6.0 Cryptography and PKI Flashcards
Any cryptographic algorithm that uses the same key to encrypt and decrypt.
Ex: AES, DES, 3DES, RC4, Blowfish, and Twofish
Symmetric Algorithm
Cryptographic algorithms that use two different keys—one key to encrypt and another to decrypt. Also called public key cryptography.
Ex: RSA, DSA, Diffie-Hellman,
Asymmetric Algorithm
A number created by executing a hashing algorithm against data, such as a file or a message.
It is commonly used for Integrity.
Ex:MD5, SHA-1, and HMAC
Hash
Bits added to a hash to make it resistant to rainbow table attacks.
Salt
The Process used to exchange keys between users who receive it. Keys can be exchanged in-band and out-of-band.
Key Exchange
An encrypted hash of a message, encrypted with the senders private key. It provides authentication, non-repudiation, and integrity.
Digital Signature
A cryptography concept that ensures small changes in plaintext result in significant changes in ciphertext.
Diffusion
A cryptography concept that indicates ciphertext is significantly different than plaintext.
Confusion
When two different inputs into a cryptographic hash produce the same output, this is known as a collision.
Collision
The practice of hiding data within data.
Steganography
An attempt to make something unclear or difficult to understand. Steganography methods use this to hide data within data.
Obfuscation
An encryption method that encrypts data as a stream of bits or bytes.
Stream Cipher
Encryption method that encrypts data in fixed-size blocks.
Block Cipher
A key that is generated for one immediate use only, and is never used again.
Ephemeral Key
Any data sent over a network. It is common to encrypt this.
Data-in-Transit
Any data stored on media. It is common to encrypt this.
Data-at-Rest
Any data currently being used by a computer. Because the computer needs to process the data, it is not encrypted while in use.
Data-in-use
A technique used to increase the strength of stored passwords. Its additional bits and can help thwart brute force and rainbow table attacks.
Key Stretching
A strong symmetric block cipher that encrypts data in 128-bit blocks. Can also use 128-bits, 192-bits, or 256-bits.
AES
A strong symmetric block cipher that encrypts data in 128-bit blocks. Can also use 128-bits, 192-bits, or 256-bits.
AES (Advanced Encryption Standard)
A legacy symmetric encryption standard used to provide confidentiality. It has been compromised and AES or 3DES should be used instead.
DES (Data Encryption Standard)
A Symmetric algorithm used to encrypt data and provide confidentiality. It is a block cipher that encrypts data in 64-bit blocks.
3DES
A symmetric stream cipher that can use between 40 and 2048 bits. Experts consider it cracked and recommend using stronger methods.
RC4 (Rivest Cipher 4)
A symmetric key block cipher. It encrypts data in 128-bit blocks and supports 128-, 192-, or 256- bit keys.
Twofish
A mode of operation used for encryption that effectively converts a block cipher into a stream cipher. It uses an IV for the first block and each subsequent block is combined with this previous block.
CBC (Cipher Block Chaining)
A mode of operation used for encryption. It combines the Counter (CTM) Mode with hashing techniques for data authenticity and confidentiality.
GCM
A mode of operation used for encryption. It combines the Counter (CTM) Mode with hashing techniques for data authenticity and confidentiality.
GCM (Galois/Counter Mode)
A legacy mode of operation used for encryption. It is weak and should not be used.
ECB (Electronic Codebook)
A mode of operation for encryption that combines an IV with a counter. The combined result is used to encrypt blocks.
CTM (Counter Mode)
An asymmetric algorithm used to encrypt data and digitally sign transmissions. It is named after its creators.
RSA (Rivest, Shamir, Adleman)