openssl version command with code examples

OpenSSL is an open-source implementation of the Secure Sockets Layer (SSL) and Transport Layer Security (TLS) protocols. It is commonly used to secure network communications and manage digital certificates. One of the most basic and important commands in OpenSSL is the "version" command, which is used to check the version of OpenSSL that is currently installed on a system.

The basic syntax of the OpenSSL version command is as follows:

openssl version

When executed, this command will display the version number of the OpenSSL library, as well as any additional information such as the version of the OpenSSL headers and the version of the underlying operating system.

Example:

$ openssl version
OpenSSL 1.1.1g 21 Apr 2020

In this example, the version of OpenSSL that is currently installed is 1.1.1g.

You can also use the -a option to show the compile-time options that were used to build the OpenSSL library.

$ openssl version -a
OpenSSL 1.1.1g 21 Apr 2020
built on: Mon Apr 27 14:36:24 2020 UTC
platform: linux-x86_64
options: bn(64,64) rc4(16x,int) des(int) aes(partial) blowfish(ptr)
compiler: gcc -fPIC -pthread -march=x86-64 -mtune=generic -O2 -pipe -fstack-protector-strong -fno-plt -DOPENSSL_USE_NODELETE -DL_ENDIAN -DOPENSSL_PIC -DOPENSSL_CPUID_OBJ -DOPENSSL_IA32_SSE2 -DOPENSSL_BN_ASM_MONT -DOPENSSL_BN_ASM_GF2m -DSHA1_ASM -DSHA256_ASM -DSHA512_ASM -DKECCAK1600_ASM -DRC4_ASM -DMD5_ASM -DAES_ASM -DVPAES_ASM -DBSAES_ASM -DGHASH_ASM -DECP_NISTZ256_ASM
OPENSSLDIR: "/usr/local/ssl"

Another option is using -v to show the version of openssl and also the options that it was build with.

$ openssl version -v
OpenSSL 1.1.1g 21 Apr 2020

It is important to note that the version of OpenSSL that is currently installed on a system can have a significant impact on security. For example, older versions of OpenSSL may contain known vulnerabilities that have been patched in more recent versions. Therefore, it is important to regularly check the version of OpenSSL that is installed on a system and to update to the latest version if necessary.

In conclusion, the OpenSSL version command is a simple but useful command that allows you to check the version of OpenSSL that is currently installed on a system. This information can be used to ensure that the system is running the most recent version of OpenSSL and is therefore as secure as possible.

In addition to checking the version of OpenSSL that is installed on a system, it is also important to manage digital certificates. Digital certificates, also known as public key certificates, are used to establish the identity of a website or other networked entity and to secure communications between them.

OpenSSL provides several commands for managing digital certificates, including the following:

• openssl genrsa: This command is used to generate a new RSA private key. The private key is typically stored in a file and protected with a password.
• openssl req: This command is used to generate a certificate signing request (CSR), which is sent to a certificate authority (CA) to request the issuance of a new certificate.
• openssl x509: This command is used to generate a self-signed certificate or to display the contents of an existing certificate.
• openssl verify: This command is used to verify the authenticity of a certificate by checking its signature against the public key of the issuing CA.

Here's an example of how to use these commands to generate a new RSA private key, create a CSR and self-signed certificate:

$ openssl genrsa -out example.com.key 2048
$ openssl req -new -key example.com.key -out example.com.csr
$ openssl x509 -req -days 365 -in example.com.csr -signkey example.com.key -out example.com.crt

It is important to note that self-signed certificates are not trusted by default by most web browsers and operating systems. Therefore, in order to use a certificate for public-facing websites or other services, it is necessary to obtain a certificate from a trusted CA. A CA is a trusted third party that verifies the identity of the certificate holder and signs the certificate.

In addition to managing digital certificates, OpenSSL also provides a wide range of other features and functionality, including support for various cryptographic algorithms, secure communications protocols, and the ability to encrypt and decrypt files.

For example, you can use the openssl enc command to encrypt a file using a symmetric key and the openssl rsautl command to encrypt or sign a file using an RSA key.

$ openssl enc -aes-256-cbc -salt -in file.txt -out file.txt.enc -k mypassword
$ openssl rsautl -encrypt -inkey example.com.key -pubin -in file.txt -out file.txt.enc

It's important to mention that OpenSSL is a complex tool and it's important to understand the basic concepts and usage of it to avoid security issues, for example, using weak ciphers, or encryption keys with low entropy.

In conclusion, OpenSSL is a powerful tool for managing digital certificates and for providing secure communications and file encryption. However, it is important to have a good understanding of the basic concepts and usage of OpenSSL to ensure that it is used in a secure and effective manner.

Popular questions

1. What is the command to check the version of OpenSSL that is installed on a system?
   Answer: The command to check the version of OpenSSL that is installed on a system is openssl version.

2. How can I generate a new RSA private key using OpenSSL?
   Answer: You can generate a new RSA private key using the openssl genrsa command. For example, openssl genrsa -out example.com.key 2048 will generate a new RSA private key with a length of 2048 bits and save it to a file named "example.com.key".

3. How can I create a certificate signing request (CSR) using OpenSSL?
   Answer: You can create a certificate signing request (CSR) using the openssl req command. For example, openssl req -new -key example.com.key -out example.com.csr will create a new CSR using the private key stored in the "example.com.key" file and save it to a file named "example.com.csr".

4. How can I generate a self-signed certificate using OpenSSL?
   Answer: You can generate a self-signed certificate using the openssl x509 command. For example, openssl x509 -req -days 365 -in example.com.csr -signkey example.com.key -out example.com.crt will generate a new self-signed certificate valid for 365 days using the CSR stored in the "example.com.csr" file, the private key stored in the "example.com.key" file and save it to a file named "example.com.crt".

5. How can I encrypt a file using a symmetric key with OpenSSL?
   Answer: You can encrypt a file using a symmetric key with the openssl enc command. For example, openssl enc -aes-256-cbc -salt -in file.txt -out file.txt.enc -k mypassword will encrypt the file "file.txt" using the AES-256-CBC algorithm with a salt and a passphrase "mypassword" and save the encrypted version to "file.txt.enc".

Tag

Cryptography.