Cryptography and Hashing Algorithms

MD5 produces a 128-bit hash value. It's important to remember that MD5, while popular once, is now considered insecure.

The hash value in bits for SHA-1 is 160. It's a popular algorithm, but modern security standards advise using SHA-256 or SHA-3.

IPSec Tunnel mode means the data only gets encrypted when it leaves the local network. Traffic is likely unencrypted between the user's device and the gateway. This makes it easier for network admins to see what traffic is leaving.

IPSec Transport mode encrypts data from the source to the destination, meaning the data remains encrypted throughout the entire journey. This is stronger security, but might make network monitoring more difficult.

Chaskey is a lightweight cryptography method for signing messages (MAC). It's ideal for resource-constrained environments like the Internet of Things (IoT) due to its minimal hardware requirements.

A salt is used to add randomness to the hashing process, making it harder to crack passwords by using precomputed hash tables (rainbow tables). It prevents the same plaintext from producing the same hash value.

RC4 is a symmetric stream cipher with a variable key size up to 2048 bits. However, the minimum recommended key size is 40 bits for strong security. Smaller key sizes are more vulnerable to attacks.

Data Encryption Standard (DES) is a block cipher with a 64-bit block size, a 56-bit key size, and 16 rounds of complex operations. Although DES is considered outdated, it's still significant for its historical impact in cryptography.

A cryptographic method used to secure data by storing it on a network of computers, rather than on a single server, making the information difficult to tamper with or hack.

An early cipher that uses a 5 × 5 matrix containing the alphabet (except for the letter "J") to encrypt plaintext characters. The cipher process involves rules based on column and row combinations.

A mono-alphabetic substitution cipher where plaintext characters are mapped to graphical characters instead of other alphabet characters.

A polyalphabetic cipher using a keyword to shift letters, creating a unique mapping for each character in the message.

A mono-alphabetic substitution cipher where each plaintext letter is shifted by a fixed number of positions down the alphabet.

An early cipher using four 5 × 5 matrices arranged in a square, each containing 25 letters, for encoding and decoding.

The block size of AES.

In this block cipher mode, the encrypted version of the Initialization Vector (IV) from the first stage is used as input for the second stage.

The key size for 3DES.

The key size used when AES operates with 10 rounds.

The block size used when AES operates with 10 rounds.

The key size used when AES operates with 14 rounds.

The key size used when AES operates with 12 rounds.

A type of Elliptic Curve cryptography used for exchanging symmetric keys.

A type of encryption where operations can be performed on encrypted data without decrypting it first.

A symmetric block cipher using 128-bit blocks, known for its strength and widespread adoption.

A symmetric block cipher using a 64-bit block size and an 80-bit key.

A symmetric block cipher with a 64-bit block size and a variable key size up to 2048 bits.

A symmetric block cipher used in XTEA.

A symmetric block cipher with 128-bit blocks.

A symmetric block cipher known for its speed and relatively low memory requirements.

A symmetric stream cipher employed in WEP (Wired Equivalent Privacy) with a 40-bit key.

A symmetric stream cipher that uses 128-bit keys.

A symmetric block cipher used in WPA2.

A substitution cipher where one letter maps to a single ciphertext letter (eg. A=Z, B=Y, etc.).

A substitution cipher where different letters can map to different ciphertext letters depending on their position in the message (eg. A in the first position = Z, A in the second position = Y, etc.).

An encryption method considered unbreakable as the same code is used only once.

A process where two different input values produce the same hash signature.

A physical hardware device that protects cryptographic secrets and performs cryptographic operations securely.

A dedicated processor in a computer system that manages encryption and provides secure storage for cryptographic keys.

In asymmetric cryptography, this key is used for encryption and is given to others. It can decrypt data encrypted by its corresponding private key.

These modes manage how blocks of data are processed in symmetric encryption. They ensure that the encryption process is secure and efficient.

These symmetric block cipher modes allow the cipher to act like a stream cipher, processing data one bit or byte at a time.

Used in symmetric block ciphers for substitution during encryption. They replace a set of bits with another set, making the data more difficult to decipher.

A light-weight symmetric block cipher with a key size of 80 or 128 bits, 32 rounds, and a 64-bit block size. It is designed for use in constrained environments.

This cryptography uses a key pair (public and private) for encryption and decryption. The public key can encrypt data, but only the private key can decrypt it.

In symmetric cryptography, this key is shared between sender and receiver. It's used for both encryption and decryption.

To decrypt a digitally signed message using public key cryptography, the recipient uses their private key.

This public key encryption method extends El Gamal by incorporating one-way hashing for improved security against attacks.

This method generates a new, unique passcode for each instance based on a time-sensitive seed.

This encoding scheme for x.509 certificates is compatible with both Base64 and ASCII formats. It provides flexibility in certificate storage and transfer.

To digitally sign a message using asymmetric cryptography, the sender uses their private key.

To verify a digitally signed message using public key cryptography, the recipient uses the sender's public key.

These are non-cryptographic hash solutions like Buzhash, Cityhash, Spookyhash, and Bernstein. They are used for hashing but don't provide cryptographic security.

One Time Passwords (OTP) allow for a new unique passcode to be created for each instance based on an initial seed. They are a good security measure as each code is used only once.

The IPSec handshake, which facilitates key exchange, takes place on UDP port 500.

The protocol number for Encapsulating Security Payload (ESP) is 50.

The protocol number for IPSec Authentication Header (AH) is 51.

With SSL/TLS, a secure tunnel uses a symmetric key method to encrypt data, and then a signature is created using a defined hashing method to ensure data integrity.

A Virtual Private Network (VPN) tunnel creates a secure connection from a host machine to a private network over a public network. Think of it like a secure tunnel.

Onion routing involves using subscriber computers to route data packets over the internet instead of publicly available routers. It's used to anonymize internet traffic.

The Tor network, using computers of volunteers globally, helps to anonymize internet traffic by routing it through multiple intermediaries. It significantly reduces the chances of tracing the original source.

Hash algorithms like SHA1 and MD5 are primarily used to establish a fingerprint or thumbprint for data in cryptography. These fingerprints are used to verify data integrity.

In blockchain mining, a new block of transactions is added to the blockchain every 10 minutes or so. This process essentially confirms the transactions within the block.

The blockchain acts as a ledger of transactions within the Bitcoin network, recording the number of bitcoins each user has in their account. This provides transparency.

In blockchain mining, miners compile a list of recent transactions and attempt to solve a complex mathematical problem. The first miner to solve the problem receives rewards.

Miners are rewarded for their successful mining efforts in blockchain networks.

Smart contracts are programs stored on a blockchain that automatically execute when specific conditions are met. They remove the need for intermediaries and are transparent.

Within the Ethereum application development context, 'gas' is a unit used to measure the amount of computational work required to perform a single Keccak-256 hash operation.

A NOBUS (Nobody But Us) backdoor is a hidden vulnerability in cryptography that allows only specific parties, such as government agencies, to decrypt encrypted data, while others cannot.

Exhaustive search is a brute-force method used to crack a cipher by trying every possible key until the correct one is found. It's computationally intensive and time-consuming.

A Man-in-the-middle (MITM) attack is a technique in which an attacker intercepts communication between two parties, impersonating each of them to the other party.

In a known plaintext attack, the attacker knows part of the ciphertext and the corresponding plaintext. This information can be used to decrypt the rest of the ciphertext.

The certificate issuance stage involves retrieval/recovery and validation of the certificate after it has been issued.

The certificate cancellation stage is when the certificate expires or is revoked due to reasons like compromise or obsolescence.

Certificate distribution takes place in the initialization stage of certificate management.

The CA (Certificate Authority) is responsible for publishing the CRL (Certificate Revocation List).

The main distinction is that a certificate in hold status can be restored to an active status, while a revoked certificate cannot be reversed, indicating a permanent status.

A certificate that has been compromised, outdated, or superseded should be revoked, making it invalid for further use.

A time attack involves determining the amount of time required to decrypt a message, potentially revealing clues about the key used.

A cut-and-paste attack involves combining parts of two encrypted messages to create a new, potentially meaningless message. It aims to trick the receiver and gain an advantage.

The replay system refers to when an attacker intercepts a legitimate message and re-sends it later to gain unauthorized access or disrupt the system.

A man-in-the-middle (MITM) attack occurs when an attacker hides between two parties and replaces their identities, manipulating the communication for malicious purposes.

Key escrow and NOBUS (Nobody But Us) are methods that can create a backdoor condition, allowing specific parties to decrypt data even if it's encrypted.