genpkey.1s

Generate RSA key

$ openssl genpkey -algorithm RSA -out [key.pem]

$ openssl genpkey -algorithm RSA -pkeyopt rsa_keygen_bits:[4096] -out [key.pem]

$ openssl genpkey -algorithm EC -pkeyopt ec_paramgen_curve:[P-256] -out [key.pem]

$ openssl genpkey -algorithm RSA -aes256 -out [key.pem]

openssl genpkey [options]

genpkey is an OpenSSL command for generating private keys. It supports modern algorithms including RSA, EC, and Ed25519 with unified syntax.
The tool creates private keys for TLS certificates, SSH, and other cryptographic uses. It provides more options than older commands like genrsa.
genpkey is the recommended way to generate keys in OpenSSL 1.0+.

-algorithm ALG

Key algorithm: RSA, EC, ED25519.

Output file.

Algorithm-specific option.

Encrypt with AES-256.

Output format: PEM, DER.

Display help information.

Key security depends on parameters. Protect private keys. Algorithm support varies by OpenSSL version.

genpkey was added to OpenSSL as a unified key generation command, replacing algorithm-specific commands like genrsa and gendsa with a consistent interface.

openssl(1), openssl-req(1)