return nil;
}
NSString *password = nil;
if (resultData) {
password = [[NSString alloc] initWithData: resultData encoding: NSUTF8StringEncoding];
}
else {
// There is an existing item, but we weren't able to get password data for it for some reason,
// Possibly as a result of an item being incorrectly entered by the previous code.
// Set the -1999 error so the code above us can prompt the user again.
if (error != nil) {
*error = [NSError errorWithDomain: SFHFKeychainUtilsErrorDomain code: -1999 userInfo: nil];
}
}
return password;
}
+ (BOOL) storeUsername: (NSString *) username andPassword: (NSString *) password forServiceName: (NSString *) serviceName updateExisting: (BOOL) updateExisting error: (NSError **) error
{
if (!username || !password || !serviceName)
{
if (error != nil)
{
*error = [NSError errorWithDomain: SFHFKeychainUtilsErrorDomain code: -2000 userInfo: nil];
}
return NO;
}
// See if we already have a password entered for these credentials.
NSError *getError = nil;
NSString *existingPassword = [SFHFKeychainUtils getPasswordForUsername: username andServiceName: serviceName error:&getError];
if ([getError code] == -1999)
{
// There is an existing entry without a password properly stored (possibly as a result of the previous incorrect version of this code.
// Delete the existing item before moving on entering a correct one.
getError = nil;
[self deleteItemForUsername: username andServiceName: serviceName error: &getError];
if ([getError code] != noErr)
{
if (error != nil)
{
*error = getError;
}
return NO;
}
}
else if ([getError code] != noErr)
{
if (error != nil)
{
*error = getError;
}
return NO;
}
if (error != nil)
{
*error = nil;
}
OSStatus status = noErr;
if (existingPassword)
{
// We have an existing, properly entered item with a password.
// Update the existing item.
if (![existingPassword isEqualToString:password] && updateExisting)
{
//Only update if we're allowed to update existing. If not, simply do nothing.
NSArray *keys = [[NSArray alloc] initWithObjects: (NSString *) kSecClass,
kSecAttrService,
kSecAttrLabel,
kSecAttrAccount,
nil];
NSArray *objects = [[NSArray alloc] initWithObjects: (NSString *) kSecClassGenericPassword,
serviceName,
serviceName,
username,
nil];
NSDictionary *query = [[NSDictionary alloc] initWithObjects: objects forKeys: keys];
status = SecItemUpdate((CFDictionaryRef) query, (CFDictionaryRef) [NSDictionary dictionaryWithObject: [password dataUsingEncoding: NSUTF8StringEncoding] forKey: (NSString *) kSecValueData]);
}
}
else
{
// No existing entry (or an existing, improperly entered, and therefore now
// deleted, entry). Create a new entry.
NSArray *keys = [[NSArray alloc] initWithObjects: (NSString *) kSecClass,
kSecAttrService,
kSecAttrLabel,
kSecAttrAccount,
kSecValueData,
nil];
NSArray *objects = [[NSArray alloc] initWithObjects: (NSString *) kSecClassGenericPassword,
serviceName,
serviceName,
username,
[password dataUsingEncoding: NSUTF8StringEncoding],
nil];
NSDictionary *query = [[NSDictionary alloc] initWithObjects: objects forKeys: keys];
status = SecItemAdd((CFDictionaryRef) query, NULL);
}
if (status != noErr)
{
// Something went wrong with adding the new item. Return the Keychain error code.
if (error != nil) {
*error = [NSError errorWithDomain: SFHFKeychainUtilsErrorDomain code: status userInfo: nil];
}
return NO;
}
return YES;
}
+ (BOOL) deleteItemForUsername: (NSString *) username andServiceName: (NSString *) serviceName error: (NSError **) error
{
if (!username || !serviceName)
{
if (error != nil)
{
*error = [NSError errorWithDomain: SFHFKeychainUtilsErrorDomain code: -2000 userInfo: nil];
}
return NO;
}
if (error != nil)
{
*error = nil;
}
NSArray *keys = [[NSArray alloc] initWithObjects: (NSString *) kSecClass, kSecAttrAccount, kSecAttrService, kSecReturnAttributes, nil];
NSArray *objects = [[NSArray alloc] initWithObjects: (NSString *) kSecClassGenericPassword, username, serviceName, kCFBooleanTrue, nil];
NSDictionary *query = [[NSDictionary alloc] initWithObjects: objects forKeys: keys];
OSStatus status = SecItemDelete((CFDictionaryRef) query);
if (status != noErr)
{
if (error != nil) {
*error = [NSError errorWithDomain: SFHFKeychainUtilsErrorDomain code: status userInfo: nil];
}
return NO;
}
return YES;
}
#endif
@end
