catarrh/pysim
1
0
Fork 0
mirror of https://gitea.osmocom.org/sim-card/pysim.git synced 2026-03-16 18:38:32 +03:00
Code Issues Packages Projects Releases Wiki Activity

global_platform/scp: fix dek_encrypt/dek_decrypt for SCP02

Browse Source 
The methods dek_encrypt/dek_decrypt use the wrong algorithm and the
wrong key material. The algorithm should be 3DES rather then single
DES and the key must be the DEK session key instead of the static
DEK key from which the DEK session key is derived.

Related: SYS#7902
Change-Id: I3d0cc7378680b346fa39152c8b7074446d2c869d
This commit is contained in:
Philipp Maier
2026-03-02 18:13:12 +01:00
parent d8f3c78135
commit f10af30aed
1 changed files with 4 additions and 2 deletions
Download Patch File Download Diff File Expand all files Collapse all files

6
pySim/global_platform/scp.py
View File

@@ -266,11 +266,13 @@ class SCP02(SCP):
super().__init__(*args, **kwargs)
def dek_encrypt(self, plaintext:bytes) -> bytes:
cipher = DES.new(self.card_keys.dek[:8], DES.MODE_ECB)
# See also GPC section B.1.1.2, E.4.7, and E.4.1
cipher = DES3.new(self.sk.data_enc, DES.MODE_ECB)
return cipher.encrypt(plaintext)
def dek_decrypt(self, ciphertext:bytes) -> bytes:
cipher = DES.new(self.card_keys.dek[:8], DES.MODE_ECB)
# See also GPC section B.1.1.2, E.4.7, and E.4.1
cipher = DES3.new(self.sk.data_enc, DES.MODE_ECB)
return cipher.decrypt(ciphertext)
def _compute_cryptograms(self, card_challenge: bytes, host_challenge: bytes):