define kASDESKEY @"0123456789ABCDEF"

const Byte s_iv[] = {0x63,0x75};

const Byte s_key[] = {0x58,0x78};

/// 使用DES加密方法

• (NSString *)encodeDesWithString2:(NSString *)string {
  NSString *ciphertext = nil;
  const char *textBytes = [string UTF8String];
  size_t dataLength = [string length];
  //==================

  uint8_t *bufferPtr = NULL;
  size_t bufferPtrSize = 0;
  size_t movedBytes = 0;

  bufferPtrSize = (dataLength + kCCBlockSizeDES) & ~(kCCBlockSizeDES - 1);
  bufferPtr = malloc( bufferPtrSize * sizeof(uint8_t));
  memset((void *)bufferPtr, 0x0, bufferPtrSize);

  CCCryptorStatus cryptStatus = CCCrypt(kCCEncrypt, kCCAlgorithmDES,
  kCCOptionPKCS7Padding,
  s_key, kCCKeySizeDES,
  s_iv,
  textBytes, dataLength,
  (void *)bufferPtr, bufferPtrSize,
  &movedBytes);
  if (cryptStatus == kCCSuccess) {

   ciphertext= [ASKDESTools parseByte2HexString:bufferPtr :(int)movedBytes];
  

  }
  ciphertext=[ciphertext uppercaseString];//字符变大写

  return ciphertext;
  }

/// 使用DES进行解密计算

• (NSString *)decodeDesWithString2:(NSString *)string {

  NSData* cipherData = [ASKDESTools convertHexStrToData:[string lowercaseString]];

  unsigned char buffer[1024];
  memset(buffer, 0, sizeof(char));
  size_t numBytesDecrypted = 0;
  // NSString *testString = kASDESKEY;
  // NSData *testData = [testString dataUsingEncoding: NSUTF8StringEncoding];
  // Byte iv = (Byte )[testData bytes];
  CCCryptorStatus cryptStatus = CCCrypt(kCCDecrypt,
  kCCAlgorithmDES,
  kCCOptionPKCS7Padding,
  s_key,
  kCCKeySizeDES,
  s_iv,
  [cipherData bytes],
  [cipherData length],
  buffer,
  1024,
  &numBytesDecrypted);
  NSString plainText = nil;
  if (cryptStatus == kCCSuccess) {
  NSData data = [NSData dataWithBytes:buffer length:(NSUInteger)numBytesDecrypted];
  plainText = [[NSString alloc] initWithData:data encoding:NSUTF8StringEncoding];
  }
  return plainText;

}

/*
加密解密中有两个方法调用，其实是为了16进制与data之间的转换。有些公司并未转换成16进制，而是需要跟base64共同加解密。方法适用，只需要将得出的plainText 的值转成base64即可。
*/

/// 加密时转成16进制

• (NSString *) parseByte2HexString:(Byte *) bytes :(int)len {

  NSLog(@"bytes ==== %s",bytes);
  NSString *hexStr = @"";
  NSMutableString *hexString = @"";
  if(bytes)
  {
  for(int i = 0; i < len ; i++)
  {
  NSString *newHexStr = [NSString stringWithFormat:@"%x",bytes[i]&0xff]; ///16进制数
  if([newHexStr length]==1){
  hexStr = [NSString stringWithFormat:@"%@0%@",hexStr,newHexStr];
  }
  else
  {
  hexStr = [NSString stringWithFormat:@"%@%@",hexStr,newHexStr];
  }
  }
  }

  return hexStr;
  }

/// 解密时转回data

• (NSData *)convertHexStrToData:(NSString *)str {
  if (!str || [str length] == 0) {
  return nil;
  }

  NSMutableData *hexData = [[NSMutableData alloc] initWithCapacity:8];
  NSRange range;
  if ([str length] % 2 == 0) {
  range = NSMakeRange(0, 2);
  } else {
  range = NSMakeRange(0, 1);
  }
  for (NSInteger i = range.location; i < [str length]; i += 2) {
  unsigned int anInt;
  NSString *hexCharStr = [str substringWithRange:range];
  NSScanner *scanner = [[NSScanner alloc] initWithString:hexCharStr];

    [scanner scanHexInt:&anInt];
    NSData *entity = [[NSData alloc] initWithBytes:&anInt length:1];
    [hexData appendData:entity];
    
    range.location += range.length;
    range.length = 2;
  

  }

  return hexData;
  }