操作步骤：
1、打开终端，然后输入命令：​​​openssl​​​ 2、生成私钥：​​genrsa -out rsa_private_key.pem 2048​​ 3、私钥转换成PKCS8格式：​​pkcs8 -topk8 -inform PEM -in rsa_private_key.pem -outform PEM -nocrypt -out rsa_private_key_pkcs8.pem​​ 4、生成公钥：​​rsa -in rsa_private_key.pem -pubout -out rsa_public_key.pem​​ 5、退出，生成的文件在当前目录：​​exit​​

如下操作内容

OpenSSL> genrsa -out rsa_private_key.pem 2048
Generating RSA private key, 2048 bit long modulus
..............................+++
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e is 65537 (0x10001)
OpenSSL> pkcs8 -topk8 -inform PEM -in rsa_private_key.pem -outform PEM -nocrypt -out rsa_private_key_pkcs8.pem
OpenSSL> rsa -in rsa_private_key.pem -pubout -out rsa_public_key.pem
writing RSA key
OpenSSL> exit