NSCharacterSet URLHostAllowedCharacterSet不替换'+'符号？

Question

我正在努力通过网络传输长加密字符串并让它们在服务器上正确传出.例如,我在客户端上有这个加密的字符串:

wcWSERZCh8Xm1hpbNo1kSD1LvFmpuUr4wmq9hQUWeK0vYcLeFPGwFR/sBTES1A4rPV6eyp9nzEEU9uKkiFSTdP + SPOSqUf6evjf3WRHrXMRe81lIrHuRyk0iRwoNe5uIk + VlpR41kETmznXa4 + gELmf53r7oayRkkffnIPDmpO + WbgE0VL3PQeOsXB01tWJyDiBIsz5WJiiEIm3ZoJW/SW ==

正如你所看到的,它不会没有一些URL编码通过网络传输(几个字符+和/,最显着的).我不完全确定在其他情况下是否会出现其他角色,所以我想确保我的解决方案"普遍"正确.我正在使用这一行:

NSString *escapedString = [cipherString stringByAddingPercentEncodingWithAllowedCharacters:[NSCharacterSet URLHostAllowedCharacterSet]];

我在高度评价的答案中找到了.

但是,我仍然无法在服务器端解密此问题,因此我在发送之前立即在客户端上打印出结果,我看到了:

wcWSERZCh8Xm1hpbNo1kSD1LvFmpuUr4wmq9hQUWeK0vYcLeFPGwFR%2FsBTES1A4rPV6eyp9nzEEU9uKkiFSTdP + SPOSqUf6evjf3WRHrXMRe81lIrHuRyk0iRwoNe5uIk + VlpR41kETmznXa4 + gELmf53r7oayRkkffnIPDmpO + WbgE0VL3PQeOsXB01tWJyDiBIsz5WJiiEIm3ZoJW%2Fsw ==

为什么'+'标志仍然存在？我使用了错误允许的字符集吗？我应该使用哪个字符集来保证我正确地逃避所有有问题的字符？

如果它有帮助,这里是我用来加密纯文本字符串的代码.完成后,我在通过网络发送之前对结果进行base64编码:

- (NSData *)phpEncryptCleartext : (NSData *)cleartext
{
    NSData *cleartextPadded = [self phpPadData:cleartext];

    CCCryptorStatus ccStatus        = kCCSuccess;
    size_t          cryptBytes      = 0;    // Number of bytes moved to buffer.
    NSMutableData  *cipherTextData  = [NSMutableData dataWithLength:cleartextPadded.length];

    ccStatus = CCCrypt(kCCEncrypt,
                       kCCAlgorithmAES128,
                       0,
                       _sessionKey.bytes,
                       kCCKeySizeAES128,
                       _iv.bytes,
                       cleartextPadded.bytes,
                       cleartextPadded.length,
                       cipherTextData.mutableBytes,
                       cipherTextData.length,
                       &cryptBytes);

    if (ccStatus == kCCSuccess) {
        cipherTextData.length = cryptBytes;
    }
    else {
        NSLog(@"kEncryptionError code: %d", ccStatus); // Add error handling
        cipherTextData = nil;
    }

    return cipherTextData;
}

谢谢你的建议!

Answer 1

Swift版本在这里.

逃避角色使用 stringByAddingPercentEncodingWithAllowedCharacters:

NSString *URLEscapedString =
[string stringByAddingPercentEncodingWithAllowedCharacters:[NSCharacterSet URLQueryAllowedCharacterSet]];

以下是有用的字符集,实际上不包括在集合中的字符:

URLFragmentAllowedCharacterSet  "#%<>[\]^`{|}
URLHostAllowedCharacterSet      "#%/<>?@\^`{|}
URLPasswordAllowedCharacterSet  "#%/:<>?@[\]^`{|}
URLPathAllowedCharacterSet      "#%;<>?[\]^`{|}
URLQueryAllowedCharacterSet     "#%<>[\]^`{|}
URLUserAllowedCharacterSet      "#%/:<>?@[\]^`

或者只使用你需要逃脱的角色创建自己的角色.

NSCharacterSet *customCharacterset = [[NSCharacterSet characterSetWithCharactersInString:@"your characters"] invertedSet];

创建一个结合了以上所有内容的字符:

NSCharacterSet *URLFullCharacterSet = [[NSCharacterSet characterSetWithCharactersInString:@" \"#%/:<>?@[\\]^`{|}"] invertedSet];

创建Base64

在Base64字符集的情况下:

NSCharacterSet *URLBase64CharacterSet = [[NSCharacterSet characterSetWithCharactersInString:@"/+=\n"] invertedSet];

注意:stringByAddingPercentEncodingWithAllowedCharacters还将编码需要编码的UTF-8字符.

验证集合中字符的示例:

void characterInSet(NSCharacterSet *set) {
    NSMutableString *characters = [NSMutableString new];
    NSCharacterSet *invertedSet = set.invertedSet;
    for (int i=32; i<127; i++) {
        if ([invertedSet characterIsMember:(unichar)i]) {
            NSString *c = [[NSString alloc] initWithBytes:&i length:1 encoding:NSUTF8StringEncoding];
            [characters appendString:c];
        }
    }
    printf("characters not in set: '%s'\n", [characters UTF8String]);
}