Openssl Rsa Generate Key Example

Introduction

Dec 28, 2017  $ openssl genpkey -algorithm RSA -out example.org.key -pkeyopt rsakeygenbits:4096 Generate encrypted private key Basic way to generate encrypted private key. Generate 4096-bit RSA private key, encrypt it using AES-192 cipher and password provided. Apr 28, 2012  Here we’re using the RSAgeneratekey function to generate an RSA public and private key which is stored in an RSA struct. The key length is the first parameter; in this case, a pretty secure 2048 bit key (don’t go lower than 1024, or 4096 for the paranoid), and the public exponent (again, not I’m not going into the math here), is the second parameter. Unless you have special requirements, generate a 2048-bit key. The key's algorithm identifier is rsaEncryption (1.2.840.113549.1.1.1), which is the most interoperable form. Almost all software will accept keys marked as such for use in RSA encryption and for RSA PKCS#1 1.5 signatures and RSA-PSS signatures. I'm trying to create a private key and having an issue. When I use ssh-keygen -t rsa -b 4096 -C 'youremail@example.com', I get a private key in the following format. As workaround I've used older version of openssh to generate key. You can test if your generated key is correct with openssl rsa -text -in keyfile -passin 'pass:passphrase'.

A Certificate Signing Request (CSR) is the first step in setting up an SSL Certificate on your website. SSL certificates are provided by Certificate Authorities (CA), which require a Certificate Signing Request (CSR).

This guide will instruct you on how to generate a Certificate Signing Request using OpenSSL.

  • Access to a user account with root or sudo privileges
  • A command line/terminal window
  • If you’re working on a remote server, an established SSH connection to the server
  • OpenSSL needs to be installed on your system to generate the key
  • A text editor, such as nano, to view your key

Open a terminal window. Use your SSH connection to log into your remote server.

Note: If you are working locally, you don’t need an SSH connection. Also, most Linux systems will launch a terminal window by pressing Ctrl-Alt-T or Ctrl-Alt-F1.

Step 2: Create an RSA Private Key and CSR

It is advised to issue a new private key each time you generate a CSR. Hence, the steps below instruct on how to generate both the private key and the CSR.

Make sure to replace your_domain with the actual domain you’re generating a CSR for.

The commands are broken out as follows:

  • openssl – activates the OpenSSL software
  • req – indicates that we want a CSR
  • –new –newkey – generate a new key
  • rsa:2048 – generate a 2048-bit RSA mathematical key
  • –nodes – no DES, meaning do not encrypt the private key in a PKCS#12 file
  • –keyout – indicates the domain you’re generating a key for
  • –out – specifies the name of the file your CSR will be saved as

Note: Use 2048-bit key pairs. The 4096-bit key pairs are more secure, however, they require a lot more server resources.

Your system should launch a text-based questionnaire for you to fill out.

Enter your information in the fields as follows:

  • Country Name – use a 2-letter country code (US for the United States)
  • State – the state in which the domain owner is incorporated
  • Locality – the city in which the domain owner is incorporated
  • Organization name – the legal entity that owns the domain
  • Organizational unit name – the name of the department or group in your organization that deals with certificates
  • Common name – typically the fully qualified domain name (FQDN), i.e. what the users type in a web browser to navigate to your website
  • Email address – the webmaster’s email address
  • Challenge password – an optional password for your key pair

Please take into account that Organization Name and Unit Name must not contain the following characters:

< > ~ ! @ # $ % ^ * / ( ) ?.,&

Once the software finishes, you should be able to find the CSR file in your working directory.

You can also enter the following:

The system should list out all certificate signing requests on the system. The one that matches the domain name you provided in Step 2 appended with the .csr extension is the one you need to look into.

Step 5: Submit the CSR as Part of Your SSL Request

You can open the .csr file in a text editor to find the alphanumeric code that was generated.

Openssl Rsa Generate Key Example

Enter the following command:

This text can be copied and pasted into a submittal form to request your SSL certificate from a Certificate Authority.

Make sure you copy the entire text. Some CAs may allow you to simply upload the .csr file you generated. Below is an example of a CSR.

You needn’t send the private key to the CA. Once you get your SSL certificate, the private key on the server will bind with it to encrypt communication.

Now you know how to generate an OpenSSL certificate signing request. Before submitting the CSR to a certificate authority, we recommend verifying the information it holds. Use one of the widely available online CSR decoders.

SSL is a crucial protocol for securing traffic between a website and its visitors. It helps to protect sensitive information online, such as credit card data.

Next, You Should Also Read:

Openssl Generate Rsa Certificate

genpkey - generate a private key

opensslgenpkey[-out filename][-outform PEM DER][-pass arg][-cipher][-engine id][-paramfile file][-algorithm alg][-pkeyopt opt:value][-genparam][-text]

The genpkey command generates a private key.

-out filename

the output filename. If this argument is not specified then standard output isused.

-outform DER PEM

This specifies the output format DER or PEM.

-pass arg

the output file password source. For more information about the format of argsee the PASS PHRASE ARGUMENTS section in openssl.

-cipher

This option encrypts the private key with the supplied cipher. Any algorithmname accepted by EVP_get_cipherbyname() is acceptable such as des3.

-engine id

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specifying an engine (by its unique id string) will cause genpkeyto attempt to obtain a functional reference to the specified engine,thus initialising it if needed. The engine will then be set as the defaultfor all available algorithms. If used this option should precede all otheroptions.

-algorithm alg

public key algorithm to use such as RSA, DSA or DH. If used this option mustprecede any -pkeyopt options. The options -paramfile and -algorithmare mutually exclusive.

-pkeyopt opt:value

set the public key algorithm option opt to value. The precise set ofoptions supported depends on the public key algorithm used and itsimplementation. See KEY GENERATION OPTIONS below for more details.

-genparam
Openssl Rsa Generate Key Example

generate a set of parameters instead of a private key. If used this option mustprecede and -algorithm, -paramfile or -pkeyopt options.

-paramfile filename

Some public key algorithms generate a private key based on a set of parameters.They can be supplied using this option. If this option is used the public keyalgorithm used is determined by the parameters. If used this option mustprecede and -pkeyopt options. The options -paramfile and -algorithmare mutually exclusive.

-text

Print an (unencrypted) text representation of private and public keys andparameters along with the PEM or DER structure.

The options supported by each algorith and indeed each implementation of analgorithm can vary. The options for the OpenSSL implementations are detailedbelow.

rsa_keygen_bits:numbits

The number of bits in the generated key. If not specified 1024 is used.

rsa_keygen_pubexp:value

The RSA public exponent value. This can be a large decimal orhexadecimal value if preceded by 0x. Default value is 65537.

dsa_paramgen_bits:numbits

The number of bits in the generated parameters. If not specified 1024 is used.

dh_paramgen_prime_len:numbits

The number of bits in the prime parameter p.

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dh_paramgen_generator:value

Openssl Rsa_generate_key Example

The value to use for the generator g.

dh_rfc5114:num

If this option is set then the appropriate RFC5114 parameters are usedinstead of generating new parameters. The value num can take thevalues 1, 2 or 3 corresponding to RFC5114 DH parameters consisting of1024 bit group with 160 bit subgroup, 2048 bit group with 224 bit subgroupand 2048 bit group with 256 bit subgroup as mentioned in RFC5114 sections2.1, 2.2 and 2.3 respectively.

ec_paramgen_curve:curve

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the EC curve to use.

Gost 2001 support is not enabled by default. To enable this algorithm,one should load the ccgost engine in the OpenSSL configuration file.See README.gost file in the engines/ccgost directiry of the sourcedistribution for more details.

Use of a parameter file for the GOST R 34.10 algorithm is optional.Parameters can be specified during key generation directly as well asduring generation of parameter file.

paramset:name

Specifies GOST R 34.10-2001 parameter set according to RFC 4357.Parameter set can be specified using abbreviated name, object short name ornumeric OID. Following parameter sets are supported:

The use of the genpkey program is encouraged over the algorithm specificutilities because additional algorithm options and ENGINE provided algorithmscan be used.

Generate an RSA private key using default parameters:

Encrypt output private key using 128 bit AES and the passphrase 'hello':

Openssl Rsa Generate Key Example Word

Generate a 2048 bit RSA key using 3 as the public exponent:

Generate 1024 bit DSA parameters:

Generate DSA key from parameters:

Generate 1024 bit DH parameters:

Output RFC5114 2048 bit DH parameters with 224 bit subgroup:

Generate DH key from parameters: