all repos — TinyCrypT @ af632790f00843c1e4a78f385fd8212246c13200

Short and sweet classical cryptographic primitives 

X25519 optimizations passing tests
Juniper Beatitudes [email protected]
Fri, 09 Jan 2026 16:37:45 -0600
commit

af632790f00843c1e4a78f385fd8212246c13200

parent

0443981d2543b79cead85cfaf98c05992a4a097f

5 files changed, 11 insertions(+), 21 deletions(-)

jump to
M flake.nix → flake.nix 
@@ -63,6 +63,7 @@ packages = with pkgs-persephone; [
           ninja
           meson
           esp-idf-xtensa
+          qemu-esp32
           clang-tools
           valgrind
           bear
M test.c → test.c 
@@ -18,7 +18,10 @@ = { 0x95, 0xcb, 0xde, 0x94, 0x76, 0xe8, 0x90, 0x7d, 0x7a, 0xad, 0xe4,
           0x5c, 0xb4, 0xb8, 0x73, 0xf8, 0x8b, 0x59, 0x5a, 0x68, 0x79, 0x9f,
           0xa1, 0x52, 0xe6, 0xf8, 0xf7, 0x64, 0x7a, 0xac, 0x79, 0x57 };
   uint8_t actual[sizeof (EXPECTED)];
-  tct_x25519 (SCALAR, U, actual);
+  for (unsigned int i = 0; i < 10000; ++i)
+    {
+      tct_x25519 (SCALAR, U, actual);
+    }
   for (unsigned int i = 0; i < sizeof (actual); ++i)
     {
       printf ("%02x", actual[i]);
M tinycrypt/portable/chacha20_poly1305.c → tinycrypt/portable/chacha20_poly1305.c 
@@ -1,8 +1,6 @@
 #include <stdbool.h>
 #include <stdint.h>
 
-#include "tinycrypt/chacha20_poly1305.h"
-
 typedef uint32_t dwpacked __attribute__ ((vector_size (16)));
 
 static dwpacked
M tinycrypt/x86_64_aarch64/x25519.c → tinycrypt/x86_64_aarch64/x25519.c 
@@ -42,10 +42,7 @@ {
       for (unsigned int j = 0; j < 4; ++j)
         {
           intermediate[i + j] += (__uint128_t)a_int[i] * (__uint128_t)b_int[j];
-          if (i + j < 7)
-            {
-              intermediate[i + j + 1] += intermediate[i + j] >> 64;
-            }
+          intermediate[i + j + 1] += intermediate[i + j] >> 64;
           intermediate[i + j] &= 0xffffffffffffffff;
         }
     }

@@ -77,16 +74,10 @@ for (unsigned int j = i + 1; j < 4; ++j)
         {
           __uint128_t prod = (__uint128_t)a_int[i] * (__uint128_t)a_int[j];
           intermediate[i + j] += prod;
-          if (i + j < 7)
-            {
-              intermediate[i + j + 1] += intermediate[i + j] >> 64;
-            }
+          intermediate[i + j + 1] += intermediate[i + j] >> 64;
           intermediate[i + j] &= 0xffffffffffffffff;
           intermediate[i + j] += prod;
-          if (i + j < 7)
-            {
-              intermediate[i + j + 1] += intermediate[i + j] >> 64;
-            }
+          intermediate[i + j + 1] += intermediate[i + j] >> 64;
           intermediate[i + j] &= 0xffffffffffffffff;
         }
     }

@@ -436,16 +427,13 @@ k_int[i] = from_le64 (key + i * 8);
       u_int[i] = from_le64 (u + i * 8);
       u_int[4 + i] = 0x0;
     }
+  u_int[3] &= 0x7fffffffffffffff;
   k_int[0] &= 0xfffffffffffffff8;
   k_int[3] &= 0x7fffffffffffffff;
   k_int[3] |= 0x4000000000000000;
   modp512_postadd (u_int, u_int);
-  uint64_t A24[4] = { 0x000000000001db41, 0x00, 0x00, 0x00 };
-  uint64_t buf[16];
-  uint64_t *x2 = buf;
-  uint64_t *z2 = buf + 4;
-  uint64_t *x3 = buf + 8;
-  uint64_t *z3 = buf + 12;
+  uint64_t A24[4] = { 0x1db41, 0, 0, 0 };
+  uint64_t x2[4], z2[4], x3[4], z3[4];
   unsigned int swap = 0;
   for (unsigned int i = 0; i < 4; ++i)
     {