I am developing a messaging app, the only 2 way encryption php method I found is openssl_encrypt(), I successfully encrypt it, but when I insert it into the database, all characters are replaced with question marks, I have changed the collation of the table and the column, I have tried half the collations with no luck, I did some research, and I found out that there were slovak, vietnamese, and characters from another language along with copyright and trademark icons in the openssl_encrypt() encrypted text. what character encoding am I supposed to use ?
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Link to original article：https://stackoverflow.com/questions/40901178/mysql-replaces-php-openssl-encrypted-text-with-question-marks