Loads a public key from a certificate, PEM string or supported key input for cryptographic verification.
Before using it, identify which data, connection or runtime state the operation reads or changes. This avoids examples that appear to work but apply to a different context.
What Is openssl_pkey_get_public() in PHP?
Loads a public key from a certificate, PEM string or supported key input for cryptographic verification.
Syntax:
<?php
// Signature for reference only
openssl_pkey_get_public($public_key) : OpenSSLAsymmetricKey|false
Parameters and Return Value
$public_key— Required value argument supplied to this operation.
The declared return type is OpenSSLAsymmetricKey|false.
Example 1: Basic Usage
<?php
$privateKey = openssl_pkey_new(["private_key_bits"=>2048]);
$publicKeyPem = openssl_pkey_get_details($privateKey)["key"];
$publicKey = openssl_pkey_get_public($publicKeyPem);
var_dump($publicKey instanceof OpenSSLAsymmetricKey);Loads a public key from a certificate, PEM string or supported key input for cryptographic verification.
Example 2: Another Case
<?php
$privateKey = openssl_pkey_new(["private_key_bits"=>2048]);
$publicKeyPem = openssl_pkey_get_details($privateKey)["key"];
$publicKey = openssl_pkey_get_public($publicKeyPem);
echo openssl_pkey_get_details($publicKey)["bits"];The second sample illustrates a different way to inspect or handle this operation. Configure the underlying session, socket, key material or connection first.
Practical Example
<?php
$privateKey = openssl_pkey_new(["private_key_bits"=>2048]);
$publicKeyPem = openssl_pkey_get_details($privateKey)["key"];
if (openssl_pkey_get_public($publicKeyPem) === false) { throw new RuntimeException("Invalid public key"); }The practical example is a teaching scenario. Change sample configuration and credentials before using a similar design in an application.
Important Behavior and Edge Cases
- Use trusted certificate and key material; never print private keys or disclose secrets in logs.
- Relevant PHP environment: openssl. Ensure the required extension and operating-system capabilities are present.
- Check results and release resources where necessary; successful syntax alone does not guarantee a successful operation.
Comparison With Related Functions
| Option | When to Use It |
|---|---|
openssl_pkey_get_public | Loads a public key from a certificate, PEM string or supported key input for cryptographic verification. |
openssl_pkey_get_details | Use this related operation for its different responsibilities; do not assume identical inputs or return values. |
Common Beginner Mistakes
| Mistake | Correct Approach |
|---|---|
| Confusing public and private keys | Use the appropriate key type for each operation and never disclose secret key data. |
| Assuming every algorithm is safe for every purpose | Choose modern algorithms and protocol combinations supported by your deployment. |
| Printing certificate and key material to visitors | Keep cryptographic diagnostics restricted and redact secrets. |
Key Takeaways
- Loads a public key from a certificate, PEM string or supported key input for cryptographic verification.
- Use trusted certificate and key material; never print private keys or disclose secrets in logs.
- Validate inputs and handle failure conditions before integrating this operation into a production workflow.
Loads a public key from a certificate, PEM string or supported key input for cryptographic verification. Use the appropriate runtime and treat any environment-dependent output as an example, not a guaranteed result.