root@generate-random:~/encryption-keys/php$ _

Generate Encryption Keys in PHP - AES & RSA Key Generation

Complete code tutorial with examples and best practices

PHP

[ Code Example - Quick Summary ]

Language: PHP

What: Learn how to generate AES encryption keys and RSA key pairs in PHP using OpenSSL and random_bytes() for cryptographically secure encryption.

Try it: Use our interactive Encryption-keys generator or integrate this code into your PHP application.

Learn how to generate AES encryption keys and RSA key pairs in PHP using OpenSSL and random_bytes() for cryptographically secure encryption. Looking for other languages? Check our code examples in JavaScript , Python , Java , C# , C++ , Ruby and Go or use our interactive web generator.

PHP Code Example

<?php
// AES-256 Encryption Key Generation
$aes_key = random_bytes(32); // 256 bits
$aes_key_hex = bin2hex($aes_key);
echo "AES-256 Key (Hex): " . $aes_key_hex . "\n";

// AES-128 Encryption Key
$aes_128_key = bin2hex(random_bytes(16)); // 128 bits
echo "AES-128 Key (Hex): " . $aes_128_key . "\n";

// RSA Key Pair Generation (2048-bit)
$config = [
    "private_key_bits" => 2048,
    "private_key_type" => OPENSSL_KEYTYPE_RSA,
];

$res = openssl_pkey_new($config);
openssl_pkey_export($res, $private_key);
$public_key = openssl_pkey_get_details($res)["key"];

echo "Private Key:\n" . $private_key . "\n";
echo "Public Key:\n" . $public_key . "\n";

// Base64 encode for storage
$encoded_key = base64_encode($aes_key);
echo "AES Key (Base64): " . $encoded_key;

[EXPLANATION]

This code demonstrates AES and RSA key generation in PHP. For symmetric encryption (AES), we use random_bytes() with 32 bytes (256 bits) for AES-256 or 16 bytes (128 bits) for AES-128. The bin2hex() converts binary to hexadecimal for easy storage. For asymmetric encryption (RSA), openssl_pkey_new() generates a key pair with configurable bit length (2048 or 4096 recommended). openssl_pkey_export() extracts the private key in PEM format, while openssl_pkey_get_details() retrieves the public key. Keys should be stored securely (environment variables, key vaults) and never hardcoded.

Expected Output

AES-256 Key (Hex): a3f5d8c2e1b4f7a9c6d3e8b2f5a1c4d7e9b3f6a2c5d8e1b4f7a9c6d3e8b2f5a1
AES-128 Key (Hex): c7e2f5a9d3b8e1c4f7a2d6b9e3c5f8a1
Private Key:
-----BEGIN PRIVATE KEY-----
MIIEvQIBADANBgkqhkiG9w0BAQEFAASCBKcwggSjAgEAAoIBAQC8...
-----END PRIVATE KEY-----
Public Key:
-----BEGIN PUBLIC KEY-----
MIIBIjANBgkqhkiG9w0BAQEFAAOCAQ8AMIIBCgKCAQEAvP...
-----END PUBLIC KEY-----
AES Key (Base64): o/XYwuG096nG0+iy9aHE1+mz9qLF2OG096nG0+iy9aE=