71. Asymmetric Algorithms

Asymmetric Algorithm

Does not require a shared secret key, often referred to as public key cryptography since their key is considered to be freely and openly available to the public

Digital Signature

A hash digest of a message encrypted with the sender’s private key to let the recipient know the document was created and sent by the person claiming to have sent it

How does asymmetric encryption ensure confidentiality?

Only the receiver can decrypt the message because we encrypted the hash with their public key

How does asymmetric encryption ensure integrity?

The hash of the message

How does asymmetric encryption ensure non-repudiation

Only the sender could encrypt the hash

Common Asymmetric Algorithms

Diffie-Hellman

(RSA) Rivest-Shamir-Adleman

(ECC) Elliptic Curve Cryptographic

Diffie-Hellman

Used to conduct key exchanges and secure key distribution over an unsecure network

RSA

Rivest-Shamir-Adleman

Rivest-Shamir-Adleman

Asymmetric algorithm that relies on the mathematical difficulty of factoring large prime numbers. Can support key sizes between 1024 bits and 4096 bits

ECC

Elliptic Curve Cryptographic

Elliptic Curve Cryptographic

Heavily used in mobile devices and it's based on the algebraic structure of elliptical curves over finite fields to define its fields. Is with a 256 bit key as secure as RSC with a 2048 bit key

ECDH

Elliptic Curve Diffie-Hellman

Elliptic Curve Diffie-Hellman

ECC version of the popular Diffie-Hellman key exchange protocol

ECDHE

Elliptic Curve Diffie-Hellman Ephemeral

Elliptic Curve Diffie-Hellman Ephemeral

Uses a different key for each portion of the key establishment process inside the Diffie-Hellman key exchange

ECDSA

Elliptic Curve Digital Signature Algorithm

Elliptic Curve Digital Signature Algorithm

Used as a public key encryption algorithm by the US government in their digital signatures

ECC is most commonly used for

Mobile devices and low-power computer devices