Wondering how to Encrypt and Decrypt string php using OpenSSL? We can help you.

As part of our Server Management Services, we assist our customers with several SSL queries.

Today, let us see how our Support techs perform encryption and decryption.

How to Encrypt and Decrypt string php using OpenSSL?

In PHP, Encryption and Decryption of a string is possible using one of the Cryptography Extensions called OpenSSL function for encrypt and decrypt.

Today, let us see the steps followed by our Support Techs to perform it.

openssl_encrypt() Function:

Basically, this function is used to encrypt the data.

Syntax:

string openssl_encrypt( string $data, string $method, string $key,
$options = 0, string $iv, string $tag= NULL,
string $aad, int $tag_length = 16 )

Parameters:

• $data: It holds the string or data which need to encrypt.
• $method: The cipher method is adopt using openssl_get_cipher_methods() function.
• $key: It holds the encryption key.
• $options: It holds the bitwise disjunction of the flags OPENSSL_RAW_DATA and OPENSSL_ZERO_PADDING.
• $iv: It holds the initialization vector which is not NULL.
• $tag: It holds the authentication tag which is pass by reference when using AEAD cipher mode (GCM or CCM).
• $aad: It holds the additional authentication data.
• $tag_length: It holds the length of the authentication tag. The length of authentication tag lies between 4 to 16 for GCM mode.

Return Value: Then, it returns the encrypted string on success or FALSE on failure.

openssl_decrypt() Function:

Secondly, The openssl_decrypt() function is used to decrypt the data.

Syntax:

string openssl_decrypt( string $data, string $method, string $key,
int $options = 0, string $iv, string $tag, string $aad)

Parameters:

• $data: It holds the string or data which need to be encrypted.
• $method: The cipher method is adopted using openssl_get_cipher_methods() function.
• $key: It holds the encryption key.
• $options: It holds the bitwise disjunction of the flags OPENSSL_RAW_DATA and OPENSSL_ZERO_PADDING.
• $iv: It holds the initialization vector which is not NULL.
• $tag: It holds the authentication tag using AEAD cipher mode (GCM or CCM). When authentication fails openssl_decrypt() returns FALSE.
• $aad: It holds the additional authentication data.

Return Value: Then, it returns the decrypted string on success or FALSE on failure.

Approach:

Firstly, declare a string and store it into variable and use openssl_encrypt() function to encrypt the given string.

Then, use openssl_decrypt() function to descrypt the given string.

Example 1: This example illustrates the encryption and decryption of string.

<?php

// Store a string into the variable which
// need to be Encrypted
$simple_string = "Welcome to GeeksforGeeks\n";

// Display the original string
echo "Original String: " . $simple_string;

// Store the cipher method
$ciphering = "AES-128-CTR";

// Use OpenSSl Encryption method
$iv_length = openssl_cipher_iv_length($ciphering);
$options = 0;

// Non-NULL Initialization Vector for encryption
$encryption_iv = '1234567891011121';

// Store the encryption key
$encryption_key = "GeeksforGeeks";

// Use openssl_encrypt() function to encrypt the data
$encryption = openssl_encrypt($simple_string, $ciphering,
$encryption_key, $options, $encryption_iv);

// Display the encrypted string
echo "Encrypted String: " . $encryption . "\n";

// Non-NULL Initialization Vector for decryption
$decryption_iv = '1234567891011121';

// Store the decryption key
$decryption_key = "GeeksforGeeks";

// Use openssl_decrypt() function to decrypt the data
$decryption=openssl_decrypt ($encryption, $ciphering,
$decryption_key, $options, $decryption_iv);

// Display the decrypted string
echo "Decrypted String: " . $decryption;

?>

Output:

Original String: Welcome to GeeksforGeeks
Encrypted String: hwB1K5NkfcIzkLTWQeQfHLNg5FlyX3PNUA==
Decrypted String: Welcome to GeeksforGeeks

Example 2: Below example illustrate the encryption and decryption of string.

Here string to encrypted and decrypted string is same but the encrypt string is randomly change respectively.

<?php

// Store a string into the variable which
// need to be Encrypted
$simple_string = "Welcome to GeeksforGeeks";

// Display the original string
echo "Original String: " . $simple_string . "\n";

// Store cipher method
$ciphering = "BF-CBC";

// Use OpenSSl encryption method
$iv_length = openssl_cipher_iv_length($ciphering);
$options = 0;

// Use random_bytes() function which gives
// randomly 16 digit values
$encryption_iv = random_bytes($iv_length);

// Alternatively, we can use any 16 digit
// characters or numeric for iv
$encryption_key = openssl_digest(php_uname(), 'MD5', TRUE);

// Encryption of string process starts
$encryption = openssl_encrypt($simple_string, $ciphering,
$encryption_key, $options, $encryption_iv);

// Display the encrypted string
echo "Encrypted String: " . $encryption . "\n";

// Decryption of string process starts
// Used random_bytes() which gives randomly
// 16 digit values
$decryption_iv = random_bytes($iv_length);

// Store the decryption key
$decryption_key = openssl_digest(php_uname(), 'MD5', TRUE);

// Descrypt the string
$decryption = openssl_decrypt ($encryption, $ciphering,
$decryption_key, $options, $encryption_iv);

// Display the decrypted string
echo "Decrypted String: " . $decryption;

?>

Output:

Original String: Welcome to GeeksforGeeks
Encrypted String: hwB1K5NkfcIzkLTWQeQfHLNg5FlyX3PNUA==
Decrypted String: Welcome to GeeksforGeeks

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Conclusion

In short, today we saw steps followed by our Support Techs to Encrypt and Decrypt string php using OpenSSL.