org.multibit.hd.hardware.core.domain.Identity - obstructing validation about multibit-hardware

[romanz]

https://github.com/bitcoin-solutions/multibit-hardware/blob/develop/core/src/main/java/org/multibit/hd/hardware/core/domain/Identity.java#L35

[romanz]

Currently, the TREZOR firmware is using max_size=256 for SignIdentity.challenge_hidden:
https://github.com/trezor/trezor-mcu/blob/master/firmware/protob/messages.options#L91

For NIST256P1 elliptic curve, I have seen 209 byte-long blobs passed to ssh-agent for signature:

2016-02-27 19:45:41,998 DEBUG        calling sign_message()                                                                               [protocol.py:53]
2016-02-27 19:45:41,998 DEBUG        key type: ecdsa-sha2-nistp256                                                                        [formats.py:51]
2016-02-27 19:45:41,998 DEBUG        curve name: nistp256                                                                                 [formats.py:58]
2016-02-27 19:45:41,998 DEBUG        looking for 58:77:de:fe:62:b0:98:2b:fd:4f:ac:03:7a:dc:5f:47                                          [protocol.py:87]
2016-02-27 19:45:41,998 DEBUG        using key 'ssh://localhost' (58:77:de:fe:62:b0:98:2b:fd:4f:ac:03:7a:dc:5f:47)                        [protocol.py:94]
2016-02-27 19:45:41,998 DEBUG        signing 209-byte blob                                                                                [protocol.py:100]
2016-02-27 19:45:41,998 DEBUG        parsed identity: {'path': None, 'host': u'localhost', 'proto': u'ssh', 'port': None, 'user': None}   [client.py:104]
2016-02-27 19:45:41,999 DEBUG        key type: ecdsa-sha2-nistp256                                                                        [formats.py:51]
2016-02-27 19:45:41,999 DEBUG        curve name: nistp256                                                                                 [formats.py:58]
2016-02-27 19:45:41,999 DEBUG        ssh-connection: user 'roman' via 'publickey' ('ecdsa-sha2-nistp256')                                 [client.py:66]
2016-02-27 19:45:41,999 DEBUG        nonce: 56320455f525293be340cf9be4a713432033cba710c32b6aebb70c877b3c3444                              [client.py:67]
2016-02-27 19:45:41,999 DEBUG        fingerprint: 58:77:de:fe:62:b0:98:2b:fd:4f:ac:03:7a:dc:5f:47                                         [client.py:68]
2016-02-27 19:45:41,999 INFO         please confirm user "roman" login to "ssh://localhost" using Trezor...                               [client.py:71]
2016-02-27 19:45:52,200 DEBUG        signature: 6a905c9842d5128af926649edf89b15d0842c206f17e30ce69e11f79116771856b1a2e8afe14808aa1bdb900697ffefcfe93f3caecd47fd08b64a92c116d06e6 [protocol.py:103]
2016-02-27 19:45:52,394 INFO         signature status: OK                                                                                 [protocol.py:107]
2016-02-27 19:45:52,394 DEBUG        signature size: 74 bytes                                                                             [protocol.py:112]
2016-02-27 19:45:52,394 DEBUG        reply: 110 bytes                                                                                     [protocol.py:56]

https://github.com/romanz/trezor-agent/blob/master/trezor_agent/protocol.py#L100

[martin-lizner]

Ok, 256 bytes will do. Please fix :-) Yeah 209 is about right... M.

[gary-rowe]

I've increased the sizes and pushed the code against develop.

Ready for review and close.

[gary-rowe]

Thanks for the additional help @romanz - much appreciated.

[martin-lizner]

Fixed. Thank you guys.