ssh-keygen-g3

ssh-keygen-g3 — authentication key pair generator

Synopsis

ssh-keygen-g3 [options...]
[key1 key2...]

Description

ssh-keygen-g3 (ssh-keygen-g3.exe on Windows) is a tool that generates and manages authentication keys for Secure Shell. Each user wishing to use a Secure Shell client with public-key authentication can run this tool to create authentication keys. Additionally, the system administrator can use this to generate host keys for the Secure Shell server.

By default, if no path for the key files is specified, the key pair is generated under the user's home directory ($HOME/.ssh2 on Unix, "%APPDATA%\SSH\UserKeys" on Windows). If no filename is specified, the key pair is likewise stored under the user's home directory with such filenames as id_dsa_1024_a and id_dsa_1024_a.pub.

When specifying file paths or other strings that contain spaces, enclose them in quotation marks ("").

Options

The following options are available:

-1 file

Converts a key file from the SSH1 format to the SSH2 format. Note: "1" is number one (not letter L).

-7 file

Extracts certificates from a PKCS #7 file.

-b bits

Specifies the length of the generated key in bits (default: 2048).

-B num

Specifies the number base for displaying key information (default: 10).

-c comment

Specifies a comment string for the generated key.

-D file

Derives the public key from the private key file.

-e file

Edits the specified key. Makes ssh-keygen-g3 interactive. You can change the key's passphrase or comment.

-F, --fingerprint file

Dumps the fingerprint of the given public key. By default, the fingerprint is given in the SSH Babble format, which makes the fingerprint look like a string of "real" words (making it easier to pronounce). The output format can be changed with the --fingerprint-type option.

The following options can be also used to modify the behaviour of this option: --fingerprint-type--hash, --hostkeys-directory, --known-hosts, --rfc4716.

-F, --fingerprint <host id>

Dumps the fingerprint of the locally stored host key identified with the given <host id>. The <host id> is a host name or string "host#port";.

The following options can be used to modify the behaviour of this option: --fingerprint-type, --hash, --hostkeys-directory, --known-hosts, --rfc4716.

-H, --hostkey

Stores the generated key pair in the default host key directory (/etc/ssh2 on Unix, "C:\Program Files\SSH Communications Security\SSH Tectia\Tectia Server" on Windows). Specify the -P option to store the private key with an empty passphrase.

-i file

Loads and displays information on the key file.

-k file

Converts a PKCS #12 file to an SSH2-format certificate and private key.

-p passphrase

Specifies the passphrase for the generated key.

-P

Specifies that the generated key will be saved with an empty passphrase.

	Note
	In FIPS mode, due to a FIPS regulation which forbids exporting unencrypted private keys out of the FIPS module, it is not possible to generate user keys without a passphrase.

-q, --quiet

Hides the progress indicator during key generation.

-r file

Adds entropy from file to the random pool. If file contains 'relatively random' data (i.e. data unpredictable by a potential attacker), the randomness of the pool is increased. Good randomness is essential for the security of the generated keys.

-t [ dsa | rsa ]

Selects the type of the key. Valid options are dsa (default) and rsa.

-x file

Converts a private key from the X.509 format to the SSH2 format.

--append [ =yes | no ]

Appends the keys. Optional values are yes and no. The default is yes to append.

--copy-host-id <host id> <destination>

Copies the host identity to the specified destination directory.

The following options can be used to modify the behaviour of this option: --append, --hostkeys-directory, --known-hosts, --overwrite.

If --hostkey-file is given, the file is treated as a normal host identity file used by the Connection Broker, and its contents will be copied to the destination directory.

--delete-host-id <host id>

Deletes the host key of the specified host id. The <host id> is a host name or string "host#port";.

The following options can be used to modify the behaviour of this option: --host-key-file, --hostkeys-directory, --known-hosts.

--fingerprint-type [ =babble | babble-upper | pgp-2 | pgp-5 | hex | hex-upper ]

Specifies the output format of the fingerprint. If this option is given, the -F option and the key filename must precede it. The default format is babble.

See the section called “Examples” for examples of using this option.

--fips-mode

Generates the key using the FIPS mode for the cryptographic library. In the FIPS mode, only DSA keys of 1024 bits and RSA keys of at least 512 bits can be generated, and the keys must have non-empty passphrases. By default (if this option is not given), the key is generated using the standard mode for the cryptographic library.

--fips-crypto-dll-path PATH

Specifies the location of the FIPS cryptographic DLL.

--hash [ =md5 | sha1 ]

Specifies the digest algorithm for fingerprint generation. Valid options are md5 and sha1.

--hostkey-file file

When copying, uses the given file as the source host key, instead of autodetecting the location. When deleting, only deletes from the given location. If the specified file does not contain identities for the specified host, does nothing.

--hostkeys-directory directory

Specifies the directory for known host keys to be used instead of the default location.

--import-public-key infile outfile

Attempts to import a public key from infile and store it to outfile in SSH2 native format.

--import-private-key infile outfile

Attempts to import an unencrypted private key from infile and store it to outfile in SSH2 native private key format.

--import-ssh1-authorized-keys infile outfile

Imports an SSH1-style authorized_keys file infile and generates an SSH2-style authorization file outfile, and stores the keys from infile to generated files into the same directory with outfile.

--known-hosts file

Uses the specified known hosts file. Enables fetching fingerprints for hosts defined in an OpenSSH-style known-hosts file. Using this option overrides the default locations of known_hosts files (/etc/ssh/ssh_known_hosts and $HOME/.ssh/known_hosts). Giving an empty string will disable known-hosts usage altogether.

--overwrite [ =yes | no ]

Overwrite files with the same filenames. The default is to overwrite.

--rfc4716

Displays the fingerprint in the format specified in RFC4716. The digest algorithm (hash) is md5, and the output format is the 16-bytes output in lowercase HEX separated with colons (:).

--set-hostkey-owner-and-dacl file

On Windows, sets the correct owner and DACL (discretionary access control list) for the host key file. This option is used internally when a host key is generated during Tectia Server installation.

-V

Displays version string and exits.

-h, --help, -?

Displays a short summary of command-line options and exits.

Examples

Create a 1024-bit RSA key pair using the cryptographic library in the FIPS mode and store the key pair in the default user key directory with filenames newkey and newkey.pub:

$ ssh-keygen-g3 --fips-mode -t rsa -b 1024 newkey

Convert an SSH1 key oldkey to SSH2 format:

$ ssh-keygen-g3 -1 oldkey

Display the fingerprint of a server host public key in SSH babble (default) format:

$ ssh-keygen-g3 -F hostkey.pub
Fingerprint for key:
xeneh-fyvam-sotaf-gutuv-rahih-kipod-poten-byfam-hufeh-tydym-syxex

Display the fingerprint of a server host public key in hex format:

$ ssh-keygen-g3 -F hostkey.pub --fingerprint-type=hex
Fingerprint for key:
25533b8c7734f6eb1556ea2ab4900d854d5d088c

ssh-keygen-g3

Synopsis

Description

Options

Examples

Reduce Secure Shell risk. Get to know the NIST 7966.

ISACA Practitioner Guide for SSH