diff --git a/ChangeLog b/ChangeLog
index 69c78d4..bd16ada 100644
--- a/ChangeLog
+++ b/ChangeLog
@@ -1,5 +1,10 @@
 2012-06-14  Niibe Yutaka  <gniibe@fsij.org>
 
+	* src/call-rsa.c (rsa_sign, rsa_decrypt, rsa_verify): Use
+	mpi_lset (was: mpi_read_string).
+	* polarssl-0.14.0/library/bignum.c (mpi_get_digit)
+	(mpi_read_string): ifdef-out.
+
 	KDF is now SHA-256 (was: SHA1).
 	* src/sha256.c: New file.  Based on the implementation by Dr Brian
 	Gladman.
diff --git a/polarssl-0.14.0/library/bignum.c b/polarssl-0.14.0/library/bignum.c
index cf39845..dbe85d8 100644
--- a/polarssl-0.14.0/library/bignum.c
+++ b/polarssl-0.14.0/library/bignum.c
@@ -225,6 +225,7 @@ int mpi_size( const mpi *X )
     return( ( mpi_msb( X ) + 7 ) >> 3 );
 }
 
+#if 0
 /*
  * Convert an ASCII character to digit value
  */
@@ -310,7 +311,6 @@ cleanup:
     return( ret );
 }
 
-#if 0
 /*
  * Helper to write the digits high-order first
  */
diff --git a/src/call-rsa.c b/src/call-rsa.c
index e64f356..13fa819 100644
--- a/src/call-rsa.c
+++ b/src/call-rsa.c
@@ -47,7 +47,7 @@ rsa_sign (const uint8_t *raw_message, uint8_t *output, int msg_len,
   rsa_init (&rsa_ctx, RSA_PKCS_V15, 0);
 
   rsa_ctx.len = KEY_CONTENT_LEN;
-  mpi_read_string (&rsa_ctx.E, 16, "10001");
+  mpi_lset (&rsa_ctx.E, 0x10001);
   mpi_read_binary (&rsa_ctx.P, &kd->data[0], rsa_ctx.len / 2);
   mpi_read_binary (&rsa_ctx.Q, &kd->data[KEY_CONTENT_LEN/2], rsa_ctx.len / 2);
   mpi_mul_mpi (&rsa_ctx.N, &rsa_ctx.P, &rsa_ctx.Q);
@@ -138,7 +138,7 @@ rsa_decrypt (const uint8_t *input, uint8_t *output, int msg_len,
   rsa_ctx.len = msg_len;
   DEBUG_WORD (msg_len);
 
-  mpi_read_string (&rsa_ctx.E, 16, "10001");
+  mpi_lset (&rsa_ctx.E, 0x10001);
   mpi_read_binary (&rsa_ctx.P, &kd->data[0], KEY_CONTENT_LEN / 2);
   mpi_read_binary (&rsa_ctx.Q, &kd->data[KEY_CONTENT_LEN/2],
 		   KEY_CONTENT_LEN / 2);
@@ -191,7 +191,7 @@ rsa_verify (const uint8_t *pubkey, const uint8_t *hash, const uint8_t *sig)
 
   rsa_init (&rsa_ctx, RSA_PKCS_V15, 0);
   rsa_ctx.len = KEY_CONTENT_LEN;
-  mpi_read_string (&rsa_ctx.E, 16, "10001");
+  mpi_lset (&rsa_ctx.E, 0x10001);
   mpi_read_binary (&rsa_ctx.N, pubkey, KEY_CONTENT_LEN);
 
   DEBUG_INFO ("RSA verify...");