GLOSSARY · BLOCKCHAIN & WEB3
Public and private key
What public and private keys are: how they sign and verify transactions, how they relate to your address and why losing the private key loses everything.
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What are public and private keys?
Public and private keys are a pair of interrelated cryptographic elements that operate on the principle of asymmetric cryptography, a fundamental pillar in the security architecture of blockchain, cryptocurrency, digital identity and multiple Web3 systems.
The private key is a secret known only to the owner, which allows them to sign transactions, access wallets and demonstrate ownership of digital assets or encrypted data.
The public key, derived mathematically from the private one using one-way cryptographic functions, acts as an identifier open to the public: it is the address to which others can send assets, validate signatures or interact.
This model allows authentication without intermediaries, eliminating the need to trust third parties to verify identity or ownership.
The system is secure as long as the private key remains protected, since its loss or leak can have irreversible consequences. In addition, this key pair is integrated into protocols such as SSL/TLS, public key infrastructure (PKI) and in the validation of smart contracts on blockchains such as Ethereum or Bitcoin.
The mathematical robustness of this scheme has made it a global standard for ensuring privacy, integrity and traceability in decentralized digital environments.
Learn more: Crypto custody providers: institutional solutions and how to choose one
Explained simply
Imagine that you have a safe with a slot for receiving letters.
The public key is like your address: anyone can use it to send you things.
But to open the box and access what they sent you, you need a private key, which is like a secret key. No one else should know that key.
If you lose it, you can't open the box. This is how many technologies such as cryptocurrencies or encrypted messages work.
Public and private key: key points
- They are two unique and mathematically linked keys.
- The private key should never be shared; it gives full access
- The public key can be freely shared; it works as an address
- They make it possible to sign and verify documents and transactions digitally
- They are used in blockchain, cryptocurrency, secure messaging and authentication
Public and private key: advantages
- Robust cryptographic security based on mathematical algorithms
- Privacy and full control over digital assets or identities
- It allows the use of digital signatures and passwordless authentication
- Technical basis for operating with wallets, smart contracts and tokens
- Does not require intermediaries, facilitating decentralized systems
Public and private key: disadvantages
- Loss of private key involves total loss of access
- Technical complexity for users not familiar with cryptography
- Risk of phishing or malware if the private key is not properly protected
- Being an asymmetric system, revoking keys may require complex solutions
- No automatic recovery, unlike traditional centralized systems
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