在线时间:8:00-16:00
迪恩网络APP
随时随地掌握行业动态
扫描二维码
关注迪恩网络微信公众号
一、编码规则Base64编码的思想是是采用64个基本的ASCII码字符对数据进行重新编码。它将需要编码的数据拆分成字节数组。以3个字节为一组。按顺序排列24 位数据,再把这24位数据分成4组,即每组6位。再在每组的的最高位前补两个0凑足一个字节。这样就把一个3字节为一组的数据重新编码成了4个字节。当所要编码的数据的字节数不是3的整倍数,也就是说在分组时最后一组不够3个字节。这时在最后一组填充1到2个0字节。并在最后编码完成后在结尾添加1到2个 “=”。 例:将对ABC进行BASE64编码:
注:BASE64字符表:ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz0123456789+/ 二、解码规则 三、C#中的实现 编码类:
/// <summary>
/// Base64编码类。 /// 将byte[]类型转换成Base64编码的string类型。 /// </summary> public class Base64Encoder { byte[] source; int length, length2; int blockCount; int paddingCount; public static Base64Encoder Encoder = new Base64Encoder(); public Base64Encoder() { } private void init(byte[] input) { source = input; length = input.Length; if ((length % 3) == 0) { paddingCount = 0; blockCount = length / 3; } else { paddingCount = 3 - (length % 3); blockCount = (length + paddingCount) / 3; } length2 = length + paddingCount; } public string GetEncoded(byte[] input) { //初始化 init(input); byte[] source2; source2 = new byte[length2]; for (int x = 0; x < length2; x++) { if (x < length) { source2[x] = source[x]; } else { source2[x] = 0; } } byte b1, b2, b3; byte temp, temp1, temp2, temp3, temp4; byte[] buffer = new byte[blockCount * 4]; char[] result = new char[blockCount * 4]; for (int x = 0; x < blockCount; x++) { b1 = source2[x * 3]; b2 = source2[x * 3 + 1]; b3 = source2[x * 3 + 2]; temp1 = (byte)((b1 & 252) >> 2); temp = (byte)((b1 & 3) << 4); temp2 = (byte)((b2 & 240) >> 4); temp2 += temp; temp = (byte)((b2 & 15) << 2); temp3 = (byte)((b3 & 192) >> 6); temp3 += temp; temp4 = (byte)(b3 & 63); buffer[x * 4] = temp1; buffer[x * 4 + 1] = temp2; buffer[x * 4 + 2] = temp3; buffer[x * 4 + 3] = temp4; } for (int x = 0; x < blockCount * 4; x++) { result[x] = sixbit2char(buffer[x]); } switch (paddingCount) { case 0: break; case 1: result[blockCount * 4 - 1] = '='; break; case 2: result[blockCount * 4 - 1] = '='; result[blockCount * 4 - 2] = '='; break; default: break; } return new string(result); } private char sixbit2char(byte b) { char[] lookupTable = new char[64]{ 'A','B','C','D','E','F','G','H','I','J','K','L','M', 'N','O','P','Q','R','S','T','U','V','W','X','Y','Z', 'a','b','c','d','e','f','g','h','i','j','k','l','m', 'n','o','p','q','r','s','t','u','v','w','x','y','z', '0','1','2','3','4','5','6','7','8','9','+','/'}; if ((b >= 0) && (b <= 63)) { return lookupTable[(int)b]; } else { return ' '; } } }
/// <summary> /// Base64解码类 /// 将Base64编码的string类型转换成byte[]类型 /// </summary> public class Base64Decoder { char[] source; int length, length2, length3; int blockCount; int paddingCount; public static Base64Decoder Decoder = new Base64Decoder(); public Base64Decoder() { } private void init(char[] input) { int temp = 0; source = input; length = input.Length; for (int x = 0; x < 2; x++) { if (input[length - x - 1] == '=') temp++; } paddingCount = temp; blockCount = length / 4; length2 = blockCount * 3; } public byte[] GetDecoded(string strInput) { //初始化 init(strInput.ToCharArray()); byte[] buffer = new byte[length]; byte[] buffer2 = new byte[length2]; for (int x = 0; x < length; x++) { buffer[x] = char2sixbit(source[x]); } byte b, b1, b2, b3; byte temp1, temp2, temp3, temp4; for (int x = 0; x < blockCount; x++) { temp1 = buffer[x * 4]; temp2 = buffer[x * 4 + 1]; temp3 = buffer[x * 4 + 2]; temp4 = |
请发表评论