SDRTrunk Encryption Keys in traffic channel logs? cant possibly be?

[hruskacha]

While looking through some SDR Trunk Decoded traffic channel logs, I saw details on an encrypted talkgroups such as encryption algorithm and "key". What does key mean though? Like Obviously encryption has keys to decode the encrypted data, but that is definitely NOT something you would just stumble upon in the log files. Is this a different kind of key? Most of the similar logs just say "KEY:0" but a couple actually had multi digit numerical values there as if it was an actual key. BUT they were only 4 or 5 digits, not the 9 or so that I think are required for even the most basic encryption ADP? Can somebody clarify what actual key this is?

 

[Mattsenft]

That's going to be the CKR or key index number. That references to the radios where the actual key value is stored.

 

[maus92]

The value of the "KEY:" field is not the key that is used to encrypt/decrypt data. It is one of the values that is used to direct the subscriber unit to use the appropriate key which is stored in the radio.

 

[GTR8000]

As if it were that easy! 😂

 

[hruskacha]

As if it were that easy! 😂

I knew there was no way, i was just curious what exactly it meant. Lol.

 

[boatbod]

P25 encryption requires three pieces of information to be sent over the air (keyId, algId and message_indicator) and the subscriber unit must be properly programmed in advance with the encryption keys for each supported algorithm. algId=0x80 means unencrypted, anything else means encryption is being used and the protocol that was chosen. keyId points to which of potentially multiple keys has been selected. MI (message indicator) is a dynamic 72bit value that gets fed into the decryption routine along with the encrypted xMBE codewords to result in plaintext xMBE codewords.