+ (NSString *)getKeyChainValue {
KeychainItemWrapper *keyChainItem=[[KeychainItemWrapper alloc]initWithIdentifier:@"LinkerApp" accessGroup:nil];
NSString *strKeyChain = [keyChainItem objectForKey:(__bridge id)kSecValueData];
if (strKeyChain == nil || [strKeyChain isEqualToString:@""])
{
[keyChainItem setObject:[Utils getUUID] forKey:(__bridge id)kSecValueData];
}
return strKeyChain;
}
+ (NSString *)getUUID {
NSUserDefaults *standardUserDefault = [NSUserDefaults standardUserDefaults];
NSString *deviceIdString = [standardUserDefault valueForKey:DEVICEID];
if (deviceIdString == nil || deviceIdString.length == 0) {
CFUUIDRef puuid = CFUUIDCreate( nil );
CFStringRef uuidString = CFUUIDCreateString( nil, puuid );
deviceIdString = (NSString *)CFBridgingRelease(CFStringCreateCopy( NULL, uuidString));
CFRelease(puuid);
CFRelease(uuidString);
if (deviceIdString.length > 15) {
deviceIdString = [deviceIdString substringToIndex:15];
}
}
return deviceIdString;
}
原文：http://www.cnblogs.com/jinzhengen/p/4560466.html