diff --git a/ed25519/ed25519-donna/ed25519-donna-impl-base.h b/ed25519/ed25519-donna/ed25519-donna-impl-base.h
index 48913ed..18736cf 100644
--- a/ed25519/ed25519-donna/ed25519-donna-impl-base.h
+++ b/ed25519/ed25519-donna/ed25519-donna-impl-base.h
@@ -188,6 +188,31 @@ ge25519_pack(unsigned char r[32], const ge25519 *p) {
 	r[31] ^= ((parity[0] & 1) << 7);
 }
 
+// assumes inz[] points to things in in[]
+// NOTE: leaves in unfinished state
+static void
+ge25519_batchpack_destructive_1(bytes32 out[], ge25519 in[], bignum25519 *inz[], bignum25519 tmp[], size_t num) {
+  bignum25519 ty;
+
+  curve25519_batchrecip(inz, tmp, inz, num);
+
+  for (size_t i = 0; i < num; ++i) {
+    curve25519_mul(ty, in[i].y, in[i].z);
+    curve25519_contract(out[i], ty);
+  }
+}
+
+static void
+ge25519_batchpack_destructive_finish(bytes32 out, ge25519 *unf) {
+  bignum25519 tx;
+  unsigned char parity[32];
+  // z of unfinished is inverted
+  curve25519_mul(tx, unf->x, unf->z);
+  curve25519_contract(parity, tx);
+  out[31] ^= ((parity[0] & 1) << 7);
+}
+
+
 static int
 ge25519_unpack_negative_vartime(ge25519 *r, const unsigned char p[32]) {
 	static const unsigned char zero[32] = {0};
diff --git a/ed25519/ed25519-donna/ed25519-donna-impl-sse2.h b/ed25519/ed25519-donna/ed25519-donna-impl-sse2.h
index 5fe3416..2401099 100644
--- a/ed25519/ed25519-donna/ed25519-donna-impl-sse2.h
+++ b/ed25519/ed25519-donna/ed25519-donna-impl-sse2.h
@@ -217,6 +217,30 @@ ge25519_pack(unsigned char r[32], const ge25519 *p) {
 	r[31] ^= ((parity[0] & 1) << 7);
 }
 
+// assumes inz[] points to things in in[]
+// NOTE: leaves in unfinished state
+static void
+ge25519_batchpack_destructive_1(bytes32 out[], ge25519 in[], bignum25519 *inz[], bignum25519 tmp[], size_t num) {
+  bignum25519 ALIGN(16) ty;
+
+  curve25519_batchrecip(inz, tmp, inz, num);
+
+  for (size_t i = 0; i < num; ++i) {
+    curve25519_mul(ty, in[i].y, in[i].z);
+    curve25519_contract(out[i], ty);
+  }
+}
+
+static void
+ge25519_batchpack_destructive_finish(bytes32 out, ge25519 *unf) {
+  bignum25519 ALIGN(16) tx;
+  unsigned char parity[32];
+  // z of unfinished is inverted
+  curve25519_mul(tx, unf->x, unf->z);
+  curve25519_contract(parity, tx);
+  out[31] ^= ((parity[0] & 1) << 7);
+}
+
 
 static int
 ge25519_unpack_negative_vartime(ge25519 *r, const unsigned char p[32]) {
diff --git a/ed25519/ed25519-donna/ed25519-donna.h b/ed25519/ed25519-donna/ed25519-donna.h
index de1120f..1e1dc34 100644
--- a/ed25519/ed25519-donna/ed25519-donna.h
+++ b/ed25519/ed25519-donna/ed25519-donna.h
@@ -94,6 +94,8 @@ typedef struct ge25519_pniels_t {
 	bignum25519 ysubx, xaddy, z, t2d;
 } ge25519_pniels;
 
+typedef unsigned char bytes32[32];
+
 #include "ed25519-donna-basepoint-table.h"
 
 #if defined(ED25519_64BIT)