For ``argon2i`` or ``argon2id`` only. Maximum memory that may be used to compute the Argon2 hash. Value must be >=10, default is `64`. If `0`, default is used.
**Notes**
1. Symfony multiplies the memory cost by `1024`, if you enter `64`, it means `64 * 1024`.
1. If [sodium](https://www.php.net/manual/en/book.sodium.php) extension is **installed**, [sodium_crypto_pwhash_str()](http://php.net/manual/en/function.sodium-crypto-pwhash-str.php) will be used, the `$memlimit` argument is in **bytes**, not in kibibytes. If you enter `64`, it means `64 * 1024` bytes only, so you may want to enter `65536` instead.
1. If [sodium](https://www.php.net/manual/en/book.sodium.php) extension is **not installed**, [password_hash()](https://www.php.net/manual/en/function.password-hash.php) will be used, the `memory_cost` option is in **kibibytes**. If you enter `64`, it means `64 * 1024` kibibytes.