python 的sm2 生成密钥的方法，gmssl里没有提供密钥生成

"""
Author: tanglei
DateTime:2024-11
#import random
#random 不安全所以替换为 secrets中的算法
# 选择素域，设置椭圆曲线参数
"""
import secrets


class SM2_Key():
    default_ecc_table = {
        'n': 'FFFFFFFEFFFFFFFFFFFFFFFFFFFFFFFF7203DF6B21C6052B53BBF40939D54123',
        'p': 'FFFFFFFEFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFF00000000FFFFFFFFFFFFFFFF',
        'g': '32c4ae2c1f1981195f9904466a39c9948fe30bbff2660be1715a4589334c74c7'
             'bc3736a2f4f6779c59bdcee36b692153d0a9877cc62a474002df32e52139f0a0',
        'a': 'FFFFFFFEFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFF00000000FFFFFFFFFFFFFFFC',
        'b': '28E9FA9E9D9F5E344D5A9E4BCF6509A7F39789F515AB8F92DDBCBD414D940E93',
    }

    def __init__(self, private_key, public_key, ecc_table=default_ecc_table, mode=0, asn1=False):
        """
        mode: 0-C1C2C3, 1-C1C3C2 (default is 1)
        """
        self.private_key = private_key
        self.public_key = public_key.lstrip("04") if public_key.startswith("04") else public_key
        self.para_len = len(ecc_table['n'])
        self.ecc_a3 = ( int(ecc_table['a'], base=16) + 3) % int(ecc_table['p'], base=16)
        self.ecc_table = ecc_table
        assert mode in (0, 1), 'mode must be one of (0, 1)'
        self.mode = mode
        self.asn1 = asn1

    def _kg(self, k, Point):  # kP运算
        Point = '%s%s' % (Point, '1')
        mask_str = '8'
        for i in range(self.para_len - 1):
            mask_str += '0'
        mask = int(mask_str, 16)
        Temp = Point
        flag = False
        for n in range(self.para_len * 4):
            if (flag):
                Temp = self._double_point(Temp)
            if (k & mask) != 0:
                if (flag):
                    Temp = self._add_point(Temp, Point)
                else:
                    flag = True
                    Temp = Point
            k = k << 1
        return self._convert_jacb_to_nor(Temp)

    def _double_point(self, Point):  # 倍点
        l = len(Point)
        len_2 = 2 * self.para_len
        if l < self.para_len * 2:
            return None
        else:
            x1 = int(Point[0:self.para_len], 16)
            y1 = int(Point[self.para_len:len_2], 16)
            if l == len_2:
                z1 = 1
            else:
                z1 = int(Point[len_2:], 16)

            T6 = (z1 * z1) % int(self.ecc_table['p'], base=16)
            T2 = (y1 * y1) % int(self.ecc_table['p'], base=16)
            T3 = (x1 + T6) % int(self.ecc_table['p'], base=16)
            T4 = (x1 - T6) % int(self.ecc_table['p'], base=16)
            T1 = (T3 * T4) % int(self.ecc_table['p'], base=16)
            T3 = (y1 * z1) % int(self.ecc_table['p'], base=16)
            T4 = (T2 * 8) % int(self.ecc_table['p'], base=16)
            T5 = (x1 * T4) % int(self.ecc_table['p'], base=16)
            T1 = (T1 * 3) % int(self.ecc_table['p'], base=16)
            T6 = (T6 * T6) % int(self.ecc_table['p'], base=16)
            T6 = (self.ecc_a3 * T6) % int(self.ecc_table['p'], base=16)
            T1 = (T1 + T6) % int(self.ecc_table['p'], base=16)
            z3 = (T3 + T3) % int(self.ecc_table['p'], base=16)
            T3 = (T1 * T1) % int(self.ecc_table['p'], base=16)
            T2 = (T2 * T4) % int(self.ecc_table['p'], base=16)
            x3 = (T3 - T5) % int(self.ecc_table['p'], base=16)

            if (T5 % 2) == 1:
                T4 = (T5 + ((T5 + int(self.ecc_table['p'], base=16)) >> 1) - T3) % int(
                    self.ecc_table['p'], base=16)
            else:
                T4 = (T5 + (T5 >> 1) - T3) % int(self.ecc_table['p'], base=16)

            T1 = (T1 * T4) % int(self.ecc_table['p'], base=16)
            y3 = (T1 - T2) % int(self.ecc_table['p'], base=16)

            form = '%%0%dx' % self.para_len
            form = form * 3
            return form % (x3, y3, z3)

    def _add_point(self, P1, P2):  # 点加函数，P2点为仿射坐标即z=1，P1为Jacobian加重射影坐标
        len_2 = 2 * self.para_len
        l1 = len(P1)
        l2 = len(P2)
        if (l1 < len_2) or (l2 < len_2):
            return None
        else:
            X1 = int(P1[0:self.para_len], 16)
            Y1 = int(P1[self.para_len:len_2], 16)
            if (l1 == len_2):
                Z1 = 1
            else:
                Z1 = int(P1[len_2:], 16)
            x2 = int(P2[0:self.para_len], 16)
            y2 = int(P2[self.para_len:len_2], 16)

            T1 = (Z1 * Z1) % int(self.ecc_table['p'], base=16)
            T2 = (y2 * Z1) % int(self.ecc_table['p'], base=16)
            T3 = (x2 * T1) % int(self.ecc_table['p'], base=16)
            T1 = (T1 * T2) % int(self.ecc_table['p'], base=16)
            T2 = (T3 - X1) % int(self.ecc_table['p'], base=16)
            T3 = (T3 + X1) % int(self.ecc_table['p'], base=16)
            T4 = (T2 * T2) % int(self.ecc_table['p'], base=16)
            T1 = (T1 - Y1) % int(self.ecc_table['p'], base=16)
            Z3 = (Z1 * T2) % int(self.ecc_table['p'], base=16)
            T2 = (T2 * T4) % int(self.ecc_table['p'], base=16)
            T3 = (T3 * T4) % int(self.ecc_table['p'], base=16)
            T5 = (T1 * T1) % int(self.ecc_table['p'], base=16)
            T4 = (X1 * T4) % int(self.ecc_table['p'], base=16)
            X3 = (T5 - T3) % int(self.ecc_table['p'], base=16)
            T2 = (Y1 * T2) % int(self.ecc_table['p'], base=16)
            T3 = (T4 - X3) % int(self.ecc_table['p'], base=16)
            T1 = (T1 * T3) % int(self.ecc_table['p'], base=16)
            Y3 = (T1 - T2) % int(self.ecc_table['p'], base=16)

            form = '%%0%dx' % self.para_len
            form = form * 3
            return form % (X3, Y3, Z3)

    def _convert_jacb_to_nor(self, Point):  # Jacobian加重射影坐标转换成仿射坐标
        len_2 = 2 * self.para_len
        x = int(Point[0:self.para_len], 16)
        y = int(Point[self.para_len:len_2], 16)
        z = int(Point[len_2:], 16)
        z_inv = pow(
            z, int(self.ecc_table['p'], base=16) - 2, int(self.ecc_table['p'], base=16))
        z_invSquar = (z_inv * z_inv) % int(self.ecc_table['p'], base=16)
        z_invQube = (z_invSquar * z_inv) % int(self.ecc_table['p'], base=16)
        x_new = (x * z_invSquar) % int(self.ecc_table['p'], base=16)
        y_new = (y * z_invQube) % int(self.ecc_table['p'], base=16)
        z_new = (z * z_inv) % int(self.ecc_table['p'], base=16)
        if z_new == 1:
            form = '%%0%dx' % self.para_len
            form = form * 2
            return form % (x_new, y_new)
        else:
            return None

    def generate_keypair(self):
        """
        生成SM2公私钥对
        私钥为随机生成的小于n的整数
        公钥通过基点乘以私钥得到
        :return: (private_key, public_key)
        """
        # 生成一个随机的私钥，范围在[1, n-1]之间
        #private_key = '%064x' % random.randint(1, int(self.ecc_table['n'], 16) - 1)
        private_key = '%064x' % secrets.randbelow(int(self.ecc_table['n'], 16) - 1)
        # 通过私钥和基点计算公钥
        public_key = self._kg(int(private_key, 16), self.ecc_table['g'])

        # 公钥是椭圆曲线点的 x 和 y 坐标，格式为 '04 + x + y'
        #public_key = '04' + public_key 不带04

        return public_key.upper(),private_key.upper()




def main():
    #private_key1 = 'B9C9A6E04E9C91F7BA880429273747D7EF5DDEB0BB2FF6317EB00BEF331A83081A6994B8993F3F5D6EADDDB81872266C87C018FB4162F5AF347B483E24620207'
    #public_key1 = 'B9AB0B828FF68872F21A837FC303668428DEA11DCD1B24429D0C99E24EED83D5'
    private_key1 = ''
    public_key1 = ''
    ecc_table1 = SM2_Key.default_ecc_table
    my_sm21 = SM2_Key(private_key=private_key1, public_key=public_key1, ecc_table=ecc_table1, mode=1)
    public_key, private_key = my_sm21.generate_keypair()
    print(f'public_key:{public_key}')
    print(f'private_key:{private_key}')

if __name__ == '__main__':
    main()