When we talk about "security" in the crypto world, we have two sides: the security of the platform (that your funds are not stolen) and the security of the asset (that it does not lose its value).
If by security we mean that a project is not going to disappear overnight, Bitcoin $BTC is the king.
On one hand, it is the most decentralized and difficult to hack network in the world.
In 2025, its price (although volatile) has a much stronger "floor" than any other cryptocurrency.
And because it does not depend on a company or a CEO (as is the case with smaller coins), there is no risk of "mismanagement" that could destroy the asset's value.
In fact, its current value is quite low, which is advisable to buy as cheaply as possible, of course, being aware of what cryptocurrency trading entails in general