Rolling Thunder Security CYBERSECURITY FUNDAMENTALS PKI MODULE

Asymmetric Encryption

How public-key cryptography keeps a message secret in transit. Anyone can encrypt with the public key, only the holder of the matching private key can decrypt. Plaintext to plaintext, end to end.
Sender
Alice
Encrypts the message
◇ Bob public key
Public network
Eve
Eavesdropper
Watching...
Receiver
Bob
Holds the key pair
◇ Bob public key (shareable)
◆ Bob private key (secret)
Plaintext message
"Meet me at the boilermaker statue at 0900 hours."
Ciphertext
7d3a9f2e 8c1b4a06 e5f7d28c 91ba3f04...
Ciphertext (in transit)
7d3a9f2e 8c1b4a06 e5f7d28c 91ba3f04...
Ciphertext (received)
7d3a9f2e 8c1b4a06 e5f7d28c 91ba3f04...
Plaintext (recovered)
"Meet me at the boilermaker statue at 0900 hours."
◇ Bob public key
▶ ENCRYPT with Bob public key
▶ DECRYPT with Bob private key
✓
Confidentiality Preserved
Plaintext recovered · Eve learned nothing
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Bob generates a key pair
Bob runs a key generation algorithm and gets two mathematically linked keys: a public key he can share with anyone, and a private key he keeps secret. Whatever the public key encrypts, only the private key can decrypt.
(public_key, private_key) = generate_keypair() // e.g. RSA-2048