What is an SSL certificate?
SSL - Secure Sockets Layer
TSL - Transport Layer Security
SSL certificates are what enable websites to move from HTTP to HTTPS
-
Which is more secure.
-
An SSL certificate is a data
file hosted in a website's origin server.
-
SSL certificates make SSL/TLS
encryption possible.
-
they contain the website's public key and the website's identity, along with
related information.
Devices attempting to communicate with the origin
server will reference this file to obtain the public key and verify the
server's identity. The private key is kept secret and secure.
Here is the full history of SSL and TLS releases:
SSL 1.0 – never publicly released due to security
issues.
SSL 2.0 – released in 1995. Deprecated in 2011. Has
known security issues.
SSL 3.0 – released in 1996. Deprecated in 2015. Has
known security issues.
TLS 1.0 – released in 1999 as an upgrade to SSL 3.0.
Planned deprecation in 2020.
TLS 1.1 – released in 2006. Planned deprecation in
2020.
TLS 1.2 – released in 2008.
TLS 1.3 – released in 2018.
What is SSL?
SSL is commonly called as TLS, is a protocol for
encrypting Internet traffic and verifying server identity. Any website with an
HTTPS web address uses SSL/TLS.
See What is SSL?
and What is TLS? to learn more.
What information does an SSL certificate contain?
SSL certificates include:
A. The domain name that
the certificate was issued for
B. Which person, organization, or device it was issued
to
C. Which certificate authority issued it
D. The certificate authority's digital signature
E. Associated subdomains
F. Issue date of the certificate
G. Expiration date of the certificate
H. The public key (the private key is kept secret)
The public and private keys used for SSL are
essentially long strings of characters used for encrypting and decrypting data.
Data encrypted with the public key can only be decrypted with the private key,
and vice versa.
Why do websites need an SSL certificate?
A website needs an SSL certificate in order to keep
user data secure, verify ownership of the website, prevent attackers to hack site.
Encryption: SSL/TLS encryption is
possible because of the public-private key pairing that SSL certificates
facilitate. Clients (such as web browsers) get the public key necessary to open
a TLS connection from a server's SSL certificate.
Authentication: SSL certificates verify
that a client is talking to the correct server that actually owns the domain.
This helps prevent domain spoofing and other kinds of attacks.
HTTPS: Most crucially for businesses,
an SSL certificate is necessary for an HTTPS web address. HTTPS is the secure
form of HTTP, and HTTPS websites are websites that have their traffic encrypted
by SSL/TLS.
User data are secure in transit most browsers have started tagging HTTP sites as "not secure"
How does a website obtain an SSL certificate?
For an SSL certificate to be valid, domains need to
obtain it from a certificate authority (CA).
A CA is an outside organization, a trusted third
party, that generates and gives out SSL certificates.
The CA will also digitally sign the certificate with
their own private key, allowing client devices to verify it.
Most, but not all, CAs will charge a fee for issuing
an SSL certificate.
Once the certificate is issued, it needs to be
installed and activated on the website's origin server. Web hosting services
can usually handle this for website operators. Once it's activated on the
origin server, the website will be able to load over HTTPS and all traffic to
and from the website will be encrypted and secure.
What is a self-signed SSL certificate?
Technically, anyone can create their own SSL
certificate by generating a public-private key pairing and including all the
information mentioned above. Such certificates are called self-signed
certificates because the digital signature used, instead of being from a CA,
would be the website's own private key.
But with self-signed certificates, there's no
outside authority to verify that the origin server is who it claims to be.
Browsers don't consider self-signed certificates trustworthy and may still mark
sites with one as "not secure," despite the https:// URL. They may
also terminate the connection altogether, blocking the website from loading.
Self-signed certificates can have the same level of
encryption as the trusted CA-signed SSL certificate
Typically, the self-signed certificates are used for
testing purposes or internal usage. You should not use a self-signed
certificate in production systems that are exposed to the Internet.
Is it possible to get a free SSL certificate?
There are few vendors provide free SSL certificate
but very cautious before signing up and generating the SSL certificate.
Better to go with paid service with enterprise provider
for SSL certificate.
Creating a Self-Signed SSL Certificate
Prerequisites
The OpenSSL toolkit is required to generate a
self-signed certificate.
To check whether the openssl package
is installed on your Linux system, open your terminal, type openssl
version
[root@node1
dbs]# openssl version
OpenSSL
1.0.2k-fips 26 Jan 2017
[root@node1
dbs]#
If the openssl package is not installed on your
system, you can install it with your distribution’s package manager:
#yum install
openssl
Creating Self-Signed SSL Certificate
To create a new Self-Signed SSL Certificate,
use the openssl
req command:
openssl req
-newkey rsa:4096 \
-x509 \
-sha256 \
-days 365 \
-nodes \
-out example.crt \
-keyout example.key
Let’s breakdown the command and understand what each
option means:
-newkey rsa:4096 --- Creates a new certificate
request and 4096 bit RSA key (The default is 2048 bits)
-x509 --- Creates a X.509 Certificate.
-sha256 --- Use 265-bit SHA (Secure Hash
Algorithm).
-days 365 --- The number of days to certify the
certificate for 365 days.
-nodes --- Creates a key without a passphrase.
-out example.crt --- Specifies the filename to
write the newly created certificate to. (You can specify any file name)
-keyout example.key --- Specifies the filename
to write the newly created private key to. (You can specify any file name)
Once you hit Enter, the command will generate the
private key and ask you a series of questions. The information you provided is
used to generate the certificate.
[root@node1
~]# mkdir Certs
[root@node1
~]# cd Certs/
[root@node1
Certs]# pwd
/root/Certs
[root@node1
Certs]# ls -ltrh
total 0
[root@node1
Certs]# openssl req -newkey rsa:4096 \
> -x509 \
> -sha256 \
> -days 365 \
> -nodes \
> -out example.crt \
> -keyout example.key
Generating a
4096 bit RSA private key
............................................++
......................................................................++
writing new
private key to 'example.key'
-----
You are about
to be asked to enter information that will be incorporated
into your
certificate request.
What you are
about to enter is what is called a Distinguished Name or a DN.
There are
quite a few fields but you can leave some blank
For some
fields there will be a default value,
If you enter
'.', the field will be left blank.
-----
Country Name
(2 letter code) [XX]:
Enter the information requested and press Enter.
Country Name
(2 letter code) [XX]:IN
State or Province
Name (full name) []:Karnataka
Locality Name
(eg, city) [Default City]:Bangalore
Organization
Name (eg, company) [Default Company Ltd]:Mallik
Organizational
Unit Name (eg, section) []:IT
Common Name
(eg, your name or your server's hostname) []:mallik.com
Email Address
[]:mallik@gmail.com
The certificate and private key will be created at
the specified location. Use the ls command to verify that the files were
created:
[root@node1
Certs]# ls -ltrh
total 8.0K
-rw-r--r-- 1
root root 3.2K May 26 01:24 example.key
-rw-r--r-- 1
root root 2.1K May 26 01:24 example.crt
[root@node1
Certs]#
That’s it! You have generated a new self-signed SSL
certificate.
It is always a good idea to back up your new
certificate and key to external storage.
Creating Self-Signed SSL Certificate without Prompt
If you want to generate a self-signed SSL
certificate without being prompted for any question use the -subj option
and specify all the subject information:
openssl req
-newkey rsa:4096 \
-x509 \
-sha256 \
-days 3650 \
-nodes \
-out example.crt \
-keyout example.key \
-subj "/C=IN/ST=Karnataka/L=Bangalore/O=Mallik/OU=IT/CN=mallik.com"
[root@node1
Certs]# pwd
/root/Certs
[root@node1
Certs]# ls -ltrh
total 0
[root@node1
Certs]# openssl req -newkey rsa:4096 \
> -x509 \
> -sha256 \
> -days 3650 \
> -nodes \
> -out example.crt \
> -keyout example.key \
> -subj
"/C=IN/ST=Karnataka/L=Bangalore/O=Mallik/OU=IT/CN=mallik.com"
Generating a
4096 bit RSA private key
................................................++
.................................................................................................++
writing new
private key to 'example.key'
-----
[root@node1
Certs]# ls -ltrh
total 8.0K
-rw-r--r-- 1
root root 3.2K May 26 01:30 example.key
-rw-r--r-- 1
root root 2.0K May 26 01:30 example.crt
[root@node1
Certs]#
The fields, specified in -subj line are
listed below:
C= --- Country name. The two-letter ISO
abbreviation.
ST= --- State or Province name.
L= --- Locality Name. The name of the city
where you are located.
O= --- The full name of your organization.
OU= --- Organizational Unit.
CN= --- The fully qualified domain name.
Conclusion
We have shown you how to generate a self-signed SSL
certificate using the openssl tool. Now that you have the certificate, you can
configure your application to use it.
Feel free to leave a comment if you have any
questions.
How to verify the SSL certificates?
You can verify the certificate using keycdn site
[root@node1
Certs]# pwd
/root/Certs
[root@node1
Certs]#
[root@node1 Certs]# cat example.key
-----BEGIN PRIVATE KEY-----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-----END PRIVATE KEY-----
[root@node1 Certs]# cat example.crt
-----BEGIN CERTIFICATE-----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-----END CERTIFICATE-----
[root@node1 Certs]#
URL: https://tools.keycdn.com/ssl
Validate of example.key file:
Validation of example.crt file:
Regards,
Mallik
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