SM2 SM3 SM4 的java软实现，经过多种语言的加密解密测试，通用性极强

package com.mlq.sm; import java.math.BigInteger; public class Util { /** * 整形转换成网络传输的字节流（字节数组）型数据 * * @param num 一个整型数据 * @return 4个字节的自己数组 */ public static byte[] intToBytes(int num) { byte[] bytes = new byte[4]; bytes[0] = (byte) (0xff & (num >> 0)); bytes[1] = (byte) (0xff & (num >> 8)); bytes[2] = (byte) (0xff & (num >> 16)); bytes[3] = (byte) (0xff & (num >> 24)); return bytes; } /** * 四个字节的字节数据转换成一个整形数据 * * @param bytes 4个字节的字节数组 * @return 一个整型数据 */ public static int byteToInt(byte[] bytes) { int num = 0; int temp; temp = (0x000000ff & (bytes[0])) << 0; num = num | temp; temp = (0x000000ff & (bytes[1])) << 8; num = num | temp; temp = (0x000000ff & (bytes[2])) << 16; num = num | temp; temp = (0x000000ff & (bytes[3])) << 24; num = num | temp; return num; } /** * 长整形转换成网络传输的字节流（字节数组）型数据 * * @param num 一个长整型数据 * @return 4个字节的自己数组 */ public static byte[] longToBytes(long num) { byte[] bytes = new byte[8]; for (int i = 0; i < 8; i++) { bytes[i] = (byte) (0xff & (num >> (i * 8))); } return bytes; } /** * 大数字转换字节流（字节数组）型数据 * * @param n * @return */ public static byte[] byteConvert32Bytes(BigInteger n) { byte tmpd[] = (byte[])null; if(n == null) { return null; } if(n.toByteArray().length == 33) { tmpd = new byte[32]; System.arraycopy(n.toByteArray(), 1, tmpd, 0, 32); } else if(n.toByteArray().length == 32) { tmpd = n.toByteArray(); } else { tmpd = new byte[32]; for(int i = 0; i < 32 - n.toByteArray().length; i++) { tmpd[i] = 0; } System.arraycopy(n.toByteArray(), 0, tmpd, 32 - n.toByteArray().length, n.toByteArray().length); } return tmpd; } /** * 换字节流（字节数组）型数据转大数字 * * @param b * @return */ public static BigInteger byteConvertInteger(byte[] b) { if (b[0] < 0) { byte[] temp = new byte[b.length + 1]; temp[0] = 0; System.arraycopy(b, 0, temp, 1, b.length); return new BigInteger(temp); } return new BigInteger(b); } /** * 根据字节数组获得值(十六进制数字) * * @param bytes * @return */ public static String getHexString(byte[] bytes) { return getHexString(bytes, true); } /** * 根据字节数组获得值(十六进制数字) * * @param bytes * @param upperCase * @return */ public static String getHexString(byte[] bytes, boolean upperCase) { String ret = ""; for (int i = 0; i < bytes.length; i++) { ret += Integer.toString((bytes[i] & 0xff) + 0x100, 16).substring(1); } return upperCase ? ret.toUpperCase() : ret; } /** * 打印十六进制字符串 * * @param bytes */ public static void printHexString(byte[] bytes) { for (int i = 0; i < bytes.length; i++) { String hex = Integer.toHexString(bytes[i] & 0xFF); if (hex.length() == 1) { hex = '0' + hex; } System.out.print("0x" + hex.toUpperCase() + ","); } System.out.println(""); } /** * Convert hex string to byte[] * * @param hexString * the hex string * @return byte[] */ public static byte[] hexStringToBytes(String hexString) { if (hexString == null || hexString.equals("")) { return null; } hexString = hexString.toUpperCase(); int length = hexString.length() / 2; char[] hexChars = hexString.toCharArray(); byte[] d = new byte[length]; for (int i = 0; i < length; i++) { int pos = i * 2; d[i] = (byte) (charToByte(hexChars[pos]) << 4 | charToByte(hexChars[pos + 1])); } return d; } /** * Convert char to byte * * @param c * char * @return byte */ public static byte charToByte(char c) { return (byte) "0123456789ABCDEF".indexOf(c); } /** * 用于建立十六进制字符的输出的小写字符数组 */ private static final char[] DIGITS_LOWER = {'0', '1', '2', '3', '4', '5', '6', '7', '8', '9', 'a', 'b', 'c', 'd', 'e', 'f'}; /** * 用于建立十六进制字符的输出的大写字符数组 */ private static final char[] DIGITS_UPPER = {'0', '1', '2', '3', '4', '5', '6', '7', '8', '9', 'A', 'B', 'C', 'D', 'E', 'F'}; /** * 将字节数组转换为十六进制字符数组 * * @param data byte[] * @return 十六进制char[] */ public static char[] encodeHex(byte[] data) { return encodeHex(data, true); } /** * 将字节数组转换为十六进制字符数组 * * @param data byte[] * @param toLowerCase <code>true</code> 传换成小写格式 ， <code>false</code> 传换成大写格式 * @return 十六进制char[] */ public static char[] encodeHex(byte[] data, boolean toLowerCase) { return encodeHex(data, toLowerCase ? DIGITS_LOWER : DIGITS_UPPER); } /** * 将字节数组转换为十六进制字符数组 * * @param data byte[] * @param toDigits 用于控制输出的char[] * @return 十六进制char[] */ protected static char[] encodeHex(byte[] data, char[] toDigits) { int l = data.length; char[] out = new char[l << 1]; // two characters form the hex value. for (int i = 0, j = 0; i < l; i++) { out[j++] = toDigits[(0xF0 & data[i]) >>> 4]; out[j++] = toDigits[0x0F & data[i]]; } return out; } /** * 将字节数组转换为十六进制字符串 * * @param data byte[] * @return 十六进制String */ public static String encodeHexString(byte[] data) { return encodeHexString(data, true); } /** * 将字节数组转换为十六进制字符串 * * @param data byte[] * @param toLowerCase <code>true</code> 传换成小写格式 ， <code>false</code> 传换成大写格式 * @return 十六进制String */ public static String encodeHexString(byte[] data, boolean toLowerCase) { return encodeHexString(data, toLowerCase ? DIGITS_LOWER : DIGITS_UPPER); } /** * 将字节数组转换为十六进制字符串 * * @param data byte[] * @param toDigits 用于控制输出的char[] * @return 十六进制String */ protected static String encodeHexString(byte[] data, char[] toDigits) { return new String(encodeHex(data, toDigits)); } /** * 将十六进制字符数组转换为字节数组 * * @param data 十六进制char[] * @return byte[] * @throws RuntimeException 如果源十六进制字符数组是一个奇怪的长度，将抛出运行时异常 */ public static byte[] decodeHex(char[] data) { int len = data.length; if ((len & 0x01) != 0) { throw new RuntimeException("Odd number of characters."); } byte[] out = new byte[len >> 1]; // two characters form the hex value. for (int i = 0, j = 0; j < len; i++) { int f = toDigit(data[j], j) << 4; j++; f = f | toDigit(data[j], j); j++; out[i] = (byte) (f & 0xFF); } return out; } /** *