Checkpoint the party/runtime stack before share-program and malicious-mode work.

Ship the TLS mesh, composer, Beaver/Yao/leaf MPC, prep/online paths, apps, and docs so the tree is pushable before elevating share_expr, security_mode, and prep resume.

Co-authored-by: Cursor <cursoragent@cursor.com>

examples/applications/splinter.cpp

@@ -0,0 +1,65 @@
+#include <cstddef>
+#include <cstdint>
+#include <iostream>
+#include <vector>
+
+#include "dpf.hpp"
+#include "dpf/app_flow.hpp"
+#include "dpf/app_plans.hpp"
+
+// Splinter, the DPF query step (Wang, Yun, Goldwasser, Vaikuntanathan, and
+// Zeldovich, NSDI 2017). Private queries on public data with two-server FSS.
+// The client's private selector is a unit DPF at a secret attribute value.
+// Each server dots that selector with a public aggregate column, so the
+// answer is the SUM (or COUNT) for the private key without either server
+// learning which key was asked.
+//
+//   c++ -std=c++17 -march=native -I include -I thirdparty \
+//       examples/applications/splinter.cpp
+
+int main()
+{
+    constexpr std::size_t domain = 256;  // attribute values
+
+    // Public data, pre-aggregated by attribute: group_sum[v] is the SUM of a
+    // value column over the rows whose attribute equals v.
+    std::vector<std::uint64_t> group_sum(domain);
+    std::vector<std::uint64_t> group_cnt(domain, 1);
+    for (std::size_t v = 0; v < domain; ++v)
+        group_sum[v] = (v * 37 + 11) % 1000;
+
+    constexpr std::uint8_t secret_key = 88;  // the private WHERE value
+
+    // One selector key per server. reconstruct = the two servers' shares.
+    auto [k0, k1] = dpf::make_dpf(secret_key, std::uint64_t{1});
+
+    // SELECT SUM(value) WHERE attribute = secret_key.
+    const auto sum = dpf::reconstruct(
+        dpf::eval_full_inner_product(dpf::paired, k0, group_sum),
+        dpf::eval_full_inner_product(dpf::paired, k1, group_sum));
+    if (sum != group_sum[secret_key])
+    {
+        std::cerr << "splinter sum\n";
+        return 1;
+    }
+
+    // SELECT COUNT(*) WHERE attribute = secret_key is the same selector on an
+    // all-ones column.
+    const auto cnt = dpf::reconstruct(
+        dpf::eval_full_inner_product(dpf::paired, k0, group_cnt),
+        dpf::eval_full_inner_product(dpf::paired, k1, group_cnt));
+    if (cnt != 1)
+    {
+        std::cerr << "splinter count\n";
+        return 1;
+    }
+
+    {
+        if (int rc = dpf::app::run_measured("splinter",
+                dpf::protocol::fss_point_plan(0), 8))
+            return rc;
+    }
+
+    std::cout << sum << "\n";
+    return 0;
+}