Hello, most probably the key is stored in the OpenSSH private key format. You'll need to use ssh-keygen -p -m PKCS8 to convert the key into a format that OpenSSL can read. Tomas Mraz, OpenSSL On Wed, 2022-10-05 at 15:00 +0900, Imazu Setsuo wrote: > Hello. > > When I read the RSA private key file created with the ssh-keygen > command that comes with Windows 10 with the PEM_read_PrivateKey() > function, the following error occurred. > > error: 0906D06C: lib(9): func(109): reason(108) > > The platform is CentOS7, OpenSSL 3.0.5. > Is the private key file created with Windows 10 not supported? > How can I use the private key file created in Windows 10 as well? > > > best regards, thank you > Setsuo Imazu -- Tomáš Mráz, OpenSSL