iphone開發：從https地址驗證證書信息

Question

當用戶使用網絡瀏覽器（Safari，Chrome，Windows）連接到「https url」時，例如：「https://encrypted.google.com」。 ..），那麼用戶可以獲得關於與這樣的「https url」相關的證書的信息;也就是說，在連接到URL「https://encrypted.google.com」的情況下，就可以驗證以下證書信息：

1. Equifax安全證書頒發機構
2. *。谷歌。 com發佈者：Google互聯網管理局。證書的到期日期。該證書是否有效或約像簽名算法，公共密鑰信息，指紋等證書沒有
3. 更多細節

所以，問題是：「什麼是爲了適當的目標C函數調用獲得上述信息（或者至少知道證書是否有效）？「

由於提前，

Answer 1

證書信息可以使用NSURLConnection的委託方法獲得：

- (BOOL)connection:(NSURLConnection *)connection canAuthenticateAgainstProtectionSpace:(NSURLProtectionSpace *)protectionSpace 

- (void)connection:(NSURLConnection *)connection didReceiveAuthenticationChallenge:(NSURLAuthenticationChallenge *)challenge 

即：

- (BOOL)connection:(NSURLConnection *)connection canAuthenticateAgainstProtectionSpace:(NSURLProtectionSpace *)protectionSpace { 
BOOL result = [protectionSpace.authenticationMethod isEqualToString:NSURLAuthenticationMethodServerTrust]; 
NSLog(@"<%p %@: %s line:%d> Result:%s", self, [[NSString stringWithUTF8String:__FILE__] lastPathComponent], __PRETTY_FUNCTION__, __LINE__, (result == YES) ? "YES" : "NO"); 
return result; 
} 

- (void)connection:(NSURLConnection *)connection  didReceiveAuthenticationChallenge:(NSURLAuthenticationChallenge *)challenge { 
NSArray *trustedHosts = [NSArray arrayWithObject:@"encrypted.google.com"]; 
BOOL isAuthMethodServerTrust = [challenge.protectionSpace.authenticationMethod isEqualToString:NSURLAuthenticationMethodServerTrust]; 
NSLog(@"<%p %@: %s line:%d> Result:%s", self, [[NSString stringWithUTF8String:__FILE__] lastPathComponent], __PRETTY_FUNCTION__, __LINE__, (isAuthMethodServerTrust == YES) ? "YES" : "NO"); 
if (isAuthMethodServerTrust) 
{ 
    if ([trustedHosts containsObject:challenge.protectionSpace.host]) 
    { 
     NSLog(@"<%p %@: %s line:%d> trustedHosts containsObject:challenge.protectionSpace.host", self, [[NSString stringWithUTF8String:__FILE__] lastPathComponent], __PRETTY_FUNCTION__, __LINE__); 
     NSURLCredential* urlCredential = [NSURLCredential credentialForTrust:challenge.protectionSpace.serverTrust]; 
     NSLog(@"<%p %@: %s line:%d> Url credential", self, [[NSString stringWithUTF8String:__FILE__] lastPathComponent], __PRETTY_FUNCTION__, __LINE__);   
     [challenge.sender useCredential:urlCredential forAuthenticationChallenge:challenge]; 

     //Code to verify certificate info 
     SecTrustRef trustRef = [[challenge protectionSpace] serverTrust]; 
     CFIndex count = SecTrustGetCertificateCount(trustRef); 

     for (CFIndex i = 0; i < count; i++) 
     { 
      SecCertificateRef certRef = SecTrustGetCertificateAtIndex(trustRef, i); 
      CFStringRef certSummary = SecCertificateCopySubjectSummary(certRef); 
      CFDataRef certData = SecCertificateCopyData(certRef); 
      NSLog(@"<%p %@: %s line:%d> Certificate summary:%@", self, [[NSString stringWithUTF8String:__FILE__] lastPathComponent], __PRETTY_FUNCTION__, __LINE__, (NSString*) certSummary); 
      NSLog(@"<%p %@: %s line:%d> Certificate data:%@", self, [[NSString stringWithUTF8String:__FILE__] lastPathComponent], __PRETTY_FUNCTION__, __LINE__, (NSString*) certData); 
      CFRelease(certData); 
     } 
    } 
} 
} 

該代碼會涉及到以下信息「HTTPS ：//encrypted.google.com「： 在」certSummary「NSString證書的頒發者。 在證書的「certData」數據中。問題是，目前我不知道如何從這樣的數據中提取信息（截止日期，公鑰，...），所以任何幫助都會受到歡迎。