For starters, you’re going to use the openssl to test connections. For example, if you have a web server you might traditionally attempt to telnet into port 80 and check you banners; however, if you have an SSL certificate on it then you might be better served connecting to port 443 using the openssl command. We have a Strategic Architecture for the development of OpenSSL from 3.0.0 and going forward, as well as a design for 3.0.0 (draft) specifically. The frequently-asked questions (FAQ) is available. Information about the first-ever open source FIPS-140 validation is also available. Using OpenSSL to encrypt/decrypt like this is just a great way to show you how crypto works. Also note: generating keys using Openssl’s command line is fine (better to use a TRNG in an HSM but I will talk about this later), just encryption and decryption operations can be considered not best practice. How To Use OpenSSL sclient To Check and Verify SSL/TLS Of HTTPS Webserver? Check TLS/SSL Of Website. The basic and most popular use case for sclient is just connecting remote TLS/SSL website. We will provide the web site. Check TLS/SSL Of Website with Specifying Certificate Authority. OpenSSL 1.0.2 supported the use of the OpenSSL FIPS Object Module (FOM), which was built to deliver FIPS approved algorithms in a FIPS 140-2 validated environment. 22 23 OpenSSL controversially decided to categorize the 1.0.2 architecture as 'End of Life' or 'EOL', effective December 31, 2019, despite objections that it was the only version.

OpenSSL is a robust, commercial-grade, and full-featured toolkit for the Transport Layer Security (TLS) and Secure Sockets Layer (SSL) protocols. It is also a general-purpose cryptography library. For more information about the team and community around the project, or to start making your own contributions, start with the community page. To get the latest news, download the source, and so on, please see the sidebar or the buttons at the top of every page.

OpenSSL is licensed under an Apache-style license, which basically means that you are free to get and use it for commercial and non-commercial purposes subject to some simple license conditions.

For a list of vulnerabilities, and the releases in which they were found and fixes, see our Vulnerabilities page.

Latest News

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DateItem
06-May-2021Alpha 16 of OpenSSL 3.0 is now available: please download and test it
22-Apr-2021Alpha 15 of OpenSSL 3.0 is now available: please download and test it
08-Apr-2021Alpha 14 of OpenSSL 3.0 is now available: please download and test it
25-Mar-2021OpenSSL 1.1.1k is now available, including bug and security fixes
11-Mar-2021Alpha 13 of OpenSSL 3.0 is now available: please download and test it
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Legalities

Please remember that export/import and/or use of strongcryptography software, providing cryptography hooks, or even justcommunicating technical details about cryptography software isillegal in some parts of the world. So when you import thispackage to your country, re-distribute it from there or evenjust email technical suggestions or even source patches to theauthors or other people you are strongly advised to pay closeattention to any laws or regulations which apply toyou. The authors of OpenSSL are not liable for any violationsyou make here. So be careful, it is your responsibility.

OpenSSL is a powerful cryptography toolkit that can be used for encryption of files and messages.

If you want to use the same password for both encryption of plaintext and decryption of ciphertext, then you have to use a method that is known as symmetric-key algorithm.

From this article you’ll learn how to encrypt and decrypt files and messages with a password from the Linux command line, using OpenSSL.

HowTo: Encrypt a File

OptionsDescription
opensslOpenSSL command line tool
encEncoding with Ciphers
-aes-256-cbcThe encryption cipher to be used
-saltAdds strength to the encryption
-inSpecifies the input file
-outSpecifies the output file.

Interesting fact: 256bit AES is what the United States government uses to encrypt information at the Top Secret level.

Warning: The -salt option should ALWAYS be used if the key is being derived from a password.

Without the -salt option it is possible to perform efficient dictionary attacks on the password and to attack stream cipher encrypted data.

The reason for this is that without the salt the same password always generates the same encryption key.Using Openssl

When the salt is being used the first eight bytes of the encrypted data are reserved for the salt: it is generated at random when encrypting a file and read from the encrypted file when it is decrypted.

HowTo: Decrypt a File

OptionsDescription
-dDecrypts data
-inSpecifies the data to decrypt
-outSpecifies the file to put the decrypted data in

Base64 Encode & Decode

Base64 encoding is a standard method for converting 8-bit binary information into a limited subset of ASCII characters.

It is needed for safe transport through e-mail systems, and other systems that are not 8-bit safe.

By default the encrypted file is in a binary format.

If you are going to send it by email, IRC, etc. you have to save encrypted file in Base64-encode.

Cool Tip: Want to keep safe your private data? Create a password protected ZIP file from the Linux command line. Really easy! Read more →

To encrypt file in Base64-encode, you should add -a option:

OptionDescription
-aTells OpenSSL that the encrypted data is in Base64-ensode

Option -a should also be added while decryption:

Non Interactive Encrypt & Decrypt

Warning: Since the password is visible, this form should only be used where security is not important.

By default a user is prompted to enter the password.

If you are creating a BASH script, you may want to set the password in non interactive way, using -k option.

Download Openssl For Windows

Cool Tip: Need to improve security of the Linux system? Encrypt DNS traffic and get the protection from DNS spoofing! Read more →

Using Openssl Python

Public key cryptography was invented just for such cases.

Encrypt a file using a supplied password:

Using Openssl

Decrypt a file using a supplied password:

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