LP - Practical Cryptography Flashcards
Practical Cryptography
Symmetric key encrypting uses the same
key to encrypt and decrypt
Popular symmetric key encryption are
AES-CBC-129/256 and AES-GCM-128/256
Symmetric encryption two types of ciphers
- block
- stream
Some common block ciphers are
DES
3DES-EDE
AES-CBC
AES-GCM
Blowfish
Stream ciphers work in plain stream bits and are
XORed
Some common stream ciphers are
FISH
CryptMT
Scream
Cryptographic hashing
PKI stands for
public key infrastructure
Asymmetric Keys are slower or faster than symmetric keys
slower
Popular Asymetric (Public Key) algorithms are
RSA (Rivest-Sharmir-Adleman) most widely used
Diffie-Hellman
ECC (Elliptic curve cryptography)
DSA (Digital signature algorithm
Diffie-Hellman key exchange is a protocol for securely exchanging cryptographic keys over an
untrusted network
FDE stands for
full disk encryption
In full disk encryption (FDE)
the master boot record (MBR) is not encrypted
Cryptographic Hashing is a one-way mathematical function that produces a digest of length?
128 to 512 bit
Cryptographic Hashing converts data of any input size to a fixed-length string called a
- hash value
- message digest
- fingerprint
Cryptographic hashing is an advanced version of a simple
checksum
Cryptographic hashing is subject to the
birthday paradox and avalanche effect
Because of the birthday paradox a cryptographic hash is only half as strong as its
bit size
The avalanche effect is
if even one bit is flipped in the origin data the fixed-length hash will be completely different, like an avalanche.
Cryptographic hashing must be collision resistance therefor we do not use
MD5
Salting is the technique of
adding pseudorandom data to a cryptographic hash function
HMACs stands for
Hash-based Message Authentication Codes
Diffie-Hellman is found in
SSH2, TLS and IPSec
Diffie-Hellman key exchange (DHKE) and RSA key transport are used for
establishing secret keys between two parties over an unsecured channel
How does Diffie-Hellman (DH) use the secret key?
Both parties use it all of the time
How does Ephemeral Diffie-Hellman (DHE/EDH) use the secret key?
Bothe parties use the same key but it changes between uses.
How does Elliptic Curve Diffie-Hellman (ECDH) use the secret key?
has a public/private key pair but use the key pair every time
Elliptic Curve Diffie-Hellman (ECDH) is good for devices like IoT with Limited
Memory and processing power
Elliptic Curve Diffie-Hellman (ECDH) is commonly used in
Key exchang, IPSec and TLS, Digital signatures
Digital Signatures commonly use what for the hashing
SHA1/2/3
Digital Signatures use for the signing or encryption
RSA (Rivest-Shar-Aldeman)
Digital Signature Algorithm (DSA)
Elliptic Curve Digital Signature Algorithm (ECDSA)
Digital certificates use the standard
X.509v3
PKI stands for
Public Key Infrastructure
CRL stands for
certificate revocation list
OCSP stands for
Online Certificate Status Protocol
TPM stands for
Trusted Platform Module
TPM (trusted platform module) is a
trusted place to store a certificate
HSMs stand for
Hardare Security Modules
What do HSMs do?
managing. processing, generating nad storing keys
verifying digital certificates
SSL connection accelerator
encrypting sensitive data
verifying the integration of stored data
What does a sewcure enclave do?
It delivers CPU hardware-level isolation and memory encryption on a server, etc.
What is steganography?
Is the process of hiding a secret message inside of something that is not secret.
