IOS obtains a unique device ID

1. Common UUID

The UDID is a 40-bit hexadecimal sequence (jailbroken devices can change the UDID through some tools) that mobile networks can use to identify mobile devices.

Many developers associate UdiDs with a user’s personal information, and snoops collect this data from multiple apps, which then lead to a lot of private data about that person, and most apps do transmit UdiDs and private information on a frequent basis. In order to avoid a class-action lawsuit, Apple finally decided to do away with this practice with iOS 5.

Method to obtain the UUID:

/ uninstall the application to be installed * * * / + (nsstrings *) getUUID {return [UIDevice currentDevice]. IdentifierForVendor. UUIDString;; }Copy the code

2.UUID+ Own storage

2.1 Two methods for obtaining UUID

*/ + (NSString *)getUUID{CFUUIDRef uuid = CFUUIDCreate(NULL); NSString *UUID = (__bridge_transfer NSString *)CFUUIDCreateString(NULL, uuid); CFRelease(uuid); return UUID; } / uninstall the application to be installed * * * / + (nsstrings *) getUUID {return [UIDevice currentDevice]. IdentifierForVendor. UUIDString;; }Copy the code

Obviously, UUID is not enough to support the uniqueness of the device. At present, many apps offer discounts for new users, but it is necessary to ensure that each device is bound to one account, which cannot be met by using UUID alone. Therefore, it is necessary to use keychain to save the device, so that even when the App is uninstalled, The obtained UUID is also unique.

2.2 Add KeyChain Sharing to the project first

2.3 Importing the third-party library Security.framework

2.4 Create a new class and encapsulate it with SSKeychain

#import "GetKeychain.h" #import "SSKeychain.h" @implementation GetKeychain + (NSString *)getDeviceUUID { NSString *currentDeviceUUIDStr = [SSKeychain passwordForService:@" account:@" uUID "]; if (currentDeviceUUIDStr == nil || [currentDeviceUUIDStr isEqualToString:@""]) { NSUUID *currentDeviceUUID = [UIDevice currentDevice].identifierForVendor; currentDeviceUUIDStr = currentDeviceUUID.UUIDString; currentDeviceUUIDStr = [currentDeviceUUIDStr stringByReplacingOccurrencesOfString:@"-" withString:@""]; currentDeviceUUIDStr = [currentDeviceUUIDStr lowercaseString]; [SSKeychain setPassword: currentDeviceUUIDStr forService:@" Boudle ID "Account :@" uUID "]; } return currentDeviceUUIDStr; } @endCopy the code

2.5 Core Code (a bit too much code)

A github search for SSKeychain will find the sskeychchain. h and sskeychain-m files

#import <Foundation/Foundation.h>
#import <Security/Security.h>

/** Error codes that can be returned in NSError objects. */
typedef enum {
	/** No error. */
	SSKeychainErrorNone = noErr,
	
	/** Some of the arguments were invalid. */
	SSKeychainErrorBadArguments = -1001,
	
	/** There was no password. */
	SSKeychainErrorNoPassword = -1002,
	
	/** One or more parameters passed internally were not valid. */
	SSKeychainErrorInvalidParameter = errSecParam,
	
	/** Failed to allocate memory. */
	SSKeychainErrorFailedToAllocated = errSecAllocate,
	
	/** No trust results are available. */
	SSKeychainErrorNotAvailable = errSecNotAvailable,
	
	/** Authorization/Authentication failed. */
	SSKeychainErrorAuthorizationFailed = errSecAuthFailed,
	
	/** The item already exists. */
	SSKeychainErrorDuplicatedItem = errSecDuplicateItem,
	
	/** The item cannot be found.*/
	SSKeychainErrorNotFound = errSecItemNotFound,
	
	/** Interaction with the Security Server is not allowed. */
	SSKeychainErrorInteractionNotAllowed = errSecInteractionNotAllowed,
	
	/** Unable to decode the provided data. */
	SSKeychainErrorFailedToDecode = errSecDecode
} SSKeychainErrorCode;

extern NSString *const kSSKeychainErrorDomain;

/** Account name. */
extern NSString *const kSSKeychainAccountKey;

/**
 Time the item was created.
 
 The value will be a string.
 */
extern NSString *const kSSKeychainCreatedAtKey;

/** Item class. */
extern NSString *const kSSKeychainClassKey;

/** Item description. */
extern NSString *const kSSKeychainDescriptionKey;

/** Item label. */
extern NSString *const kSSKeychainLabelKey;

/** Time the item was last modified.
 
 The value will be a string.
 */
extern NSString *const kSSKeychainLastModifiedKey;

/** Where the item was created. */
extern NSString *const kSSKeychainWhereKey;

/**
 Simple wrapper for accessing accounts, getting passwords, setting passwords, and deleting passwords using the system
 Keychain on Mac OS X and iOS.
 
 This was originally inspired by EMKeychain and SDKeychain (both of which are now gone). Thanks to the authors.
 SSKeychain has since switched to a simpler implementation that was abstracted from [SSToolkit](http://sstoolk.it).
 */
@interface SSKeychain : NSObject

///-----------------------
/// @name Getting Accounts
///-----------------------

/**
 Returns an array containing the Keychain's accounts, or `nil` if the Keychain has no accounts.
 
 See the `NSString` constants declared in SSKeychain.h for a list of keys that can be used when accessing the
 dictionaries returned by this method.
 
 @return An array of dictionaries containing the Keychain's accounts, or `nil` if the Keychain doesn't have any
 accounts. The order of the objects in the array isn't defined.
 
 @see allAccounts:
 */
+ (NSArray *)allAccounts;

/**
 Returns an array containing the Keychain's accounts, or `nil` if the Keychain doesn't have any
 accounts.
 
 See the `NSString` constants declared in SSKeychain.h for a list of keys that can be used when accessing the
 dictionaries returned by this method.
 
 @param error If accessing the accounts fails, upon return contains an error that describes the problem.
 
 @return An array of dictionaries containing the Keychain's accounts, or `nil` if the Keychain doesn't have any
 accounts. The order of the objects in the array isn't defined.
  
 @see allAccounts
 */
+ (NSArray *)allAccounts:(NSError **)error;

/**
 Returns an array containing the Keychain's accounts for a given service, or `nil` if the Keychain doesn't have any
 accounts for the given service.
 
 See the `NSString` constants declared in SSKeychain.h for a list of keys that can be used when accessing the
 dictionaries returned by this method.
 
 @param serviceName The service for which to return the corresponding accounts.
 
 @return An array of dictionaries containing the Keychain's accountsfor a given `serviceName`, or `nil` if the Keychain
 doesn't have any accounts for the given `serviceName`. The order of the objects in the array isn't defined.
 
 @see accountsForService:error:
 */
+ (NSArray *)accountsForService:(NSString *)serviceName;

/**
 Returns an array containing the Keychain's accounts for a given service, or `nil` if the Keychain doesn't have any
 accounts for the given service.
 
 @param serviceName The service for which to return the corresponding accounts.
 
 @param error If accessing the accounts fails, upon return contains an error that describes the problem.
 
 @return An array of dictionaries containing the Keychain's accountsfor a given `serviceName`, or `nil` if the Keychain
 doesn't have any accounts for the given `serviceName`. The order of the objects in the array isn't defined.
 
 @see accountsForService:
 */
+ (NSArray *)accountsForService:(NSString *)serviceName error:(NSError **)error;


///------------------------
/// @name Getting Passwords
///------------------------

/**
 Returns a string containing the password for a given account and service, or `nil` if the Keychain doesn't have a
 password for the given parameters.
 
 @param serviceName The service for which to return the corresponding password.
 
 @param account The account for which to return the corresponding password.
 
 @return Returns a string containing the password for a given account and service, or `nil` if the Keychain doesn't
 have a password for the given parameters.
 
 @see passwordForService:account:error:
 */
+ (NSString *)passwordForService:(NSString *)serviceName account:(NSString *)account;

/**
 Returns a string containing the password for a given account and service, or `nil` if the Keychain doesn't have a
 password for the given parameters.
 
 @param serviceName The service for which to return the corresponding password.
 
 @param account The account for which to return the corresponding password.
 
 @param error If accessing the password fails, upon return contains an error that describes the problem.
 
 @return Returns a string containing the password for a given account and service, or `nil` if the Keychain doesn't
 have a password for the given parameters.
 
 @see passwordForService:account:
 */
+ (NSString *)passwordForService:(NSString *)serviceName account:(NSString *)account error:(NSError **)error;

/**
 Returns the password data for a given account and service, or `nil` if the Keychain doesn't have data 
 for the given parameters.
 
 @param serviceName The service for which to return the corresponding password.
 
 @param account The account for which to return the corresponding password.
 
 @param error If accessing the password fails, upon return contains an error that describes the problem.
 
 @return Returns a the password data for the given account and service, or `nil` if the Keychain doesn't
 have data for the given parameters.
 
 @see passwordDataForService:account:error:
 */
+ (NSData *)passwordDataForService:(NSString *)serviceName account:(NSString *)account;

/**
 Returns the password data for a given account and service, or `nil` if the Keychain doesn't have data 
 for the given parameters.
 
 @param serviceName The service for which to return the corresponding password.
 
 @param account The account for which to return the corresponding password.
 
 @param error If accessing the password fails, upon return contains an error that describes the problem.
 
 @return Returns a the password data for the given account and service, or `nil` if the Keychain doesn't
 have a password for the given parameters.
 
 @see passwordDataForService:account:
 */
+ (NSData *)passwordDataForService:(NSString *)serviceName account:(NSString *)account error:(NSError **)error;


///-------------------------
/// @name Deleting Passwords
///-------------------------

/**
 Deletes a password from the Keychain.
 
 @param serviceName The service for which to delete the corresponding password.
 
 @param account The account for which to delete the corresponding password.
 
 @return Returns `YES` on success, or `NO` on failure.
 
 @see deletePasswordForService:account:error:
 */
+ (BOOL)deletePasswordForService:(NSString *)serviceName account:(NSString *)account;

/**
 Deletes a password from the Keychain.
 
 @param serviceName The service for which to delete the corresponding password.
 
 @param account The account for which to delete the corresponding password.
 
 @param error If deleting the password fails, upon return contains an error that describes the problem.
 
 @return Returns `YES` on success, or `NO` on failure.
 
 @see deletePasswordForService:account:
 */
+ (BOOL)deletePasswordForService:(NSString *)serviceName account:(NSString *)account error:(NSError **)error;


///------------------------
/// @name Setting Passwords
///------------------------

/**
 Sets a password in the Keychain.
 
 @param password The password to store in the Keychain.
 
 @param serviceName The service for which to set the corresponding password.
 
 @param account The account for which to set the corresponding password.
 
 @return Returns `YES` on success, or `NO` on failure.
 
 @see setPassword:forService:account:error:
 */
+ (BOOL)setPassword:(NSString *)password forService:(NSString *)serviceName account:(NSString *)account;

/**
 Sets a password in the Keychain.
 
 @param password The password to store in the Keychain.
 
 @param serviceName The service for which to set the corresponding password.
 
 @param account The account for which to set the corresponding password.
 
 @param error If setting the password fails, upon return contains an error that describes the problem.
 
 @return Returns `YES` on success, or `NO` on failure.
 
 @see setPassword:forService:account:
 */
+ (BOOL)setPassword:(NSString *)password forService:(NSString *)serviceName account:(NSString *)account error:(NSError **)error;

/**
 Sets arbirary data in the Keychain.
 
 @param password The data to store in the Keychain.
 
 @param serviceName The service for which to set the corresponding password.
 
 @param account The account for which to set the corresponding password.
 
 @param error If setting the password fails, upon return contains an error that describes the problem.
 
 @return Returns `YES` on success, or `NO` on failure.
 
 @see setPasswordData:forService:account:error:
 */
+ (BOOL)setPasswordData:(NSData *)password forService:(NSString *)serviceName account:(NSString *)account;

/**
 Sets arbirary data in the Keychain.
 
 @param password The data to store in the Keychain.
 
 @param serviceName The service for which to set the corresponding password.
 
 @param account The account for which to set the corresponding password.
 
 @param error If setting the password fails, upon return contains an error that describes the problem.
 
 @return Returns `YES` on success, or `NO` on failure.
 
 @see setPasswordData:forService:account:
 */
+ (BOOL)setPasswordData:(NSData *)password forService:(NSString *)serviceName account:(NSString *)account error:(NSError **)error;


///--------------------
/// @name Configuration
///--------------------

#if __IPHONE_4_0 && TARGET_OS_IPHONE
/**
 Returns the accessibility type for all future passwords saved to the Keychain.
 
 @return Returns the accessibility type.
 
 The return value will be `NULL` or one of the "Keychain Item Accessibility Constants" used for determining when a
 keychain item should be readable.
 
 @see accessibilityType
 */
+ (CFTypeRef)accessibilityType;

/**
 Sets the accessibility type for all future passwords saved to the Keychain.
 
 @param accessibilityType One of the "Keychain Item Accessibility Constants" used for determining when a keychain item
 should be readable.
 
 If the value is `NULL` (the default), the Keychain default will be used.
 
 @see accessibilityType
 */
+ (void)setAccessibilityType:(CFTypeRef)accessibilityType;
#endif

@end

Copy the code

#import "SSKeychain.h"

NSString *const kSSKeychainErrorDomain = @"com.samsoffes.sskeychain";

NSString *const kSSKeychainAccountKey = @"acct";
NSString *const kSSKeychainCreatedAtKey = @"cdat";
NSString *const kSSKeychainClassKey = @"labl";
NSString *const kSSKeychainDescriptionKey = @"desc";
NSString *const kSSKeychainLabelKey = @"labl";
NSString *const kSSKeychainLastModifiedKey = @"mdat";
NSString *const kSSKeychainWhereKey = @"svce";

#if __IPHONE_4_0 && TARGET_OS_IPHONE  
CFTypeRef SSKeychainAccessibilityType = NULL;
#endif

@interface SSKeychain ()
+ (NSMutableDictionary *)_queryForService:(NSString *)service account:(NSString *)account;
@end

@implementation SSKeychain

#pragma mark - Getting Accounts

+ (NSArray *)allAccounts {
    return [self accountsForService:nil error:nil];
}


+ (NSArray *)allAccounts:(NSError **)error {
    return [self accountsForService:nil error:error];
}


+ (NSArray *)accountsForService:(NSString *)service {
    return [self accountsForService:service error:nil];
}


+ (NSArray *)accountsForService:(NSString *)service error:(NSError **)error {
    OSStatus status = SSKeychainErrorBadArguments;
    NSMutableDictionary *query = [self _queryForService:service account:nil];
#if __has_feature(objc_arc)
	[query setObject:(__bridge id)kCFBooleanTrue forKey:(__bridge id)kSecReturnAttributes];
    [query setObject:(__bridge id)kSecMatchLimitAll forKey:(__bridge id)kSecMatchLimit];
#else
    [query setObject:(id)kCFBooleanTrue forKey:(id)kSecReturnAttributes];
    [query setObject:(id)kSecMatchLimitAll forKey:(id)kSecMatchLimit];
#endif
	
	CFTypeRef result = NULL;
#if __has_feature(objc_arc)
    status = SecItemCopyMatching((__bridge CFDictionaryRef)query, &result);
#else
	status = SecItemCopyMatching((CFDictionaryRef)query, &result);
#endif
    if (status != noErr && error != NULL) {
		*error = [NSError errorWithDomain:kSSKeychainErrorDomain code:status userInfo:nil];
		return nil;
	}
	
#if __has_feature(objc_arc)
	return (__bridge_transfer NSArray *)result;
#else
    return [(NSArray *)result autorelease];
#endif
}


#pragma mark - Getting Passwords

+ (NSString *)passwordForService:(NSString *)service account:(NSString *)account {
	return [self passwordForService:service account:account error:nil];
}


+ (NSString *)passwordForService:(NSString *)service account:(NSString *)account error:(NSError **)error {
    NSData *data = [self passwordDataForService:service account:account error:error];
	if (data.length > 0) {
		NSString *string = [[NSString alloc] initWithData:(NSData *)data encoding:NSUTF8StringEncoding];
#if !__has_feature(objc_arc)
		[string autorelease];
#endif
		return string;
	}
	
	return nil;
}


+ (NSData *)passwordDataForService:(NSString *)service account:(NSString *)account {
    return [self passwordDataForService:service account:account error:nil];
}


+ (NSData *)passwordDataForService:(NSString *)service account:(NSString *)account error:(NSError **)error {
    OSStatus status = SSKeychainErrorBadArguments;
	if (!service || !account) {
		if (error) {
			*error = [NSError errorWithDomain:kSSKeychainErrorDomain code:status userInfo:nil];
		}
		return nil;
	}
	
	CFTypeRef result = NULL;	
	NSMutableDictionary *query = [self _queryForService:service account:account];
#if __has_feature(objc_arc)
	[query setObject:(__bridge id)kCFBooleanTrue forKey:(__bridge id)kSecReturnData];
	[query setObject:(__bridge id)kSecMatchLimitOne forKey:(__bridge id)kSecMatchLimit];
	status = SecItemCopyMatching((__bridge CFDictionaryRef)query, &result);
#else
	[query setObject:(id)kCFBooleanTrue forKey:(id)kSecReturnData];
	[query setObject:(id)kSecMatchLimitOne forKey:(id)kSecMatchLimit];
	status = SecItemCopyMatching((CFDictionaryRef)query, &result);
#endif
	
	if (status != noErr && error != NULL) {
		*error = [NSError errorWithDomain:kSSKeychainErrorDomain code:status userInfo:nil];
		return nil;
	}
	
#if __has_feature(objc_arc)
	return (__bridge_transfer NSData *)result;
#else
    return [(NSData *)result autorelease];
#endif
}


#pragma mark - Deleting Passwords

+ (BOOL)deletePasswordForService:(NSString *)service account:(NSString *)account {
	return [self deletePasswordForService:service account:account error:nil];
}


+ (BOOL)deletePasswordForService:(NSString *)service account:(NSString *)account error:(NSError **)error {
	OSStatus status = SSKeychainErrorBadArguments;
	if (service && account) {
		NSMutableDictionary *query = [self _queryForService:service account:account];
#if __has_feature(objc_arc)
		status = SecItemDelete((__bridge CFDictionaryRef)query);
#else
		status = SecItemDelete((CFDictionaryRef)query);
#endif
	}
	if (status != noErr && error != NULL) {
		*error = [NSError errorWithDomain:kSSKeychainErrorDomain code:status userInfo:nil];
	}
	return (status == noErr);
    
}


#pragma mark - Setting Passwords

+ (BOOL)setPassword:(NSString *)password forService:(NSString *)service account:(NSString *)account {
	return [self setPassword:password forService:service account:account error:nil];
}


+ (BOOL)setPassword:(NSString *)password forService:(NSString *)service account:(NSString *)account error:(NSError **)error {
    NSData *data = [password dataUsingEncoding:NSUTF8StringEncoding];
    return [self setPasswordData:data forService:service account:account error:error];
}


+ (BOOL)setPasswordData:(NSData *)password forService:(NSString *)service account:(NSString *)account {
    return [self setPasswordData:password forService:service account:account error:nil];
}


+ (BOOL)setPasswordData:(NSData *)password forService:(NSString *)service account:(NSString *)account error:(NSError **)error {
    OSStatus status = SSKeychainErrorBadArguments;
	if (password && service && account) {
        [self deletePasswordForService:service account:account];
        NSMutableDictionary *query = [self _queryForService:service account:account];
#if __has_feature(objc_arc)
		[query setObject:password forKey:(__bridge id)kSecValueData];
#else
		[query setObject:password forKey:(id)kSecValueData];
#endif
		
#if __IPHONE_4_0 && TARGET_OS_IPHONE
		if (SSKeychainAccessibilityType) {
#if __has_feature(objc_arc)
			[query setObject:(id)[self accessibilityType] forKey:(__bridge id)kSecAttrAccessible];
#else
			[query setObject:(id)[self accessibilityType] forKey:(id)kSecAttrAccessible];
#endif
		}
#endif
		
#if __has_feature(objc_arc)
        status = SecItemAdd((__bridge CFDictionaryRef)query, NULL);
#else
		status = SecItemAdd((CFDictionaryRef)query, NULL);
#endif
	}
	if (status != noErr && error != NULL) {
		*error = [NSError errorWithDomain:kSSKeychainErrorDomain code:status userInfo:nil];
	}
	return (status == noErr);
}


#pragma mark - Configuration

#if __IPHONE_4_0 && TARGET_OS_IPHONE 
+ (CFTypeRef)accessibilityType {
	return SSKeychainAccessibilityType;
}


+ (void)setAccessibilityType:(CFTypeRef)accessibilityType {
	CFRetain(accessibilityType);
	if (SSKeychainAccessibilityType) {
		CFRelease(SSKeychainAccessibilityType);
	}
	SSKeychainAccessibilityType = accessibilityType;
}
#endif


#pragma mark - Private

+ (NSMutableDictionary *)_queryForService:(NSString *)service account:(NSString *)account {
    NSMutableDictionary *dictionary = [NSMutableDictionary dictionaryWithCapacity:3];
#if __has_feature(objc_arc)
    [dictionary setObject:(__bridge id)kSecClassGenericPassword forKey:(__bridge id)kSecClass];
#else
	[dictionary setObject:(id)kSecClassGenericPassword forKey:(id)kSecClass];
#endif
	
    if (service) {
#if __has_feature(objc_arc)
		[dictionary setObject:service forKey:(__bridge id)kSecAttrService];
#else
		[dictionary setObject:service forKey:(id)kSecAttrService];
#endif
	}
	
    if (account) {
#if __has_feature(objc_arc)
		[dictionary setObject:account forKey:(__bridge id)kSecAttrAccount];
#else
		[dictionary setObject:account forKey:(id)kSecAttrAccount];
#endif
	}
	
    return dictionary;
}

@end

Copy the code

1. Common UUID

2.UUID+ Own storage

2.1 Two methods for obtaining UUID

2.2 Add KeyChain Sharing to the project first

2.3 Importing the third-party library Security.framework

2.4 Create a new class and encapsulate it with SSKeychain

2.5 Core Code (a bit too much code)

Related Posts

MD5 encryption is commonly used

Underlying principle -28-LLVM flow

Exploring the underlying iOS: The Nature of the approach