Concept:
Asymmetric encryption, also known as public-key cryptography, is a method of secure communication that uses two mathematically related keys: a public key and a private key. Unlike symmetric encryption, the keys are not identical, which enhances security and enables secure data exchange over insecure networks.
Step 1: {\color{red}Key Pair Generation}
A user generates two keys:
- Public Key — shared openly with others
- Private Key — kept secret by the owner
These keys are mathematically linked such that data encrypted with one can only be decrypted with the other.
Step 2: {\color{red}Encryption Using Public Key}
When a sender wants to send a secure message:
- The sender obtains the receiver’s public key
- The message is encrypted using this public key
Once encrypted, the message becomes unreadable to anyone without the corresponding private key.
Step 3: {\color{red}Transmission Over Insecure Channel}
The encrypted data can be safely transmitted over insecure networks such as the internet because:
- The public key does not reveal the private key
- Even if intercepted, the message remains secure
Step 4: {\color{red}Decryption Using Private Key}
Upon receiving the encrypted message:
- The receiver uses their private key
- The original plaintext message is recovered
Only the private key holder can decrypt the message, ensuring confidentiality.
Step 5: {\color{red}Additional Use — Digital Signatures}
Asymmetric encryption can also provide authentication:
- A sender can encrypt a hash with their private key (digital signature)
- Anyone can verify it using the sender’s public key