在iOS中，使用Keychain可以把我們要存儲(chǔ)的數(shù)據(jù)以加密的形式存儲(chǔ)在獨(dú)立于App的位置。

通過(guò)當(dāng)前項(xiàng)目的Capabilities>Keychain Sharing>On開(kāi)啟Keychain后，會(huì)自動(dòng)生成一個(gè)對(duì)應(yīng)的Keychain Groups，以及一個(gè)entitlements文件，文件里會(huì)有一個(gè)Keychain Access Groups，這里存儲(chǔ)了所有想要共享部分Keychain數(shù)據(jù)的App對(duì)應(yīng)的keychain groups的ID，默認(rèn)第一項(xiàng)名為“(teamID)就是你開(kāi)發(fā)者賬號(hào)的teamID，xcode之前的版本也寫(xiě)做${AppIdentifierPrefix}。

那么怎么獲取這個(gè)teamID，從而避免硬編碼呢。示例代碼如下：

OC

/** 獲取TeamID，又名AppIdentifierPrefix  */
+ (NSString *)teamID
{
    NSDictionary *query = @{(id)kSecClass:(id)kSecClassGenericPassword,
                            (id)kSecAttrAccount:@"bundleSeedID",
                            (id)kSecAttrService:@"",
                            (id)kSecReturnAttributes:(id)kCFBooleanTrue
    };
    CFDictionaryRef result = nil;
    OSStatus status = SecItemCopyMatching((CFDictionaryRef)query, (CFTypeRef *)&result);
    if (status == errSecItemNotFound)
        status = SecItemAdd((CFDictionaryRef)query, (CFTypeRef *)&result);
    if (status != errSecSuccess)
        return nil;
    NSString *accessGroup = [(__bridge NSDictionary *)result objectForKey:(id)kSecAttrAccessGroup];
    NSArray *components = [accessGroup componentsSeparatedByString:@"."];
    NSString *teamID = [[components objectEnumerator] nextObject];
    CFRelease(result);
    return teamID;
}

Swift

    func teamID() -> String {
        let unknown = "unknown"
        let query = NSDictionary(dictionaryLiteral:(kSecClass,kSecClassGenericPassword),
                                 (kSecAttrAccount,"bundleSeedID"),
                                 (kSecAttrService,""),
                                 (kSecReturnAttributes,kCFBooleanTrue as Any)
        )
        var result:CFTypeRef?
        var status = SecItemCopyMatching(query, &result)
        if status  == errSecItemNotFound{
            status = SecItemAdd(query, &result)
        }
        if status != errSecSuccess{
            return unknown
        }
        let accessGroup:String = result?.object(forKey: kSecAttrAccessGroup)! as! String
        let components = accessGroup.components(separatedBy: ".")
        let teamID = components.first!
        return teamID
    }

PS

Keychain 中默認(rèn)的accessGroup為:teamID.bundleID，例如:39E8LGDFGR.com.company.test