What is a private key?
DefinitionA private key is a secret number, usually 256 bits long, that proves you own a crypto address and lets you sign transactions from it. Anyone who knows the private key controls the funds, and it cannot be reset or changed.
How a private key works
A private key works as one half of a key pair. From the private key, the wallet calculates a public key, and from the public key, your address; the math only runs one way, so sharing your address reveals nothing about the key.
When you send crypto, the wallet uses the private key to create a digital signature for that exact transaction. Every node can check the signature against your address without ever seeing the key itself.
Private key vs seed phrase vs address
A private key, a seed phrase and an address are related but not interchangeable:
- Address: public and safe to share; it is where others send you funds
- Private key: secret; it controls one address and is often shown as 64 hexadecimal characters
- Seed phrase: secret; 12 to 24 words from which a wallet derives all your private keys on every network
How private keys get stolen
Private keys are almost never cracked by computers: there are about 2 to the power of 256 possible keys, far too many to guess. They are stolen through people and devices instead:
- Phishing sites that ask you to “validate” or “sync” your wallet
- Fake support agents in chats and on social media
- Malware on rooted phones or infected computers
- Keys or phrases saved in screenshots, notes or cloud storage
Private keys in Waletifi
In Waletifi, private keys are derived from your 24-word phrase on your phone and never leave it. They are encrypted with a hardware-backed key in the Android Keystore and unlocked by your fingerprint or PIN; transactions are signed on the phone, and our server only relays transactions that are already signed.
