本文共 3309 字，大约阅读时间需要 11 分钟。
iOS的keychain服务提供了一种安全的保存私密信息（密码，序列号，证书等）的方式。每个ios程序都有一个独立的keychain存储。从ios 3.0开始，跨程序分享keychain变得可行。
下面就使用keychain来实现存取用户名和密码。
苹果已经有现成的类封装好了keychain,KeychainItemWrapper.h和KeychainItemWrapper.m文件,可以在实例里找到。
但是这里我只需要存取用户名和密码，就不用苹果提供的类了，自己写个简单的类来实现就好。
代码如下：
CHKeychain.h
- #import <Foundation/Foundation.h>
- #import <Security/Security.h>
-
-
- @interface CHKeychain : NSObject
-
- + (void)save:(NSString *)service data:(id)data;
- + (id)load:(NSString *)service;
- + (void)delete:(NSString *)service;
-
-
- @end
CHKeychain.m
- #import "CHKeychain.h"
-
- @implementation CHKeychain
- + (NSMutableDictionary *)getKeychainQuery:(NSString *)service {
- return [NSMutableDictionary dictionaryWithObjectsAndKeys:
- (id)kSecClassGenericPassword,(id)kSecClass,
- service, (id)kSecAttrService,
- service, (id)kSecAttrAccount,
- (id)kSecAttrAccessibleAfterFirstUnlock,(id)kSecAttrAccessible,
- nil];
- }
-
- + (void)save:(NSString *)service data:(id)data {
-
- NSMutableDictionary *keychainQuery = [self getKeychainQuery:service];
-
- SecItemDelete((CFDictionaryRef)keychainQuery);
-
- [keychainQuery setObject:[NSKeyedArchiver archivedDataWithRootObject:data] forKey:(id)kSecValueData];
-
- SecItemAdd((CFDictionaryRef)keychainQuery, NULL);
- }
-
- + (id)load:(NSString *)service {
- id ret = nil;
- NSMutableDictionary *keychainQuery = [self getKeychainQuery:service];
-
-
- [keychainQuery setObject:(id)kCFBooleanTrue forKey:(id)kSecReturnData];
- [keychainQuery setObject:(id)kSecMatchLimitOne forKey:(id)kSecMatchLimit];
- CFDataRef keyData = NULL;
- if (SecItemCopyMatching((CFDictionaryRef)keychainQuery, (CFTypeRef *)&keyData) == noErr) {
- @try {
- ret = [NSKeyedUnarchiver unarchiveObjectWithData:(NSData *)keyData];
- } @catch (NSException *e) {
- NSLog(@"Unarchive of %@ failed: %@", service, e);
- } @finally {
- }
- }
- if (keyData)
- CFRelease(keyData);
- return ret;
- }
-
- + (void)delete:(NSString *)service {
- NSMutableDictionary *keychainQuery = [self getKeychainQuery:service];
- SecItemDelete((CFDictionaryRef)keychainQuery);
- }
-
-
- @end
首先需要定义几个字符串用来做key：
- NSString * const KEY_USERNAME_PASSWORD = @"com.company.app.usernamepassword";
- NSString * const KEY_USERNAME = @"com.company.app.username";
- NSString * const KEY_PASSWORD = @"com.company.app.password";
把用户名和密码存入keychain：
- NSMutableDictionary *usernamepasswordKVPairs = [NSMutableDictionary dictionary];
- [usernamepasswordKVPairs setObject:txtfldUsername.text forKey:KEY_USERNAME];
- [usernamepasswordKVPairs setObject:txtfldPassword.text forKey:KEY_PASSWORD];
- [CHKeychain save:KEY_USERNAME_PASSWORD data:usernamepasswordKVPairs];
从keychain中取出用户名和密码：
- NSMutableDictionary *usernamepasswordKVPairs = (NSMutableDictionary *)[CHKeychain load:KEY_USERNAME_PASSWORD];
- txtfldUsername.text = [usernamepasswordKVPairs objectForKey:KEY_USERNAME];
- txtfldPassword.text = [usernamepasswordKVPairs objectForKey:KEY_PASSWORD];
删除一个keychain item:
- [CHKeychain delete:KEY_USERNAME_PASSWORD];
这样一个简单的使用keychain存取用户名密码的功能就做好了。
另外附上一篇写得更详细的e文：
如果还有问题请看此篇文章：http://ken.bokele.com/?ArticleID=86996
转载地址：http://nqgub.baihongyu.com/