Generating Keys Using Command Line
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How do I generate ssh RSA keys under Linux operating systems?
You need to use the ssh-keygen command as follows to generate RSA keys (open terminal and type the following command):
ssh-keygen -t rsa
OR
ssh-keygen
Sample outputs:

May 27, 2010  Linux Generate RSA SSH Keys last updated May 27, 2010 in Categories Linux. H ow do I generate ssh RSA keys under Linux operating systems? You need to use the ssh-keygen command as follows to generate RSA keys (open terminal and type the following command): ssh-keygen -t rsa OR. 20 Unix/Linux Command Line Tricks - Part I. To generate the public/private key pair, enter this in the Command Prompt: ssh-keygen At the first prompt, “Enter file in which to save the key,” press Enter to save it in the default location. May 27, 2010 H ow do I generate ssh RSA keys under Linux operating systems? You need to use the ssh-keygen command as follows to generate RSA keys (open terminal and type the following command): ssh-keygen -t rsa OR ssh-keygen Sample outputs.

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The -t type option specifies the type of key to create. The possible values “rsa” or “dsa” for protocol version 2. The $HOME/.ssh stores the following two files:

  • $HOME/.ssh/id_rsa – Your private RSA key
  • $HOME/.ssh/id_rsa.pub – Your public RSA key

Please do not share keys file with anyone else. You can upload keys to remote server as follows:
ssh-copy-id [email protected]
Finally, you can login to remote server as follows:
ssh [email protected]
scp file.txt [email protected]:~/data2/

See also:

  • Howto Linux / UNIX setup SSH with DSA public key authentication (password less login)
  • sshpass: Login To SSH Server / Provide SSH Password Using A Shell Script
  • keychain: Set Up Secure Passwordless SSH Access For Backup Scripts

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Previous: The quick key manipulation interface, Up: Unattended Usage of GPG [Contents][Index]

4.5.4 Unattended key generation

The command --generate-key may be used along with the option--batch for unattended key generation. This is the mostflexible way of generating keys, but it is also the most complex one.Consider using the quick key manipulation interface described in theprevious subsection “The quick key manipulation interface”.

The parameters for the key are either read from stdin or given as afile on the command line. The format of the parameter file is asfollows:

  • Text only, line length is limited to about 1000 characters.
  • UTF-8 encoding must be used to specify non-ASCII characters.
  • Empty lines are ignored.
  • Leading and trailing white space is ignored.
  • A hash sign as the first non white space character indicates a comment line.
  • Control statements are indicated by a leading percent sign, the arguments are separated by white space from the keyword.
  • Parameters are specified by a keyword, followed by a colon. Arguments are separated by white space.
  • The first parameter must be ‘Key-Type’; control statements may be placed anywhere.
  • The order of the parameters does not matter except for ‘Key-Type’ which must be the first parameter. The parameters are only used for the generated keyblock (primary and subkeys); parameters from previous sets are not used. Some syntactically checks may be performed.
  • Key generation takes place when either the end of the parameter file is reached, the next ‘Key-Type’ parameter is encountered or at the control statement ‘%commit’ is encountered.

Control statements:

%echo text

Print text as diagnostic.

%dry-run

Suppress actual key generation (useful for syntax checking).

%commit

Perform the key generation. Note that an implicit commit is done atthe next Key-Type parameter.

%pubring filename

Do not write the key to the default or commandline given keyring butto filename. This must be given before the first commit to takeplace, duplicate specification of the same filename is ignored, thelast filename before a commit is used. The filename is used until anew filename is used (at commit points) and all keys are written tothat file. If a new filename is given, this file is created (andoverwrites an existing one).

See the previous subsection “Ephemeral home directories” for a morerobust way to contain side-effects.

%secring filename

This option is a no-op for GnuPG 2.1 and later.

See the previous subsection “Ephemeral home directories”.

%ask-passphrase
%no-ask-passphrase

This option is a no-op for GnuPG 2.1 and later. Driver easy serial license key free download.

%no-protection

Using this option allows the creation of keys without any passphraseprotection. This option is mainly intended for regression tests.

%transient-key

If given the keys are created using a faster and a somewhat lesssecure random number generator. This option may be used for keyswhich are only used for a short time and do not require fullcryptographic strength. It takes only effect if used together withthe control statement ‘%no-protection’.

General Parameters:

Key-Type: algo

Starts a new parameter block by giving the type of the primarykey. The algorithm must be capable of signing. This is a requiredparameter. algo may either be an OpenPGP algorithm number or astring with the algorithm name. The special value ‘default’ maybe used for algo to create the default key type; in this case a‘Key-Usage’ shall not be given and ‘default’ also be usedfor ‘Subkey-Type’.

Key-Length: nbits

The requested length of the generated key in bits. The default isreturned by running the command ‘gpg --gpgconf-list’.

Key-Grip: hexstring

This is optional and used to generate a CSR or certificate for analready existing key. Key-Length will be ignored when given.

Key-Usage: usage-list

Space or comma delimited list of key usages. Allowed values are‘encrypt’, ‘sign’, and ‘auth’. This is used togenerate the key flags. Please make sure that the algorithm iscapable of this usage. Note that OpenPGP requires that all primarykeys are capable of certification, so no matter what usage is givenhere, the ‘cert’ flag will be on. If no ‘Key-Usage’ isspecified and the ‘Key-Type’ is not ‘default’, all allowedusages for that particular algorithm are used; if it is not given but‘default’ is used the usage will be ‘sign’.

Subkey-Type: algo

This generates a secondary key (subkey). Currently only one subkeycan be handled. See also ‘Key-Type’ above.

Subkey-Length: nbits

Length of the secondary key (subkey) in bits. The default is returnedby running the command ‘gpg --gpgconf-list’.

Subkey-Usage: usage-list

Key usage lists for a subkey; similar to ‘Key-Usage’.

Passphrase: string

If you want to specify a passphrase for the secret key, enter it here.Default is to use the Pinentry dialog to ask for a passphrase.

Name-Real: name
Generating keys using command lines
Name-Comment: comment
Name-Email: email

The three parts of a user name. Remember to use UTF-8 encoding here.If you don’t give any of them, no user ID is created.

Expire-Date: iso-date (number[d w m y])

Set the expiration date for the key (and the subkey). It may eitherbe entered in ISO date format (e.g. '20000815T145012') or as number ofdays, weeks, month or years after the creation date. The specialnotation 'seconds=N' is also allowed to specify a number of secondssince creation. Without a letter days are assumed. Note that thereis no check done on the overflow of the type used by OpenPGP fortimestamps. Thus you better make sure that the given value makesense. Although OpenPGP works with time intervals, GnuPG uses anabsolute value internally and thus the last year we can represent is2105.

Creation-Date: iso-date

Set the creation date of the key as stored in the key information andwhich is also part of the fingerprint calculation. Either a date like'1986-04-26' or a full timestamp like '19860426T042640' may be used.The time is considered to be UTC. The special notation 'seconds=N'may be used to directly specify a the number of seconds since Epoch(Unix time). If it is not given the current time is used.

Preferences: string

Set the cipher, hash, and compression preference values for this key.This expects the same type of string as the sub-command ‘setpref’in the --edit-key menu.

Revoker: algo:fpr [sensitive]
Generating keys using command line interface

Add a designated revoker to the generated key. Algo is the public keyalgorithm of the designated revoker (i.e. RSA=1, DSA=17, etc.)fpr is the fingerprint of the designated revoker. The optional‘sensitive’ flag marks the designated revoker as sensitiveinformation. Only v4 keys may be designated revokers.

Keyserver: string

This is an optional parameter that specifies the preferred keyserverURL for the key.

Handle: string

This is an optional parameter only used with the status linesKEY_CREATED and KEY_NOT_CREATED. string may be up to 100characters and should not contain spaces. It is useful for batch keygeneration to associate a key parameter block with a status line.

Here is an example on how to create a key in an ephemeral home directory:

Generating Keys Using Command Line Parameters

If you want to create a key with the default algorithms you would usethese parameters:

Troubleshooting Network Using Command Lines

Previous: The quick key manipulation interface, Up: Unattended Usage of GPG [Contents][Index]