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TM112: Block 3 > Part 4, Going dark > Flashcards

Part 4, Going dark Flashcards

1
Q

how would law enforcement use the Law Enforcement Access Field (LEAF) if they were investigating alice or bob

A
  1. Intercept the LEAF and the encrypted message
  2. Arrange with a judge that their unit key be released by the US treasury and the national institute of standards and technology (NIST)
  3. Decrypt the first layer of encryption using the family key
  4. Decrypt the second layer of the LEAF using the unit key revealing bob and alices symmetric key
  5. Decrypt the message using the symmetric key
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2
Q

the

unit key of the clipper chip

was held in key escrow but how exactly was it held

A

this was split in half and split between:

  1. The US treasury
  2. The National Institute of Standards and Technology (NIST)
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3
Q

the keys this held were:

  1. An 80 bit unit key - a unique key for each device
  2. A family key - a generic key, held by government
A

what two keys were held by the

clipper chip

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4
Q

this is a claim or statement that you would like your audience to believe

A

what is the

main claim

within an argument

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5
Q

what is a

TOR node

A

this is a computer that is currently connected to the TOR network and is able to relay messages and be part of a TOR circuit

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6
Q

this used the

skipjack symmetric algorithm

A

what encryption algorith did the

clipper chip

use

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7
Q

why did the

clipper chip fail

A
  1. Weaknesses were found with the hash authentication of the LEAF being that collisions were present
  2. Later it was found that skipjack itself was not strong as it was cracked just days after the documents for it were published

Since collisions existed within clipper it was possible to find a collision for the symmetric key with a fake symmetric key

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8
Q

this was created because the U.S government needed a way to keep the communications from intelligence agents anonymous while overseas

A

why was

TOR

created

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9
Q

what is the

Law Enforcement Access Field (LEAF)

generated by the clipper chip and what does it allow

A

this is a session key that has been:

  1. encrypted by said users unit key
  2. a hash of the encrypted session key generated
  3. the hash and encrypted session key combined and encrypted using the family key

this allows authoritys to decrypt communications of anyone they are investigating

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10
Q

what are four

problems with banning the importation of encryption software

A
  1. Many everyday applications such as payment apps require encryption in order to work
  2. Encryption software can be easily smuggled in to a country
  3. The source code of encryption software is widely available on the internet
  4. The underlying mathematics of encryption is widely available and if one so wished could be used to mimic a specific type of encryption
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11
Q

this is a computer that is currently connected to the TOR network and is able to relay messages and be part of a TOR circuit

A

what is a

TOR node

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12
Q

this was split in half and split between:

  1. The US treasury
  2. The National Institute of Standards and Technology (NIST)
A

the

unit key of the clipper chip

was held in key escrow but how exactly was it held

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13
Q
  1. Intercept the LEAF and the encrypted message
  2. Arrange with a judge that their unit key be released by the US treasury and the national institute of standards and technology (NIST)
  3. Decrypt the first layer of encryption using the family key
  4. Decrypt the second layer of the LEAF using the unit key revealing bob and alices symmetric key
  5. Decrypt the message using the symmetric key
A

how would law enforcement use the Law Enforcement Access Field (LEAF) if they were investigating alice or bob

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14
Q

this was created by the

united states naval research laboratory

A

where was

TOR created

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15
Q

this is a servers public key that has been hashed and then appended with .onion

A

how is a

.onion address created

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16
Q

these make up most of the internet and are areas of the internet that either cannot be indexed or have had indexing restricted. These pages will probably exist only for authorised users such as existing behind a login screen

A

what is the

deep web

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17
Q

you should keep the argument balanced that means creating a supporting claim that supports and opposes your main claim

A

when constructing an argument what is one important aspect that should be followed

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18
Q
  1. Alice wishes to have secure and anonymous communication with bob so alice starts by building a circuit
  2. Alice contacts the directory node which holds a list of every node currently connected to the tor network
  3. Alice then selects at random a list of nodes from the directory node
  4. The nodes are then used to create a circuit
A

what are the four steps of building a

TOR circuit

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19
Q

once alice has created an onion what are the three steps involved in sending it to bob

A
  1. alice sends the onion to the guard node in her tor circuit
  2. alices guard node decrypts the first layer of encryption to reavel a ciphertext and the next address to send the onion
  3. this process repeats until the exit node is reached which will decrypt the last layer of encryption to reveal alices message
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20
Q

what two keys were held by the

clipper chip

A

the keys this held were:

  1. An 80 bit unit key - a unique key for each device
  2. A family key - a generic key, held by government
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21
Q
  1. Single use addresses - addresses that are linked to one transaction only
  2. Multisignature bitcoins - these require the permission from multiple users to be spent
  3. Bitcoin tumblers - This mixes groups of bitcoin transactions and redistributes coins amongst users in theory making it impossible to link a single transaction
A

what are three

strategies that bitcoin has implemented to further protect the identity of those using bitcoin

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22
Q

name three reasons that

key escrow failed

A

some reasons that this failed are:

  1. Can it be guaranteed that employees cannot steal keys
  2. Can it be guaranteed that there will be no misuse by government
  3. Can it be guaranteed that theft by hacking will not occur
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23
Q

these are sites that cannot be visited by standard web browsers and rely on the tor network to exist. In essence a darknet is any site/page that is hidden from unauthorised users or requires specialist software to access

A

what is the

dark web / dark net

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24
Q

this is a session key that has been:

  1. encrypted by said users unit key
  2. a hash of the encrypted session key generated
  3. the hash and encrypted session key combined and encrypted using the family key

this allows authoritys to decrypt communications of anyone they are investigating

A

what is the

Law Enforcement Access Field (LEAF)

generated by the clipper chip and what does it allow

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25
Q

what is the

surface web

A

this only accounts for a fraction of the material that exists on the web and can be indexed by search engines and accessed by anyone

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26
Q

why could TOR not be kept a secret and be used solely by the united states

A

keeping this a secret would mean that any communication on it would be linked back to america. instead it was made public

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27
Q

to alice what is an

exit node

A

the node furthest from alice and the last node of alices tor circuit and where data leaves the tor network

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28
Q

the node closest to alice and the first node of alices tor circuit where data enters the tor network

A

to alice what is the

guard node

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29
Q

what is another form of

controlling the use of encryption software

that has historically proposed

A

Another form of control that has been proposed is to allow citizens to use encryption but limit the key length meaning that there are less key values and it is possible to brute force the encryption

The suggestion is that the key length should be long enough that everyday hackers cannot brute force the key but short enough so that governments can

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30
Q

this stands for

The Onion Router

A

what does

TOR

stand for

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31
Q

how is a

.onion address created

A

this is a servers public key that has been hashed and then appended with .onion

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32
Q

what are the four steps of building a

TOR circuit

A
  1. Alice wishes to have secure and anonymous communication with bob so alice starts by building a circuit
  2. Alice contacts the directory node which holds a list of every node currently connected to the tor network
  3. Alice then selects at random a list of nodes from the directory node
  4. The nodes are then used to create a circuit
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33
Q

what is a

TOR circuit

A

this is a chain or path of computers (NODES) that allow a client and server to communicate with each other anonymously

34
Q

what does

TOR

stand for

A

this stands for

The Onion Router

35
Q

what does the TOR browser produce upon

installation

A

when this activity occurs the TOR browser will

generates an asymmetric key pair and stores them in a secure vault on the hard drive

36
Q
  1. Alices tor browser requests the public key of each node in her circuit in exchange for her own public key
  2. After receiving alices public key Each node in alices circuit then creates a symmetric session key and creates a copy as well as creating a copy of their own public key
  3. Each node then encrypts the copy of the session key and their public key using alices public key and forwards their message to alice
  4. Alice now has the public key of each node in her circuit as well as a session key for each node
A

what are the four steps which involve alice and her tor circuit nodes

creating and exchanging keys for encryption

37
Q

in five points when alice sends an onion message to bob what information is known by:

  1. each of the nodes (3 points)
  2. bobs computer (1 point)
  3. eve monitoring connections to bobs computer (1 point)
A
  1. The guard node cannot tell if alice was a relay or if the message originated from her
  2. Each node stores the address of the node that it receives the message from
  3. Each node is only aware of the address before it and the address after it
  4. Bobs computer only knows the address of alices exit node
  5. If eve is monitoring the connection to bobs computer it will look as though the exit node has made the request to bobs computer
38
Q

to alice what is the

guard node

A

the node closest to alice and the first node of alices tor circuit where data enters the tor network

39
Q

when constructing an argument what is one important aspect that should be followed

A

you should keep the argument balanced that means creating a supporting claim that supports and opposes your main claim

40
Q
  1. When bob reply s to the message that Alice sent is he will first send his message to the exit node in Alice’s circuit
  2. The exit node will then use the symmetric key it shared with Alice to encrypt bobs message
  3. The exit node will then pass the encrypted message on to the address it has stored for the original request
  4. The next node then carries out steps 2 and three and so on until the message reaches Alice
  5. When Alice receives the message from her guard node she will decrypt the onion using each of the symmetric keys that she has stored for each of the nodes
A

explain in five steps the process of bob replying to alices message via the

TOR network

41
Q

why was

TOR

created

A

this was created because the U.S government needed a way to keep the communications from intelligence agents anonymous while overseas

42
Q

what is a

TOR directory node

A

this is a computer that holds and maintains a directory of every node currently connected to the TOR network

43
Q

this only accounts for a fraction of the material that exists on the web and can be indexed by search engines and accessed by anyone

A

what is the

surface web

44
Q

what two components MUST an

argument

made up of

A

this MUST contain:

  1. a main claim
  2. a supporting claim or reason
45
Q

if alices TOR circuit nodes are 2, 5, 8, 17, 22

how does alice go about encrypting her message to bob and

creating an onion

A
  1. The first round of encryption will encrypt the message using the exit node (22) public key
  2. The second round of encryption will encrypt the ciphertext from step 1 with the address of the exit node (22) using the relay node (17) public key
  3. The third round of encryption will encrypt the ciphertext from step 2 with the address of the relay node (17) using the relay node (8) public key
  4. And so on…
46
Q

who is involved in

funding the maintenance of the TOR network

A

the following are involved in which activity:

  1. US state department
  2. national science foundation
  3. swedish government
  4. individual donors who wish to donate
47
Q

what are the names of the three mathematicians that were

tasked with creating TOR

A

what were these three mathematicians tasked with

  1. paul syverson
  2. micheal reed
  3. david goldschlag
48
Q

what were these three mathematicians tasked with

  1. paul syverson
  2. micheal reed
  3. david goldschlag
A

what are the names of the three mathematicians that were

tasked with creating TOR

49
Q

what was the

clipper chip

A

this was a chip that america wanted installed inside every machine that was manufactured or imported into the US.

the chip would enable authoritys to decrypt any communications if they so wished

50
Q
  1. The guard node cannot tell if alice was a relay or if the message originated from her
  2. Each node stores the address of the node that it receives the message from
  3. Each node is only aware of the address before it and the address after it
  4. Bobs computer only knows the address of alices exit node
  5. If eve is monitoring the connection to bobs computer it will look as though the exit node has made the request to bobs computer
A

in five points when alice sends an onion message to bob what information is known by:

  1. each of the nodes (3 points)
  2. bobs computer (1 point)
  3. eve monitoring connections to bobs computer (1 point)
51
Q
  1. alice sends the onion to the guard node in her tor circuit
  2. alices guard node decrypts the first layer of encryption to reavel a ciphertext and the next address to send the onion
  3. this process repeats until the exit node is reached which will decrypt the last layer of encryption to reveal alices message
A

once alice has created an onion what are the three steps involved in sending it to bob

52
Q

these are nodes between the first node and the last node of the circuit

A

what are

Relay nodes / intermediate nodes

53
Q
  1. The first round of encryption will encrypt the message using the exit node (22) public key
  2. The second round of encryption will encrypt the ciphertext from step 1 with the address of the exit node (22) using the relay node (17) public key
  3. The third round of encryption will encrypt the ciphertext from step 2 with the address of the relay node (17) using the relay node (8) public key
  4. And so on…
A

if alices TOR circuit nodes are 2, 5, 8, 17, 22

how does alice go about encrypting her message to bob and

creating an onion

54
Q

this is maintained by

the tor project inc

A

who maintains the

TOR network

55
Q

what are the four steps which involve alice and her tor circuit nodes

creating and exchanging keys for encryption

A
  1. Alices tor browser requests the public key of each node in her circuit in exchange for her own public key
  2. After receiving alices public key Each node in alices circuit then creates a symmetric session key and creates a copy as well as creating a copy of their own public key
  3. Each node then encrypts the copy of the session key and their public key using alices public key and forwards their message to alice
  4. Alice now has the public key of each node in her circuit as well as a session key for each node
56
Q

this is an idea that was proposed in both the US and UK and involves having a third party hold a copy of all encryption keys used by software

A

what is a

key escrow

57
Q

what are

Relay nodes / intermediate nodes

A

these are nodes between the first node and the last node of the circuit

58
Q
  1. Alice and bobs clipper chips negotiate a symmetric key
  2. Alice encrypts her message using the symmetric key
  3. Alice encrypts the symmetric key using her unit key
  4. The encrypted session key is combined with a hash and re encrypted with the family key generating what is called a Law Enforcement Access Field (LEAF)
  5. Alice sends the encrypted message and LEAF to bob
  6. Bob discards the LEAF and decrypts alices message using the agreed symmetric key
A

describe the six steps of how secure communication is acheived using the clipper chip

59
Q

when this activity occurs the TOR browser will

generates an asymmetric key pair and stores them in a secure vault on the hard drive

A

what does the TOR browser produce upon

installation

60
Q

describe the six steps of how secure communication is acheived using the clipper chip

A
  1. Alice and bobs clipper chips negotiate a symmetric key
  2. Alice encrypts her message using the symmetric key
  3. Alice encrypts the symmetric key using her unit key
  4. The encrypted session key is combined with a hash and re encrypted with the family key generating what is called a Law Enforcement Access Field (LEAF)
  5. Alice sends the encrypted message and LEAF to bob
  6. Bob discards the LEAF and decrypts alices message using the agreed symmetric key
61
Q

what is the

main claim

within an argument

A

this is a claim or statement that you would like your audience to believe

62
Q

this is a chain or path of computers (NODES) that allow a client and server to communicate with each other anonymously

A

what is a

TOR circuit

63
Q

this is a computer that holds and maintains a directory of every node currently connected to the TOR network

A

what is a

TOR directory node

64
Q

what encryption algorith did the

clipper chip

use

A

this used the

skipjack symmetric algorithm

65
Q

some reasons that this failed are:

  1. Can it be guaranteed that employees cannot steal keys
  2. Can it be guaranteed that there will be no misuse by government
  3. Can it be guaranteed that theft by hacking will not occur
A

name three reasons that

key escrow failed

66
Q

this was a chip that america wanted installed inside every machine that was manufactured or imported into the US.

the chip would enable authoritys to decrypt any communications if they so wished

A

what was the

clipper chip

67
Q
  1. Many everyday applications such as payment apps require encryption in order to work
  2. Encryption software can be easily smuggled in to a country
  3. The source code of encryption software is widely available on the internet
  4. The underlying mathematics of encryption is widely available and if one so wished could be used to mimic a specific type of encryption
A

what are four

problems with banning the importation of encryption software

68
Q

keeping this a secret would mean that any communication on it would be linked back to america. instead it was made public

A

why could TOR not be kept a secret and be used solely by the united states

69
Q

where was

TOR created

A

this was created by the

united states naval research laboratory

70
Q

the following are involved in which activity:

  1. US state department
  2. national science foundation
  3. swedish government
  4. individual donors who wish to donate
A

who is involved in

funding the maintenance of the TOR network

71
Q

explain in five steps the process of bob replying to alices message via the

TOR network

A
  1. When bob reply s to the message that Alice sent is he will first send his message to the exit node in Alice’s circuit
  2. The exit node will then use the symmetric key it shared with Alice to encrypt bobs message
  3. The exit node will then pass the encrypted message on to the address it has stored for the original request
  4. The next node then carries out steps 2 and three and so on until the message reaches Alice
  5. When Alice receives the message from her guard node she will decrypt the onion using each of the symmetric keys that she has stored for each of the nodes
72
Q

what are three

strategies that bitcoin has implemented to further protect the identity of those using bitcoin

A
  1. Single use addresses - addresses that are linked to one transaction only
  2. Multisignature bitcoins - these require the permission from multiple users to be spent
  3. Bitcoin tumblers - This mixes groups of bitcoin transactions and redistributes coins amongst users in theory making it impossible to link a single transaction
73
Q

who maintains the

TOR network

A

this is maintained by

the tor project inc

74
Q

what is a

key escrow

A

this is an idea that was proposed in both the US and UK and involves having a third party hold a copy of all encryption keys used by software

75
Q

what is the

dark web / dark net

A

these are sites that cannot be visited by standard web browsers and rely on the tor network to exist. In essence a darknet is any site/page that is hidden from unauthorised users or requires specialist software to access

76
Q

what is the

deep web

A

these make up most of the internet and are areas of the internet that either cannot be indexed or have had indexing restricted. These pages will probably exist only for authorised users such as existing behind a login screen

77
Q

this is a statement that will support your main claim it is often the why of your claim and may start with words such as (for example, because, therefore, so)

A

what is a

supporting claim or reason

within an argument

78
Q

what is a

supporting claim or reason

within an argument

A

this is a statement that will support your main claim it is often the why of your claim and may start with words such as (for example, because, therefore, so)

79
Q

Another form of control that has been proposed is to allow citizens to use encryption but limit the key length meaning that there are less key values and it is possible to brute force the encryption

The suggestion is that the key length should be long enough that everyday hackers cannot brute force the key but short enough so that governments can

A

what is another form of

controlling the use of encryption software

that has historically proposed

80
Q

this MUST contain:

  1. a main claim
  2. a supporting claim or reason
A

what two components MUST an

argument

made up of

81
Q
  1. Weaknesses were found with the hash authentication of the LEAF being that collisions were present
  2. Later it was found that skipjack itself was not strong as it was cracked just days after the documents for it were published

Since collisions existed within clipper it was possible to find a collision for the symmetric key with a fake symmetric key

A

why did the

clipper chip fail

82
Q

the node furthest from alice and the last node of alices tor circuit and where data leaves the tor network

A

to alice what is an

exit node

TM112: Block 3 (7 decks)

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