prop250: Add unit tests

Signed-off-by: David Goulet <dgoulet@torproject.org>
Signed-off-by: George Kadianakis <desnacked@riseup.net>

1 files changed, 71 insertions, 0 deletions

diff --git a/src/test/sr_srv_calc_ref.py b/src/test/sr_srv_calc_ref.py
new file mode 100644
index 0000000000..492ca62b15
--- /dev/null
+++ b/src/test/sr_srv_calc_ref.py
@@ -0,0 +1,71 @@
+# This is a reference implementation of the SRV calculation for prop250. We
+# use it to generate a test vector for the test_sr_compute_srv() unittest.
+# (./test shared-random/sr_compute_srv)
+#
+# Here is the SRV computation formula:
+#
+#      HASHED_REVEALS = H(ID_a | R_a | ID_b | R_b | ..)
+#
+#      SRV = SHA3-256("shared-random" | INT_8(reveal_num) | INT_4(version) |
+#                     HASHED_REVEALS | previous_SRV)
+#
+
+import sys
+import hashlib
+import struct
+
+# Python 3.6+, the SHA3 is available in hashlib natively. Else this requires
+# the pysha3 package (pip install pysha3).
+if sys.version_info < (3, 6):
+	import sha3
+
+# Test vector to make sure the right sha3 version will be used. pysha3 < 1.0
+# used the old Keccak implementation. During the finalization of SHA3, NIST
+# changed the delimiter suffix from 0x01 to 0x06. The Keccak sponge function
+# stayed the same. pysha3 1.0 provides the previous Keccak hash, too.
+TEST_VALUE = "e167f68d6563d75bb25f3aa49c29ef612d41352dc00606de7cbd630bb2665f51"
+if TEST_VALUE != sha3.sha3_256(b"Hello World").hexdigest():
+  print("pysha3 version is < 1.0. Please install from:")
+  print("https://github.com/tiran/pysha3https://github.com/tiran/pysha3")
+  sys.exit(1)
+
+# In this example, we use three reveal values.
+reveal_num = 3
+version = 1
+
+# We set directly the ascii value because memset(buf, 'A', 20) makes it to 20
+# times "41" in the final string.
+
+# Identity and reveal value of dirauth a
+ID_a = 20 * "41" # RSA identity of 40 base16 bytes.
+R_a = 56 * 'A' # 56 base64 characters
+
+# Identity and reveal value of dirauth b
+ID_b = 20 * "42" # RSA identity of 40 base16 bytes.
+R_b = 56 * 'B' # 56 base64 characters
+
+# Identity and reveal value of dirauth c
+ID_c = 20 * "43" # RSA identity of 40 base16 bytes.
+R_c = 56 * 'C' # 56 base64 characters
+
+# Concatenate them all together and hash them to form HASHED_REVEALS.
+REVEALS = (ID_a + R_a + ID_b + R_b + ID_c + R_c).encode()
+hashed_reveals_object = hashlib.sha3_256(REVEALS)
+hashed_reveals = hashed_reveals_object.digest()
+
+previous_SRV = (32 * 'Z').encode()
+
+# Now form the message.
+#srv_msg = struct.pack('13sQL256ss', "shared-random", reveal_num, version,
+#                      hashed_reveals, previous_SRV)
+invariant_token = b"shared-random"
+srv_msg = invariant_token + \
+          struct.pack('!QL', reveal_num, version) + \
+          hashed_reveals + \
+          previous_SRV
+
+# Now calculate the HMAC
+srv = hashlib.sha3_256(srv_msg)
+print("%s" % srv.hexdigest().upper())
+
+# 2A9B1D6237DAB312A40F575DA85C147663E7ED3F80E9555395F15B515C74253D