[steve] 04/04: finish open(). add is_tampered()

[gs...@apache.org]

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gstein pushed a commit to branch trunk
in repository https://gitbox.apache.org/repos/asf/steve.git

commit 2ecae5af2fcb60d4bd41dcf3e047a12e1a2ad040
Author: Greg Stein <gs...@gmail.com>
AuthorDate: Sun May 29 19:49:33 2022 -0500

    finish open(). add is_tampered()
---
 v3/steve/election.py | 32 +++++++++++++++++++++++++++++++-
 1 file changed, 31 insertions(+), 1 deletion(-)

diff --git a/v3/steve/election.py b/v3/steve/election.py
index 6c27e0d..2d8aa1c 100644
--- a/v3/steve/election.py
+++ b/v3/steve/election.py
@@ -37,6 +37,8 @@ class Election:
             '''UPDATE ISSUES SET salt = ? WHERE _ROWID_ = ?''')
         self.c_salt_record = self.db.add_statement(
             '''UPDATE RECORD SET salt = ? WHERE _ROWID_ = ?''')
+        self.c_open = self.db.add_statement(
+            'UPDATE METADATA SET salt = ?, opened_key = ?')
         self.c_close = self.db.add_statement(
             'UPDATE METADATA SET closed = 1')
 
@@ -49,7 +51,18 @@ class Election:
             'SELECT * FROM RECORD ORDER BY rid')
 
     def open(self):
-        print('EDATA:', self.gather_election_data())
+        # Double-check that the election is not already open.
+        md = self.q_metadata.first_row()
+        assert md.salt is None and md.opened_key is None
+
+        edata = self.gather_election_data()
+        print('EDATA:', edata)
+        salt = crypto.gen_salt()
+        opened_key = crypto.gen_opened_key(edata, salt)
+
+        print('SALT:', salt)
+        print('KEY:', opened_key)
+        self.c_open.perform((salt, opened_key))
 
     def gather_election_data(self):
         "Gather a definition of this election for keying and anti-tamper."
@@ -102,6 +115,23 @@ class Election:
         for_table('issues', self.c_salt_issue)
         for_table('record', self.c_salt_record)
 
+    def is_tampered(self):
+
+        # The election should be open.
+        md = self.q_metadata.first_row()
+        assert md.salt is not None and md.opened_key is not None
+
+        # Compute an opened_key based on the current data.
+        edata = self.gather_election_data()
+        opened_key = crypto.gen_opened_key(edata, md.salt)
+
+        print('EDATA:', edata)
+        print('SALT:', md.salt)
+        print('KEY:', opened_key)
+
+        # The computed key should be unchanged.
+        return opened_key != md.opened_key
+
 
 def new_eid():
     "Create a new ElectionID."