diff --git a/library/bignum.c b/library/bignum.c
index a2f2a9f..1d258db 100644
--- a/library/bignum.c
+++ b/library/bignum.c
@@ -46,6 +46,7 @@
 #include "mbedtls/bignum.h"
 #include "mbedtls/bn_mul.h"
 #include "mbedtls/platform_util.h"
+#include "mbedtls/error.h"
 
 #include <string.h>
 
@@ -314,7 +315,7 @@
  */
 int mbedtls_mpi_lset( mbedtls_mpi *X, mbedtls_mpi_sint z )
 {
-    int ret;
+    int ret = MBEDTLS_ERR_ERROR_CORRUPTION_DETECTED;
     MPI_VALIDATE_RET( X != NULL );
 
     MBEDTLS_MPI_CHK( mbedtls_mpi_grow( X, 1 ) );
@@ -457,7 +458,7 @@
  */
 int mbedtls_mpi_read_string( mbedtls_mpi *X, int radix, const char *s )
 {
-    int ret;
+    int ret = MBEDTLS_ERR_ERROR_CORRUPTION_DETECTED;
     size_t i, j, slen, n;
     mbedtls_mpi_uint d;
     mbedtls_mpi T;
@@ -532,7 +533,7 @@
 static int mpi_write_hlp( mbedtls_mpi *X, int radix,
                           char **p, const size_t buflen )
 {
-    int ret;
+    int ret = MBEDTLS_ERR_ERROR_CORRUPTION_DETECTED;
     mbedtls_mpi_uint r;
     size_t length = 0;
     char *p_end = *p + buflen;
@@ -697,7 +698,7 @@
  */
 int mbedtls_mpi_write_file( const char *p, const mbedtls_mpi *X, int radix, FILE *fout )
 {
-    int ret;
+    int ret = MBEDTLS_ERR_ERROR_CORRUPTION_DETECTED;
     size_t n, slen, plen;
     /*
      * Buffer should have space for (short) label and decimal formatted MPI,
@@ -832,7 +833,7 @@
 int mbedtls_mpi_read_binary_le( mbedtls_mpi *X,
                                 const unsigned char *buf, size_t buflen )
 {
-    int ret;
+    int ret = MBEDTLS_ERR_ERROR_CORRUPTION_DETECTED;
     size_t i;
     size_t const limbs = CHARS_TO_LIMBS( buflen );
 
@@ -864,7 +865,7 @@
  */
 int mbedtls_mpi_read_binary( mbedtls_mpi *X, const unsigned char *buf, size_t buflen )
 {
-    int ret;
+    int ret = MBEDTLS_ERR_ERROR_CORRUPTION_DETECTED;
     size_t const limbs    = CHARS_TO_LIMBS( buflen );
     size_t const overhead = ( limbs * ciL ) - buflen;
     unsigned char *Xp;
@@ -991,7 +992,7 @@
  */
 int mbedtls_mpi_shift_l( mbedtls_mpi *X, size_t count )
 {
-    int ret;
+    int ret = MBEDTLS_ERR_ERROR_CORRUPTION_DETECTED;
     size_t i, v0, t1;
     mbedtls_mpi_uint r0 = 0, r1;
     MPI_VALIDATE_RET( X != NULL );
@@ -1170,7 +1171,7 @@
  */
 int mbedtls_mpi_add_abs( mbedtls_mpi *X, const mbedtls_mpi *A, const mbedtls_mpi *B )
 {
-    int ret;
+    int ret = MBEDTLS_ERR_ERROR_CORRUPTION_DETECTED;
     size_t i, j;
     mbedtls_mpi_uint *o, *p, c, tmp;
     MPI_VALIDATE_RET( X != NULL );
@@ -1251,7 +1252,7 @@
 int mbedtls_mpi_sub_abs( mbedtls_mpi *X, const mbedtls_mpi *A, const mbedtls_mpi *B )
 {
     mbedtls_mpi TB;
-    int ret;
+    int ret = MBEDTLS_ERR_ERROR_CORRUPTION_DETECTED;
     size_t n;
     MPI_VALIDATE_RET( X != NULL );
     MPI_VALIDATE_RET( A != NULL );
@@ -1474,7 +1475,7 @@
  */
 int mbedtls_mpi_mul_mpi( mbedtls_mpi *X, const mbedtls_mpi *A, const mbedtls_mpi *B )
 {
-    int ret;
+    int ret = MBEDTLS_ERR_ERROR_CORRUPTION_DETECTED;
     size_t i, j;
     mbedtls_mpi TA, TB;
     MPI_VALIDATE_RET( X != NULL );
@@ -1629,7 +1630,7 @@
 int mbedtls_mpi_div_mpi( mbedtls_mpi *Q, mbedtls_mpi *R, const mbedtls_mpi *A,
                          const mbedtls_mpi *B )
 {
-    int ret;
+    int ret = MBEDTLS_ERR_ERROR_CORRUPTION_DETECTED;
     size_t i, n, t, k;
     mbedtls_mpi X, Y, Z, T1, T2;
     mbedtls_mpi_uint TP2[3];
@@ -1775,7 +1776,7 @@
  */
 int mbedtls_mpi_mod_mpi( mbedtls_mpi *R, const mbedtls_mpi *A, const mbedtls_mpi *B )
 {
-    int ret;
+    int ret = MBEDTLS_ERR_ERROR_CORRUPTION_DETECTED;
     MPI_VALIDATE_RET( R != NULL );
     MPI_VALIDATE_RET( A != NULL );
     MPI_VALIDATE_RET( B != NULL );
@@ -1937,7 +1938,7 @@
                          const mbedtls_mpi *E, const mbedtls_mpi *N,
                          mbedtls_mpi *_RR )
 {
-    int ret;
+    int ret = MBEDTLS_ERR_ERROR_CORRUPTION_DETECTED;
     size_t wbits, wsize, one = 1;
     size_t i, j, nblimbs;
     size_t bufsize, nbits;
@@ -2152,7 +2153,7 @@
  */
 int mbedtls_mpi_gcd( mbedtls_mpi *G, const mbedtls_mpi *A, const mbedtls_mpi *B )
 {
-    int ret;
+    int ret = MBEDTLS_ERR_ERROR_CORRUPTION_DETECTED;
     size_t lz, lzt;
     mbedtls_mpi TA, TB;
 
@@ -2214,7 +2215,7 @@
                      int (*f_rng)(void *, unsigned char *, size_t),
                      void *p_rng )
 {
-    int ret;
+    int ret = MBEDTLS_ERR_ERROR_CORRUPTION_DETECTED;
     size_t const limbs = CHARS_TO_LIMBS( size );
     size_t const overhead = ( limbs * ciL ) - size;
     unsigned char *Xp;
@@ -2245,7 +2246,7 @@
  */
 int mbedtls_mpi_inv_mod( mbedtls_mpi *X, const mbedtls_mpi *A, const mbedtls_mpi *N )
 {
-    int ret;
+    int ret = MBEDTLS_ERR_ERROR_CORRUPTION_DETECTED;
     mbedtls_mpi G, TA, TU, U1, U2, TB, TV, V1, V2;
     MPI_VALIDATE_RET( X != NULL );
     MPI_VALIDATE_RET( A != NULL );
@@ -2498,7 +2499,7 @@
                               int (*f_rng)(void *, unsigned char *, size_t),
                               void *p_rng )
 {
-    int ret;
+    int ret = MBEDTLS_ERR_ERROR_CORRUPTION_DETECTED;
     mbedtls_mpi XX;
     MPI_VALIDATE_RET( X     != NULL );
     MPI_VALIDATE_RET( f_rng != NULL );