Public key cryptography

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Generate a public key from a PEM private key

• openssl rsa -in mykey.pem -pubout > mykey.pub

Generate fingerpring

• ssh-keygen -l -f /etc/ssh/ssh_host_XXXXkey.pub

Generate public key from private key:

• ssh-keygen -y -f ~/.ssh/id_rsa > ~./.ssh/id_rsa.pub

OpenSSH 7.6 (2017)

• Refuse keys <1024 bits in length and improve reporting for keys that do not meet this requirement.

Related terms

• ssh-copy-id
• ssh-keygen and puttygen
• sshd logs: Failed publickey for
• Athena IDProtect card
• Minerva attack
• Cisco IOS: Configure public RSA key authentication
• Whitfield Diffie
• Key length
• RSA, DSA, ECDSA and ed25519.

See also

• SSH: ssh, TLS, .ppk, .pem, .crt, .pub, ED25519, Key exchange method (KEX), public key, private key, ssh -Q kex, IAMUserSSHKeys, known_hosts, ssh tunnel, Dropbear
• Public key certificate
• CA, FreeIPA, PKI, OpenCA, Wildcard certificate, certtool, certbot (Let's Encrypt), certinfo (Cloudflare), ACME, Boulder, cfssl (Cloudflare), Public key certificate, public key, TLS and X.509, OCSP, Subject Alternative Name (SAN), openssl ca, Self signed certificate, CSR, keytool, ACM, KMS, aws acm, IdenTrust, multirootca, cert-manager