推荐一款加密解密的算法，用于简单数据的传输。

水深无声 2022-08-02 01:58 123阅读 0赞

package TestCodeAndEnCode;  
  
public class SecBase64 \{  
private static final byte\[\] encodingTable = \{ (byte) 'A', (byte) 'B',  
(byte) 'C', (byte) 'D', (byte) 'E', (byte) 'F', (byte) 'G',  
(byte) 'H', (byte) 'I', (byte) 'J', (byte) 'K', (byte) 'L',  
(byte) 'M', (byte) 'N', (byte) 'O', (byte) 'P', (byte) 'Q',  
(byte) 'R', (byte) 'S', (byte) 'T', (byte) 'U', (byte) 'V',  
(byte) 'W', (byte) 'X', (byte) 'Y', (byte) 'Z', (byte) 'a',  
(byte) 'b', (byte) 'c', (byte) 'd', (byte) 'e', (byte) 'f',  
(byte) 'g', (byte) 'h', (byte) 'i', (byte) 'j', (byte) 'k',  
(byte) 'l', (byte) 'm', (byte) 'n', (byte) 'o', (byte) 'p',  
(byte) 'q', (byte) 'r', (byte) 's', (byte) 't', (byte) 'u',  
(byte) 'v', (byte) 'w', (byte) 'x', (byte) 'y', (byte) 'z',  
(byte) '0', (byte) '1', (byte) '2', (byte) '3', (byte) '4',  
(byte) '5', (byte) '6', (byte) '7', (byte) '8', (byte) '9',  
(byte) '+', (byte) '/' \};  
  
private static final byte\[\] decodingTable;  
  
static \{  
decodingTable = new byte\[128\];  
for (int i = 0; i < 128; i++) \{  
decodingTable\[i\] = (byte) -1;  
\}  
for (int i = 'A'; i <= 'Z'; i++) \{  
decodingTable\[i\] = (byte) (i - 'A');  
\}  
for (int i = 'a'; i <= 'z'; i++) \{  
decodingTable\[i\] = (byte) (i - 'a' + 26);  
\}  
for (int i = '0'; i <= '9'; i++) \{  
decodingTable\[i\] = (byte) (i - '0' + 52);  
\}  
decodingTable\['+'\] = 62;  
decodingTable\['/'\] = 63;  
\}  
  
// 加密  
public static byte\[\] encode(byte\[\] data) \{  
byte\[\] bytes;  
int modulus = data.length % 3;  
if (modulus == 0) \{  
bytes = new byte\[(4 \* data.length) / 3\];  
\} else \{  
bytes = new byte\[4 \* ((data.length / 3) + 1)\];  
\}  
int dataLength = (data.length - modulus);  
int a1;  
int a2;  
int a3;  
for (int i = 0, j = 0; i < dataLength; i += 3, j += 4) \{  
a1 = data\[i\] & 0xff;  
a2 = data\[i + 1\] & 0xff;  
a3 = data\[i + 2\] & 0xff;  
bytes\[j\] = encodingTable\[(a1 >>> 2) & 0x3f\];  
bytes\[j + 1\] = encodingTable\[((a1 << 4) | (a2 >>> 4)) & 0x3f\];  
bytes\[j + 2\] = encodingTable\[((a2 << 2) | (a3 >>> 6)) & 0x3f\];  
bytes\[j + 3\] = encodingTable\[a3 & 0x3f\];  
\}  
int b1;  
int b2;  
int b3;  
int d1;  
int d2;  
switch (modulus) \{  
case 0:  
break;  
case 1:  
d1 = data\[data.length - 1\] & 0xff;  
b1 = (d1 >>> 2) & 0x3f;  
b2 = (d1 << 4) & 0x3f;  
bytes\[bytes.length - 4\] = encodingTable\[b1\];  
bytes\[bytes.length - 3\] = encodingTable\[b2\];  
bytes\[bytes.length - 2\] = (byte) '=';  
bytes\[bytes.length - 1\] = (byte) '=';  
break;  
case 2:  
d1 = data\[data.length - 2\] & 0xff;  
d2 = data\[data.length - 1\] & 0xff;  
b1 = (d1 >>> 2) & 0x3f;  
b2 = ((d1 << 4) | (d2 >>> 4)) & 0x3f;  
b3 = (d2 << 2) & 0x3f;  
bytes\[bytes.length - 4\] = encodingTable\[b1\];  
bytes\[bytes.length - 3\] = encodingTable\[b2\];  
bytes\[bytes.length - 2\] = encodingTable\[b3\];  
bytes\[bytes.length - 1\] = (byte) '=';  
break;  
\}  
return bytes;  
\}  
  
// 解密  
public static byte\[\] decode(byte\[\] data) \{  
byte\[\] bytes;  
byte b1;  
byte b2;  
byte b3;  
byte b4;  
data = discardNonBase64Bytes(data);  
if (data\[data.length - 2\] == '=') \{  
bytes = new byte\[(((data.length / 4) - 1) \* 3) + 1\];  
\} else if (data\[data.length - 1\] == '=') \{  
bytes = new byte\[(((data.length / 4) - 1) \* 3) + 2\];  
\} else \{  
bytes = new byte\[((data.length / 4) \* 3)\];  
\}  
for (int i = 0, j = 0; i < (data.length - 4); i += 4, j += 3) \{  
b1 = decodingTable\[data\[i\]\];  
b2 = decodingTable\[data\[i + 1\]\];  
b3 = decodingTable\[data\[i + 2\]\];  
b4 = decodingTable\[data\[i + 3\]\];  
bytes\[j\] = (byte) ((b1 << 2) | (b2 >> 4));  
bytes\[j + 1\] = (byte) ((b2 << 4) | (b3 >> 2));  
bytes\[j + 2\] = (byte) ((b3 << 6) | b4);  
\}  
if (data\[data.length - 2\] == '=') \{  
b1 = decodingTable\[data\[data.length - 4\]\];  
b2 = decodingTable\[data\[data.length - 3\]\];  
bytes\[bytes.length - 1\] = (byte) ((b1 << 2) | (b2 >> 4));  
\} else if (data\[data.length - 1\] == '=') \{  
b1 = decodingTable\[data\[data.length - 4\]\];  
b2 = decodingTable\[data\[data.length - 3\]\];  
b3 = decodingTable\[data\[data.length - 2\]\];  
bytes\[bytes.length - 2\] = (byte) ((b1 << 2) | (b2 >> 4));  
bytes\[bytes.length - 1\] = (byte) ((b2 << 4) | (b3 >> 2));  
\} else \{  
b1 = decodingTable\[data\[data.length - 4\]\];  
b2 = decodingTable\[data\[data.length - 3\]\];  
b3 = decodingTable\[data\[data.length - 2\]\];  
b4 = decodingTable\[data\[data.length - 1\]\];  
bytes\[bytes.length - 3\] = (byte) ((b1 << 2) | (b2 >> 4));  
bytes\[bytes.length - 2\] = (byte) ((b2 << 4) | (b3 >> 2));  
bytes\[bytes.length - 1\] = (byte) ((b3 << 6) | b4);  
\}  
return bytes;  
\}  
  
// 解密  
public static byte\[\] decode(String data) \{  
byte\[\] bytes;  
byte b1;  
byte b2;  
byte b3;  
byte b4;  
data = discardNonBase64Chars(data);  
if (data.charAt(data.length() - 2) == '=') \{  
bytes = new byte\[(((data.length() / 4) - 1) \* 3) + 1\];  
\} else if (data.charAt(data.length() - 1) == '=') \{  
bytes = new byte\[(((data.length() / 4) - 1) \* 3) + 2\];  
\} else \{  
bytes = new byte\[((data.length() / 4) \* 3)\];  
\}  
for (int i = 0, j = 0; i < (data.length() - 4); i += 4, j += 3) \{  
b1 = decodingTable\[data.charAt(i)\];  
b2 = decodingTable\[data.charAt(i + 1)\];  
b3 = decodingTable\[data.charAt(i + 2)\];  
b4 = decodingTable\[data.charAt(i + 3)\];  
bytes\[j\] = (byte) ((b1 << 2) | (b2 >> 4));  
bytes\[j + 1\] = (byte) ((b2 << 4) | (b3 >> 2));  
bytes\[j + 2\] = (byte) ((b3 << 6) | b4);  
\}  
if (data.charAt(data.length() - 2) == '=') \{  
b1 = decodingTable\[data.charAt(data.length() - 4)\];  
b2 = decodingTable\[data.charAt(data.length() - 3)\];  
bytes\[bytes.length - 1\] = (byte) ((b1 << 2) | (b2 >> 4));  
\} else if (data.charAt(data.length() - 1) == '=') \{  
b1 = decodingTable\[data.charAt(data.length() - 4)\];  
b2 = decodingTable\[data.charAt(data.length() - 3)\];  
b3 = decodingTable\[data.charAt(data.length() - 2)\];  
bytes\[bytes.length - 2\] = (byte) ((b1 << 2) | (b2 >> 4));  
bytes\[bytes.length - 1\] = (byte) ((b2 << 4) | (b3 >> 2));  
\} else \{  
b1 = decodingTable\[data.charAt(data.length() - 4)\];  
b2 = decodingTable\[data.charAt(data.length() - 3)\];  
b3 = decodingTable\[data.charAt(data.length() - 2)\];  
b4 = decodingTable\[data.charAt(data.length() - 1)\];  
bytes\[bytes.length - 3\] = (byte) ((b1 << 2) | (b2 >> 4));  
bytes\[bytes.length - 2\] = (byte) ((b2 << 4) | (b3 >> 2));  
bytes\[bytes.length - 1\] = (byte) ((b3 << 6) | b4);  
\}  
return bytes;  
\}  
  
private static byte\[\] discardNonBase64Bytes(byte\[\] data) \{  
byte\[\] temp = new byte\[data.length\];  
int bytesCopied = 0;  
for (int i = 0; i < data.length; i++) \{  
if (isValidBase64Byte(data\[i\])) \{  
temp\[bytesCopied++\] = data\[i\];  
\}  
\}  
byte\[\] newData = new byte\[bytesCopied\];  
System.arraycopy(temp, 0, newData, 0, bytesCopied);  
return newData;  
\}  
  
private static String discardNonBase64Chars(String data) \{  
StringBuffer sb = new StringBuffer();  
int length = data.length();  
for (int i = 0; i < length; i++) \{  
if (isValidBase64Byte((byte) (data.charAt(i)))) \{  
sb.append(data.charAt(i));  
\}  
\}  
return sb.toString();  
\}  
  
private static boolean isValidBase64Byte(byte b) \{  
if (b == '=') \{  
return true;  
\} else if ((b < 0) || (b >= 128)) \{  
return false;  
\} else if (decodingTable\[b\] == -1) \{  
return false;  
\}  
return true;  
\}  
  
// 测试类  
public static void main(String\[\] args) \{  
String data = "this is test about encode and decode 22222 $%^%^";  
byte\[\] result = SecBase64.encode(data.getBytes());// 加密  
System.out.println("Basic " + data);  
System.out.println("enCode Basic " + new String(result));  
System.out.println("DeCode Basic "+new String(SecBase64.decode(new String(result))));// 解密  
\}  
  
\}