国密算法SM2-java实现

Maven依赖

    org.bouncycastle
    bcprov-jdk15on
    1.56

工具类Util

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'};
 
    /**