diff --git a/Makefile b/Makefile
index 8274a58..d31611a 100644
--- a/Makefile
+++ b/Makefile
@@ -13,7 +13,7 @@ V            ?= 0
 GOCACHE      ?= off
 GOARCH       ?=
 ETC_DIR      = $(PRJ_DIR)/etc
-BENCH_NAME	 = .
+BENCH_NAME	 = BenchmarkXMul
 DBG 		 = 1
 OPTS_ENV	 =
 ifeq ($(NOASM),1)
@@ -21,9 +21,9 @@ ifeq ($(NOASM),1)
 endif
 
 ifeq ($(DBG),1)
-	DBG_FLAGS+= -m -m 	# escape analysis
-	DBG_FLAGS+= -l		# no inline
-	DBG_FLAGS+= -N		# debug symbols
+	DBG_FLAGS+= #-m 	# escape analysis
+	DBG_FLAGS+= -l	# no inline
+	DBG_FLAGS+= -N	# debug symbols
 	#OPTS+=-gcflags=all="$(DBG_FLAGS)"
 	OPTS+=-gcflags "$(DBG_FLAGS)"
 	OPTS_ENV+= GOTRACEBACK=crash	# enable core dumps
@@ -68,3 +68,15 @@ vendor-sidh-for-tls: clean
 bench: clean $(addprefix prep-,$(TARGETS))
 	cd $(GOPATH_LOCAL); $(OPTS_ENV) GOCACHE=$(GOCACHE) GOPATH=$(GOPATH_LOCAL) GOMAXPROCS=1 $(GO) test \
 		$(BENCH_OPTS) ./...
+
+bench_csidh: clean make_dirs $(addprefix prep-,$(TARGETS))
+	cd $(GOPATH_LOCAL); $(OPTS_ENV) GOCACHE=$(GOCACHE) GOPATH=$(GOPATH_LOCAL) GOMAXPROCS=1 $(GO) test \
+		$(OPTS) -run="^_" -bench=$(BENCH_NAME) -memprofile mem.prof -benchmem github.com/henrydcase/nobs/dh/csidh
+
+test_drbg: clean make_dirs $(addprefix prep-,$(TARGETS))
+	cd $(GOPATH_LOCAL); $(OPTS_ENV) GOCACHE=$(GOCACHE) GOPATH=$(GOPATH_LOCAL) GOMAXPROCS=1 $(GO) test \
+		$(OPTS) -c -run=. github.com/henrydcase/nobs/drbg
+
+bench_drbg: clean make_dirs $(addprefix prep-,$(TARGETS))
+	cd $(GOPATH_LOCAL); $(OPTS_ENV) GOCACHE=$(GOCACHE) GOPATH=$(GOPATH_LOCAL) GOMAXPROCS=1 $(GO) test \
+		$(OPTS) -run="XXX" -bench=. -benchmem -memprofile=drbg_prof github.com/henrydcase/nobs/drbg
diff --git a/dh/csidh/api.go b/dh/csidh/api.go
index e935d83..290e381 100644
--- a/dh/csidh/api.go
+++ b/dh/csidh/api.go
@@ -10,6 +10,10 @@ type PublicKey struct {
 // Defines operations on private key
 type PrivateKey struct {
 	e [37]int8
+
+	// Temporary buffer used during key generation. Placed
+	// here to avoid heap memory allocation
+	tmp [64]byte
 }
 
 // PrivateKey
diff --git a/dh/csidh/csidh.go b/dh/csidh/csidh.go
index 6bb9a83..220e1e9 100644
--- a/dh/csidh/csidh.go
+++ b/dh/csidh/csidh.go
@@ -3,12 +3,15 @@ package csidh
 import "io"
 import "crypto/rand"
 
+// OZAPTF
+var buf [8 * limbByteSize]byte
+
 // TODO: this is weird. How do I know loop will end?
 func randFp(fp *Fp) {
+	//	var buf [len(fp) * limbByteSize]byte
 	mask := uint64(1<<(pbits%limbBitSize)) - 1
 	for {
 		*fp = Fp{}
-		var buf [len(fp) * limbByteSize]byte
 		if _, err := io.ReadFull(rand.Reader, buf[:]); err != nil {
 			// OZAPTF: to be re-done (AES_CTR)
 			panic("Can't read random number")
@@ -60,15 +63,14 @@ func (c *PrivateKey) Generate(rand io.Reader) error {
 	}
 
 	for i := 0; i < len(primes); {
-		var buf [64]byte
-		_, err := io.ReadFull(rand, buf[:])
+		_, err := io.ReadFull(rand, c.tmp[:])
 		if err != nil {
 			return err
 		}
 
-		for j, _ := range buf {
-			if int8(buf[j]) <= expMax && int8(buf[j]) >= -expMax {
-				c.e[i>>1] |= int8((buf[j] & 0xf) << uint((i%2)*4))
+		for j, _ := range c.tmp {
+			if int8(c.tmp[j]) <= expMax && int8(c.tmp[j]) >= -expMax {
+				c.e[i>>1] |= int8((c.tmp[j] & 0xf) << uint((i%2)*4))
 				i = i + 1
 				if i == len(primes) {
 					break
diff --git a/dh/csidh/csidh_test.go b/dh/csidh/csidh_test.go
index 6ee9294..855a8c4 100644
--- a/dh/csidh/csidh_test.go
+++ b/dh/csidh/csidh_test.go
@@ -272,31 +272,31 @@ func testProcessTestVectors(t *testing.T) {
 
 func TestProcessTestVectors(t *testing.T) { testProcessTestVectors(t) }
 
+var prv1, prv2 PrivateKey
+
 // Private key generation
 func BenchmarkGeneratePrivate(b *testing.B) {
 	for n := 0; n < b.N; n++ {
-		var prv PrivateKey
-		prv.Generate(rng)
+		prv1.Generate(rng)
 	}
 }
 
 // Public key generation from private (group action on empty key)
 func BenchmarkGeneratePublic(b *testing.B) {
 	for n := 0; n < b.N; n++ {
-		var prv PrivateKey
 		var pub PublicKey
-		prv.Generate(rng)
-		pub.Generate(&prv)
+		prv1.Generate(rng)
+		pub.Generate(&prv1)
 	}
 }
 
 // Benchmark validation on same key multiple times
 func BenchmarkValidate(b *testing.B) {
-	var pub PublicKey
-	var prv PrivateKey
+	prvBytes := []byte{0xaa, 0x54, 0xe4, 0xd4, 0xd0, 0xbd, 0xee, 0xcb, 0xf4, 0xd0, 0xc2, 0xbc, 0x52, 0x44, 0x11, 0xee, 0xe1, 0x14, 0xd2, 0x24, 0xe5, 0x0, 0xcc, 0xf5, 0xc0, 0xe1, 0x1e, 0xb3, 0x43, 0x52, 0x45, 0xbe, 0xfb, 0x54, 0xc0, 0x55, 0xb2}
+	prv1.Import(prvBytes)
 
-	prv.Generate(rng)
-	pub.Generate(&prv)
+	var pub PublicKey
+	pub.Generate(&prv1)
 
 	for n := 0; n < b.N; n++ {
 		pub.Validate()
@@ -320,18 +320,15 @@ func BenchmarkValidateRandom(b *testing.B) {
 // Benchmark validation on different keys
 func BenchmarkValidateGenerated(b *testing.B) {
 	var pub PublicKey
-	var prv PrivateKey
-
 	for n := 0; n < b.N; n++ {
-		prv.Generate(rng)
-		pub.Generate(&prv)
+		prv1.Generate(rng)
+		pub.Generate(&prv1)
 		pub.Validate()
 	}
 }
 
 func BenchmarkDeriveGenerated(b *testing.B) {
 	var ss [64]uint8
-	var prv1, prv2 PrivateKey
 	var pub1, pub2 PublicKey
 	for n := 0; n < b.N; n++ {
 		prv1.Generate(rng)
@@ -346,7 +343,6 @@ func BenchmarkDeriveGenerated(b *testing.B) {
 
 func BenchmarkDerive(b *testing.B) {
 	var ss [64]uint8
-	var prv1, prv2 PrivateKey
 	var pub1, pub2 PublicKey
 
 	prv1.Generate(rng)
diff --git a/dh/csidh/curve.go b/dh/csidh/curve.go
index de65607..f93bcf5 100644
--- a/dh/csidh/curve.go
+++ b/dh/csidh/curve.go
@@ -79,6 +79,7 @@ func cswapPoint(P1, P2 *Point, choice uint8) {
 // see this: https://eprint.iacr.org/2017/264.pdf
 func xMul512(kP, P *Point, co *Coeff, k *Fp) {
 	var A24 Coeff
+
 	R := *P
 	// P = P-Q
 	PdQ := *P