Which key is used to send a signed message from Bob to Alice?
public key
Today the key is Alice’s public key, last time it was Bob’s private key. The key pair for signing messages is generated in exactly the same way as the one used for encrypting messages. It’s very common to use the same key pair for both signing and encryption.
What would happen if there’s an Eve who tries to intercept Alice’s key on its way to Bob?
Before sending a message to Bob, Alice would encrypt it with a secret key, turning plaintext into ciphertext; even if Eve intercepted the ciphertext, she could make no sense of it. But Bob had the decryption key, so he could recover the plaintext.
What key would Bob use to verify the signature?
Alice sends the signature to Bob. Bob decrypts the document with Alice’s public key thereby verifying the signature.
Why is Bob always Alice?
The Alice and Bob characters were invented by Ron Rivest, Adi Shamir, and Leonard Adleman in their 1978 paper “A Method for Obtaining Digital Signatures and Public-key Cryptosystems”. As the use of Alice and Bob became more widespread, additional characters were added, sometimes each with a particular meaning.
What is used to encrypt a message for confidentiality?
Symmetric key cryptography is suited for encrypting and decrypting messages, thus providing privacy and confidentiality. The sender can generate a key for each data session to encrypt the message and the receiver can decrypt the message but needs to have the same key for the same session.
How can Alice have proof that Bob has received the message sent from Alice?
Assuming Alice signs the message using her private key and sends it to Bob, Bob can use Alice’s public key to verify the signature hence Alice cannot deny sending the message. This only proves that Alice is the sender of the message. How can Alice have proof that Bob has received the message sent from Alice?
What’s the story of Alice and Bob about?
This is a story about Alice and Bob. Alice wants to send a private message to Bob, and the only easy way they have to communicate is via postal mail. Unfortunately, Alice is pretty sure that the postman is reading the mail she sends.
What do you call element from Bob to Alice?
Let’s call ma the element that is to be conveyed from Alice to Bob, and mb the element that should go from Bob to Alice. When the exchange protocol is played, at some point in the sequence of messages, Alice will obtain enough information to be able to rebuild mb.
How does Alice and Bob use the symmetric key?
Alice then generates a temporary symmetric key (the pair of orange keys) and uses Bob’s public key (red padlock) to securely send it to Bob. Bob then uses his private key (red key) to unlock his copy of the symmetric key (orange key). Bob and Alice can then use those symmetric keys to securely send messages back and forth.