Elliptical curve was replaced by RSA, That is 2048 bit. There is no perfect entropy, But 2048 bit is significantly more complex than 256 bit. It is possible to decrypt 256 bit by RSA 2048, But not RSA by Elliptical curve. Your encryption is safe from people without RSA encryption. This is the relevance of Multisig in Bitcoin wallets, That the time investment needs to outweigh the rewards, And you should never trust one service provider to protect you, Instead you need to mutually ensure your security through their competition.