- From your computer, run the
ssh-keygen
utility.Specify a
filename
for the private key. Also specify the RSA type and a size of 2048.The command format is:
ssh-keygen -b 2048 -t rsa -f filename
For example:
ssh-keygen -b 2048 -t rsa -f mykey
- When prompted, enter a passphrase for the private key, or press Enter to create a private key without a passphrase.
Enter passphrase (empty for no passphrase): YourPassphrase
Note:
While a passphrase is not required, Oracle recommends using one as a security measure to protect the private key from unauthorized use. When you specify a passphrase, a user must enter the passphrase every time the private key is used.
- If you provided a passphrase, enter it a second time when prompted.
This topic tells you how to generate self-signed SSL certificate requests using the OpenSSL toolkit to enable HTTPS connections. Run the following OpenSSL command to generate your private key and public certificate. Answer the questions and enter the Common Name when prompted. In the Password text field, enter the password for the. Generate server certificate/key pair -no password required. 2) openssl genrsa -out server.key 1024 3) openssl req -key server.key -new -out server.req 4) openssl x509 -req -in server.req -CA CA.pem -CAkey privkey.pem -CAserial file.srl -out server.pem -contents of 'file.srl' is a two digit number. '00' Generate client certificate/key pair.
The ssh-keygen
utility creates two files:
filename
- The private keyfilename.pub
- The public key
While Encrypting a File with a Password from the Command Line using OpenSSLis very useful in its own right, the real power of the OpenSSL library is itsability to support the use of public key cryptograph for encrypting orvalidating data in an unattended manner (where the password is not required toencrypt) is done with public keys.
The Commands to Run
Generate a 2048 bit RSA Key
You can generate a public and private RSA key pair like this:
openssl genrsa -des3 -out private.pem 2048
That generates a 2048-bit RSA key pair, encrypts them with a password you provideand writes them to a file. You need to next extract the public key file. You willuse this, for instance, on your web server to encrypt content so that it canonly be read with the private key.
Export the RSA Public Key to a File
This is a command that is
openssl rsa -in private.pem -outform PEM -pubout -out public.pem
The -pubout
flag is really important. Be sure to include it.
Next open the public.pem
and ensure that it starts with-----BEGIN PUBLIC KEY-----
. This is how you know that this file is thepublic key of the pair and not a private key.
To check the file from the command line you can use the less
command, like this:
less public.pem
Do Not Run This, it Exports the Private Key
A previous version of the post gave this example in error.
openssl rsa -in private.pem -out private_unencrypted.pem -outform PEM
The error is that the -pubout
was dropped from the end of the command.That changes the meaning of the command from that of exporting the public keyto exporting the private key outside of its encrypted wrapper. Inspecting theoutput file, in this case private_unencrypted.pem
clearly shows that the keyis a RSA private key as it starts with -----BEGIN RSA PRIVATE KEY-----
.
Visually Inspect Your Key Files
It is important to visually inspect you private and public key files to makesure that they are what you expect. OpenSSL will clearly explain the nature ofthe key block with a -----BEGIN RSA PRIVATE KEY-----
or -----BEGIN PUBLIC KEY-----
.
You can use less to inspect each of your two files in turn:
less private.pem
to verify that it starts with a-----BEGIN RSA PRIVATE KEY-----
less public.pem
to verify that it starts with a-----BEGIN PUBLIC KEY-----
The next section shows a full example of what each key file should look like.
The Generated Key Files
The generated files are base64-encoded encryption keys in plain text format.If you select a password for your private key, its file will be encrypted withyour password. Be sure to remember this password or the key pair becomes useless.
The private.pem file looks something like this:
The public key, public.pem, file looks like:
Protecting Your Keys
Depending on the nature of the information you will protect, it’s important tokeep the private key backed up and secret. The public key can be distributedanywhere or embedded in your web application scripts, such as in your PHP,Ruby, or other scripts. Again, backup your keys!
Openssl Generate Key Pair Without Passphrase
Remember, if the key goes away the data encrypted to it is gone. Keeping aprinted copy of the key material in a sealed envelope in a bank safety depositbox is a good way to protect important keys against loss due to fire or harddrive failure.
Openssl Generate Key Pair No Password Code
Oh, and one last thing.
If you, dear reader, were planning any funny business with the private key that I have just published here. Know that they were made especially for this series of blog posts. I do not use them for anything else.
Found an issue?
Rietta plans, develops, and maintains applications.
Learn more about our services or drop us your email and we'll e-mail you back.