将公钥从PEM文件加载到NSData

Question

我有一个存储在PEM文件中的公钥，我想加载这个文件并将公钥提取到NSData中，然后我可以发送到[SecKeyWrapper addPeerPublicKey：keyBits：]（参见http://developer.apple.com/library/ios/#samplecode/CryptoExercise/Listings/Classes_SecKeyWrapper_h.html ）。

我如何在Objective-C（在iOS上）上做到这一点？

Answer 1

假设您知道公钥存在并以“----- BEGIN PUBLIC KEY -----”开头并以“----- END PUBLIC KEY -----”结尾，您可以以下内容：

NSString *startPublicKey = @"-----BEGIN PUBLIC KEY-----";
NSString *endPublicKey = @"-----END PUBLIC KEY-----";
NSString* path = [[NSBundle mainBundle] pathForResource:@"mykey"
                                                     ofType:@"pem"];
NSString* content = [NSString stringWithContentsOfFile:path
                                                  encoding:NSUTF8StringEncoding
                                                     error:NULL];
NSString *publicKey;
NSScanner *scanner = [NSScanner scannerWithString:content];
[scanner scanUpToString:startPublicKey intoString:nil];
[scanner scanString:startPublicKey intoString:nil];
[scanner scanUpToString:endPublicKey intoString:&publicKey];

NSData *data = [NSData base64DataFromString:publicKey];