2 files changed, 115 insertions, 0 deletions
diff --git a/src/cli/tss.cpp b/src/cli/tss.cpp
new file mode 100644
index 000000000..2e6882745
--- /dev/null
+++ b/src/cli/tss.cpp
@@ -0,0 +1,114 @@
+/*
+* (C) 2018 Jack Lloyd
+*
+* Botan is released under the Simplified BSD License (see license.txt)
+*/
+
+#include "cli.h"
+
+#if defined(BOTAN_HAS_THRESHOLD_SECRET_SHARING)
+   #include <botan/tss.h>
+   #include <botan/hex.h>
+   #include <fstream>
+#endif
+
+namespace Botan_CLI {
+
+#if defined(BOTAN_HAS_THRESHOLD_SECRET_SHARING)
+
+class TSS_Split final : public Command
+   {
+   public:
+      TSS_Split() : Command("tss_split M N input --id= --share-prefix=share --share-suffix=tss --hash=SHA-256") {}
+
+      std::string group() const override
+         {
+         return "tss";
+         }
+
+      std::string description() const override
+         {
+         return "Split a secret into parts";
+         }
+
+      void go() override
+         {
+         const std::string hash_algo = get_arg("hash");
+         const std::string input = get_arg("input");
+         const std::string id_str = get_arg("id");
+         const std::string share_prefix = get_arg("share-prefix");
+         const std::string share_suffix = get_arg("share-suffix");
+         const size_t N = get_arg_sz("N");
+         const size_t M = get_arg_sz("M");
+
+         Botan::secure_vector<uint8_t> secret = slurp_file_lvec(input);
+
+         const std::vector<uint8_t> id = Botan::hex_decode(id_str);
+
+         std::vector<Botan::RTSS_Share> shares =
+            Botan::RTSS_Share::split(M, N, secret.data(), secret.size(), id, hash_algo, rng());
+
+         for(size_t i = 0; i != shares.size(); ++i)
+            {
+            const std::string share_name = share_prefix + std::to_string(i + 1) + "." + share_suffix;
+            std::ofstream out(share_name.c_str());
+            if(!out)
+               throw CLI_Error("Failed to open output file " + share_name);
+
+            out.write(reinterpret_cast<const char*>(shares[i].data().data()), shares[i].data().size());
+            }
+
+         }
+
+   private:
+      Botan::secure_vector<uint8_t> slurp_file_lvec(const std::string& input_file)
+         {
+         Botan::secure_vector<uint8_t> buf;
+         auto insert_fn = [&](const uint8_t b[], size_t l)
+            {
+            buf.insert(buf.end(), b, b + l);
+            };
+         this->read_file(input_file, insert_fn, 4096);
+         return buf;
+         }
+   };
+
+BOTAN_REGISTER_COMMAND("tss_split", TSS_Split);
+
+class TSS_Recover final : public Command
+   {
+   public:
+      TSS_Recover() : Command("tss_recover *shares") {}
+
+      std::string group() const override
+         {
+         return "tss";
+         }
+
+      std::string description() const override
+         {
+         return "Recover a split secret";
+         }
+
+      void go() override
+         {
+         std::vector<Botan::RTSS_Share> shares;
+
+         for(std::string share_fsname : get_arg_list("shares"))
+            {
+            auto v = slurp_file(share_fsname);
+            shares.push_back(Botan::RTSS_Share(v.data(), v.size()));
+            }
+
+         Botan::secure_vector<uint8_t> rec = Botan::RTSS_Share::reconstruct(shares);
+
+         output().write(Botan::cast_uint8_ptr_to_char(rec.data()), rec.size());
+         }
+   };
+
+BOTAN_REGISTER_COMMAND("tss_recover", TSS_Recover);
+
+#endif
+
+}
+
diff --git a/src/cli/utils.cpp b/src/cli/utils.cpp
index 2e096f586..1a7639937 100644
--- a/src/cli/utils.cpp
+++ b/src/cli/utils.cpp
@@ -70,6 +70,7 @@ class Print_Help final : public Command
             { "psk", "PSK Database" },
             { "pubkey", "Public Key Cryptography" },
             { "tls", "TLS" },
+            { "tss", "Secret Sharing" },
             { "x509", "X.509" },
             { "misc", "Miscellaneous" }
          };