Legal Definitions - key encryption

Key encryption, often referred to as public-key cryptography, is a fundamental security system that uses a unique pair of mathematically linked digital keys: a public key and a private key. The public key can be freely shared with anyone, while the private key must be kept absolutely secret by its owner.

This system enables two primary security functions:

• Confidentiality: Information encrypted using someone's public key can only be decrypted by that person's corresponding private key, ensuring that only the intended recipient can read it.
• Authenticity and Integrity: Information "signed" using a person's private key can be verified by anyone with their public key. This confirms that the information originated from the legitimate sender and has not been altered since it was signed.

Here are some examples of how key encryption is used:

• Secure Online Banking: When you access your bank's website, your web browser uses key encryption to establish a secure connection. The bank's server uses its private key to prove its identity and encrypt the communication. Your browser then uses the bank's widely available public key (obtained through a digital certificate) to verify the bank's identity and decrypt the incoming data. This ensures that your login credentials, account numbers, and transaction details remain confidential and protected from eavesdropping as they travel across the internet.

• Verifying Software Updates: A software company wants to ensure that users only install legitimate updates and not malicious versions. When the company releases a new software update, they use their unique private key to digitally sign the update file. When you download this update, your computer uses the company's corresponding public key to verify the digital signature. If the signature is valid, it confirms that the update truly came from the software company and has not been tampered with or altered by an unauthorized party since it was released.

• Confidential Document Sharing: Imagine a lawyer needs to send a highly sensitive client document to a colleague. Instead of just attaching it to a regular email, the lawyer can use their colleague's public key to encrypt the document. Once encrypted, only the colleague, who possesses the matching private key, can decrypt and read the document. This prevents anyone else who might intercept the email from accessing the confidential information.