PHP OpenSSL Functions

What is OpenSSL?

OpenSSL is a free open-source module designed to handle communication over computer networks. OpenSSL is a tool used for Transport Layer Security (TLS) and Secure Sockets Layer (SSL) protocols.

What is an SSL certificate?

Websites use the Secure Sockets Layer (SSL) to secure data transmission between two computers. SSL certificates are responsible for encrypting data between two computers. The two computers involved can be the data sharing between a client and a server. When you share data such as passwords, credit card details, home address, social security numbers, etc., it must be protected, and SSL certificates will protect it. SSL certificates ensure the authentication of the identity of the two computers involved to ensure a secure connection.

OpenSSL Installation in PHP

By default, the OpenSSL module has been added to PHP. You can remove it by deleting it in php.ini.; extension = php_openssl.dllStartUse the semicolon (;) to enable them. After that, restart Apache and confirm that the changes have taken effect, then save the following code as .php and execute .php in the browser.

<?php
　　　phpinfo();
?>

You should see OpenSSL enabled in your browser as follows:

OpenSSL Configuration

openssl.cnf is the configuration file that contains all the default configurations required for OpenSSL to work properly. To execute OpenSSL, the first thing php will try to find is the configuration file. To get the same file, you must add the Php folder to the environment variable.

If you are a Windows user, please follow the steps below to set the environment variable for the Php folder:

1.Right-click on My Computer and go to Properties.

2.Go to Advanced System Settings.

3.Click the 'Environment Variables' button.

4.Edit the path variable and then click the 'Edit' button.

5.Now add the Php folder path at the end. I am using XAMPP, and my Php folder is c:\xampp\php;

6.After completion, click the OK button.

7.Now open the Command Prompt and enter the command: openssl version -a.

C:\Windows\system32>openssl version　-a
OpenSSL　1.0.2l　　25　May　2017
built　on:　reproducible　build,　date　unspecified
platform:　mingw64
options:　　bn(64,64)　rc4(16x,int)　des(idx,cisc,2,long)　idea(int)　blowfish(idx)
compiler:　x86_64-w64-mingw32-gcc　-I.　-I..　-I../include　　-D_WINDLL　-DOPENSSL_PIC
-DOPENSSL_THREADS　-D_MT　-DDSO_WIN32　-static-libgcc　-DL_ENDIAN　-O3　-Wall　-DWIN32_
LEAN_AND_MEAN　-DUNICODE　-D_UNICODE　-DOPENSSL_IA32_SSE2　-DOPENSSL_BN_ASM_MONT　-DO
PENSSL_BN_ASM_MONT5　-DOPENSSL_BN_ASM_GF2m　-DRC4_ASM　-DSHA1_ASM　-DSHA256_ASM　-DSH
A512_ASM　-DMD5_ASM　-DAES_ASM　-DVPAES_ASM　-DBSAES_ASM　-DWHIRLPOOL_ASM　-DGHASH_ASM
　-DECP_NISTZ256_ASM
OPENSSLDIR:　"/etc/ssl"

Now, php will be able to find the openssl.cnf configuration file.

OpenSSL Functions

The following table lists all functions related to PHP OpenSSL. Here, 'version' indicates the earliest version of PHP that supports the function feature.