diff --git a/include/jets/w.h b/include/jets/w.h
index 4581e2e15..3158a4d49 100644
--- a/include/jets/w.h
+++ b/include/jets/w.h
@@ -156,6 +156,7 @@
     u3_noun u3wee_veri(u3_noun);
     u3_noun u3wee_shar(u3_noun);
     u3_noun u3wee_point_add(u3_noun);
+    u3_noun u3wee_scalarmult(u3_noun);
     u3_noun u3wee_double_scalarmult(u3_noun);
     u3_noun u3wee_scalarmult_base(u3_noun);
 
diff --git a/jets/e/ed_scalarmult.c b/jets/e/ed_scalarmult.c
new file mode 100644
index 000000000..7eeaf5bd0
--- /dev/null
+++ b/jets/e/ed_scalarmult.c
@@ -0,0 +1,66 @@
+/* gen164/5/ed_scalarmult.c
+**
+*/
+#include "all.h"
+
+#include <ed25519.h>
+
+#include "ge_additions.h"
+
+/* functions
+*/
+  u3_noun
+  u3qc_scalarmult(u3_atom a,
+                  u3_atom b)
+  {
+    c3_y met_w;
+
+    met_w = u3r_met(3, a);
+    if (met_w > 32) {
+      return u3m_bail(c3__exit);
+    }
+    c3_y a_y[32];
+    memset(a_y, 0, 32);
+    u3r_bytes(0, met_w, a_y, a);
+
+    met_w = u3r_met(3, b);
+    if (met_w > 32) {
+      return u3m_bail(c3__exit);
+    }
+    c3_y b_y[32];
+    memset(b_y, 0, 32);
+    u3r_bytes(0, met_w, b_y, b);
+
+    ge_p3 B;
+    if (ge_frombytes_negate_vartime(&B, b_y) != 0) {
+      return u3m_bail(c3__exit);
+    }
+
+    // Undo the negation from above. See add_scalar.c in the ed25519 distro.
+    fe_neg(B.X, B.X);
+    fe_neg(B.T, B.T);
+
+    ge_p3 result;
+    ge_scalarmult(&result, a_y, &B);
+
+    c3_y output_y[32];
+    ge_p3_tobytes(output_y, &result);
+
+    return u3i_bytes(32, output_y);
+  }
+
+  u3_noun
+  u3wee_scalarmult(u3_noun cor)
+  {
+    u3_noun a, b;
+
+    if ( (c3n == u3r_mean(cor, u3x_sam_2, &a,
+                               u3x_sam_3, &b, 0)) ||
+         (c3n == u3ud(a)) ||
+         (c3n == u3ud(b)) )
+    {
+      return u3m_bail(c3__exit);
+    } else {
+      return u3qc_scalarmult(a, b);
+    }
+  }
diff --git a/jets/e/ge_additions.c b/jets/e/ge_additions.c
new file mode 100644
index 000000000..43166558e
--- /dev/null
+++ b/jets/e/ge_additions.c
@@ -0,0 +1,169 @@
+// Group Element Additions
+//
+// Urbit uses the ge.h code from the ed25519 library, which was ported from the
+// ref10 SUPERCOP public domain implementation. That implementation doesn't
+// contain several functions needed for ring signatures.
+//
+// This file is does. The providence of this code starts with Adam Langley
+// taking the SUPERCOP C implementation and producing an ed25519 implementation
+// for in golang (https://godoc.org/golang.org/x/crypto/ed25519). (If you look
+// at the go code, you'll see the comments are the same as the comments in the
+// C implementation.)
+//
+// From there, the DEDIS group from ETH Zurich took that implementation and
+// added the additional methods to make a generalized ECC point library. While
+// their project as a whole is MPL, they deliberately left their ed25519
+// implementation under the Go BSD-3 license:
+// (https://github.com/dedis/kyber/blob/master/group/edwards25519/LICENSE)
+//
+// This file is a fairly straight translation from Go to C of DEDIS' additions,
+// so this falls under the same license.
+//
+// ------
+//
+// Copyright (c) 2009 The Go Authors. All rights reserved.
+//
+// Redistribution and use in source and binary forms, with or without
+// modification, are permitted provided that the following conditions are
+// met:
+//
+//    * Redistributions of source code must retain the above copyright
+// notice, this list of conditions and the following disclaimer.
+//    * Redistributions in binary form must reproduce the above
+// copyright notice, this list of conditions and the following disclaimer
+// in the documentation and/or other materials provided with the
+// distribution.
+//    * Neither the name of Google Inc. nor the names of its
+// contributors may be used to endorse or promote products derived from
+// this software without specific prior written permission.
+//
+// THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
+// "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
+// LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
+// A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
+// OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
+// SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
+// LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
+// DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
+// THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
+// (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
+// OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+
+#include "ge_additions.h"
+
+#include <fe.h>
+
+static unsigned char equal(signed char b, signed char c) {
+    unsigned char ub = b;
+    unsigned char uc = c;
+    unsigned char x = ub ^ uc; /* 0: yes; 1..255: no */
+    uint64_t y = x; /* 0: yes; 1..255: no */
+    y -= 1; /* large: yes; 0..254: no */
+    y >>= 63; /* 1: yes; 0: no */
+    return (unsigned char) y;
+}
+
+static unsigned char negative(signed char b) {
+    uint64_t x = b; /* 18446744073709551361..18446744073709551615: yes; 0..255: no */
+    x >>= 63; /* 1: yes; 0: no */
+    return (unsigned char) x;
+}
+
+void ge_cached_0(ge_cached* c) {
+  fe_1(c->YplusX);
+  fe_1(c->YminusX);
+  fe_1(c->Z);
+  fe_0(c->T2d);
+}
+
+void ge_cached_cmov(ge_cached* r, const ge_cached* u, int32_t b)
+{
+  fe_cmov(r->YplusX, u->YplusX, b);
+  fe_cmov(r->YminusX, u->YminusX, b);
+  fe_cmov(r->Z, u->Z, b);
+  fe_cmov(r->T2d, u->T2d, b);
+}
+
+void ge_cached_neg(ge_cached* r, const ge_cached* t)
+{
+  fe_copy(r->YplusX, t->YminusX);
+  fe_copy(r->YminusX, t->YplusX);
+  fe_copy(r->Z, t->Z);
+  fe_neg(r->T2d, t->T2d);
+}
+
+void select_cached(ge_cached* c, const ge_cached Ai[8], int32_t b)
+{
+  int32_t is_negative = negative(b);
+  int32_t b_abs = b - (((-is_negative) & b) << 1);
+
+  ge_cached_0(c);
+  for (int32_t i = 0; i < 8; ++i) {
+    ge_cached_cmov(c, &Ai[i], equal(b_abs, i+1));
+  }
+
+  ge_cached minusC;
+  ge_cached_neg(&minusC, c);
+  ge_cached_cmov(c, &minusC, is_negative);
+}
+
+//
+void ge_scalarmult(ge_p3* h, const unsigned char* a, const ge_p3* A)
+{
+  signed char e[64];
+  int i;
+  ge_p1p1 t;
+  ge_p3 u;
+
+  for (i = 0; i < 32; ++i) {
+    e[2 * i + 0] = (a[i] >> 0) & 15;
+    e[2 * i + 1] = (a[i] >> 4) & 15;
+  }
+
+  /* each e[i] is between 0 and 15 */
+  /* e[63] is between 0 and 7 */
+  signed char carry = 0;
+  for (i = 0; i < 63; ++i) {
+      e[i] += carry;
+      carry = e[i] + 8;
+      carry >>= 4;
+      e[i] -= carry << 4;
+  }
+  e[63] += carry;
+  /* each e[i] is between -8 and 8 */
+
+  // compute cached array of multiples of A from 1A through 8A
+  ge_cached Ai[8];
+  ge_p3_to_cached(&Ai[0], A);
+  for (i = 0; i < 7; ++i) {
+    ge_add(&t, A, &Ai[i]);
+    ge_p1p1_to_p3(&u, &t);
+    ge_p3_to_cached(&Ai[i+1], &u);
+  }
+
+  // special case for exponent nybble i == 63
+  ge_p3_0(&u);
+  ge_cached c;
+  select_cached(&c, Ai, e[63]);
+  ge_add(&t, &u, &c);
+
+  ge_p2 r;
+  for (i = 62; i >= 0; i--) {
+    // t <<= 4
+    ge_p1p1_to_p2(&r, &t);
+    ge_p2_dbl(&t, &r);
+    ge_p1p1_to_p2(&r, &t);
+    ge_p2_dbl(&t, &r);
+    ge_p1p1_to_p2(&r, &t);
+    ge_p2_dbl(&t, &r);
+    ge_p1p1_to_p2(&r, &t);
+    ge_p2_dbl(&t, &r);
+
+    // Add next nyble
+    ge_p1p1_to_p3(&u, &t);
+    select_cached(&c, Ai, e[i]);
+    ge_add(&t, &u, &c);
+  }
+
+  ge_p1p1_to_p3(h, &t);
+}
diff --git a/jets/e/ge_additions.h b/jets/e/ge_additions.h
new file mode 100644
index 000000000..3424ac689
--- /dev/null
+++ b/jets/e/ge_additions.h
@@ -0,0 +1,8 @@
+#ifndef GE_ADDITIONS_H
+#define GE_ADDITIONS_H
+
+#include <ge.h>
+
+void ge_scalarmult(ge_p3* h, const unsigned char* a, const ge_p3* A);
+
+#endif
diff --git a/jets/tree.c b/jets/tree.c
index 8e0ab518f..fecfc1a98 100644
--- a/jets/tree.c
+++ b/jets/tree.c
@@ -178,19 +178,23 @@ static c3_c* _141_hex_coed__ed_shar_ha[] = {
 static u3j_harm _141_hex_coed__ed_add_a[] =
     {{".2", u3wee_point_add}, {}};
 
+static u3j_harm _141_hex_coed__ed_scalarmult_a[] =
+    {{".2", u3wee_scalarmult}, {}};
+
+static u3j_harm _141_hex_coed__ed_scalarmult_base_a[] =
+    {{".2", u3wee_scalarmult_base}, {}};
+
 static u3j_harm _141_hex_coed__ed_double_scalarmult_a[] =
     {{".2", u3wee_double_scalarmult}, {}};
 
-static u3j_harm _141_hex_coed__ed_scalarmult_a[] =
-    {{".2", u3wee_scalarmult_base}, {}};
-
 static u3j_core _141_hex_coed__ed_d[] =
   { { "sign", 7, _141_hex_coed__ed_sign_a, 0, _141_hex_coed__ed_sign_ha },
     { "puck", 7, _141_hex_coed__ed_puck_a, 0, _141_hex_coed__ed_puck_ha },
     { "veri", 7, _141_hex_coed__ed_veri_a, 0, _141_hex_coed__ed_veri_ha },
     { "shar", 7, _141_hex_coed__ed_shar_a, 0, _141_hex_coed__ed_shar_ha },
     { "add", 7, _141_hex_coed__ed_add_a, 0, 0 },
-    { "scalarmult-base", 7, _141_hex_coed__ed_scalarmult_a, 0, 0 },
+    { "scalarmult", 7, _141_hex_coed__ed_scalarmult_a, 0, 0 },
+    { "scalarmult-base", 7, _141_hex_coed__ed_scalarmult_base_a, 0, 0 },
     { "double-scalarmult", 7, _141_hex_coed__ed_double_scalarmult_a, 0, 0 },
     {}
   };
diff --git a/meson.build b/meson.build
index f1791bccb..216ee5b28 100644
--- a/meson.build
+++ b/meson.build
@@ -138,6 +138,7 @@ jets_e_ed_src = [
 'jets/e/ed_veri.c',
 'jets/e/ed_shar.c',
 'jets/e/ed_point_add.c',
+'jets/e/ed_scalarmult.c',
 'jets/e/ed_scalarmult_base.c',
 'jets/e/ed_double_scalarmult.c'
 ]
@@ -333,9 +334,27 @@ murmur3_dep = dependency('murmur3', version: '>=0.1.0', fallback: ['murmur3', 'm
 secp256k1_dep = dependency('libsecp256k1', version: '>=0.1.0', fallback: ['secp256k1', 'secp256k1_dep'])
 softfloat3_dep = dependency('softfloat3', version: '>=3.0.0', fallback: ['softfloat3', 'softfloat3_dep'])
 
+# Our ge additions must be in their own library because they cannot be compiled
+#  with '-funsigned-char' since they rely on signed characters.
+ge_additions_src = [
+  'jets/e/ge_additions.c',
+]
+
+ge_additions_include = include_directories('jets/e/')
+
+ge_additions_lib = static_library('ge-additions',
+sources: ge_additions_src,
+include_directories: ge_additions_include,
+c_args: ['-Wall'],
+dependencies: ed25519_dep,
+install: false)
+
+gd_additions_dep = declare_dependency(link_with : ge_additions_lib)
+
 deps = [argon2_dep,
         curl_dep,
         ed25519_dep,
+        gd_additions_dep,
         gmp_dep,
         libent_dep,
         libh2o_dep,