Net::SS...uth::RSA(3)

💖 Net::SS...uth::RSA(3) 💖

okay bestie, so this is Net::SSH::Perl::Auth::RSA, from the User Contributed Perl Documentation, and she is literally the module that does RSA authentication. no cap. let's get into it 🫶

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✨ NAME ✨

Net::SSH::Perl::Auth::RSA — perform RSA authentication. that's it, that's the whole job, and she does it beautifully 💅

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🌸 SYNOPSIS 🌸

look at this little cutie doing her thing:

use Net::SSH::Perl::Auth;
my $auth = Net::SSH::Perl::Auth->new('RSA', $ssh);
print "Valid auth" if $auth->authenticate;

like. iconic. four lines. she ate 🔥

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🦋 DESCRIPTION 🦋

so Net::SSH::Perl::Auth::RSA performs RSA authentication with a remote sshd server. when you create a new RSA auth object, you hand it an $ssh object, and that $ssh object should contain an open connection to an ssh daemon, plus whatever data the authentication module needs to do her thing. in this case, for example, the $ssh object might contain a list of RSA identity files (go read the docs for Net::SSH::Perl, iykyk).

okay so here's the whole vibe of the authenticate method 👑

first, she tries to establish a connection to an authentication agent. if that connection attempt is successful, the client loops through the identities returned from the agent and tries each identity/key against the server. then the client enters into a dialog with the server — very main character energy:

• the client sends the public portion of the key returned from the agent 💌
• the server responds, telling the client whether that key is authorized for authentication
• if the key is authorized, the server sends an RSA challenge encrypted with the user's public key 🔐
• the client then asks the agent to decrypt the challenge using the private portion of the key, and sends back its response
• if the response is correct, the client is authenticated successfully ✨ slay

but like. what if the agent thing doesn't work out 😭 if the client cannot connect to the authentication agent, or if none of the identities returned from the agent successfully authenticate the user, then authenticate loops through each of the files listed as identity files (check the Net::SSH::Perl constructor for that). and if no identity files are explicitly listed, $ENV{HOME}/.ssh/identity is used as a default. so she's got a fallback, she's prepared, we love a resourceful queen 🎀

for each identity, the client enters into a dialog with the sshd server. the client sends the public key to the server, then waits for a challenge. once that challenge arrives, the client has to decrypt it using the private key (loaded from the identity file).

ngl, when loading that private key you might need to enter a passphrase to decrypt the private key itself. so first, authenticate tries to decrypt the key using an empty passphrase — which requires zero user intervention, very chill of her 🙈

if that fails, the client checks to see if it's running in an interactive session. if so, it queries the user for a passphrase, which is then used to decrypt the private key. but if the session is non-interactive and the private key cannot be loaded, the client simply sends a dummy response to the RSA challenge, to comply with the SSH protocol. no drama, just protocol compliance 💀

otherwise — if the private key has been loaded, and the challenge decrypted — the client sends its response to the server, then waits for success or failure. and we hold our breath. 💜

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👑 AUTHOR & COPYRIGHTS 👑

please see the Net::SSH::Perl manpage for author, copyright, and license information. go give them their flowers 🌸

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and that's the whole page bestie!! this one's brought to you by perl v5.42.0, dated 2026-01-17, and honestly? she's serving. mwah 💋✨