Description:
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We get an SSL error when connecting to a secure MySQL server for some queries:

Warning: PDOStatement::execute(): SSL operation failed with code 1. OpenSSL Error messages:
error:0607A082:digital envelope routines:EVP_CIPHER_CTX_set_key_length:invalid key length
error:0607A082:digital envelope routines:EVP_CIPHER_CTX_set_key_length:invalid key length

The error happens for the next query after we used the openssl_decrypt function in our code. It seems like this function is not properly encapsulated or leaves some state behind which then triggers the error in PDO.

I was not able to reproduce a test-case with values that would not expose our secret, but making a second call to openssl_decrypt with no meaningful values fixes it.

Test script:
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// This query runs fine.
$con->prepare("SELECT 1")->execute()->fetchColumn();

// This call leaves some state behind that causes error on second query.
openssl_decrypt(/* real arguments here */);

// Adding a call like this works around the bug.
// openssl_decrypt('', 'AES-256-CBC', '', 0, '');

// Error on this query.
$con->prepare("SELECT 1")->execute()->fetchColumn();