CODEWITHSUNDEEP
csmartcardglobalplatform
abc
abc

Reputation: 1

Using 32byte keys establish platform scp03 secure channel

I want establish a scp03 secure channel.

My static keys are of length 32bytes or 256bits

Using 32 byte keys I want to generate session keys according to scp03 protocol, when I tried implementing after generating session keys when I use the generate mac key to verify card cryptogram it is failing.

Following are steps that I have implemented:

  1. Initialize update
  2. Generate session keys. According to diversification scheme input for session-enc - 11(0's)+derivation constant(0x04-enc,0x06-mac,0x07-rmac)+00(separation indicator)+0x0100(L value bcz 32 byte key length)+0x02+hostchallange(8 bytes)+card challenge(8 bytes) -- total 32 bytes

This is how I generate enc, mac, r-mac keys

  1. Verify card cryptogram - I use 16byte generated mac key and applied derivation scheme. When I am verifying the card cryptogram which is 8 bytes the comparison is failing.

Can I know the proper values to generate session keys and verify card cryptogram

Upvotes: 0

Views: 129

Answers (1)

k_o_
k_o_

Reputation: 6298

globalplatform for c on GitHub can do this. There might be also a test case in a file scp03Test.c

Upvotes: 0

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