Description:
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1) The function openssl_seal by default uses RC4 cipher, which is considered broken and should not be used.
I believe it is not a best practice to leave a weak cipher as a default option as many non-experts (like me) will use it.

2) Even if you want to change ciphers by using the parameter $method, you are limited to ciphers without initialization vectors (so no AES CBC). This is leaves us with ciphers like AES ECB, which is also not recommended.




Test script:
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openssl_seal($data, $sealed, $ekeys, array($pk1), 'AES-256-CBC');

// this fails, because CBC cannot be used, this is not documented, so the users must use trial and error to figure out which cipher is actually working

Expected result:
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Somebody with cyrpto knowledge could read my text and decide if it's worth looking into. I could be wrong, if so, I apologise in advance.