Cryptography Concepts Flashcards
Integrity protection operations
When Materials, Plaintext, needs to be protected from unauthorized interception or alteration, it is encrypted into ciphertext.
Key exchange
Key exchange (also known as “key establishment”) is any method in cryptography by which cryptographic keys are exchanged between two parties, allowing use of a cryptographic algorithm.
Steganography
Greek steganos, or “covered,” and graphie, or “writing”) is the hiding of a secret message within an ordinary message and the extraction of it at its destination.
A digital signature
is a mathematical technique used to validate the authenticity and integrity of a message, software or digital document.
A digital certificate
is an electronic “passport” that allows a person, computer or organization to exchange information securely over the Internet using the public key infrastructure (PKI).
A public key infrastructure (PKI)
supports the distribution and identification of public encryption keys, enabling users and computers to both securely exchange data over networks such as the internet and verify the identity of the other party.
A public key certificate
is a digitally signed document that serves to validate the sender’s authorization and name.
Crypto Analysis
is the process of analyzing available information in an attempt to return the encrypted message to its original form.
Cryptographic process involve
algorithms and increasingly complex keys.
There are two types of cryptanalysis:
- Differential Cryptanalysis
- Linear Cryptanalysis
Differential Cryptanalysis
is done by comparing the input plaintext to the output ciphertext to try to determine the key used to encrypt the information.
Linear Cryptanalysis
is similar in that it uses both plaintext and ciphertext, but it puts the plaintext through a simplified cipher to try to deduce what key is likely to be In the full version of the cipher.
There are two Major types of key Algorithm (Cryptographic Techniques):
- Symmetric Key Algorithm
- Asymmetric Key Algorithm
Symmetric-key algorithms
Symmetric-key algorithms are algorithms for cryptography that use the same cryptographic keys for both encryption of plaintext and decryption of ciphertext.
The keys may be identical or there may be a simple transformation to go between the two keys.
Asymmetric Cryptography,
Asymmetric cryptograhy, also known as public key cryptography, uses public and private keys to encrypt and decrypt data.
Public-key cryptography, or asymmetric cryptography, is an encryption scheme that uses two mathematically related, but not identical, keys - a public key and a private key. …
The public key is used to encrypt and the private key is used to decrypt.
Hashing Functions
Hashing functions are commonly used encryption methods.
A Hash Function is a special mathematical function that performs one-key encryption.
There is no feasible way to generate two different plaintexts that compute to the same hash value.
Common use of hashing algorithms are to store computer password and to ensure message integrity.
Cryptography
is the science of encrypting, or hiding, information.
According to Shannon, there are two basic approaches to Encryption:
Confusion
Diffusion
Confusion
Encryption operation where the relationship between
cleartext and ciphertext is obscured.
The key does not relate in a simple way to the ciphertext. In Particular, each character of the ciphertext should depend on several parts of the key.
Diffusion
Diffusion:- Encryption by spreading out the influence of one
cleartext letter over many ciphertext letters.
- If we change a character of the plaintext, then several characters of the ciphertext should change, and similarly, if we change a character of the ciphertext, then several characters of the plaintext should change.
Non-Repudiation
Is a property that deals with the ability to verify that a message has been sent and received so that the sender (or receiver) cannot refute sending (receiving) the information.
Key Escrow
is a system by which your private key is kept both by you and a third party.
- provide a method of obtaining a key in the event that the key holder is not available.
- can solve many problems resulting from an inaccessible key, and the nature of cryptography makes the access of the data impossible without the key.
