Public-Key Cryptography

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Symmetric-key encryption only involves one key, and you just use that one key to both encrypt and decrypt a message. Whereas, public-key (asymmetric-key) cryptography is any cryptographic system that uses pairs of keys:

• Public key, which is a large numerical value that is used to encrypt data, and is made available to everyone through a publicly accessible repository or directory.


• Private key, which is another large numerical value that is mathematically linked to the public key. Whatever is encrypted with a public key may only be decrypted by its corresponding private key and vice versa.

The cryptography accomplishes two functions:

• Authentication, where the public key verifies that a holder of the paired private key sent the message, and


• Encryption, where only the paired private key holder can decrypt the message encrypted with the public key.

Review: Cryptography

Which statement is NOT true?   Asymmetric-key encryption only involves one key.   Public key is made available to everyone.   Two major functions of cryptography is authentication and encryption.   Whatever is encrypted with a public key may only be decrypted by its corresponding private key and vice versa.

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