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.
You can generate a public and private RSA key pair like this:
Api key generator for location on iphone. Click on the API security tab. On the following page, under the API Keys section, you'll see both your Private and Public API keys. Click on the eye icon to make the full API key visible. SMTP Credentials. Your SMTP credentials are different for each domain you add. Apr 10, 2020 To get an API key: Go to the Google Cloud Platform Console. Click the project drop-down and select or create the project for which you want to add an API key. Click the menu button and select APIs & Services Credentials. On the Credentials page, click Create credentials API key. The API key created dialog displays your newly created API key. Apr 10, 2020 To get an API key: Visit the Google Cloud Platform Console. Click the project drop-down and select or create the project for which you want to add an API key. Click the menu button and select APIs & Services Credentials. On the Credentials page, click Create credentials API key. The API key created dialog displays your newly created API key.
It contains e (public exponent) so that public RSA key can be generated/extracted/derived from the private.pem private RSA key. The rest 5 components are there to speed up the decryption process. It turns out that by pre-computing and storing those 5 values it is possible to speed the RSA decryption by the factor of 4.
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.
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
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-----
.
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 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.
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!
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.
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.
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# Generate Private Key and Certificate using RSA 256 encryption (4096-bit key) |
openssl req -x509 -newkey rsa:4096 -keyout privatekey.pem -out certificate.pem -days 365 |
# Alternatively, setting the '-newkey' parameter to 'rsa:2048' will generate a 2048-bit key. |
# Generate PKCS#12 (P12) file for cert; combines both key and certificate together |
openssl pkcs12 -export -inkey privatekey.pem -in certificate.pem -out cert.pfx |
# Generate SHA256 Fingerprint for Certificate and export to a file |
openssl x509 -noout -fingerprint -sha256 -inform pem -in certificate.pem >> fingerprint.txt |
# Generate SHA1 Fingerprint for Certificate and export to a file |
#openssl x509 -noout -fingerprint -sha1 -inform pem -in certificate.pem >> fingerprint.txt |
# FYI, it's best practice to use SHA256 instead of SHA1 for better security, but this shows how to do it if you REALLY need to. |
Here's a couple useful links related to this: |