Asymmetric Encryption

Security+ 🏆 • Cryptography 🔒 • Difficulty: free

Definition

Asymmetric encryption is an encryption method that uses a pair of related keys, a public key and a private key. The public key can be shared openly, while the private key is kept secret, enabling secure communication, key exchange, and digital signatures without sharing a single secret key in advance.

Examples

  • A website uses certificates and asymmetric cryptography during the TLS handshake to prove its identity and establish secure session keys.
  • An employee encrypts a file with a colleague’s public key so only the colleague can decrypt it with their private key.

Discover 🔎

Symmetric encryption is fast, but it has a big practical problem: how do two parties share a secret key safely in the first place. Asymmetric encryption solves this trust and distribution problem by using two keys instead of one. One key can be public and shared widely, while the other stays private. This makes it possible to set up secure communication with people you have never met and systems you have never connected to before.

Remember: Public key can be shared. Private key must be protected. If the private key is stolen, security is usually lost.
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