package/python-hkdf: new package

HMAC-based Extract-and-Expand Key Derivation Function (HKDF).

https://github.com/casebeer/python-hkdf

Signed-off-by: Julien Olivain <ju.o@free.fr>
[Thomas: justify the license.]
Signed-off-by: Thomas Petazzoni <thomas.petazzoni@bootlin.com>

support/testing/tests/package/sample_python_hkdf.py

@@ -0,0 +1,22 @@
+import hashlib
+from binascii import hexlify, unhexlify
+
+from hkdf import Hkdf, hkdf_expand, hkdf_extract
+
+salt = b"ThisIsTheSalt."
+key_in = b"ThisIsTheSecretKey"
+key_info = b"KeyInfo1"
+key_len = 16
+expected_key = unhexlify(b"b49d6cc9065b72f3a0859377d8bb7299")
+
+prk = hkdf_extract(salt, input_key_material=key_in, hash=hashlib.sha512)
+key1 = hkdf_expand(prk, info=key_info, length=key_len)
+
+print("key1:", hexlify(key1))
+assert key1 == expected_key
+
+kdf = Hkdf(salt, input_key_material=key_in, hash=hashlib.sha512)
+key2 = kdf.expand(info=key_info, length=key_len)
+
+print("key2:", hexlify(key2))
+assert key2 == expected_key