Linux ssh keygen rsa dsa

Using Ed25519 for OpenSSH keys (instead of DSA/RSA/ECDSA. Introduction into Ed25519. OpenSSH 6.5 added support for Ed25519 as a public key type. It is using an elliptic curve signature scheme, which offers better security than ECDSA and DSA. At the same time it also has good performance. This type of keys may be used for user and host keys. With this in mind, it is great to be used together with OpenSSH. In this article we have a look at this new key type. Many forum threads have been created regarding the choice between DSA or RSA. DSA is being limited to 1024 bits, as specified by FIPS 186-2. This is also the default length of ssh-keygen. While the length can be increased, it may not be compatible with all clients. So it is common to see RSA keys, which are often also used for signing. With Ed25519 now available, the usage for both will slowly decrease. Configuring the server. The first thing to check is if your current OpenSSH package is up-to-date. You will need at least version 5.6 of OpenSSH. Create SSH host keys. Change SSH configuration (server. Next step is changing the sshd_config file. Add the new host key type. Remove any of the other HostKey settings that are defined. Client Configuration. After configuring the server, it is time to do the client. We have to create a new key first. Make sure that your ssh-keygen is also up-to-date, to support the new key type. Note: the tilde. ) is an alias for your home directory and expanded by your shell. Optional step: Check the key before copying it. If that looks good, copy it to the destination host. Then determine if we can log in with it. michael@192.168.1.251 Enter passphrase for key. When using this newer type of key, you can configure to use it in your local SSH configuration file. Defining the key file is done with the IdentityFile option. Host [name] HostName [hostname] User [your-username] IdentityFile. Insight: using -o. Normally you can use the -o option to save SSH private keys using the new OpenSSH format. It uses bcrypt/pbkdf2 to hash the private key, which makes it more resilient against brute-force attempts to crack the password. Only newer versions (OpenSSH 6.5+) support it though. For this key type, the -o option is implied and does not have to be provided. Also a bit size is not needed, as it is always 256 bits for this key type. Are you already using the new key type? Or other tips for our readers? Leave a comment. Automate security audits with Lynis and Lynis Enterprise. This blog post is part of our Linux security series to get Linux (and Unix-based) systems more secure. Want to go to the next level of security scanning and system hardening? Start with automated security scans for Linux: Lynis and Lynis Enterprise. Post navigation. About Linux Audit. This blog is part of our mission: help individuals and companies, to scan and secure their systems . We simply love Linux security, system hardening, and questions regarding compliance. Besides the blog, we have our security auditing tool Lynis. Open source, GPL, and free to use. For those with enterprise needs, or want to audit multiple systems, there is an Enterprise version. One security solution to audit, harden, and secure your Linux/UNIX systems. Perform audits within a few minutes. Central management. Powerful reporting. Compliance checks (e.g. PCI DSS. Additional plugins and more tests. Enjoy the articles. Recent Posts. Receive Updates. Outsmart your colleagues and receive the latest updates. This blog is part of our mission to share valuable tips about Linux security. We are reachable via @linuxaudit. CISOfy De Klok 28, 5251 DN, Vlijmen, The Netherlands +31202260055. Linux and UNIX security automation. Lynis is a free and open source security scanner. It helps with automated security audits of Linux and UNIX-based systems. It detects vulnerabilities and provides hints for system hardening.