diff --git a/lib/mpi/mpiutil.c b/lib/mpi/mpiutil.c
index 0082502..e6c4b31 100644
--- a/lib/mpi/mpiutil.c
+++ b/lib/mpi/mpiutil.c
@@ -20,6 +20,63 @@
 
 #include "mpi-internal.h"
 
+/* Constants allocated right away at startup.  */
+static MPI constants[MPI_NUMBER_OF_CONSTANTS];
+
+/* Initialize the MPI subsystem.  This is called early and allows to
+ * do some initialization without taking care of threading issues.
+ */
+static int __init mpi_init(void)
+{
+	int idx;
+	unsigned long value;
+
+	for (idx = 0; idx < MPI_NUMBER_OF_CONSTANTS; idx++) {
+		switch (idx) {
+		case MPI_C_ZERO:
+			value = 0;
+			break;
+		case MPI_C_ONE:
+			value = 1;
+			break;
+		case MPI_C_TWO:
+			value = 2;
+			break;
+		case MPI_C_THREE:
+			value = 3;
+			break;
+		case MPI_C_FOUR:
+			value = 4;
+			break;
+		case MPI_C_EIGHT:
+			value = 8;
+			break;
+		default:
+			pr_err("MPI: invalid mpi_const selector %d\n", idx);
+			return -EFAULT;
+		}
+		constants[idx] = mpi_alloc_set_ui(value);
+		constants[idx]->flags = (16|32);
+	}
+
+	return 0;
+}
+postcore_initcall(mpi_init);
+
+/* Return a constant MPI descripbed by NO which is one of the
+ * MPI_C_xxx macros.  There is no need to copy this returned value; it
+ * may be used directly.
+ */
+MPI mpi_const(enum gcry_mpi_constants no)
+{
+	if ((int)no < 0 || no > MPI_NUMBER_OF_CONSTANTS)
+		pr_err("MPI: invalid mpi_const selector %d\n", no);
+	if (!constants[no])
+		pr_err("MPI: MPI subsystem not initialized\n");
+	return constants[no];
+}
+EXPORT_SYMBOL_GPL(mpi_const);
+
 /****************
  * Note:  It was a bad idea to use the number of limbs to allocate
  *	  because on a alpha the limbs are large but we normally need
@@ -69,7 +126,7 @@
 	if (!a)
 		return;
 
-	kzfree(a);
+	kfree_sensitive(a);
 }
 
 void mpi_assign_limb_space(MPI a, mpi_ptr_t ap, unsigned nlimbs)
@@ -95,7 +152,7 @@
 		if (!p)
 			return -ENOMEM;
 		memcpy(p, a->d, a->alloced * sizeof(mpi_limb_t));
-		kzfree(a->d);
+		kfree_sensitive(a->d);
 		a->d = p;
 	} else {
 		a->d = kcalloc(nlimbs, sizeof(mpi_limb_t), GFP_KERNEL);
@@ -106,13 +163,22 @@
 	return 0;
 }
 
+void mpi_clear(MPI a)
+{
+	if (!a)
+		return;
+	a->nlimbs = 0;
+	a->flags = 0;
+}
+EXPORT_SYMBOL_GPL(mpi_clear);
+
 void mpi_free(MPI a)
 {
 	if (!a)
 		return;
 
 	if (a->flags & 4)
-		kzfree(a->d);
+		kfree_sensitive(a->d);
 	else
 		mpi_free_limb_space(a->d);
 
@@ -122,5 +188,143 @@
 }
 EXPORT_SYMBOL_GPL(mpi_free);
 
+/****************
+ * Note: This copy function should not interpret the MPI
+ *	 but copy it transparently.
+ */
+MPI mpi_copy(MPI a)
+{
+	int i;
+	MPI b;
+
+	if (a) {
+		b = mpi_alloc(a->nlimbs);
+		b->nlimbs = a->nlimbs;
+		b->sign = a->sign;
+		b->flags = a->flags;
+		b->flags &= ~(16|32); /* Reset the immutable and constant flags. */
+		for (i = 0; i < b->nlimbs; i++)
+			b->d[i] = a->d[i];
+	} else
+		b = NULL;
+	return b;
+}
+
+/****************
+ * This function allocates an MPI which is optimized to hold
+ * a value as large as the one given in the argument and allocates it
+ * with the same flags as A.
+ */
+MPI mpi_alloc_like(MPI a)
+{
+	MPI b;
+
+	if (a) {
+		b = mpi_alloc(a->nlimbs);
+		b->nlimbs = 0;
+		b->sign = 0;
+		b->flags = a->flags;
+	} else
+		b = NULL;
+
+	return b;
+}
+
+
+/* Set U into W and release U.  If W is NULL only U will be released. */
+void mpi_snatch(MPI w, MPI u)
+{
+	if (w) {
+		mpi_assign_limb_space(w, u->d, u->alloced);
+		w->nlimbs = u->nlimbs;
+		w->sign   = u->sign;
+		w->flags  = u->flags;
+		u->alloced = 0;
+		u->nlimbs = 0;
+		u->d = NULL;
+	}
+	mpi_free(u);
+}
+
+
+MPI mpi_set(MPI w, MPI u)
+{
+	mpi_ptr_t wp, up;
+	mpi_size_t usize = u->nlimbs;
+	int usign = u->sign;
+
+	if (!w)
+		w = mpi_alloc(mpi_get_nlimbs(u));
+	RESIZE_IF_NEEDED(w, usize);
+	wp = w->d;
+	up = u->d;
+	MPN_COPY(wp, up, usize);
+	w->nlimbs = usize;
+	w->flags = u->flags;
+	w->flags &= ~(16|32); /* Reset the immutable and constant flags.  */
+	w->sign = usign;
+	return w;
+}
+EXPORT_SYMBOL_GPL(mpi_set);
+
+MPI mpi_set_ui(MPI w, unsigned long u)
+{
+	if (!w)
+		w = mpi_alloc(1);
+	/* FIXME: If U is 0 we have no need to resize and thus possible
+	 * allocating the the limbs.
+	 */
+	RESIZE_IF_NEEDED(w, 1);
+	w->d[0] = u;
+	w->nlimbs = u ? 1 : 0;
+	w->sign = 0;
+	w->flags = 0;
+	return w;
+}
+EXPORT_SYMBOL_GPL(mpi_set_ui);
+
+MPI mpi_alloc_set_ui(unsigned long u)
+{
+	MPI w = mpi_alloc(1);
+	w->d[0] = u;
+	w->nlimbs = u ? 1 : 0;
+	w->sign = 0;
+	return w;
+}
+
+/****************
+ * Swap the value of A and B, when SWAP is 1.
+ * Leave the value when SWAP is 0.
+ * This implementation should be constant-time regardless of SWAP.
+ */
+void mpi_swap_cond(MPI a, MPI b, unsigned long swap)
+{
+	mpi_size_t i;
+	mpi_size_t nlimbs;
+	mpi_limb_t mask = ((mpi_limb_t)0) - swap;
+	mpi_limb_t x;
+
+	if (a->alloced > b->alloced)
+		nlimbs = b->alloced;
+	else
+		nlimbs = a->alloced;
+	if (a->nlimbs > nlimbs || b->nlimbs > nlimbs)
+		return;
+
+	for (i = 0; i < nlimbs; i++) {
+		x = mask & (a->d[i] ^ b->d[i]);
+		a->d[i] = a->d[i] ^ x;
+		b->d[i] = b->d[i] ^ x;
+	}
+
+	x = mask & (a->nlimbs ^ b->nlimbs);
+	a->nlimbs = a->nlimbs ^ x;
+	b->nlimbs = b->nlimbs ^ x;
+
+	x = mask & (a->sign ^ b->sign);
+	a->sign = a->sign ^ x;
+	b->sign = b->sign ^ x;
+}
+
 MODULE_DESCRIPTION("Multiprecision maths library");
 MODULE_LICENSE("GPL");