avainkryptografian

Avainkryptografia, or asymmetric cryptography, is a cryptographic system that uses pairs of keys. These keys are mathematically related: one is a public key, and the other is a private key. The public key can be freely shared with anyone, while the private key must be kept secret by its owner.

The core principle of avainkryptografia is that data encrypted with a public key can only be decrypted with the corresponding private key, and conversely, data encrypted with a private key can be decrypted with the corresponding public key. This duality enables two primary cryptographic functions: confidentiality and authentication.

Confidentiality is achieved when someone uses the recipient's public key to encrypt a message. Only the recipient, possessing the matching private key, can decrypt and read the message. This ensures that even if the encrypted message is intercepted, its content remains secret.

Authentication, also known as digital signatures, is achieved when someone uses their own private key to encrypt a piece of data. Anyone can then use the sender's public key to decrypt it. If the decryption is successful, it proves that the data originated from the sender and has not been tampered with, as only the sender could have created the signature with their private key.

Avainkryptografia is fundamental to many modern security protocols, including secure email (PGP, S/MIME), secure web browsing (SSL/TLS), and secure online transactions. Its ability to provide both secure communication and verifiable identity makes it a cornerstone of digital security.