Digital certificates are used in Internet communications. A Certificate Authority (CA) is responsible for issuing digital certificates. Name three data items present in a digital certificate. The method of issuing a digital certificate is as follows: A user starts an application for a digital certificate using their computer. On this computer a key pair is generated. This key pair consists of a public key and an associated private key. The user submits the application to the CA. The generated key and other application data are sent. The key and data are encrypted using the CA’s key. The CA creates a digital document containing all necessary data items and signs it using the CA’s key. The CA sends the digital certificate to the individual. In the above method there are three missing words. Each missing word is either ‘public’ or ‘private’. State the correct word. Justify your choice. Justification Justification Justification Alexa sends an email to Beena. Alexa’s email program: • produces a message digest • uses Alexa’s private key to encrypt the message digest • adds the encrypted message digest to the plain text of her message • encrypts the whole message with Beena’s public key • sends the encrypted message with a copy of Alexa’s digital certificate Beena’s email program decrypts the encrypted message using her private key. State the name given to the encrypted message digest. Explain how Beena can be sure that she has received a message that is authentic (not corrupted or tampered with) and that it came from Alexa. Name two uses where encrypted message digests are advisable.

9608_s16_qp_32

THEORY

2016

Paper 3, Variant 2

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Digital certificates are used in Internet communications. A Certificate Authority (CA) is responsible for issuing digital certificates. Name three data items present in a digital certificate. The method of issuing a digital certificate is as follows: A user starts an application for a digital certificate using their computer. On this computer a key pair is generated. This key pair consists of a public key and an associated private key. The user submits the application to the CA. The generated key and other application data are sent. The key and data are encrypted using the CA’s key. The CA creates a digital document containing all necessary data items and signs it using the CA’s key. The CA sends the digital certificate to the individual. In the above method there are three missing words. Each missing word is either ‘public’ or ‘private’. State the correct word. Justify your choice. Justification Justification Justification Alexa sends an email to Beena. Alexa’s email program: • produces a message digest • uses Alexa’s private key to encrypt the message digest • adds the encrypted message digest to the plain text of her message • encrypts the whole message with Beena’s public key • sends the encrypted message with a copy of Alexa’s digital certificate Beena’s email program decrypts the encrypted message using her private key. State the name given to the encrypted message digest. Explain how Beena can be sure that she has received a message that is authentic (not corrupted or tampered with) and that it came from Alexa. Name two uses where encrypted message digests are advisable.

9608_s16_qp_33

THEORY

2016

Paper 3, Variant 3

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The following incomplete table shows descriptions and terms relating to malware. Complete the table with appropriate description and terms. Description Term A standalone piece of malicious software that can replicate itself using a network. Use email to attempt to obtain an individual’s confidential data. Virus State two vulnerabilities that the malware in part or part can exploit. Vulnerability 1 Vulnerability 2 Question 2 continues on the next page. Anna has to send an email to Bob containing confidential information. Bob and Anna have never sent emails to each other before. Bob and Anna both have public and private keys. The first step is for Anna to request that Bob sends her one of his keys. State the key that Bob sends. Explain how Anna can be sure that it is Bob who has sent the key. Anna has received the key from Bob. The following incomplete table shows the sequence of actions between Anna and Bob to communicate the confidential information. Complete the table. The person performing the action What that person does Anna Requests Bob’s key. Bob Anna Anna Sends the email to Bob. Bob

9608_s17_qp_31

THEORY

2017

Paper 3, Variant 1

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The following incomplete table shows descriptions and terms relating to malware. Complete the table with appropriate description and terms. Description Term A standalone piece of malicious software that can replicate itself using a network. Use email to attempt to obtain an individual’s confidential data. Virus State two vulnerabilities that the malware in part or part can exploit. Vulnerability 1 Vulnerability 2 Question 2 continues on the next page. Anna has to send an email to Bob containing confidential information. Bob and Anna have never sent emails to each other before. Bob and Anna both have public and private keys. The first step is for Anna to request that Bob sends her one of his keys. State the key that Bob sends. Explain how Anna can be sure that it is Bob who has sent the key. Anna has received the key from Bob. The following incomplete table shows the sequence of actions between Anna and Bob to communicate the confidential information. Complete the table. The person performing the action What that person does Anna Requests Bob’s key. Bob Anna Anna Sends the email to Bob. Bob

9608_s17_qp_33

THEORY

2017

Paper 3, Variant 3

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Katarina works for a company specialising in the sale of computer parts and accessories. She works in the London office and her colleague Lucy works in the Hong Kong office. Katarina emails confidential information to Lucy so that only Lucy can read the information. Explain how public and private keys are used to ensure that only Lucy has a readable copy of the confidential information. Julio is buying items from the online shop. He already has an account with the shop. Explain how the use of Secure Socket Layer (SSL) or Transport Layer Security (TLS) helps to keep Julio’s confidential information secure. The manager of the company is concerned about the threat of malware. State three vulnerabilities that a malware can exploit.

9608_s18_qp_32

THEORY

2018

Paper 3, Variant 2

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Martha wants to send a private message to Joshua over the Internet. Martha and Joshua’s computers have already exchanged digital certificates. Identify three items that could be contained in a digital certificate. Joshua and Martha’s digital certificates are used to ensure that Martha’s message has not been altered during transmission. Explain how asymmetric encryption uses the contents of the digital certificates to ensure that the message has not been altered during transmission.

9608_s20_qp_31

THEORY

2020

Paper 3, Variant 1

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Martha wants to send a private message to Joshua over the Internet. Martha and Joshua’s computers have already exchanged digital certificates. Identify three items that could be contained in a digital certificate. Joshua and Martha’s digital certificates are used to ensure that Martha’s message has not been altered during transmission. Explain how asymmetric encryption uses the contents of the digital certificates to ensure that the message has not been altered during transmission.

9608_s20_qp_33

THEORY

2020

Paper 3, Variant 3

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A digital certificate and a digital signature are used to ensure that a message is not changed during transmission. Write an appropriate term in each space to complete the descriptions. A digital certificate contains the key of the owner. A digital certificate is obtained from the . Before a private message is sent to the owner of the digital certificate, this key is used to the message. A digital signature is also sent. The message is hashed to produce a , which is then encrypted with the sender’s key to obtain the digital signature. State two encryption protocols used in data transmission. Malware can harm computer systems. Describe two methods that can be used to restrict the effect of malware.

9608_s21_qp_32

THEORY

2021

Paper 3, Variant 2

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The table below gives descriptions of three types of malware. Description Term Malware that attaches itself to another program. Malware that redirects the web browser to a fake website. Email that encourages the receiver to access a website and give their banking details. Complete the table by adding the correct terms. Ben wants to send a highly confidential email to Mariah so that only she can read it. Plain text and cipher text will be used in this communication. Explain the terms plain text and cipher text. Plain text Cipher text Explain how the use of asymmetric key cryptography ensures that only Mariah can read the email.

9608_w16_qp_31

THEORY

2016

Paper 3, Variant 1

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The table below gives descriptions of three types of malware. Description Term Malware that attaches itself to another program. Malware that redirects the web browser to a fake website. Email that encourages the receiver to access a website and give their banking details. Complete the table by adding the correct terms. Ben wants to send a highly confidential email to Mariah so that only she can read it. Plain text and cipher text will be used in this communication. Explain the terms plain text and cipher text. Plain text Cipher text Explain how the use of asymmetric key cryptography ensures that only Mariah can read the email.

9608_w16_qp_33

THEORY

2016

Paper 3, Variant 3

View

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