ssh-add

- add RSA or DSA identities to the authentication agent

Synopsis

ssh-add [-lLdDxX] [-t life] [ file ]...

Description

The ssh-add utility adds RSA or DSA identities to the authentication agent, ssh-agent(1). When run without arguments, it attempts to add all of the files $HOME/.ssh/identity (RSA v1), $HOME/.ssh/id_rsa (RSA v2), and $HOME/.ssh/id_dsa (DSA v2) that exist. If more than one of the private keys exists, an attempt to decrypt each with the same passphrase is made before reprompting for a different passphrase. The passphrase is read from the user's tty or by running the program defined in SSH_ASKPASS (see below).

The authentication agent must be running.

Options

The following options are supported:

-d

Instead of adding the identity, this option removes the identity from the agent.

-D

Deletes all identities from the agent.

-l

Lists fingerprints of all identities currently represented by the agent.

-L

Lists public key parameters of all identities currently represented by the agent.

-t life

Sets a maximum lifetime when adding identities to an agent. The lifetime can be specified in seconds or in a time format specified in sshd(1M).

-x

Locks the agent with a password.

-X

Unlocks the agent.

Environment Variables

DISPLAY

SSH_ASKPASS

If ssh-add needs a passphrase, it reads the passphrase from the current terminal if it was run from a terminal. If ssh-add does not have a terminal associated with it but DISPLAY and SSH_ASKPASS are set, it executes the program specified by SSH_ASKPASS and open an X11 window to read the passphrase. This is particularly useful when calling ssh-add from a .Xsession or related script. The system is shipped with /usr/lib/ssh/ssh-askpass which is the default value for SSH_ASKPASS.

SSH_AUTH_SOCK

Identifies the path of a unix-domain socket used to communicate with the agent.

Exit Status

The following exit values are returned:

0

Successful completion.

1

An error occurred.

Files

These files should not be readable by anyone but the user. Notice that ssh-add ignores a file if it is accessible by others. It is possible to specify a passphrase when generating the key; that passphrase is used to encrypt the private part of this file.

If these files are stored on a network file system it is assumed that either the protection provided in the file themselves or the transport layer of the network file system provides sufficient protection for the site policy. If this is not the case, then it is recommended the key files are stored on removable media or locally on the relevant hosts.

Recommended names for the DSA and RSA key files:

$HOME/.ssh/identity

Contains the RSA authentication identity of the user for protocol version 1.

$HOME/.ssh/identity.pub

Contains the public part of the RSA authentication identity of the user for protocol version 1.

$HOME/.ssh/id_dsa

Contains the private DSA authentication identity of the user.

$HOME/.ssh/id_dsa.pub

Contains the public part of the DSA authentication identity of the user.

$HOME/.ssh/id_rsa

Contains the private RSA authentication identity of the user.

$HOME/.ssh/id_rsa.pub

Contains the public part of the RSA authentication identity of the user.

/usr/lib/ssh/ssh-askpass

Contains the default value for SSH_ASKPASS.

Attributes

See attributes(5) for descriptions of the following attributes:

See Also

ssh(1), ssh-agent(1), ssh-keygen(1), sshd(1M), attributes(5)