数据加密

encrypt.java

public static byte[] encrypt(byte[] plain, String key) throws Exception {
 
    if (plain == null) {
        throw new Exception("plain cannot be null");
    }
 
    if (key == null) {
        throw new Exception("key cannot be null");
    }
 
    byte[] keyBytes = key.getBytes();
    if (keyBytes.length < 16) {
        throw new Exception("The key must have length larger than 16");
    }
 
 
 
    int[] keyInts = GTransformer.bytes2ints(keyBytes);
    int plainLength = plain.length;
    byte[] plain2Ints = new byte[(plainLength / 8) * 8];
    System.arraycopy(plain, 0, plain2Ints, 0, plain2Ints.length);
    int[] plainInts = GTransformer.bytes2ints(plain2Ints);
 
    ByteBuffer resultBuffer = ByteBuffer.allocate(plainLength);
 
    for (int i = 0; i < plainInts.length; i += 2) {
 
        int delta = 0x9e3779b9;
        int sum = 0;
        int a = plainInts[i];
        int b = plainInts[i + 1];
 
        for (int j = 0; j < 8; j++) {
 
            sum += delta;
            a += ((b << 4) + keyInts[0]) ^ (b + sum) ^ ((b >>> 5) + keyInts[1]);
            b += ((a << 4) + keyInts[2]) ^ (a + sum) ^ ((a >>> 5) + keyInts[3]);
        }
 
        resultBuffer.putInt(a);
        resultBuffer.putInt(b);
    }
 
    resultBuffer.put(plain, plain2Ints.length, plainLength - plain2Ints.length);
    byte[] encrypted = resultBuffer.array();
 
    return  encrypted;
}
 
 
// GTransformer.java
public class GTransformer {
    public static int[] bytes2ints(byte[] datas) {

        if (datas == null) {
           return null;
        }

        int length = datas.length;
        if (length == 0) {
           return new int[0];
        }

        IntBuffer buffer = ByteBuffer.wrap(datas).asIntBuffer();
        int[] out = new int[buffer.remaining()];
        buffer.get(out);

        return out;
    }
}