Recommended Free Tools
Public-key encryption protects information using a mathematically related pair of keys: a sender encrypts with the recipient’s public key, and the recipient decrypts with the matching private key. The public key can be shared; the private key must be kept secret. NIST describes this as asymmetric cryptography, where deriving the private key from the public key is computationally infeasible.
How public-key encryption works
-
The recipient makes a public key available and keeps the matching private key secret.
As an Amazon Associate I earn from qualifying purchases.
-
The sender uses the recipient’s public key with an encryption algorithm to protect information.
Do these 3 things before closing this tab:
1Fix the driver behind crashes, sound loss and screen glitches2Repair Windows errors before they cause bigger problems3Scan for outdated or missing drivers - takes under a minuteSpecial offer. See more information about Outbyte and uninstall instructions. Please review EULA and Privacy policy. -
The recipient uses the corresponding private key to decrypt it.
#1 Best Overall
The keys are mathematical values used by cryptographic algorithms, not physical keys. The simple idea is that anyone can use your public key to send you protected information, but only the holder of the corresponding private key can decrypt it.
NIST defines public-key cryptography as cryptography that uses two separate keys to exchange data, one to encrypt or digitally sign data and one to decrypt data or verify a signature. NIST CSRC glossary: public-key cryptography
Public-key cryptography is broader than encryption
Public-key cryptography is a family of techniques. Public-key encryption specifically refers to protecting confidentiality through encryption and decryption. Other operations have different purposes:
What’s actually slowing this PC down?
Pick the symptom - the matching free tool is one click away.
-
Digital signatures: A private key generates a signature, and the corresponding public key verifies it. Signing is a distinct cryptographic operation, not simply “encrypting with the private key.”
-
Key agreement: Parties use public-key methods to compute shared secret material.
-
Key transport: Public-key methods can help establish or convey key material for another cryptographic operation.
NIST’s glossary describes public keys as supporting encryption, signature verification and shared-secret uses, depending on the algorithm and protocol. NIST CSRC glossary: public key
The Tool Desk
Outbyte PC Repair FREEClear out junk files and repair common Windows errorsFree Scan →Outbyte Driver Updater FREEScan for outdated or missing drivers - takes under a minuteDriver Scan →Public-key encryption and symmetric encryption compared
| Feature | Public-key encryption | Symmetric encryption |
|---|---|---|
| Key arrangement | A mathematically related public and private key pair | A shared secret key |
| Key distribution | The public key may be shared openly; the private key must remain secret | The shared secret must be handled securely by the parties using it |
| Common role | Can support confidentiality and other public-key operations, such as key establishment or signatures | Commonly used to encrypt bulk data |
| Large-message suitability | NIST characterizes asymmetric algorithms as relatively slow and poorly suited to encrypting large messages directly | Commonly used for bulk-data encryption |
In practice, public-key methods are often used for key management, while symmetric encryption handles the larger body of data. NIST’s SP 800-32 explains this general division; it is an older explanatory publication, not current advice for choosing a specific algorithm. NIST SP 800-32, Introduction to Public Key Technology and the Federal PKI Infrastructure
Best Value
A public key does not prove who owns it
Anyone may be able to obtain a public key, but that alone does not establish that it belongs to the intended person or service. A public-key certificate is a digitally signed document that binds an identifier to a subscriber’s public key. Public key infrastructure (PKI) comprises the policies, processes and systems used to administer certificates and key pairs. NIST SP 800-63B Revision 4
That distinction matters: encryption with a key can protect information for the holder of its matching private key, but a trustworthy process is needed to associate the public key with the right recipient.
Quick Recap
Product prices and availability are accurate as of the date/time indicated and are subject to change. Any price and availability information displayed on Amazon at the time of purchase will apply.
