通常情况下，我们用NSUserDefaults存储数据信息，但是对于一些私密信息，比如密*、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，在用户重新安装App后依然有效，数据还在。
使用苹果官方发布的KeychainItemWrapper或者SFHFKeychainUtils很方便，后来看到 使用keychain来存取用户名和密* 一文，觉得对了解keychain有很大的帮助，于是ARC控也尝试了一把。
需要导入Security.framework
@implementation WQKeyChain
+ (NSMutableDictionary *)getKeychainQuery:(NSString *)service { return [NSMutableDictionary dictionaryWithObjectsAndKeys: (__bridge_transfer id)kSecClassGenericPassword,(__bridge_transfer id)kSecClass, service, (__bridge_transfer id)kSecAttrService, service, (__bridge_transfer id)kSecAttrAccount, (__bridge_transfer id)kSecAttrAccessibleAfterFirstUnlock,(__bridge_transfer id)kSecAttrAccessible, nil];}+ (void)save:(NSString *)service data:(id)data { //Get search dictionary NSMutableDictionary *keychainQuery = [self getKeychainQuery:service]; //Delete old item before add new item SecItemDelete((__bridge_retained CFDictionaryRef)keychainQuery); //Add new object to search dictionary(Attention:the data format) [keychainQuery setObject:[NSKeyedArchiver archivedDataWithRootObject:data] forKey:(__bridge_transfer id)kSecValueData]; //Add item to keychain with the search dictionary SecItemAdd((__bridge_retained CFDictionaryRef)keychainQuery, NULL);}+ (id)load:(NSString *)service { id ret = nil; NSMutableDictionary *keychainQuery = [self getKeychainQuery:service]; //Configure the search setting [keychainQuery setObject:(id)kCFBooleanTrue forKey:(__bridge_transfer id)kSecReturnData]; [keychainQuery setObject:(__bridge_transfer id)kSecMatchLimitOne forKey:(__bridge_transfer id)kSecMatchLimit]; CFDataRef keyData = NULL; if (SecItemCopyMatching((__bridge_retained CFDictionaryRef)keychainQuery, (CFTypeRef *)&keyData) == noErr) { @try { ret = [NSKeyedUnarchiver unarchiveObjectWithData:(__bridge_transfer NSData *)keyData]; } @catch (NSException *e) { NSLog(@"Unarchive of %@ failed: %@", service, e); } @finally { } } return ret;}+ (void)delete:(NSString *)service { NSMutableDictionary *keychainQuery = [self getKeychainQuery:service]; SecItemDelete((__bridge_retained CFDictionaryRef)keychainQuery);}@end
@inte***ce WQUserDataManager : NSObject
/** * @brief 存储密* * * @param password 密*内容 */+(void)savePassWord:(NSString *)password;/** * @brief 读取密* * * @return 密*内容 */+(id)readPassWord;/** * @brief 删除密*数据 */+(void)deletePassWord;@end
#import "WQUserDataManager.h"
@implementation WQUserDataManagerstatic NSString * const KEY_IN_KEYCHAIN = @"com.wuqian.app.allinfo";static NSString * const KEY_PASSWORD = @"com.wuqian.app.password";+(void)savePassWord:(NSString *)password{ NSMutableDictionary *usernamepasswordKVPairs = [NSMutableDictionary dictionary]; [usernamepasswordKVPairs setObject:password forKey:KEY_PASSWORD]; [WQKeyChain save:KEY_IN_KEYCHAIN data:usernamepasswordKVPairs];}+(id)readPassWord{ NSMutableDictionary *usernamepasswordKVPair = (NSMutableDictionary *)[WQKeyChain load:KEY_IN_KEYCHAIN]; return [usernamepasswordKVPair objectForKey:KEY_PASSWORD];}+(void)deletePassWord{ [WQKeyChain delete:KEY_IN_KEYCHAIN];}@end
-(IBAction)btnAciton:(id)sender
{ [WQUserDataManager savePassWord:self.textfield.text]; self.label.text = [WQUserDataManager readPassWord];}
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