diff --git a/lib/mpi/mpicoder.c b/lib/mpi/mpicoder.c
index eead4b3..7ea225b 100644
--- a/lib/mpi/mpicoder.c
+++ b/lib/mpi/mpicoder.c
@@ -25,6 +25,7 @@
 #include <linux/string.h>
 #include "mpi-internal.h"
 
+#define MAX_EXTERN_SCAN_BYTES (16*1024*1024)
 #define MAX_EXTERN_MPI_BITS 16384
 
 /**
@@ -109,6 +110,112 @@
 }
 EXPORT_SYMBOL_GPL(mpi_read_from_buffer);
 
+/****************
+ * Fill the mpi VAL from the hex string in STR.
+ */
+int mpi_fromstr(MPI val, const char *str)
+{
+	int sign = 0;
+	int prepend_zero = 0;
+	int i, j, c, c1, c2;
+	unsigned int nbits, nbytes, nlimbs;
+	mpi_limb_t a;
+
+	if (*str == '-') {
+		sign = 1;
+		str++;
+	}
+
+	/* Skip optional hex prefix.  */
+	if (*str == '0' && str[1] == 'x')
+		str += 2;
+
+	nbits = strlen(str);
+	if (nbits > MAX_EXTERN_SCAN_BYTES) {
+		mpi_clear(val);
+		return -EINVAL;
+	}
+	nbits *= 4;
+	if ((nbits % 8))
+		prepend_zero = 1;
+
+	nbytes = (nbits+7) / 8;
+	nlimbs = (nbytes+BYTES_PER_MPI_LIMB-1) / BYTES_PER_MPI_LIMB;
+
+	if (val->alloced < nlimbs)
+		mpi_resize(val, nlimbs);
+
+	i = BYTES_PER_MPI_LIMB - (nbytes % BYTES_PER_MPI_LIMB);
+	i %= BYTES_PER_MPI_LIMB;
+	j = val->nlimbs = nlimbs;
+	val->sign = sign;
+	for (; j > 0; j--) {
+		a = 0;
+		for (; i < BYTES_PER_MPI_LIMB; i++) {
+			if (prepend_zero) {
+				c1 = '0';
+				prepend_zero = 0;
+			} else
+				c1 = *str++;
+
+			if (!c1) {
+				mpi_clear(val);
+				return -EINVAL;
+			}
+			c2 = *str++;
+			if (!c2) {
+				mpi_clear(val);
+				return -EINVAL;
+			}
+			if (c1 >= '0' && c1 <= '9')
+				c = c1 - '0';
+			else if (c1 >= 'a' && c1 <= 'f')
+				c = c1 - 'a' + 10;
+			else if (c1 >= 'A' && c1 <= 'F')
+				c = c1 - 'A' + 10;
+			else {
+				mpi_clear(val);
+				return -EINVAL;
+			}
+			c <<= 4;
+			if (c2 >= '0' && c2 <= '9')
+				c |= c2 - '0';
+			else if (c2 >= 'a' && c2 <= 'f')
+				c |= c2 - 'a' + 10;
+			else if (c2 >= 'A' && c2 <= 'F')
+				c |= c2 - 'A' + 10;
+			else {
+				mpi_clear(val);
+				return -EINVAL;
+			}
+			a <<= 8;
+			a |= c;
+		}
+		i = 0;
+		val->d[j-1] = a;
+	}
+
+	return 0;
+}
+EXPORT_SYMBOL_GPL(mpi_fromstr);
+
+MPI mpi_scanval(const char *string)
+{
+	MPI a;
+
+	a = mpi_alloc(0);
+	if (!a)
+		return NULL;
+
+	if (mpi_fromstr(a, string)) {
+		mpi_free(a);
+		return NULL;
+	}
+	mpi_normalize(a);
+	return a;
+}
+EXPORT_SYMBOL_GPL(mpi_scanval);
+
 static int count_lzeros(MPI a)
 {
 	mpi_limb_t alimb;
@@ -413,3 +520,232 @@
 	return val;
 }
 EXPORT_SYMBOL_GPL(mpi_read_raw_from_sgl);
+
+/* Perform a two's complement operation on buffer P of size N bytes.  */
+static void twocompl(unsigned char *p, unsigned int n)
+{
+	int i;
+
+	for (i = n-1; i >= 0 && !p[i]; i--)
+		;
+	if (i >= 0) {
+		if ((p[i] & 0x01))
+			p[i] = (((p[i] ^ 0xfe) | 0x01) & 0xff);
+		else if ((p[i] & 0x02))
+			p[i] = (((p[i] ^ 0xfc) | 0x02) & 0xfe);
+		else if ((p[i] & 0x04))
+			p[i] = (((p[i] ^ 0xf8) | 0x04) & 0xfc);
+		else if ((p[i] & 0x08))
+			p[i] = (((p[i] ^ 0xf0) | 0x08) & 0xf8);
+		else if ((p[i] & 0x10))
+			p[i] = (((p[i] ^ 0xe0) | 0x10) & 0xf0);
+		else if ((p[i] & 0x20))
+			p[i] = (((p[i] ^ 0xc0) | 0x20) & 0xe0);
+		else if ((p[i] & 0x40))
+			p[i] = (((p[i] ^ 0x80) | 0x40) & 0xc0);
+		else
+			p[i] = 0x80;
+
+		for (i--; i >= 0; i--)
+			p[i] ^= 0xff;
+	}
+}
+
+int mpi_print(enum gcry_mpi_format format, unsigned char *buffer,
+			size_t buflen, size_t *nwritten, MPI a)
+{
+	unsigned int nbits = mpi_get_nbits(a);
+	size_t len;
+	size_t dummy_nwritten;
+	int negative;
+
+	if (!nwritten)
+		nwritten = &dummy_nwritten;
+
+	/* Libgcrypt does no always care to set clear the sign if the value
+	 * is 0.  For printing this is a bit of a surprise, in particular
+	 * because if some of the formats don't support negative numbers but
+	 * should be able to print a zero.  Thus we need this extra test
+	 * for a negative number.
+	 */
+	if (a->sign && mpi_cmp_ui(a, 0))
+		negative = 1;
+	else
+		negative = 0;
+
+	len = buflen;
+	*nwritten = 0;
+	if (format == GCRYMPI_FMT_STD) {
+		unsigned char *tmp;
+		int extra = 0;
+		unsigned int n;
+
+		tmp = mpi_get_buffer(a, &n, NULL);
+		if (!tmp)
+			return -EINVAL;
+
+		if (negative) {
+			twocompl(tmp, n);
+			if (!(*tmp & 0x80)) {
+				/* Need to extend the sign.  */
+				n++;
+				extra = 2;
+			}
+		} else if (n && (*tmp & 0x80)) {
+			/* Positive but the high bit of the returned buffer is set.
+			 * Thus we need to print an extra leading 0x00 so that the
+			 * output is interpreted as a positive number.
+			 */
+			n++;
+			extra = 1;
+		}
+
+		if (buffer && n > len) {
+			/* The provided buffer is too short. */
+			kfree(tmp);
+			return -E2BIG;
+		}
+		if (buffer) {
+			unsigned char *s = buffer;
+
+			if (extra == 1)
+				*s++ = 0;
+			else if (extra)
+				*s++ = 0xff;
+			memcpy(s, tmp, n-!!extra);
+		}
+		kfree(tmp);
+		*nwritten = n;
+		return 0;
+	} else if (format == GCRYMPI_FMT_USG) {
+		unsigned int n = (nbits + 7)/8;
+
+		/* Note:  We ignore the sign for this format.  */
+		/* FIXME: for performance reasons we should put this into
+		 * mpi_aprint because we can then use the buffer directly.
+		 */
+
+		if (buffer && n > len)
+			return -E2BIG;
+		if (buffer) {
+			unsigned char *tmp;
+
+			tmp = mpi_get_buffer(a, &n, NULL);
+			if (!tmp)
+				return -EINVAL;
+			memcpy(buffer, tmp, n);
+			kfree(tmp);
+		}
+		*nwritten = n;
+		return 0;
+	} else if (format == GCRYMPI_FMT_PGP) {
+		unsigned int n = (nbits + 7)/8;
+
+		/* The PGP format can only handle unsigned integers.  */
+		if (negative)
+			return -EINVAL;
+
+		if (buffer && n+2 > len)
+			return -E2BIG;
+
+		if (buffer) {
+			unsigned char *tmp;
+			unsigned char *s = buffer;
+
+			s[0] = nbits >> 8;
+			s[1] = nbits;
+
+			tmp = mpi_get_buffer(a, &n, NULL);
+			if (!tmp)
+				return -EINVAL;
+			memcpy(s+2, tmp, n);
+			kfree(tmp);
+		}
+		*nwritten = n+2;
+		return 0;
+	} else if (format == GCRYMPI_FMT_SSH) {
+		unsigned char *tmp;
+		int extra = 0;
+		unsigned int n;
+
+		tmp = mpi_get_buffer(a, &n, NULL);
+		if (!tmp)
+			return -EINVAL;
+
+		if (negative) {
+			twocompl(tmp, n);
+			if (!(*tmp & 0x80)) {
+				/* Need to extend the sign.  */
+				n++;
+				extra = 2;
+			}
+		} else if (n && (*tmp & 0x80)) {
+			n++;
+			extra = 1;
+		}
+
+		if (buffer && n+4 > len) {
+			kfree(tmp);
+			return -E2BIG;
+		}
+
+		if (buffer) {
+			unsigned char *s = buffer;
+
+			*s++ = n >> 24;
+			*s++ = n >> 16;
+			*s++ = n >> 8;
+			*s++ = n;
+			if (extra == 1)
+				*s++ = 0;
+			else if (extra)
+				*s++ = 0xff;
+			memcpy(s, tmp, n-!!extra);
+		}
+		kfree(tmp);
+		*nwritten = 4+n;
+		return 0;
+	} else if (format == GCRYMPI_FMT_HEX) {
+		unsigned char *tmp;
+		int i;
+		int extra = 0;
+		unsigned int n = 0;
+
+		tmp = mpi_get_buffer(a, &n, NULL);
+		if (!tmp)
+			return -EINVAL;
+		if (!n || (*tmp & 0x80))
+			extra = 2;
+
+		if (buffer && 2*n + extra + negative + 1 > len) {
+			kfree(tmp);
+			return -E2BIG;
+		}
+		if (buffer) {
+			unsigned char *s = buffer;
+
+			if (negative)
+				*s++ = '-';
+			if (extra) {
+				*s++ = '0';
+				*s++ = '0';
+			}
+
+			for (i = 0; i < n; i++) {
+				unsigned int c = tmp[i];
+
+				*s++ = (c >> 4) < 10 ? '0'+(c>>4) : 'A'+(c>>4)-10;
+				c &= 15;
+				*s++ = c < 10 ? '0'+c : 'A'+c-10;
+			}
+			*s++ = 0;
+			*nwritten = s - buffer;
+		} else {
+			*nwritten = 2*n + extra + negative + 1;
+		}
+		kfree(tmp);
+		return 0;
+	} else
+		return -EINVAL;
+}
+EXPORT_SYMBOL_GPL(mpi_print);