105 lines
3.1 KiB
Java
105 lines
3.1 KiB
Java
package com.cscn;
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/**
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* 辅助工具：装载/存储、位运算、线性变换、打印等。
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*/
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public final class Zuc256Util {
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private Zuc256Util() {}
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/** 辅助方法：将字节数组转换为32位整数 */
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public static int getU32(byte[] p, int offset) {
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return ((p[offset] & 0xFF) << 24) |
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((p[offset + 1] & 0xFF) << 16) |
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((p[offset + 2] & 0xFF) << 8) |
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(p[offset + 3] & 0xFF);
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}
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/** 辅助方法：将32位整数转换为字节数组 */
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public static void putU32(byte[] p, int offset, int v) {
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p[offset] = (byte) (v >> 24);
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p[offset + 1] = (byte) (v >> 16);
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p[offset + 2] = (byte) (v >> 8);
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p[offset + 3] = (byte) v;
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}
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// === 31/32 位运算 ===
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/** 31位加法 */
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public static int add31(int a, int b) {
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long sum = (long)a + b;
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return (int) ((sum & 0x7FFFFFFF) + (sum >> 31));
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}
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/** 31位旋转 */
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public static int rot31(int a, int k) {
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return ((a << k) | (a >>> (31 - k))) & 0x7FFFFFFF;
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}
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/** 32位旋转 */
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public static int rot32(int a, int k) {
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return (a << k) | (a >>> (32 - k));
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}
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/**
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* L1函数
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*/
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public static int L1(int x) {
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return x ^ rot32(x, 2) ^ rot32(x, 10) ^ rot32(x, 18) ^ rot32(x, 24);
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}
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/**
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* L2函数
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*/
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public static int L2(int x) {
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return x ^ rot32(x, 8) ^ rot32(x, 14) ^ rot32(x, 22) ^ rot32(x, 30);
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}
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/** 创建31位无符号整数 */
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public static int makeU31(int a, int b, int c, int d) {
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return (((a & 0xFF) << 23) |
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((b & 0xFF) << 16) |
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((c & 0xFF) << 8) |
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(d & 0xFF)) & 0x7FFFFFFF;
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}
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/** 创建32位无符号整数 */
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public static int makeU32(int a, int b, int c, int d) {
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return ((a & 0xFF) << 24) |
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((b & 0xFF) << 16) |
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((c & 0xFF) << 8) |
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(d & 0xFF);
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}
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/** 提取IV */
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public static void extractIv(byte[] input25Byte, byte[] output23Byte) {
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if (input25Byte == null || output23Byte == null) return;
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// 复制前17字节
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System.arraycopy(input25Byte, 0, output23Byte, 0, 17);
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// 处理剩余8字节
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byte[] src = new byte[8];
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for (int i = 0; i < 8; i++) {
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src[i] = (byte) (input25Byte[17 + i] & 0x3F);
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}
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output23Byte[17] = (byte) ((src[0] << 2) | (src[1] >>> 4));
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output23Byte[18] = (byte) (((src[1] & 0x0F) << 4) | (src[2] >>> 2));
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output23Byte[19] = (byte) (((src[2] & 0x03) << 6) | src[3]);
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output23Byte[20] = (byte) ((src[4] << 2) | (src[5] >>> 4));
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output23Byte[21] = (byte) (((src[5] & 0x0F) << 4) | (src[6] >>> 2));
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output23Byte[22] = (byte) (((src[6] & 0x03) << 6) | src[7]);
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}
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/** 打印十六进制（调试用，TODO 生产/JC 环境可移除） */
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public static void printHex(String label, byte[] data, int len) {
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System.out.print(label + ": ");
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for (int i = 0; i < len; i++) {
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System.out.printf("%02x ", data[i] & 0xFF);
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}
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System.out.println();
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}
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}
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