diff --git a/lib/BioByteArray.cpp b/lib/BioByteArray.cpp
index 17d8a2b0..849e0923 100644
--- a/lib/BioByteArray.cpp
+++ b/lib/BioByteArray.cpp
@@ -6,8 +6,24 @@
  */
 
 #include "BioByteArray.h"
+#include "func_base.h"
 #include <QDebug>
 
+BioByteArray::BioByteArray(const BIGNUM *bn, int bits)
+{
+	int len = (bits+7) >> 3;
+	qDebug() << bits << len;
+	if (!bn)
+		return;
+	store.resize(BN_num_bytes(bn));
+	BN_bn2bin(bn, (unsigned char *)store.data());
+	openssl_error();
+	if (store.size() > 0 && (char)store[0] < 0)
+		store.prepend('\0');
+	if (len > 0 && store.size() < len)
+		store.prepend(len - store.size(), 0);
+}
+
 void BioByteArray::set(const QByteArray &qba)
 {
 	if (read_write) {
diff --git a/lib/BioByteArray.h b/lib/BioByteArray.h
index 1cddb3bf..759b4593 100644
--- a/lib/BioByteArray.h
+++ b/lib/BioByteArray.h
@@ -11,6 +11,7 @@
 #include <QByteArray>
 #include <QString>
 #include <openssl/bio.h>
+#include <openssl/bn.h>
 
 class BioByteArray
 {
@@ -27,6 +28,7 @@ class BioByteArray
   public:
 	BioByteArray(const QByteArray &qba) : store(qba) { }
 	BioByteArray(const BioByteArray &bba) : store(bba.byteArray()) { }
+	BioByteArray(const BIGNUM *bn, int len = 0);
 	BioByteArray() { }
 	~BioByteArray();
 	int size() const;
diff --git a/lib/CMakeLists.txt b/lib/CMakeLists.txt
index 727c198a..28807140 100644
--- a/lib/CMakeLists.txt
+++ b/lib/CMakeLists.txt
@@ -66,7 +66,8 @@ macro(Test name)
 endmacro()
 
 if(BUILD_TESTING)
-  Test(test_biobytearray BioByteArray.cpp BioByteArray.h)
+  Test(test_biobytearray BioByteArray.cpp BioByteArray.h
+                                    func_base.cpp func_base.h)
   Test(test_asn1int asn1int.cpp asn1int.h func_base.h func_base.cpp)
   Test(test_asn1time asn1time.cpp asn1time.h func_base.h func_base.cpp)
   Test(test_entropy entropy.cpp entropy.h func.h func_base.cpp xfile.h)
diff --git a/lib/pki_key.cpp b/lib/pki_key.cpp
index 787d34fb..aabf42d5 100644
--- a/lib/pki_key.cpp
+++ b/lib/pki_key.cpp
@@ -382,22 +382,10 @@ void pki_key::writePublic(XFile &file, bool pem) const
 
 QString pki_key::BN2QString(const BIGNUM *bn) const
 {
-	if (bn == NULL)
-		return "--";
-	QString x="";
-	char zs[10];
-	int j, size = BN_num_bytes(bn);
-	unsigned char *buf = (unsigned char *)OPENSSL_malloc(size);
-	Q_CHECK_PTR(buf);
-	BN_bn2bin(bn, buf);
-	for (j = 0; j< size; j++) {
-		snprintf(zs, sizeof zs, "%02X%c",buf[j], ((j+1)%16 == 0) ? '\n' :
-				j<size-1 ? ':' : ' ');
-		x += zs;
-	}
-	OPENSSL_free(buf);
-	pki_openssl_error();
-	return x;
+	QByteArray hex, ba = BioByteArray(bn);
+	for(int i = 0; i<ba.size(); i += 16)
+		hex += ba.mid(i, 16).toHex(':') + '\n';
+	return QString::fromLatin1(hex);
 }
 
 QVariant pki_key::column_data(const dbheader *hd) const
@@ -638,13 +626,7 @@ void pki_key::ssh_key_QBA2data(const QByteArray &ba, QByteArray *data) const
 
 void pki_key::ssh_key_bn2data(const BIGNUM *bn, QByteArray *data) const
 {
-	QByteArray big;
-	big.resize(BN_num_bytes(bn));
-	BN_bn2bin(bn, (unsigned char *)big.data());
-	pki_openssl_error();
-	if ((unsigned char)big[0] >= 0x80)
-		big.prepend('\0');
-	ssh_key_QBA2data(big, data);
+	ssh_key_QBA2data(BioByteArray(bn), data);
 }
 
 bool pki_key::SSH2_compatible() const