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Choosing Cryptographically Secure Token Generation Methods
The current practice of using md5(uniqid(mt_rand(), true)) to generate API access tokens has security concerns due to its dependency on the system clock and predictability. As a more robust solution, openssl_random_pseudo_bytes is recommended for its enhanced protection against prediction.
Equivalent Code and Length Considerations
The equivalent code utilizing openssl_random_pseudo_bytes is:
<code class="php">$token = bin2hex(openssl_random_pseudo_bytes(16));</code>
For PHP 7 and above, the following syntax is also available:
<code class="php">$token = bin2hex(random_bytes(16));</code>
The optimal length for the random string depends on the desired security level and the sensitivity of the data being protected. For most cases, a length of 16 bytes (128 bits) is considered sufficient. However, for highly sensitive applications, a longer length may be recommended.
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