MySQ612Z

1class UrlParser
2    {
3        private const string secretKey = "TT18WlV5TXVeLXFXYn1WTF5qSmR9TXYpOHklYlFXWGY+SUZCRGNKPiU0emcyQ2l8dGVsamBkVlpA";
4        private string registeredSecretCharPool = String.Empty;
5
6        public UrlParser()
7        {
8            // Register secret char pool
9            registeredSecretCharPool = RegisterCharPool(secretKey);
10        }
11
12        private string RegisterCharPool(string key)
13        {
14            Dictionary<char, int> k = new Dictionary<char, int>();
15            int a = 0, l = 0, d = 0, c = 0, h = key.Length, b;
16            string charPool = "";
17           
18            for (a = 0;  64 > a; a++)
19            { 
20                k.Add("ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz0123456789+/"[a], a);
21            }
22
23            for (d = 0; d < h; d++)
24            {
25                char index = key[d];
26                for (a = (k.ContainsKey(index) ? k[index] : 0), l =(l<<6)+a, c+=6; 8 <=c;)
27                {
28                    b = (int)((uint)l >> (c -= 8) & 255);
29                    bool bIsGreaterThan0 = Convert.ToBoolean(b);
30                    
31                    if (bIsGreaterThan0 || d < h - 2)
32                        charPool += (char)(b);
33                }
34            }
35
36            return charPool;
37        }
38
39        public string ProcessRecording(string urlEncoded)
40        {
41            if (2 > urlEncoded.Length || 0 != urlEncoded.IndexOf("e:"))
42                return urlEncoded;
43
44            string publicCharPool = RegisterCharPool(urlEncoded.Substring(2));
45            Dictionary<int, int> a = new Dictionary<int, int>();
46            int h = 0;
47            int d;
48            string urlDecoded = "";
49            int b;
50
51            for (b = 0; 256 > b; b++)
52                a.Add(b, b);
53
54            for (b = 0; 256 > b; b++)
55            {
56                h = (h + a[b] + registeredSecretCharPool.ToCharArray()[(b % registeredSecretCharPool.Length)]) % 256;
57                d = a[b];
58                a[b] = a[h];
59                a[h] = d;
60            }
61
62            
63            for (int e = b = h = 0; e < publicCharPool.Length; e++)
64            {
65                b = (b + 1) % 256;
66                h = (h + a[b]) % 256;
67                d = a[b];
68                a[b] = a[h];
69                a[h] = d;
70                urlDecoded += (char)(publicCharPool.ToCharArray()[e] ^ a[(a[b] + a[h]) % 256]);
71            }
72
73            if(0 != urlDecoded.IndexOf("http"))
74            {
75                return $"Failed to decode URL { urlEncoded }; got { urlDecoded }";
76            }
77          
78            return urlDecoded;
79        }
80    }