C # The base64 encryption and decryption algorithm class that can customize the code table,

C # The base64 encryption and decryption algorithm class that can customize the code table,

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1 using System; 2 using System. collections. generic; 3 using System. linq; 4 using System. text; 5 using System. threading. tasks; 6 7 namespace Libraries 8 {9 public class Base64Crypt 10 {11 private string S; 12 private string K; 13 private List <char> T; 14 public Base64Crypt () 15 {16 T = new List <char> (); 17 K = "zookeeper when there are too many threads, there are too many threads, too many threads "; 18 // K = "ABCDEFGHI JKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz0123456789 +/"; // standard code table 19} 20 public string Token 21 {22 get 23 {24 return S = null? K: S; 25} 26 set 27 {28 T. clear (); 29 S = value; 30 if (S = null) 31 {32 foreach (var item in K) 33 {34 T. add (item); 35} 36} else if (S. length <64) 37 {38 foreach (var item in S) 39 {40 T. add (item); 41} 42 for (int I = 0; I <64-S.Length; I ++) 43 {44 T. add (K [I]); 45} 46} 47 else 48 {49 for (int I = 0; I <64; I ++) 50 {51 T. add (S [I]); 52} 53} 54} 55} 56 57 public string Encode (s Tring x) 58 {59 return string. IsNullOrEmpty (x )? X: InternalEncode (Encoding. UTF8.GetBytes (x); 60} 61 public string Decode (string x) 62 {63 return string. IsNullOrEmpty (x )? X: Encoding. UTF8.GetString (InternalDecode (x); 64} 65 66 public byte [] Encode (byte [] x) 67 {68 return x = null? Null: Encoding. UTF8.GetBytes (InternalEncode (x); 69} 70 public byte [] Decode (byte [] x) 71 {72 return x = null? Null: InternalDecode (Encoding. UTF8.GetString (x); 73} 74 private void CheckToken () 75 {76 if (T. Count! = 64) 77 {78 Token = K; 79} 80} 81 private byte [] InternalDecode (string x) 82 {83 CheckToken (); 84 byte [] r; 85 string t; 86 int p = 0; 87 int m = x. length/4; 88 int n = x. length % 4; 89 if (n = 0) 90 {91 r = new byte [3 * m]; 92} 93 else 94 {95 r = new byte [3 * m + n-1]; 96 t = string. empty; 97 98 for (int I = n; I> 0; I --) 99 {100 t + = ByteToBin (byte) T. indexOf (x [x. length-I]). substring (2); 101} 102 103 for (int I = 0; I <n-1; I ++) 104 {105 r [3 * m + I] = BinToByte (t. substring (8 * I, 8); 106} 107} 108 for (int I = 0; I <m; I ++) 109 {110 t = string. empty; 111 for (int j = 0; j <4; j ++) 112 {113 t + = ByteToBin (byte) T. indexOf (x [4 * I + j]). substring (2); 114} 115 for (int j = 0; j <t. length/8; j ++) 116 {117 r [p ++] = BinToByte (t. substring (8 * j, 8); 118} 119} 120 return r; 121} 122 private string InternalEncode (byte [] x) 123 {124 CheckToken (); 125 string r = string. empty; 126 string t; 127 int m = x. length/3; 128 int n = x. length % 3; 129 for (int I = 0; I <m; I ++) 130 {131 t = string. empty; 132 for (int j = 0; j <3; j ++) 133 {134 t + = ByteToBin (x [3 * I + j]); 135} 136 r + = base64Encode (t); 137} 138 if (n = 1) 139 {140 t = ByteToBin (x [x. length-1]). padRight (12, '0'); 142 r + = base64Encode (t); 143} 144 else if (n = 2) 145 {146 t = string. empty; 147 for (int I = n; I> 0; I --) 148 {149 t + = ByteToBin (x [x. length-I]); 150} 151 t = t. padRight (18, '0'); 152 r + = base64Encode (t); 153} 154 return r; 155} 156 private string base64Encode (string x) 157 {158 string r = string. empty; 159 for (int I = 0; I <x. length/6; I ++) 160 {161 r + = T [BinToByte (x. substring (6 * I, 6)]; 162} 163 return r; 164} 165 166 private string ByteToBin (byte x) 167 {168 return Convert. toString (x, 2 ). padLeft (8, '0'); 169} 170 private byte BinToByte (string x) 171 {172 return Convert. toByte (x, 2); 173} 174 175} 176} 177