lwm2m with dtls: multiple psk keys?

asked 2018-08-06 14:20:13 +0000

giuseppe.melis gravatar image

I'm analysing lwm2m sessions with dtls (psk keys) and I would need that wireshark helps me in decoding this scenario:

the client starts handshake with bootstrap server:

I know which is the psk between client and server, so I configure it in Preferences --> Protocol --> DTLS --> Pre-Shared-Key

the handshake is ok,

the bootstrap server provides the DM server psk key in Coap "PUT /0/1 resource #5" packet:

I have to copy the value of this key, remove the ":" characters and configure the new key in Preferences --> Protocol --> DTLS --> Pre-Shared-Key, overwritting the bootstrap key.

  1. is there a way to avoid this annoying procedure?
  2. is there an automatic procedure or a script?

now I'm able to decrypt the communication between client and DM server, but not with bootstrap one.

  1. the text box of Preferences --> Protocol --> DTLS --> Pre-Shared-Key could become a combobox in order to store the last used keys, or automatically fill with the recognized keys (from Coap "PUT /0/n resource #5" packets).

the bootstrap server provides also a second DM server psk key, so I have to change again the psk key to decript the communication between client and DM2, so I lost the decrypted communication between client and DM...

it's quite annoying...

Regards Giuseppe Melis

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Support for multiple DTLS PSK (just like the existing support for multiple RSA DTLS keys) would be useful for me as well.

mfalkvidd gravatar imagemfalkvidd ( 2019-09-19 13:39:04 +0000 )edit