Bitcoin Forum

Hello, I am wondering if it is possible for a private key to  have a validity period. And if so if there is a possibility to reactivate it?
And can I check somewhere if the money in my wallet has been moved when I only have the public key?

You can write a smart contract which will automatically move the funds if they are not being used for a specific time or until a specific block is mined.

There are also a couple of new wallet(s) coming out with this feature. So it's not a private-key per-se but rather a wallet with a private key that has an expiration date/block.

As to your second questions, yes, you have several options to have a watch only address with alert function if the balance change for that specific public key.

You can also write custom tools for this, in python if you run a node locally (for that specific block chain)

/KX

The private key is the bit of a code which is paired with a public key. Basically it is the key that is used for both encryption and decryption. The public key is held publicaly so there is no possibility of a loss of the keys but in private key, the key may be lost which is used by a particular individual.

Most coins (including Bitcoin) are only pseudo-anonymous and that means that if you know the address (which is public) you can easily see, on a block explorer, all the transactions and also the current amount.
Just fill your Bitcoin address in https://www.blockchain.com/explorer or https://chain.so/ and you'll see.

On the other hand, on Bitcoin network the private key validity is infinite. You have to keep it safe, because anybody who has it can spend your coins.

Another thing to keep in mind, is address reuse. You can think of it, as, once you have used and spent from that address, it's "expired" or not valid. Even if it actually, technically is still valid. You can reuse it, but that is not recommended, when it is so easy to use another one, and in normal usage your wallet sends the remaining unused balance to a change address.

Private key dont have validity period (in Bitcoin, maybe some altcoins do that?).
You can create watch-only wallets to observe in secure way your funds :)

think of the private key as a special "pen" you use to sign "checks" before giving it to someone else to go to back and cash them out. you can't have any limits on your pen, it is just a pen! what you can do is to add conditions such as "validity period" to your check so for example the person could only cash it after 10 days not sooner.
with bitcoin that pen is your private key and the checks are the locking scripts used in each transaction. altcoins are pretty similar, most of them copy bitcoin scripts others do similar with additional conditions.

No, as far as I know, no private key has a fixed term. You can use so much throughout your life. But when you lose it you can't bring that wallet back in any way, even the private key. For example, below you can see what is the works of the bitcoin private key and the public key.

https://i.postimg.cc/L6zk6TqL/chrome-s-DZd6b-LFum.png

source : https://coinsutra.com/bitcoin-private-key/

Since you have only the public key you can see the transaction of your portfolio. To check this transaction you need to scan the private key on the explorer/chain of the specific coin. It would have been easier to indicate an appropriate explorer if you had mentioned your coin name on the OP.