3 ms·

What exactly were TETRA radios used for? I assume they were government/infra related, but then I don't understand why they'd need to backdoor the keying

by k8svet 3y ago

tptacek 3y ago
They don't so much backdoor the keying as that they have 4 different cipher profiles, and the one approved for global rather than European use (TEA1) compresses the key from 80 to 32 bits. It's essentially a surreptitious version of what the US did in the 1990s with "export ciphers".
- gwbas1c 3y ago
  Which makes me question describing this as a "deliberate backdoor."
  - tptacek 3y ago
    It's pretty clearly a deliberate backdoor.
    - swells34 3y ago
      And that is supported by the known past actions of "some government authorities". This is definitely not the first time the US government has deliberately sabotaged crypto.
      - tptacek 3y ago
        This isn't an American product.
  - wkat4242 3y ago
    It's deliberate in making the crypto so weak that our guys can decrypt their guys' radio traffic. How's that not a backdoor?
    - ChoHag 3y ago
      [dead]
mcpherrinm 3y ago
They are used for many things, like fire, ambulance, railways, harbour operations, police, military, coast guard, and so on. The weaker cipher mode, TEA1, is used when selling the radios to anyone who may not necessarily be an ally or highly trusted. This is the legacy of strong crypto being export-controlled. It was public that these ciphers were weaker, but they were actually much weaker than advertised. This is the backdoor.
qwertox 3y ago
I think the most relevant use in the context of deliberate backdoor is its use by police and military forces. Apparently some energy providers also use it for remote controlling tasks (no voice).
timthorn 3y ago
There was also the Dolphin network in the UK, offering a public national subscription TETRA network. It didn't prove commercially viable. https://www.rcrwireless.com/19980309/archived-articles/dolphin-to-use-tetra-system https://www.rcrwireless.com/19980309/archived-articles/dolph...

What exactly were TETRA radios used for? I assume they were government/infra related, but then I don't understand why they'd need to backdoor the keying

by k8svet 3y ago

What exactly were TETRA radios used for? I assume they were government/infra related, but then I don't understand why they'd need to backdoor the keying

tptacek 3y ago

They don't so much backdoor the keying as that they have 4 different cipher profiles, and the one approved for global rather than European use (TEA1) compresses the key from 80 to 32 bits. It's essentially a surreptitious version of what the US did in the 1990s with "export ciphers".

gwbas1c 3y ago
Which makes me question describing this as a "deliberate backdoor."
- tptacek 3y ago
  It's pretty clearly a deliberate backdoor.
  - swells34 3y ago
    And that is supported by the known past actions of "some government authorities". This is definitely not the first time the US government has deliberately sabotaged crypto.
    - tptacek 3y ago
      This isn't an American product.
- wkat4242 3y ago
  It's deliberate in making the crypto so weak that our guys can decrypt their guys' radio traffic. How's that not a backdoor?
  - ChoHag 3y ago
    [dead]

mcpherrinm 3y ago

They are used for many things, like fire, ambulance, railways, harbour operations, police, military, coast guard, and so on. The weaker cipher mode, TEA1, is used when selling the radios to anyone who may not necessarily be an ally or highly trusted. This is the legacy of strong crypto being export-controlled. It was public that these ciphers were weaker, but they were actually much weaker than advertised. This is the backdoor.

qwertox 3y ago

I think the most relevant use in the context of deliberate backdoor is its use by police and military forces. Apparently some energy providers also use it for remote controlling tasks (no voice).

timthorn 3y ago

There was also the Dolphin network in the UK, offering a public national subscription TETRA network. It didn't prove commercially viable. https://www.rcrwireless.com/19980309/archived-articles/dolphin-to-use-tetra-system https://www.rcrwireless.com/19980309/archived-articles/dolph...