Definition
A private key is secret cryptographic material used to create signatures that authorize actions associated with its corresponding public key or blockchain address.
In market context
Control of a blockchain private key commonly enables transfer of the assets associated with its address, so confidentiality and reliable backup are critical. The key should not be shared with support staff, websites, or anyone claiming it is needed to verify an account. If it is lost without a recovery method, access may be permanent; if copied by an attacker, transactions may be irreversible.
Risk context
Anyone who obtains an unprotected private key may be able to transfer the controlled assets without the owner’s consent.
Source
Use the primary source for fuller regulatory or market context.
