diff --git a/library/bignum.c b/library/bignum.c
index e9d090463..a15c6f11b 100644
--- a/library/bignum.c
+++ b/library/bignum.c
@@ -1091,72 +1091,6 @@ int mbedtls_mpi_cmp_mpi( const mbedtls_mpi *X, const mbedtls_mpi *Y )
     return( 0 );
 }
 
-/*
- * Compare signed values in constant time
- */
-int mbedtls_mpi_lt_mpi_ct( const mbedtls_mpi *X, const mbedtls_mpi *Y,
-        unsigned *ret )
-{
-    size_t i;
-    /* The value of any of these variables is either 0 or 1 at all times. */
-    unsigned cond, done, X_is_negative, Y_is_negative;
-
-    MPI_VALIDATE_RET( X != NULL );
-    MPI_VALIDATE_RET( Y != NULL );
-    MPI_VALIDATE_RET( ret != NULL );
-
-    if( X->n != Y->n )
-        return MBEDTLS_ERR_MPI_BAD_INPUT_DATA;
-
-    /*
-     * Set sign_N to 1 if N >= 0, 0 if N < 0.
-     * We know that N->s == 1 if N >= 0 and N->s == -1 if N < 0.
-     */
-    X_is_negative = ( X->s & 2 ) >> 1;
-    Y_is_negative = ( Y->s & 2 ) >> 1;
-
-    /*
-     * If the signs are different, then the positive operand is the bigger.
-     * That is if X is negative (X_is_negative == 1), then X < Y is true and it
-     * is false if X is positive (X_is_negative == 0).
-     */
-    cond = ( X_is_negative ^ Y_is_negative );
-    *ret = cond & X_is_negative;
-
-    /*
-     * This is a constant-time function. We might have the result, but we still
-     * need to go through the loop. Record if we have the result already.
-     */
-    done = cond;
-
-    for( i = X->n; i > 0; i-- )
-    {
-        /*
-         * If Y->p[i - 1] < X->p[i - 1] then X < Y is true if and only if both
-         * X and Y are negative.
-         *
-         * Again even if we can make a decision, we just mark the result and
-         * the fact that we are done and continue looping.
-         */
-        cond = mbedtls_cf_mpi_uint_lt( Y->p[i - 1], X->p[i - 1] );
-        *ret |= cond & ( 1 - done ) & X_is_negative;
-        done |= cond;
-
-        /*
-         * If X->p[i - 1] < Y->p[i - 1] then X < Y is true if and only if both
-         * X and Y are positive.
-         *
-         * Again even if we can make a decision, we just mark the result and
-         * the fact that we are done and continue looping.
-         */
-        cond = mbedtls_cf_mpi_uint_lt( X->p[i - 1], Y->p[i - 1] );
-        *ret |= cond & ( 1 - done ) & ( 1 - X_is_negative );
-        done |= cond;
-    }
-
-    return( 0 );
-}
-
 /*
  * Compare signed values
  */
diff --git a/library/constant_time.c b/library/constant_time.c
index 65547a9a0..9ddd21d19 100644
--- a/library/constant_time.c
+++ b/library/constant_time.c
@@ -637,4 +637,70 @@ cleanup:
     return( ret );
 }
 
+/*
+ * Compare signed values in constant time
+ */
+int mbedtls_mpi_lt_mpi_ct( const mbedtls_mpi *X, const mbedtls_mpi *Y,
+        unsigned *ret )
+{
+    size_t i;
+    /* The value of any of these variables is either 0 or 1 at all times. */
+    unsigned cond, done, X_is_negative, Y_is_negative;
+
+    MPI_VALIDATE_RET( X != NULL );
+    MPI_VALIDATE_RET( Y != NULL );
+    MPI_VALIDATE_RET( ret != NULL );
+
+    if( X->n != Y->n )
+        return MBEDTLS_ERR_MPI_BAD_INPUT_DATA;
+
+    /*
+     * Set sign_N to 1 if N >= 0, 0 if N < 0.
+     * We know that N->s == 1 if N >= 0 and N->s == -1 if N < 0.
+     */
+    X_is_negative = ( X->s & 2 ) >> 1;
+    Y_is_negative = ( Y->s & 2 ) >> 1;
+
+    /*
+     * If the signs are different, then the positive operand is the bigger.
+     * That is if X is negative (X_is_negative == 1), then X < Y is true and it
+     * is false if X is positive (X_is_negative == 0).
+     */
+    cond = ( X_is_negative ^ Y_is_negative );
+    *ret = cond & X_is_negative;
+
+    /*
+     * This is a constant-time function. We might have the result, but we still
+     * need to go through the loop. Record if we have the result already.
+     */
+    done = cond;
+
+    for( i = X->n; i > 0; i-- )
+    {
+        /*
+         * If Y->p[i - 1] < X->p[i - 1] then X < Y is true if and only if both
+         * X and Y are negative.
+         *
+         * Again even if we can make a decision, we just mark the result and
+         * the fact that we are done and continue looping.
+         */
+        cond = mbedtls_cf_mpi_uint_lt( Y->p[i - 1], X->p[i - 1] );
+        *ret |= cond & ( 1 - done ) & X_is_negative;
+        done |= cond;
+
+        /*
+         * If X->p[i - 1] < Y->p[i - 1] then X < Y is true if and only if both
+         * X and Y are positive.
+         *
+         * Again even if we can make a decision, we just mark the result and
+         * the fact that we are done and continue looping.
+         */
+        cond = mbedtls_cf_mpi_uint_lt( X->p[i - 1], Y->p[i - 1] );
+        *ret |= cond & ( 1 - done ) & ( 1 - X_is_negative );
+        done |= cond;
+    }
+
+    return( 0 );
+}
+
 #endif /* MBEDTLS_BIGNUM_C */