Itsec an der Universität Mannheim | Karteikarten & Zusammenfassungen

# Lernmaterialien für Itsec an der Universität Mannheim

Greife auf kostenlose Karteikarten, Zusammenfassungen, Übungsaufgaben und Altklausuren für deinen Itsec Kurs an der Universität Mannheim zu.

TESTE DEIN WISSEN

Unconditional Security

Lösung anzeigen
TESTE DEIN WISSEN

No matter how much computer power is available, the cipher cannot be broken since the ciphertext provides insufficient information to uniquely determine the corresponding plaintext

Lösung ausblenden
TESTE DEIN WISSEN

Computational security

Lösung anzeigen
TESTE DEIN WISSEN

Given limited computing resources, the cipher cannot be broken

Lösung ausblenden
TESTE DEIN WISSEN

Stream Cipher

Lösung anzeigen
TESTE DEIN WISSEN

key from OTP replaced with pseudo-random sequence that is ‘seeded’ with the key

instead of using a Pseudo-random generator (PRG) on the key, it is used on an Initialization vector and a key. Make sure IV is never used twice!

Lösung ausblenden
TESTE DEIN WISSEN

Block Cipher

Lösung anzeigen
TESTE DEIN WISSEN

To encrypt a plaintext consisting of n-bits, a key is used the size of k-bits, to result in a ciphertext the same size as the plaintext. This n-bit sized vector is called a block

Lösung ausblenden
TESTE DEIN WISSEN

Modes of Block Ciphers

Lösung anzeigen
TESTE DEIN WISSEN

Electronic Code-Book (ECB)

Cipher Block Chaining (CBC)

Counter (CTR)

Lösung ausblenden
TESTE DEIN WISSEN

ECB

Lösung anzeigen
TESTE DEIN WISSEN

Electronic Code-Book

= Message is broken into blocks, which are encoded independently of other blocks

Lösung ausblenden
TESTE DEIN WISSEN

CBC

Lösung anzeigen
TESTE DEIN WISSEN

Cipher Block Chaining

= 1. Message is broken into blocks

2. each previous cipher block is chained with current plaintext

3. To make ciphertext depends on all blocks before it

4. Start process with IV

Does not provide protection against data modification such as deletion and insertion

Lösung ausblenden
TESTE DEIN WISSEN

CTR

Lösung anzeigen
TESTE DEIN WISSEN

Counter

= Each block is encrypted with a new IV consisting of a random number (nonce) and a counter. Then the IV is combined with the key to create each individual ciphertext.

Lösung ausblenden
TESTE DEIN WISSEN

Ciphertext-only attack

Lösung anzeigen
TESTE DEIN WISSEN

Attacker tries to deduce the decryption key or plaintext by only observing ciphertext

Encryption schemes vulnerable to this attack are completely insecure

Lösung ausblenden
TESTE DEIN WISSEN

Known-plaintext

Lösung anzeigen
TESTE DEIN WISSEN

Attacker has a quantity of plaintext and corresponding ciphertext

Lösung ausblenden
TESTE DEIN WISSEN

chosen plaintext attack

Lösung anzeigen
TESTE DEIN WISSEN

Attacker chooses plaintext and is then given corresponding ciphertext

Lösung ausblenden
TESTE DEIN WISSEN

Security Goals

Lösung anzeigen
TESTE DEIN WISSEN

Confidentiality

Integrity

Authenticity

Availability

Access Control

Lösung ausblenden
• 55505 Karteikarten
• 1092 Studierende
• 31 Lernmaterialien

## Beispielhafte Karteikarten für deinen Itsec Kurs an der Universität Mannheim - von Kommilitonen auf StudySmarter erstellt!

Q:

Unconditional Security

A:

No matter how much computer power is available, the cipher cannot be broken since the ciphertext provides insufficient information to uniquely determine the corresponding plaintext

Q:

Computational security

A:

Given limited computing resources, the cipher cannot be broken

Q:

Stream Cipher

A:

key from OTP replaced with pseudo-random sequence that is ‘seeded’ with the key

instead of using a Pseudo-random generator (PRG) on the key, it is used on an Initialization vector and a key. Make sure IV is never used twice!

Q:

Block Cipher

A:

To encrypt a plaintext consisting of n-bits, a key is used the size of k-bits, to result in a ciphertext the same size as the plaintext. This n-bit sized vector is called a block

Q:

Modes of Block Ciphers

A:

Electronic Code-Book (ECB)

Cipher Block Chaining (CBC)

Counter (CTR)

Q:

ECB

A:

Electronic Code-Book

= Message is broken into blocks, which are encoded independently of other blocks

Q:

CBC

A:

Cipher Block Chaining

= 1. Message is broken into blocks

2. each previous cipher block is chained with current plaintext

3. To make ciphertext depends on all blocks before it

4. Start process with IV

Does not provide protection against data modification such as deletion and insertion

Q:

CTR

A:

Counter

= Each block is encrypted with a new IV consisting of a random number (nonce) and a counter. Then the IV is combined with the key to create each individual ciphertext.

Q:

Ciphertext-only attack

A:

Attacker tries to deduce the decryption key or plaintext by only observing ciphertext

Encryption schemes vulnerable to this attack are completely insecure

Q:

Known-plaintext

A:

Attacker has a quantity of plaintext and corresponding ciphertext

Q:

chosen plaintext attack

A:

Attacker chooses plaintext and is then given corresponding ciphertext

Q:

Security Goals

A:

Confidentiality

Integrity

Authenticity

Availability

Access Control

### Erstelle und finde Lernmaterialien auf StudySmarter.

Greife kostenlos auf tausende geteilte Karteikarten, Zusammenfassungen, Altklausuren und mehr zu.

## Das sind die beliebtesten Itsec Kurse im gesamten StudySmarter Universum

##### ITG

Ostbayerische Technische Hochschule Regensburg

##### ITIL

IUBH Internationale Hochschule