laforge has uploaded this change for review. (
https://gerrit.osmocom.org/c/pysim/+/41765?usp=email )
Change subject: global_platform: Add KCV computation for TLS-PSK keys
......................................................................
global_platform: Add KCV computation for TLS-PSK keys
This adds support for computing the KCV (key check value) for TLS-PSK
keys such as those used in SCP81.
The spec reference is "Remote Application Management over HTTP
Card Specification v2.2 - Amendment B Version 1.1.3"
Change-Id: I8c56ba1341fd4615f8a9ed0c13f25790639f9098
---
M pySim/global_platform/__init__.py
1 file changed, 9 insertions(+), 0 deletions(-)
git pull ssh://gerrit.osmocom.org:29418/pysim refs/changes/65/41765/1
diff --git a/pySim/global_platform/__init__.py
b/pySim/global_platform/__init__.py
index 8a99677..a1f4824 100644
--- a/pySim/global_platform/__init__.py
+++ b/pySim/global_platform/__init__.py
@@ -18,6 +18,7 @@
"""
import io
+import hashlib
from copy import deepcopy
from typing import Optional, List, Dict, Tuple
from construct import Optional as COptional
@@ -1051,10 +1052,18 @@
cipher = AES.new(key, AES.MODE_ECB)
return cipher.encrypt(plaintext)
+def compute_kcv_sha1(key:bytes) -> bytes:
+ # GPC 2.2 B RAM over HTTP Section 3.8: A key check value shall be computed
as the three most
+ # significant bytes of the SHA-1 digest of the PSK TLS Key
+ m = hashlib.sha1()
+ m.update(key)
+ return m.digest()[:3]
+
# dict is keyed by the string name of the KeyType enum above in this file
KCV_CALCULATOR = {
'aes': compute_kcv_aes,
'des': compute_kcv_des,
+ 'tls_psk': compute_kcv_sha1,
}
def compute_kcv(key_type: str, key: bytes) -> Optional[bytes]:
--
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Gerrit-MessageType: newchange
Gerrit-Project: pysim
Gerrit-Branch: master
Gerrit-Change-Id: I8c56ba1341fd4615f8a9ed0c13f25790639f9098
Gerrit-Change-Number: 41765
Gerrit-PatchSet: 1
Gerrit-Owner: laforge <[email protected]>
