PEM_read_RSA_PUBKEY() reads the PKCS#8 format.
PEM_read_RSAPublicKey() reads the PKCS#1 format.
PKCS#1 和PKCS#8区别PKCS#1有rsa标识如下图:
PKCS#8无rsa标识如下图:
PKCS#1 和PKCS#8相互转换pkcs1格式私钥转为pkcs8格式私钥：
openssl pkcs8 -topk8 -inform PEM -in private_pkcs1.pem -outform pem -nocrypt -out private_pkcs8.pem
pkcs8格式私钥转为pkcs1格式私钥：
openssl pkcs8 -in private_pkcs8.pem -nocrypt -out private_plcs1.pem
pkcs1格式公钥与pkcs8格式公钥转换：
openssl rsa -in pricate_pkcs1.pem -pubout -out public_pkcs8.pem
