Diffie-Hellman Key Exchange Concepts - Chapter 4-2

A type of cryptography using different keys for encryption and decryption.

An asymmetric encryption algorithm based on the difficulty of factoring large numbers.

Finding prime numbers and performing large-scale mathematical operations is computationally intensive.

Asymmetric keys typically need to be longer than symmetric keys to provide equivalent security.

A type of cryptography where the same key is used for encryption and decryption.

A cyberattack where an attacker intercepts communications between two parties, posing as one to the other.

Asymmetric encryption is generally slower than symmetric encryption.

The process of securely sharing secret keys between communicating parties. This is often done using asymmetric methods, since transferring a symmetric key is more secure via asymmetric encryption.

A method of encryption that uses two keys: a public key to encrypt and a private key to decrypt.

Establishes a shared secret key between two parties without exchanging the key itself directly.

An algorithm used for key exchange in cryptography.

A key that can be shared publicly for encryption.

A key that must be kept secret for decryption.

A temporary key used for a specific communication session.

Encryption that uses the same key both for encryption and decryption.

The art of protecting information by transforming it into an unreadable format.

To securely establish a private key between two parties even if their communication is intercepted.

A method for two parties to agree on a shared secret key without ever directly sharing it.

Even if someone intercepts the messages exchanged during key establishment, they cannot deduce the final shared secret key.

Whitfield Diffie and Martin Hellman are credited with inventing the Diffie-Hellman key exchange algorithm.

The first key agreement algorithm, enabling secure communication without pre-shared secrets.

Diffie-Hellman's contribution ushered in the era of public key cryptography, allowing for secure key exchange without sharing keys in advance.

Allows secure exchange of messages even in the presence of eavesdroppers by establishing a shared secret key that only the communicating parties know.

An attack where an attacker intercepts communications between two parties, posing as one to the other and potentially stealing information.

Diffie-Hellman is designed to prevent man-in-the-middle attacks, as the shared key is established securely and cannot be easily deduced by an eavesdropper.

A method for two parties to agree on a secret key without sharing it directly, enabling secure communication even in untrusted environments.

g and p are public parameters used in the Diffie-Hellman key exchange. g is a generator (a number that can generate all other numbers in a specific group), and p is a large prime number. These parameters are chosen for their mathematical properties that make it secure.

A mathematical problem that makes Diffie-Hellman secure. It's difficult to find the private key (x) given the public key (gx mod p) and the parameters (g, p).

Diffie-Hellman is secure because it relies on the difficulty of solving the Discrete Logarithm Problem. It's computationally expensive for an attacker to determine the private keys from the public information, making it impractical to intercept the communication.

Diffie-Hellman offers a secure way for parties to establish a shared secret key, enabling confidential communication over insecure channels. It provides a secure alternative to exchanging keys directly, ensuring privacy even in the presence of potential eavesdroppers. This is crucial in today's online world.

A whole number greater than 1 that is only divisible by 1 and itself. Used as a parameter in Diffie-Hellman, providing a foundation for the algorithm.

A number in modular arithmetic used in the Diffie-Hellman algorithm to generate a series of numbers. It's combined with the secret numbers to create the shared key.

A large, randomly chosen number kept secret by each participating party. These numbers are essential for generating the shared key in Diffie-Hellman.

A number calculated by each party from their secret random number and the shared parameters. It's shared with the other party to facilitate the key exchange.

The final, shared secret key agreed upon by both parties using the Diffie-Hellman algorithm. It's used for secure communication between them.

A system of arithmetic where numbers 'wrap around' a fixed value (modulus). It's essential for the Diffie-Hellman algorithm to generate and share keys.

Alice calculates her public key (α) by raising the generator (g) to the power of her secret random number (x) and performing a modulo operation with the prime number (p): α = g^x mod p.

Both Alice and Bob independently calculate the shared secret key (k) using their own secret random number and the other party's public key. They perform the same calculation but with swapped values: Alice uses Bob's public key (β) and her secret number (x), while Bob uses Alice's public key (α) and his secret number (y) . k = β^x mod p = α^y mod p.

These are numbers known to everyone involved in the Diffie-Hellman key exchange. 'g' is a generator, a number that can produce all other numbers in a specific group. 'p' is a large prime number. They are chosen for their mathematical properties that make the exchange secure.

These are secret numbers chosen randomly by Alice and Bob. They are kept hidden and are crucial for generating the shared key. The security of Diffie-Hellman relies on keeping these numbers private.

The final key agreed upon by Alice and Bob after exchanging public information. They both end up with the same secret key even though they never directly shared it. This key can be used for secure communication.

The Diffie-Hellman algorithm allows two parties to establish a shared secret key over an insecure channel, even if an attacker intercepts the messages exchanged during key establishment.

The Diffie-Hellman algorithm uses a public generator (g) and a prime number (p). Each party generates a secret random number (x, y) and calculates their public key (α, β). The parties exchange their public keys, and each party can then calculate the same shared secret key using their secret number and the other's public key.

The Discrete Logarithm Problem makes it computationally hard to reverse the operation of raising a generator to a power modulo a prime number. This difficulty prevents an attacker from deducing the shared secret key from the exchanged information.

The Diffie-Hellman algorithm allows secure communication over insecure channels by establishing a shared secret key that only the communicating parties know. This is crucial for online security, enabling confidential communication in the presence of potential eavesdroppers.

RSA cryptography faces challenges like computationally intensive operations (finding prime numbers and modulo calculations) and potential vulnerabilities to attacks if key lengths and usage are not carefully considered.

Asymmetric cryptography is generally slower and less computationally efficient than symmetric cryptography for encrypting large amounts of data.

The public parameters in DH (g and p) are publicly known values that help create the shared secret key. 'g' is a generator, which can be used to generate other numbers, and 'p' is a large prime number.

A mathematical problem that forms the foundation of DH's security. It's incredibly difficult to solve, meaning it's hard to find the secret key even with public information.

DH provides secure key exchange, allowing two parties to share a secret without sharing the key itself. This protection makes communication secure even in the presence of eavesdroppers.

The Diffie-Hellman algorithm allows two parties to establish a shared secret key over an insecure channel, even if an attacker intercepts the messages exchanged during key establishment.