openssl-genrsa
Generate RSA private keys. tldr-pages
On several platforms
Several platforms
Generate an RSA private key of 2048 bits to stdout
openssl genrsaIdentifySave an RSA private key of an arbitrary number of bits to the output file
openssl genrsa -out output_file.key 1234IdentifyGenerate an RSA private key and encrypt it with AES256 (you will be prompted for a passphrase)
openssl genrsa -aes256Identify