Description:
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Although the OCB mode (authenticated encryption) is included in the list of available algorithms (e.g. [33] => aes-256-ocb) it is not properly supported. openssl_encrypt causes the error message: >The authenticated tag cannot be provided for cipher that doesn not support AEAD<. No tag is provided. However, the generated ciphertext seems to be correct. openssl_decrypt returns false. If aes-256-ocb is replaced by e.g. aes-256-gcm, it works as expected.


Test script:
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//echo print_r(openssl_get_cipher_methods(), true);

$plaintext = "The quick brown fox jumps over the lazy dog";
$cipher = 'aes-256-ocb';
$key = '01234567890123456789012345678901';
$iv = '012345678901';

$ciphertext = openssl_encrypt($plaintext, $cipher, $key, OPENSSL_RAW_DATA, $iv, $tag);
echo "tag (hex): " . bin2hex($tag) . PHP_EOL ;
echo "ciphertext (hex): " . bin2hex($ciphertext) . PHP_EOL ;

$recovered = openssl_decrypt($ciphertext, $cipher, $key, OPENSSL_RAW_DATA, $iv, $tag);
echo "recovered: " . ($recovered == false ? 'false' : $recovered) . PHP_EOL ;


Expected result:
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For the OCB mode, analogous to the GCM/CCM mode, a tag should be generated during encryption (6th parameter, $tag), which is used for authentication during decryption. 

Actual result:
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See description / test script