安卓实现魔改版 CRC32 算法

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关于 CRC32 算法介绍可以参考这篇文章：常用加解密算法介绍

标准 CRC32 算法

创建 crc32.cpp，使用 C++ 实现标准 CRC32 算法

#include <jni.h>
#include <string>
#include <android/log.h>#define TAG "CRC32"unsigned int crc32_table[256];// 初始化 CRC32 查找表
void init_crc32_table() {unsigned int crc;for (int i = 0; i < 256; i++) {crc = i;for (int j = 8; j > 0; j--) {if (crc & 1) {crc = (crc >> 1) ^ 0xedb88320;} else {crc >>= 1;}}crc32_table[i] = crc;}
}// 计算 CRC32
unsigned int crc32(const std::string& str) {unsigned int crc = 0xffffffff;for (size_t i = 0; i < str.size(); i++) {unsigned char byte = str[i];crc = (crc >> 8) ^ crc32_table[(crc ^ byte) & 0xff];}return ~crc;
}

kotlin 层声明 native 方法

package com.cyrus.example.crc32class CRC32Utils {companion object {// 加载 native 库init {System.loadLibrary("crc32")}// 声明 native 静态方法@JvmStaticexternal fun crc32(input: String): String}}

实现 native 方法并调用 crc32 方法进行加密并返回 hex 字符串

extern "C" JNIEXPORT jstring JNICALL
Java_com_cyrus_example_crc32_CRC32Utils_crc32(JNIEnv *env, jclass , jstring input) {// 初始化 CRC32 表（只需调用一次）static bool is_initialized = false;if (!is_initialized) {init_crc32_table();is_initialized = true;}// 获取输入的字符串const char* str = env->GetStringUTFChars(input, nullptr);std::string input_str(str);env->ReleaseStringUTFChars(input, str);// 计算 CRC32 值unsigned int crc = crc32(input_str);// 返回 CRC32 的十六进制字符串char crcHex[9];  // CRC32 是 32 位，最大为 8 位十六进制数snprintf(crcHex, sizeof(crcHex), "%08x", crc);return env->NewStringUTF(crcHex);
}

调用示例：

CRC32Utils.crc32("txj1Dc")

效果如下：

word/media/image1.png

自定义 Table 版 CRC32 算法

CRC32 Table 是通过 init_crc32_table 方法中位移和异或常量 0xedb88320 运算得来的

crc = (crc >> 1) ^ 0xedb88320;

标准的 CRC32 Table 如下：

 0, 0x77073096, 0xEE0E612C, 0x990951BA,0x076DC419, 0x706AF48F, 0xE963A535, 0x9E6495A3,0x0EDB8832, 0x79DCB8A4, 0xE0D5E91E, 0x97D2D988,0x09B64C2B, 0x7EB17CBD, 0xE7B82D07, 0x90BF1D91,0x1DB71064, 0x6AB020F2, 0xF3B97148, 0x84BE41DE,0x1ADAD47D, 0x6DDDE4EB, 0xF4D4B551, 0x83D385C7,0x136C9856, 0x646BA8C0, 0xFD62F97A, 0x8A65C9EC,0x14015C4F, 0x63066CD9, 0xFA0F3D63, 0x8D080DF5,0x3B6E20C8, 0x4C69105E, 0xD56041E4, 0xA2677172,0x3C03E4D1, 0x4B04D447, 0xD20D85FD, 0xA50AB56B,0x35B5A8FA, 0x42B2986C, 0xDBBBC9D6, 0xACBCF940,0x32D86CE3, 0x45DF5C75, 0xDCD60DCF, 0xABD13D59,0x26D930AC, 0x51DE003A, 0xC8D75180, 0xBFD06116,0x21B4F4B5, 0x56B3C423, 0xCFBA9599, 0xB8BDA50F,0x2802B89E, 0x5F058808, 0xC60CD9B2, 0xB10BE924,0x2F6F7C87, 0x58684C11, 0xC1611DAB, 0xB6662D3D,0x76DC4190, 0x01DB7106, 0x98D220BC, 0xEFD5102A,0x71B18589, 0x06B6B51F, 0x9FBFE4A5, 0xE8B8D433,0x7807C9A2, 0x0F00F934, 0x9609A88E, 0xE10E9818,0x7F6A0DBB, 0x086D3D2D, 0x91646C97, 0xE6635C01,0x6B6B51F4, 0x1C6C6162, 0x856530D8, 0xF262004E,0x6C0695ED, 0x1B01A57B, 0x8208F4C1, 0xF50FC457,0x65B0D9C6, 0x12B7E950, 0x8BBEB8EA, 0xFCB9887C,0x62DD1DDF, 0x15DA2D49, 0x8CD37CF3, 0xFBD44C65,0x4DB26158, 0x3AB551CE, 0xA3BC0074, 0xD4BB30E2,0x4ADFA541, 0x3DD895D7, 0xA4D1C46D, 0xD3D6F4FB,0x4369E96A, 0x346ED9FC, 0xAD678846, 0xDA60B8D0,0x44042D73, 0x33031DE5, 0xAA0A4C5F, 0xDD0D7CC9,0x5005713C, 0x270241AA, 0xBE0B1010, 0xC90C2086,0x5768B525, 0x206F85B3, 0xB966D409, 0xCE61E49F,0x5EDEF90E, 0x29D9C998, 0xB0D09822, 0xC7D7A8B4,0x59B33D17, 0x2EB40D81, 0xB7BD5C3B, 0xC0BA6CAD,0xEDB88320, 0x9ABFB3B6, 0x03B6E20C, 0x74B1D29A,0xEAD54739, 0x9DD277AF, 0x04DB2615, 0x73DC1683,0xE3630B12, 0x94643B84, 0x0D6D6A3E, 0x7A6A5AA8,0xE40ECF0B, 0x9309FF9D, 0x0A00AE27, 0x7D079EB1,0xF00F9344, 0x8708A3D2, 0x1E01F268, 0x6906C2FE,0xF762575D, 0x806567CB, 0x196C3671, 0x6E6B06E7,0xFED41B76, 0x89D32BE0, 0x10DA7A5A, 0x67DD4ACC,0xF9B9DF6F, 0x8EBEEFF9, 0x17B7BE43, 0x60B08ED5,0xD6D6A3E8, 0xA1D1937E, 0x38D8C2C4, 0x4FDFF252,0xD1BB67F1, 0xA6BC5767, 0x3FB506DD, 0x48B2364B,0xD80D2BDA, 0xAF0A1B4C, 0x36034AF6, 0x41047A60,0xDF60EFC3, 0xA867DF55, 0x316E8EEF, 0x4669BE79,0xCB61B38C, 0xBC66831A, 0x256FD2A0, 0x5268E236,0xCC0C7795, 0xBB0B4703, 0x220216B9, 0x5505262F,0xC5BA3BBE, 0xB2BD0B28, 0x2BB45A92, 0x5CB36A04,0xC2D7FFA7, 0xB5D0CF31, 0x2CD99E8B, 0x5BDEAE1D,0x9B64C2B0, 0xEC63F226, 0x756AA39C, 0x026D930A,0x9C0906A9, 0xEB0E363F, 0x72076785, 0x05005713,0x95BF4A82, 0xE2B87A14, 0x7BB12BAE, 0x0CB61B38,0x92D28E9B, 0xE5D5BE0D, 0x7CDCEFB7, 0x0BDBDF21,0x86D3D2D4, 0xF1D4E242, 0x68DDB3F8, 0x1FDA836E,0x81BE16CD, 0xF6B9265B, 0x6FB077E1, 0x18B74777,0x88085AE6, 0xFF0F6A70, 0x66063BCA, 0x11010B5C,0x8F659EFF, 0xF862AE69, 0x616BFFD3, 0x166CCF45,0xA00AE278, 0xD70DD2EE, 0x4E048354, 0x3903B3C2,0xA7672661, 0xD06016F7, 0x4969474D, 0x3E6E77DB,0xAED16A4A, 0xD9D65ADC, 0x40DF0B66, 0x37D83BF0,0xA9BCAE53, 0xDEBB9EC5, 0x47B2CF7F, 0x30B5FFE9,0xBDBDF21C, 0xCABAC28A, 0x53B39330, 0x24B4A3A6,0xBAD03605, 0xCDD70693, 0x54DE5729, 0x23D967BF,0xB3667A2E, 0xC4614AB8, 0x5D681B02, 0x2A6F2B94,0xB40BBE37, 0xC30C8EA1, 0x5A05DF1B, 0x2D02EF8D

我们可以通过修改常量值，实现自定义 Table，比如改成 0xd76aa478

#include <jni.h>
#include <string>
#include <android/log.h>#define TAG "CustomCRC32"unsigned int custom_crc32_table[256];// 初始化 CRC32 查找表
void init_custom_crc32_table() {unsigned int crc;for (int i = 0; i < 256; i++) {crc = i;for (int j = 8; j > 0; j--) {if (crc & 1) {crc = (crc >> 1) ^ 0xd76aa478;} else {crc >>= 1;}}custom_crc32_table[i] = crc;}
}// 计算 CRC32
unsigned int custom_crc32(const std::string& str) {unsigned int crc = 0xffffffff;for (size_t i = 0; i < str.size(); i++) {unsigned char byte = str[i];crc = (crc >> 8) ^ custom_crc32_table[(crc ^ byte) & 0xff];}return ~crc;
}extern "C" JNIEXPORT jstring JNICALL
Java_com_cyrus_example_crc32_CRC32Utils_customTableCRC32(JNIEnv *env, jclass , jstring input) {// 初始化 CRC32 表（只需调用一次）static bool is_initialized = false;if (!is_initialized) {init_custom_crc32_table();is_initialized = true;}// 获取输入的字符串const char* str = env->GetStringUTFChars(input, nullptr);std::string input_str(str);env->ReleaseStringUTFChars(input, str);// 计算 CRC32 值unsigned int crc = custom_crc32(input_str);// 返回 CRC32 的十六进制字符串char crcHex[9];  // CRC32 是 32 位，最大为 8 位十六进制数snprintf(crcHex, sizeof(crcHex), "%08x", crc);return env->NewStringUTF(crcHex);
}

效果如下：

word/media/image2.png

魔改版 CRC32 算法

魔改逻辑：

修改常量 0xedb88320 改为 0x82F63B78
初始值 0xffffffff 改为 0xDEADBEEF。
XOR 0xA5 扰动输入。
右移 7 位，而非 8 位。
计算 CRC 时额外 XOR 0xA5A5A5A5 进一步扰动结果。

#include <jni.h>
#include <string>
#include <android/log.h>#define TAG "ModifiedCRC32"// 魔改版 CRC32 表
unsigned int modified_crc32_table[256];// 初始化魔改版 CRC32 查找表
void init_modified_crc32_table() {for (int i = 0; i < 256; i++) {unsigned int crc = i;for (int j = 8; j > 0; j--) {if (crc & 1) {crc = (crc >> 1) ^ 0x82F63B78;} else {crc >>= 1;}}modified_crc32_table[i] = crc;}
}// 魔改版 CRC32 计算
unsigned int modified_crc32(const std::string& str) {unsigned int crc = 0xDEADBEEF;  // 魔改初始值for (size_t i = 0; i < str.size(); i++) {unsigned char byte = str[i] ^ 0xA5;  // 额外扰动crc = ((crc >> 7) ^ modified_crc32_table[(crc ^ byte) & 0xff]) ^ 0xA5A5A5A5; // 变更位移方式 & 额外 XOR 干扰}return ~crc;
}extern "C" JNIEXPORT jstring JNICALL
Java_com_cyrus_example_crc32_CRC32Utils_modifiedCRC32(JNIEnv *env, jclass, jstring input) {// 初始化 CRC32 表（只需调用一次）static bool is_initialized = false;if (!is_initialized) {init_modified_crc32_table();is_initialized = true;}// 获取输入字符串const char* str = env->GetStringUTFChars(input, nullptr);std::string input_str(str);env->ReleaseStringUTFChars(input, str);// 计算魔改版 CRC32unsigned int crc = modified_crc32(input_str);// 返回十六进制格式的 CRC32 结果char crcHex[9];snprintf(crcHex, sizeof(crcHex), "%08x", crc);return env->NewStringUTF(crcHex);
}

效果如下：

word/media/image3.png