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68 Cards in this Set
- Front
- Back
What is cryptography? |
Cryptography is the science of hiding information in plain sight, in order to conceal it from unauthorized parties. |
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What cipher did Ceasar use for battlefield communications? |
Substitution cipher. |
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What was the first cipher used and by whom? |
Substitution cipher first used by Ceasar for battlefield communications. |
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What is plaintext? |
An original message. |
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What is ciphertext? |
An encrypted message. |
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What is encryption? |
The process of transforming plaintext into ciphertext (also encipher). |
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What is decryption? |
The process of transforming ciphertext into plaintext (also decipher). |
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What is an encryption key? |
The text value required to encrypt and decrypt data. |
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What are the 6 methods of encryption? |
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What are the 2 types of encryption? |
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What are the 3 types of encryption keys? |
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What is a symmetric key? |
A common secret that all parties who participate must know. |
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What is an asymmetric key? |
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What is a one-time pad? |
Used once, is as large as the message to be encrypted. |
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What was Ceasar's version of the substitution cipher? |
Ceasar rotated three to the right.
A > D, B > E, C > F, etc |
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What is the substitution cipher? |
Plaintext characters are substituted to form ciphertext.
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What is the transposition cipher? |
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What is the vulnerability of the transposition cipher? |
Subject to frequency analysis attack. |
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What is a monoalphabetic cipher? |
One alphabetic character is substituted for another. |
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What is the vulnerability of the monoalphabetic cipher? |
Subject to frequency analysis attack. |
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What is a polyalphabetic cipher? |
Two or more substitution alphabets. |
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What is the advantage of a polyalphabetic cipher? |
Not subject to frequency attack. |
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What is a running-key cipher? |
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What is Modulo arithmetic? |
Add 26 if result <0, subtract 26 if result >26. |
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What is a one-time pad? |
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What is a block cipher? |
Encrypt and decrypt a block of data at a time (typically 128 bits). |
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What is the typical length of a block cipher? |
128 bits. |
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What are the typical uses for a block cipher? (4) |
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What are the well known encryption algorithms for block ciphers? (7) |
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For block cipher, what is Electronic Code Book? |
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For block cipher, what is Cipher-block Chaining (CBC)? |
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What does IV stand for? |
Initialization vector. |
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For block cipher, what is Cipher Feedback (CFB)? |
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What does CBC stand for? |
Cipher-block Chaining (CBC) |
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What does CFB stand for? |
Cipher Feedback |
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What does OFB stand for? |
Output Feedback. |
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For block cipher, what is Output Feedback? |
Plaintext is XOR'd with the encrypted material in the previous block to produce ciphertext. |
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For block cipher, what is Counter? |
Uses a "nonce" (a random number that is used once) that is concatenated with a counter or other simple function, which is encrypted by the block cipher, and the output XOR'd with the plaintext block to produce the ciphertext block. |
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What does CTR stand for? |
Counter. |
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What are stream ciphers used for? |
Used to encrypt a continuous stream of data, such as an audio or video transmission. |
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What is a stream cipher? |
A stream cipher is a substitution cipher that typically uses an exclusive -or (XOR) operation that can be performed very quickly by a computer. |
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Plaintext 1 1 0 1 0 Key 0 1 1 0 0 |
Ciphertext 1 0 1 1 0 |
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What is a symmetric key? |
Same key used at both ends of a communications channel or session
A symmetric key is also known as a shared secret |
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List 7 encryption algorithms that use symmetric keys. |
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What are asymmetric keys? |
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What encryption algorithms use asymmetric keys? |
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List 2 hardening techniques. |
1. Separation of duties
2. Split custody. |
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List 8 cryptanalysis attacks. |
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What are the uses for cryptography? (5) |
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What type of encryption does WinZip version 9 use? |
AES. |
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What does EFS stand for? |
Encrypting File System. |
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What are the two common ways email is encrypted? |
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What does S/MIME stand for? |
Secure / Multipurpose Internet Mail Extensions |
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What does PEM stand for? |
Privacy Enhanced Mail |
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What does SSL/TLS stand for? |
Secure Sockets Layer / Transport Layer Security |
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What is IPsec? |
Encrypts all packets between established pairs of hosts. |
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What is key escrow? |
Keys held by a trusted third party. |
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What is a message digest? |
The result of a cryptographic operation on a file or message.
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What algorithms are used to create a message digest? (3) |
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What algorithms are used to create digital signatures? (3) |
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What is a digital signature? |
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What is non-repudiation? |
Inability for a user to repudiate (deny) an action, because of the methods used to permit or authorize the action. |
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What does PKI stand for? |
Public Key Infrastructure |
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What are two PKI platforms? |
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What is steganography? |
Data hidden in image files, subtle changes that the eye won't see; can be encrypted as well. |
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What is watermarking? |
Like a digital signature - a visible or invisible mark that claims ownership. |
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What is cryptanalysis? |
An attack on a cryptosystem. |
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What is a PKI? |
is a network-based service used to store digital certificates or public encryption keys of individuals in a community. |