我正在使用Apple提供的keychainwrapper示例代码来存储我在申请授权中获得的NSDictionary数据。我收到来自SecItemAdd API的错误代码errSecParam（-50）。 以下是keychainwrapper.m的代码
#import "KeychainItemWrapper.h"
#import "SynthesizeSingleton.h"
#import <Security/Security.h>
@interface KeychainItemWrapper (PrivateMethods)
/*
The decision behind the following two methods (secItemFormatToDictionary and dictionaryToSecItemFormat) was
to encapsulate the transition between what the detail view controller was expecting (NSString *) and what the
Keychain API expects as a validly constructed container class.
*/
- (NSMutableDictionary *)secItemFormatToDictionary:(NSDictionary *)dictionaryToConvert;
- (NSMutableDictionary *)dictionaryToSecItemFormat:(NSDictionary *)dictionaryToConvert;
// Updates the item in the keychain, or adds it if it doesn't exist.
- (void)writeToKeychain;
@end
@implementation KeychainItemWrapper
{
NSMutableDictionary *keychainItemData; // The actual keychain item data backing store.
NSMutableDictionary *genericPasswordQuery; // A placeholder for the generic keychain item query used to locate the item.
}
SYNTHESIZE_SINGLETON_FOR_CLASS(KeychainItemWrapper);
#pragma mark singleton implementation
+(KeychainItemWrapper *) sharedInstance
{
return [self sharedKeychainItemWrapper];
}
- (id) init
{
self = [super init];
if (self) {
// Do Nothing
}
return self;
}
- (void)createKeychainItemWithIdentifier: (NSString *)identifier accessGroup:(NSString *) accessGroup;
{
// Begin Keychain search setup. The genericPasswordQuery leverages the special user
// defined attribute kSecAttrGeneric to distinguish itself between other generic Keychain
// items which may be included by the same application.
genericPasswordQuery = [[NSMutableDictionary alloc] init];
[genericPasswordQuery setObject:(__bridge id)kSecClassGenericPassword forKey:(__bridge id)kSecClass];
[genericPasswordQuery setObject:identifier forKey:(__bridge id)kSecAttrGeneric];
// The keychain access group attribute determines if this item can be shared
// amongst multiple apps whose code signing entitlements contain the same keychain access group.
if (accessGroup != nil)
{
#if TARGET_IPHONE_SIMULATOR
// Ignore the access group if running on the iPhone simulator.
//
// Apps that are built for the simulator aren't signed, so there's no keychain access group
// for the simulator to check. This means that all apps can see all keychain items when run
// on the simulator.
//
// If a SecItem contains an access group attribute, SecItemAdd and SecItemUpdate on the
// simulator will return -25243 (errSecNoAccessForItem).
#else
[genericPasswordQuery setObject:accessGroup forKey:(__bridge id)kSecAttrAccessGroup];
#endif
}
// Use the proper search constants, return only the attributes of the first match.
[genericPasswordQuery setObject:[NSNumber numberWithBool:YES] forKey:(__bridge id)kSecMatchLimitOne];
[genericPasswordQuery setObject:[NSNumber numberWithBool:YES] forKey:(__bridge id)kSecReturnAttributes];
NSDictionary *tempQuery = [NSDictionary dictionaryWithDictionary:genericPasswordQuery];
CFMutableDictionaryRef outDictionary = NULL;
if (!SecItemCopyMatching((__bridge CFDictionaryRef)tempQuery, (CFTypeRef *)&outDictionary) == noErr)
{
// Stick these default values into keychain item if nothing found.
[self resetKeychainItem];
// Add the generic attribute and the keychain access group.
[keychainItemData setObject:identifier forKey:(__bridge id)kSecAttrGeneric];
if (accessGroup != nil)
{
#if TARGET_IPHONE_SIMULATOR
// Ignore the access group if running on the iPhone simulator.
//
// Apps that are built for the simulator aren't signed, so there's no keychain access group
// for the simulator to check. This means that all apps can see all keychain items when run
// on the simulator.
//
// If a SecItem contains an access group attribute, SecItemAdd and SecItemUpdate on the
// simulator will return -25243 (errSecNoAccessForItem).
#else
[keychainItemData setObject:accessGroup forKey:(__bridge id)kSecAttrAccessGroup];
#endif
}
}
else
{
// load the saved data from Keychain.
keychainItemData = [self secItemFormatToDictionary:(__bridge NSDictionary *)outDictionary];
}
if(outDictionary) CFRelease(outDictionary);
}
- (void)setObject:(id)inObject forKey:(id)key
{
if (inObject == nil) return;
id currentObject = [keychainItemData objectForKey:key];
if (![currentObject isEqual:inObject])
{
[keychainItemData setObject:inObject forKey:key];
[self writeToKeychain];
}
}
- (id)objectForKey:(id)key
{
return [keychainItemData objectForKey:key];
}
- (void)resetKeychainItem
{
OSStatus junk = noErr;
if (!keychainItemData)
{
keychainItemData = [[NSMutableDictionary alloc] init];
}
else if (keychainItemData)
{
NSMutableDictionary *tempDictionary = [self dictionaryToSecItemFormat:keychainItemData];
junk = SecItemDelete((__bridge CFDictionaryRef)tempDictionary);
NSAssert( junk == noErr || junk == errSecItemNotFound, @"Problem deleting current dictionary." );
}
// Default attributes for keychain item.
[keychainItemData setObject:@"" forKey:(__bridge id)kSecAttrAccount];
[keychainItemData setObject:@"" forKey:(__bridge id)kSecAttrLabel];
[keychainItemData setObject:@"" forKey:(__bridge id)kSecAttrDescription];
// Default data for keychain item.
[keychainItemData setObject:@"" forKey:(__bridge id)kSecValueData];
// [keychainItemData setObject:[NSData data] forKey:(__bridge id)kSecValueData];
}
- (NSMutableDictionary *)dictionaryToSecItemFormat:(NSDictionary *)dictionaryToConvert
{
// The assumption is that this method will be called with a properly populated dictionary
// containing all the right key/value pairs for a SecItem.
// Create a dictionary to return populated with the attributes and data.
NSMutableDictionary *returnDictionary = [NSMutableDictionary dictionaryWithDictionary:dictionaryToConvert];
// Add the Generic Password keychain item class attribute.
[returnDictionary setObject:(__bridge id)kSecClassGenericPassword forKey:(__bridge id)kSecClass];
// Convert the NSString to NSData to meet the requirements for the value type kSecValueData.
// This is where to store sensitive data that should be encrypted.
NSString *passwordString = [dictionaryToConvert objectForKey:(__bridge id)kSecValueData];
[returnDictionary setObject:[passwordString dataUsingEncoding:NSUTF8StringEncoding] forKey:(__bridge id)kSecValueData];
return returnDictionary;
}
- (NSMutableDictionary *)secItemFormatToDictionary:(NSDictionary *)dictionaryToConvert
{
// The assumption is that this method will be called with a properly populated dictionary
// containing all the right key/value pairs for the UI element.
// Create a dictionary to return populated with the attributes and data.
NSMutableDictionary *returnDictionary = [NSMutableDictionary dictionaryWithDictionary:dictionaryToConvert];
// Add the proper search key and class attribute.
[returnDictionary setObject:(__bridge id)kCFBooleanTrue forKey:(__bridge id)kSecReturnData];
[returnDictionary setObject:(__bridge id)kSecClassGenericPassword forKey:(__bridge id)kSecClass];
// Acquire the password data from the attributes.
CFDataRef passwordData = NULL;
if (SecItemCopyMatching((__bridge CFDictionaryRef)returnDictionary, (CFTypeRef *)&passwordData) == noErr)
{
// Remove the search, class, and identifier key/value, we don't need them anymore.
[returnDictionary removeObjectForKey:(__bridge id)kSecReturnData];
// Add the password to the dictionary, converting from NSData to NSString.
NSString *password = [[NSString alloc] initWithBytes:[(__bridge NSData *)passwordData bytes] length:[(__bridge NSData *)passwordData length]
encoding:NSUTF8StringEncoding];
[returnDictionary setObject:password forKey:(__bridge id)kSecValueData];
}
else
{
// Don't do anything if nothing is found.
NSAssert(NO, @"Serious error, no matching item found in the keychain.\n");
}
if(passwordData) CFRelease(passwordData);
return returnDictionary;
}
- (void)writeToKeychain
{
CFDictionaryRef attributes = NULL;
NSMutableDictionary *updateItem = nil;
OSStatus result;
if (SecItemCopyMatching((__bridge CFDictionaryRef)genericPasswordQuery, (CFTypeRef *)&attributes) == noErr)
{
// First we need the attributes from the Keychain.
updateItem = [NSMutableDictionary dictionaryWithDictionary:(__bridge NSDictionary *)attributes];
// Second we need to add the appropriate search key/values.
[updateItem setObject:[genericPasswordQuery objectForKey:(__bridge id)kSecClass] forKey:(__bridge id)kSecClass];
// Lastly, we need to set up the updated attribute list being careful to remove the class.
NSMutableDictionary *tempCheck = [self dictionaryToSecItemFormat:keychainItemData];
[tempCheck removeObjectForKey:(__bridge id)kSecClass];
#if TARGET_IPHONE_SIMULATOR
// Remove the access group if running on the iPhone simulator.
//
// Apps that are built for the simulator aren't signed, so there's no keychain access group
// for the simulator to check. This means that all apps can see all keychain items when run
// on the simulator.
//
// If a SecItem contains an access group attribute, SecItemAdd and SecItemUpdate on the
// simulator will return -25243 (errSecNoAccessForItem).
//
// The access group attribute will be included in items returned by SecItemCopyMatching,
// which is why we need to remove it before updating the item.
[tempCheck removeObjectForKey:(__bridge id)kSecAttrAccessGroup];
#endif
// An implicit assumption is that you can only update a single item at a time.
result = SecItemUpdate((__bridge CFDictionaryRef)updateItem, (__bridge CFDictionaryRef)tempCheck);
NSAssert( result == noErr, @"Couldn't update the Keychain Item." );
}
else
{
// No previous item found; add the new one.
result = SecItemAdd((__bridge CFDictionaryRef)[self dictionaryToSecItemFormat:keychainItemData], NULL);
NSAssert( result == noErr, @"Couldn't add the Keychain Item." );
}
if(attributes) CFRelease(attributes);
}
@end
使用此时..
KeychainItemWrapper *secClientIDMapping = [KeychainItemWrapper sharedInstance];
[secClientIDMapping createKeychainItemWithIdentifier:@"com.xxx.ClientID" accessGroup:nil];
NSString *error;
NSData *dictionaryRep = [NSPropertyListSerialization dataFromPropertyList:clientIDMapping format:NSPropertyListXMLFormat_v1_0 errorDescription:&error];
[secClientIDMapping setObject:dictionaryRep forKey:@"com.xxx.ClientID"];
早上无法解决。基本上我到处都是如何存储字符串而不是字典对象。
答案 0 :(得分：4)
由于没有人回答这个问题，我自己发布，因为我找到了解决方法。当添加到钥匙串时，如果我们传递NSString以外的NSData，我们需要在添加到钥匙串之前序列化数据。
以下是答案..
NSDictionary *secTokenDic = [dictionaryToConvert objectForKey:(__bridge id)kSecValueData];
NSString *error;
NSData *dictionaryRep = [NSPropertyListSerialization dataFromPropertyList:secTokenDic format:NSPropertyListXMLFormat_v1_0 errorDescription:&error];
[returnDictionary setObject:dictionaryRep forKey:(__bridge id)kSecValueData];
同样在检索时需要反序列化NSData。希望这有助于其他正在努力解决类似问题的人。