Introduction to the--keychain use of IOS development __ios

iOS's Keychain service provides a safe way to save private information (passwords, serial numbers, certificates, etc.). Each iOS program has a separate keychain store. Starting with iOS 3.0, sharing keychain across programs becomes feasible.

It is convenient to use Apple's official keychainitemwrapper or sfhfkeychainutils.

Apple already has a ready-made class that encapsulates keychain,keychainitemwrapper.h and keychainitemwrapper.m files and can be found in generickeychain instances.

The following is the use of keychain to access user names and passwords.

The code is as follows:

CHKeychain.h

[CPP] view plain copy #import <Foundation/Foundation.h> #import <Security/Security.h> @int   Erface Chkeychain:nsobject + (void) Save: (NSString *) service data: (ID) data;   + (ID) Load: (NSString *) service;         + (void) Delete: (NSString *) service; @end

Chkeychain.m

[CPP]  View plain copy #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 {       //Get search dictionary        NSMutableDictionary *keychainQuery = [self getKeychainQuery:service];        //Delete old item before add new item        secitemdelete ((cfdictionaryref) keychainquery);        //add new object to search dictionary (Attention:the data format)        [keychainQuery setObject:[NSKeyedArchiver  Archiveddatawithrootobject:data] forkey: (ID) ksecvaluedata];       //add  item to keychain with the search dictionary        secitemadd ((cfdictionaryref) keychainquery, null);  }      +  (ID) Load: (nsstring *) service {       id ret = nil;       nsmutabledictionary  *keychainQuery = [self getKeychainQuery:service];       // configure the search setting       //Since in our  Simple case we are expecting only a single attribute to be  returned  (The password)  we can set the attribute ksecreturndata  to kCFBooleanTrue       [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;   }