diff --git a/Makefile b/Makefile
index 039f573..b613ee0 100644
--- a/Makefile
+++ b/Makefile
@@ -5,7 +5,7 @@ EXE_DIR=bin
 SRC_SRC=fp.cpp bn_c256.cpp bn_c384.cpp bn_c512.cpp she_c256.cpp
 TEST_SRC=fp_test.cpp ec_test.cpp fp_util_test.cpp window_method_test.cpp elgamal_test.cpp fp_tower_test.cpp gmp_test.cpp bn_test.cpp bn384_test.cpp glv_test.cpp paillier_test.cpp she_test.cpp vint_test.cpp bn512_test.cpp ecdsa_test.cpp conversion_test.cpp
 TEST_SRC+=bn_c256_test.cpp bn_c384_test.cpp bn_c512_test.cpp she_c256_test.cpp she_c384_test.cpp
-TEST_SRC+=aggregate_sig_test.cpp
+TEST_SRC+=aggregate_sig_test.cpp vector_test.cpp
 TEST_SRC+=bls12_test.cpp
 TEST_SRC+=ecdsa_c_test.cpp
 ifeq ($(CPU),x86-64)
diff --git a/include/mcl/bn.hpp b/include/mcl/bn.hpp
index 04397f6..1070c44 100644
--- a/include/mcl/bn.hpp
+++ b/include/mcl/bn.hpp
@@ -10,6 +10,7 @@
 #include <mcl/ec.hpp>
 #include <mcl/curve_type.h>
 #include <assert.h>
+#include <vector>
 
 /*
 	set bit size of Fp and Fr
@@ -105,7 +106,7 @@ void Frobenius3(G2& D, const G2& S);
 
 namespace local {
 
-typedef std::vector<int8_t> SignVec;
+typedef mcl::Vector<int8_t> SignVec;
 
 inline size_t getPrecomputeQcoeffSize(const SignVec& sv)
 {
@@ -1707,6 +1708,13 @@ inline void precomputeG2(std::vector<Fp6>& Qcoeff, const G2& Q)
 	Qcoeff.resize(BN::param.precomputedQcoeffSize);
 	precomputeG2(Qcoeff.data(), Q);
 }
+inline bool precomputeG2(mcl::Vector<Fp6>& Qcoeff, const G2& Q)
+{
+	bool b = Qcoeff.resize(BN::param.precomputedQcoeffSize);
+	if (!b) return false;
+	precomputeG2(Qcoeff.data(), Q);
+	return true;
+}
 inline void precomputedMillerLoop(Fp12& f, const G1& P_, const Fp6* Qcoeff)
 {
 	G1 P(P_);
@@ -1747,6 +1755,10 @@ inline void precomputedMillerLoop(Fp12& f, const G1& P, const std::vector<Fp6>&
 {
 	precomputedMillerLoop(f, P, Qcoeff.data());
 }
+inline void precomputedMillerLoop(Fp12& f, const G1& P, const mcl::Vector<Fp6>& Qcoeff)
+{
+	precomputedMillerLoop(f, P, Qcoeff.data());
+}
 /*
 	f = MillerLoop(P1, Q1) x MillerLoop(P2, Q2)
 */
@@ -1805,6 +1817,10 @@ inline void precomputedMillerLoop2(Fp12& f, const G1& P1, const std::vector<Fp6>
 {
 	precomputedMillerLoop2(f, P1, Q1coeff.data(), P2, Q2coeff.data());
 }
+inline void precomputedMillerLoop2(Fp12& f, const G1& P1, const mcl::Vector<Fp6>& Q1coeff, const G1& P2, const mcl::Vector<Fp6>& Q2coeff)
+{
+	precomputedMillerLoop2(f, P1, Q1coeff.data(), P2, Q2coeff.data());
+}
 inline void mapToG1(bool *pb, G1& P, const Fp& x) { *pb = BN::param.mapTo.calcG1(P, x); }
 inline void mapToG2(bool *pb, G2& P, const Fp2& x) { *pb = BN::param.mapTo.calcG2(P, x); }
 inline void mapToG1(G1& P, const Fp& x)
diff --git a/include/mcl/fp.hpp b/include/mcl/fp.hpp
index 6c39d1f..4b6d848 100644
--- a/include/mcl/fp.hpp
+++ b/include/mcl/fp.hpp
@@ -6,9 +6,7 @@
 	@license modified new BSD license
 	http://opensource.org/licenses/BSD-3-Clause
 */
-#include <iostream>
-#include <sstream>
-#include <vector>
+#include <iosfwd>
 #ifdef _MSC_VER
 	#pragma warning(push)
 	#pragma warning(disable : 4127)
diff --git a/include/mcl/gmp_util.hpp b/include/mcl/gmp_util.hpp
index 47c1ab8..f27253c 100644
--- a/include/mcl/gmp_util.hpp
+++ b/include/mcl/gmp_util.hpp
@@ -9,7 +9,6 @@
 */
 #include <stdio.h>
 #include <stdlib.h>
-#include <vector>
 #include <assert.h>
 #include <stdint.h>
 #include <cybozu/exception.hpp>
@@ -440,8 +439,13 @@ inline void getRand(mpz_class& z, size_t bitSize, fp::RandGen rg = fp::RandGen()
 	assert(bitSize > 1);
 	const size_t rem = bitSize & 31;
 	const size_t n = (bitSize + 31) / 32;
-	std::vector<uint32_t> buf(n);
-	rg.read(buf.data(), n * sizeof(buf[0]));
+	uint32_t buf[128];
+	assert(n <= CYBOZU_NUM_OF_ARRAY(buf));
+	if (n > CYBOZU_NUM_OF_ARRAY(buf)) {
+		z = 0;
+		return;
+	}
+	rg.read(buf, n * sizeof(buf[0]));
 	uint32_t v = buf[n - 1];
 	if (rem == 0) {
 		v |= 1U << 31;
@@ -450,7 +454,7 @@ inline void getRand(mpz_class& z, size_t bitSize, fp::RandGen rg = fp::RandGen()
 		v |= 1U << (rem - 1);
 	}
 	buf[n - 1] = v;
-	setArray(z, &buf[0], n);
+	setArray(z, buf, n);
 }
 
 inline void getRandPrime(mpz_class& z, size_t bitSize, fp::RandGen rg = fp::RandGen(), bool setSecondBit = false, bool mustBe3mod4 = false)
@@ -482,9 +486,9 @@ template<class Vec>
 void convertToBinary(Vec& v, const mpz_class& x)
 {
 	const size_t len = gmp::getBitSize(x);
-	v.clear();
+	v.resize(len);
 	for (size_t i = 0; i < len; i++) {
-		v.push_back(gmp::testBit(x, len - 1 - i) ? 1 : 0);
+		v[i] = gmp::testBit(x, len - 1 - i) ? 1 : 0;
 	}
 }
 
@@ -501,7 +505,8 @@ size_t getContinuousVal(const Vec& v, size_t pos, int val)
 template<class Vec>
 void convertToNAF(Vec& v, const Vec& in)
 {
-	v = in;
+//	v = in;
+	v.copy(in);
 	size_t pos = v.size() - 1;
 	for (;;) {
 		size_t p = getContinuousVal(v, pos, 0);
diff --git a/include/mcl/op.hpp b/include/mcl/op.hpp
index c0c1098..b947284 100644
--- a/include/mcl/op.hpp
+++ b/include/mcl/op.hpp
@@ -8,6 +8,7 @@
 */
 #include <mcl/gmp_util.hpp>
 #include <memory.h>
+#include <mcl/vector.hpp>
 
 #ifndef MCL_MAX_BIT_SIZE
 	#define MCL_MAX_BIT_SIZE 521
@@ -179,7 +180,7 @@ struct Op {
 	Unit one[maxUnitSize];
 	Unit R2[maxUnitSize];
 	Unit R3[maxUnitSize];
-	std::vector<Unit> invTbl;
+	mcl::Vector<Unit> invTbl;
 	size_t N;
 	size_t bitSize;
 	bool (*fp_isZero)(const Unit*);
diff --git a/include/mcl/vector.hpp b/include/mcl/vector.hpp
new file mode 100644
index 0000000..eb0fb07
--- /dev/null
+++ b/include/mcl/vector.hpp
@@ -0,0 +1,77 @@
+#pragma once
+/**
+	@file
+	@brief tiny vector class
+	@author MITSUNARI Shigeo(@herumi)
+	@license modified new BSD license
+	http://opensource.org/licenses/BSD-3-Clause
+*/
+#include <malloc.h>
+#include <stddef.h>
+#include <algorithm>
+
+namespace mcl {
+template<class T>
+class Vector {
+	T *p_;
+	size_t n_;
+	Vector(const Vector&);
+	void operator=(const Vector&);
+public:
+	Vector() : p_(0), n_(0) {}
+	~Vector()
+	{
+		free(p_);
+	}
+	bool resize(size_t n)
+	{
+		if (n <= n_) {
+			n_ = n;
+			if (n == 0) {
+				free(p_);
+				p_ = 0;
+			}
+			return true;
+		}
+		T *q = (T*)malloc(sizeof(T) * n);
+		if (q == 0) return false;
+		for (size_t i = 0; i < n_; i++) {
+			q[i] = p_[i];
+		}
+		free(p_);
+		p_ = q;
+		n_ = n;
+		return true;
+	}
+	bool copy(const Vector<T>& rhs)
+	{
+		if (this == &rhs) return true;
+		if (n_ < rhs.n_) {
+			clear();
+			if (!resize(rhs.n_)) return false;
+		}
+		for (size_t i = 0; i < rhs.n_; i++) {
+			p_[i] = rhs.p_[i];
+		}
+		n_ = rhs.n_;
+		return true;
+	}
+	void clear()
+	{
+		free(p_);
+		p_ = 0;
+		n_ = 0;
+	}
+	size_t size() const { return n_; }
+	void swap(Vector<T>& rhs)
+	{
+		std::swap(p_, rhs.p_);
+		std::swap(n_, rhs.n_);
+	}
+	T& operator[](size_t n) { return p_[n]; }
+	const T& operator[](size_t n) const { return p_[n]; }
+	T* data() { return p_; }
+	const T* data() const { return p_; }
+};
+} // mcl
+
diff --git a/include/mcl/vint.hpp b/include/mcl/vint.hpp
index 5530b46..1ffeba2 100644
--- a/include/mcl/vint.hpp
+++ b/include/mcl/vint.hpp
@@ -4,11 +4,10 @@
 */
 #include <cybozu/exception.hpp>
 #include <cybozu/bit_operation.hpp>
-#include <vector>
-#include <stdlib.h>
 #include <assert.h>
 #include <cmath>
 #include <iostream>
+#include <mcl/vector.hpp>
 #include <mcl/util.hpp>
 #include <mcl/randgen.hpp>
 #include <mcl/conversion.hpp>
@@ -619,34 +618,6 @@ void divNM(T *q, size_t qn, T *r, const T *x, size_t xn, const T *y, size_t yn)
 	}
 }
 
-template<class T>
-class VariableBuffer {
-	std::vector<T> v_;
-public:
-	typedef T Unit;
-	VariableBuffer()
-	{
-	}
-	void clear() { v_.clear(); }
-
-	/*
-		@note extended buffer may be not cleared
-	*/
-	void alloc(size_t n)
-	{
-		v_.resize(n);
-	}
-	void swap(VariableBuffer& rhs) { v_.swap(rhs.v_); }
-
-	/*
-		*this = rhs
-		rhs may be destroyed
-	*/
-	size_t allocSize() const { return v_.size(); }
-	const T& operator[](size_t n) const { return v_[n]; }
-	T& operator[](size_t n) { return v_[n]; }
-};
-
 template<class T>
 class Buffer {
 	size_t allocSize_;
@@ -680,6 +651,7 @@ public:
 		std::swap(allocSize_, rhs.allocSize_);
 		std::swap(ptr_, rhs.ptr_);
 	}
+#if 0
 #if CYBOZU_CPP_VERSION >= CYBOZU_CPP_VERSION_CPP11
 	Buffer(Buffer&& rhs) noexcept
 		: allocSize_(0)
@@ -692,6 +664,7 @@ public:
 		swap(rhs);
 		return *this;
 	}
+#endif
 #endif
 	void clear()
 	{
@@ -1789,7 +1762,6 @@ public:
 	VintT operator>>(size_t n) const { VintT c = *this; c >>= n; return c; }
 };
 
-//typedef VintT<vint::VariableBuffer<mcl::vint::Unit> > Vint;
 #ifdef MCL_VINT_FIXED_BUFFER
 typedef VintT<vint::FixedBuffer<mcl::vint::Unit, MCL_MAX_BIT_SIZE * 2> > Vint;
 #else
diff --git a/test/fp_util_test.cpp b/test/fp_util_test.cpp
index 3e77b3b..b11311b 100644
--- a/test/fp_util_test.cpp
+++ b/test/fp_util_test.cpp
@@ -3,6 +3,7 @@
 #include <mcl/conversion.hpp>
 #include <mcl/gmp_util.hpp>
 #include <mcl/fp.hpp>
+#include <vector>
 
 CYBOZU_TEST_AUTO(arrayToHex)
 {
diff --git a/test/vector_test.cpp b/test/vector_test.cpp
new file mode 100644
index 0000000..d593e4c
--- /dev/null
+++ b/test/vector_test.cpp
@@ -0,0 +1,32 @@
+#include <mcl/vector.hpp>
+#include <cybozu/test.hpp>
+
+CYBOZU_TEST_AUTO(resize)
+{
+	mcl::Vector<int> a, b;
+	CYBOZU_TEST_EQUAL(a.size(), 0);
+	CYBOZU_TEST_EQUAL(b.size(), 0);
+
+	const size_t n = 3;
+	bool ok = a.resize(n);
+	CYBOZU_TEST_ASSERT(ok);
+	CYBOZU_TEST_EQUAL(n, a.size());
+	for (size_t i = 0; i < n; i++) {
+		a[i] = i;
+	}
+	ok = b.copy(a);
+	CYBOZU_TEST_ASSERT(ok);
+	CYBOZU_TEST_EQUAL(b.size(), n);
+	CYBOZU_TEST_EQUAL_ARRAY(a.data(), b.data(), n);
+
+	const size_t small = n - 1;
+	ok = b.resize(small);
+	CYBOZU_TEST_ASSERT(ok);
+	CYBOZU_TEST_EQUAL(b.size(), small);
+	CYBOZU_TEST_EQUAL_ARRAY(a.data(), b.data(), small);
+	const size_t large = n * 2;
+	ok = b.resize(large);
+	CYBOZU_TEST_ASSERT(ok);
+	CYBOZU_TEST_EQUAL(b.size(), large);
+	CYBOZU_TEST_EQUAL_ARRAY(a.data(), b.data(), small);
+}