【iOS】Keychain key string

The keystring is actually an encrypted database, as shown below. Even if the App is deleted, the data inside the keystring will not be lost.

Data is stored as items, each of which consists of an encrypted Data and a series of Attributes that describe the Attributes of the Item. Because it is a database, there are only four key methods, increase, delete, change and check, corresponding to

• SecItemAdd
• SecItemDelete
• SecItemUpdate
• SecItemCopyMatching

Here is a brief description of how to use it

SecItemAdd

CFTypeRef result; NSDictionary *query = @{// A typical new method argument contains three parts // 1.kSecClass key, which specifies the type of the new object (NSString *)kSecClass: (NSString *)kSecClassGenericPassword, // 2. Several attributes, such as kSecAttrAccount, kSecAttrLabel, etc. describe the attributes of the new object (NSString *)kSecAttrAccount: @uniqueID, // 3.kSecValueData key, which is used to set the data stored in the new object (NSString *)kSecValueData: [@ "token" dataUsingEncoding: NSUTF8StringEncoding], / / optional / / if you need to obtain additional attributes of the object Item, need the following attributes, kSecReturnData nsstrings (*) : (NSNumber *)kCFBooleanTrue, (NSString *)kSecReturnAttributes: (NSNumber *)kCFBooleanTrue, }; OSStatus status = SecItemAdd((CFDictionaryRef)query, &result); If (result == errSecSuccess) {NSDictionary *itemInfo = (__bridge NSDictionary *)result; NSLog(@"info: %@", itemInfo); } else {// other errors}Copy the code

Result Indicates the type identification mode

SecItemDelete

NSDictionary *query = @{// A typical delete method argument contains two parts // 1, kSecClass key, which specifies the type of object to delete, mandatory. (nsstrings *) kSecClass: kSecClassGenericPassword nsstrings *, / / 2, several key attribute, optional. // By default, all items that meet the criteria are deleted. (NSString *) @"uniqueID", }; OSStatus status = SecItemDelete((CFDictionaryRef)query); If (result == errSecSuccess) {// delete successful} else {// other error}Copy the code

SecItemUpdate

NSDictionary *query = @{(NSString *)kSecClass: (NSString *)kSecClassGenericPassword, (NSString *)kSecAttrAccount: @"uniqueID", }; NSDictionary *update = @{(NSString *)kSecAttrAccount: @"another uniqueID", (NSString *)kSecValueData: @"another value", }; OSStatus status = SecItemUpdate((CFDictionaryRef)query, (CFDictionaryRef)update); If (result == errSecSuccess) {// Update successful} else {// other error}Copy the code

SecItemDelete

NSDictionary *query = @{// A typical delete method argument contains two parts // 1, kSecClass key, which specifies the type of object to delete, mandatory. (nsstrings *) kSecClass: kSecClassGenericPassword nsstrings *, / / 2, several key attribute, optional. // By default, all items that meet the criteria are deleted. (NSString *) @"uniqueID", }; OSStatus status = SecItemDelete((CFDictionaryRef)query); If (result == errSecSuccess) {// delete successful} else {// other error}Copy the code

SecItemCopyMatching

CFTypeRef result; NSDictionary *query = @{// A typical search method argument contains three parts // 1, kSecClass key (mandatory), which specifies the type of the search object (NSString *)kSecClass: KSecClassGenericPassword nsstrings *, / / 2, several key attribute (optional), such as kSecAttrAccount, kSecAttrLabel etc., The attribute used to describe the search object (NSString *)kSecAttrAccount: @"uniqueID", // 3, search attributes (optional) // for example kSecMatchLimit // kSecMatchCaseInsensitive is case sensitive (NSString *)kSecMatchLimit: (NSString *)kSecMatchLimitAll, (NSString *) kSecMatchCaseInsensitive: (NSNumber *) kCFBooleanTrue, // (optional) If you want to get the attribute of the new Item object, you need the following attribute, (NSString *)kSecReturnData: (NSNumber *)kCFBooleanTrue, (NSString *)kSecReturnAttributes: (NSNumber *)kCFBooleanTrue, }; OSStatus status = SecItemCopyMatching((CFDictionaryRef)query, &result); If (result == errSecSuccess) {NSDictionary *itemInfo = (__bridge NSDictionary *)result; NSLog(@"info: %@", itemInfo); } else {// other errors}Copy the code

Result Indicates the type identification mode

Reference documentation developer.apple.com/documentati…

The Demo address github.com/huangrrui/K…