diff --git a/ChangeLog b/ChangeLog
index 9794375..9649780 100644
--- a/ChangeLog
+++ b/ChangeLog
@@ -8,6 +8,10 @@
    * Added support for wildcard certificates
    * Added support for multi-domain certificates through the X509 Subject
      Alternative Name extension
+   * Added preliminary ASN.1 buffer writing support
+   * Added preliminary X509 Certificate Request writing support
+   * Added key_app_writer example application
+   * Added cert_req example application
 
 Changes
    * Removed redundant POLARSSL_DEBUG_MSG define
diff --git a/include/polarssl/asn1.h b/include/polarssl/asn1.h
index bc7b6bb..dc3f2fe 100644
--- a/include/polarssl/asn1.h
+++ b/include/polarssl/asn1.h
@@ -47,12 +47,12 @@
  * ASN1 is a standard to specify data structures.
  * \{
  */
-#define POLARSSL_ERR_ASN1_OUT_OF_DATA                      -0x0014  /**< Out of data when parsing an ASN1 data structure. */
-#define POLARSSL_ERR_ASN1_UNEXPECTED_TAG                   -0x0016  /**< ASN1 tag was of an unexpected value. */
-#define POLARSSL_ERR_ASN1_INVALID_LENGTH                   -0x0018  /**< Error when trying to determine the length or invalid length. */
-#define POLARSSL_ERR_ASN1_LENGTH_MISMATCH                  -0x001A  /**< Actual length differs from expected length. */
-#define POLARSSL_ERR_ASN1_INVALID_DATA                     -0x001C  /**< Data is invalid. (not used) */
-#define POLARSSL_ERR_ASN1_MALLOC_FAILED                    -0x001E  /**< Memory allocation failed */
+#define POLARSSL_ERR_ASN1_OUT_OF_DATA                      -0x0060  /**< Out of data when parsing an ASN1 data structure. */
+#define POLARSSL_ERR_ASN1_UNEXPECTED_TAG                   -0x0062  /**< ASN1 tag was of an unexpected value. */
+#define POLARSSL_ERR_ASN1_INVALID_LENGTH                   -0x0064  /**< Error when trying to determine the length or invalid length. */
+#define POLARSSL_ERR_ASN1_LENGTH_MISMATCH                  -0x0066  /**< Actual length differs from expected length. */
+#define POLARSSL_ERR_ASN1_INVALID_DATA                     -0x0068  /**< Data is invalid. (not used) */
+#define POLARSSL_ERR_ASN1_MALLOC_FAILED                    -0x006A  /**< Memory allocation failed */
 /* \} name */
 
 /**
diff --git a/include/polarssl/asn1write.h b/include/polarssl/asn1write.h
new file mode 100644
index 0000000..38f6eea
--- /dev/null
+++ b/include/polarssl/asn1write.h
@@ -0,0 +1,46 @@
+/**
+ * \file asn1write.h
+ *
+ * \brief ASN.1 buffer writing functionality
+ *
+ *  Copyright (C) 2006-2012, Brainspark B.V.
+ *
+ *  This file is part of PolarSSL (http://www.polarssl.org)
+ *  Lead Maintainer: Paul Bakker <polarssl_maintainer at polarssl.org>
+ *
+ *  All rights reserved.
+ *
+ *  This program is free software; you can redistribute it and/or modify
+ *  it under the terms of the GNU General Public License as published by
+ *  the Free Software Foundation; either version 2 of the License, or
+ *  (at your option) any later version.
+ *
+ *  This program is distributed in the hope that it will be useful,
+ *  but WITHOUT ANY WARRANTY; without even the implied warranty of
+ *  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ *  GNU General Public License for more details.
+ *
+ *  You should have received a copy of the GNU General Public License along
+ *  with this program; if not, write to the Free Software Foundation, Inc.,
+ *  51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA.
+ */
+#ifndef POLARSSL_ASN1_WRITE_H
+#define POLARSSL_ASN1_WRITE_H
+
+#include "asn1.h"
+
+#define POLARSSL_ERR_ASN1_BUF_TOO_SMALL                    -0x006C  /**< Buffer too small when writing ASN.1 data structure. */
+
+#define ASN1_CHK_ADD(g, f) if( ( ret = f ) < 0 ) return( ret ); else g += ret
+
+int asn1_write_len( unsigned char **p, unsigned char *start, size_t len );
+int asn1_write_tag( unsigned char **p, unsigned char *start, unsigned char tag );
+int asn1_write_mpi( unsigned char **p, unsigned char *start, mpi *X );
+int asn1_write_null( unsigned char **p, unsigned char *start );
+int asn1_write_oid( unsigned char **p, unsigned char *start, char *oid );
+int asn1_write_algorithm_identifier( unsigned char **p, unsigned char *start, char *algorithm_oid );
+int asn1_write_int( unsigned char **p, unsigned char *start, int val );
+int asn1_write_printable_string( unsigned char **p, unsigned char *start,
+                                 char *text );
+
+#endif /* POLARSSL_ASN1_WRITE_H */
diff --git a/include/polarssl/config.h b/include/polarssl/config.h
index bb9e680..62663ce 100644
--- a/include/polarssl/config.h
+++ b/include/polarssl/config.h
@@ -289,6 +289,15 @@
 #define POLARSSL_ASN1_PARSE_C
 
 /**
+ * \def POLARSSL_ASN1_WRITE_C
+ *
+ * Enable the generic ASN1 writer.
+ *
+ * Module:  library/asn1write.c
+ */
+#define POLARSSL_ASN1_WRITE_C
+
+/**
  * \def POLARSSL_BASE64_C
  *
  * Enable the Base64 module.
@@ -698,6 +707,19 @@
 #define POLARSSL_X509_PARSE_C
 
 /**
+ * \def POLARSSL_X509_WRITE_C
+ *
+ * Enable X.509 buffer writing.
+ *
+ * Module:  library/x509write.c
+ *
+ * Requires: POLARSSL_BIGNUM_C, POLARSSL_RSA_C
+ *
+ * This module is required for X.509 certificate request writing.
+ */
+#define POLARSSL_X509_WRITE_C
+
+/**
  * \def POLARSSL_XTEA_C
  *
  * Enable the XTEA block cipher.
diff --git a/include/polarssl/error.h b/include/polarssl/error.h
index 9c17071..e2e91f9 100644
--- a/include/polarssl/error.h
+++ b/include/polarssl/error.h
@@ -49,16 +49,16 @@
  *
  * Module   Nr  Codes assigned 
  * MPI       7  0x0002-0x0010
- * ASN1      6  0x0014-0x001E
  * AES       2  0x0020-0x0022
  * CAMELLIA  2  0x0024-0x0026
  * XTEA      1  0x0028-0x0028
  * BASE64    2  0x002A-0x002C
  * PADLOCK   1  0x0030-0x0030
  * DES       1  0x0032-0x0032
- * NET      11  0x0040-0x0054
  * CTR_DBRG  3  0x0034-0x003A
  * ENTROPY   3  0x003C-0x0040
+ * NET      11  0x0042-0x0056
+ * ASN1      7  0x0060-0x006C
  * MD2       1  0x0070-0x0070
  * MD4       1  0x0072-0x0072
  * MD5       1  0x0074-0x0074
diff --git a/include/polarssl/net.h b/include/polarssl/net.h
index 89e3a00..88302ac 100644
--- a/include/polarssl/net.h
+++ b/include/polarssl/net.h
@@ -29,7 +29,7 @@
 
 #include <string.h>
 
-#define POLARSSL_ERR_NET_UNKNOWN_HOST                      -0x0040  /**< Failed to get an IP address for the given hostname. */
+#define POLARSSL_ERR_NET_UNKNOWN_HOST                      -0x0056  /**< Failed to get an IP address for the given hostname. */
 #define POLARSSL_ERR_NET_SOCKET_FAILED                     -0x0042  /**< Failed to open a socket. */
 #define POLARSSL_ERR_NET_CONNECT_FAILED                    -0x0044  /**< The connection to the given server / port failed. */
 #define POLARSSL_ERR_NET_BIND_FAILED                       -0x0046  /**< Binding of the socket failed. */
diff --git a/include/polarssl/x509.h b/include/polarssl/x509.h
index 385c8b5..2cd883f 100644
--- a/include/polarssl/x509.h
+++ b/include/polarssl/x509.h
@@ -99,9 +99,15 @@
 
 #define OID_X520                "\x55\x04"
 #define OID_CN                  OID_X520 "\x03"
+#define OID_COUNTRY             OID_X520 "\x06"
+#define OID_LOCALITY            OID_X520 "\x07"
+#define OID_STATE               OID_X520 "\x08"
+#define OID_ORGANIZATION        OID_X520 "\x0A"
+#define OID_ORG_UNIT            OID_X520 "\x0B"
 
 #define OID_PKCS1               "\x2A\x86\x48\x86\xF7\x0D\x01\x01"
 #define OID_PKCS1_RSA           OID_PKCS1 "\x01"
+#define OID_PKCS1_SHA1          OID_PKCS1 "\x05"
 
 #define OID_RSA_SHA_OBS         "\x2B\x0E\x03\x02\x1D"
 
diff --git a/include/polarssl/x509write.h b/include/polarssl/x509write.h
new file mode 100644
index 0000000..c24f3e1
--- /dev/null
+++ b/include/polarssl/x509write.h
@@ -0,0 +1,46 @@
+/**
+ * \file x509write.h
+ *
+ * \brief X509 buffer writing functionality
+ *
+ *  Copyright (C) 2006-2012, Brainspark B.V.
+ *
+ *  This file is part of PolarSSL (http://www.polarssl.org)
+ *  Lead Maintainer: Paul Bakker <polarssl_maintainer at polarssl.org>
+ *
+ *  All rights reserved.
+ *
+ *  This program is free software; you can redistribute it and/or modify
+ *  it under the terms of the GNU General Public License as published by
+ *  the Free Software Foundation; either version 2 of the License, or
+ *  (at your option) any later version.
+ *
+ *  This program is distributed in the hope that it will be useful,
+ *  but WITHOUT ANY WARRANTY; without even the implied warranty of
+ *  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ *  GNU General Public License for more details.
+ *
+ *  You should have received a copy of the GNU General Public License along
+ *  with this program; if not, write to the Free Software Foundation, Inc.,
+ *  51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA.
+ */
+#ifndef POLARSSL_X509_WRITE_H
+#define POLARSSL_X509_WRITE_H
+
+#include "rsa.h"
+
+typedef struct _x509_req_name
+{
+    char oid[128];
+    char name[128];
+
+    struct _x509_req_name *next;
+}
+x509_req_name;
+
+int x509_write_pubkey_der( unsigned char *buf, size_t size, rsa_context *rsa );
+int x509_write_key_der( unsigned char *buf, size_t size, rsa_context *rsa );
+int x509_write_cert_req( unsigned char *buf, size_t size, rsa_context *rsa,
+                         x509_req_name *req_name );
+
+#endif /* POLARSSL_X509_WRITE_H */
diff --git a/library/CMakeLists.txt b/library/CMakeLists.txt
index de72735..bb600d4 100644
--- a/library/CMakeLists.txt
+++ b/library/CMakeLists.txt
@@ -4,6 +4,7 @@
      aes.c
      arc4.c
      asn1parse.c
+     asn1write.c
      base64.c
      bignum.c
      camellia.c
diff --git a/library/Makefile b/library/Makefile
index 26de4d7..968ca31 100644
--- a/library/Makefile
+++ b/library/Makefile
@@ -23,6 +23,7 @@
 # DLEXT=dll
 
 OBJS=	aes.o		arc4.o		asn1parse.o		\
+		asn1write.o								\
 		base64.o	bignum.o	camellia.o		\
 		certs.o		cipher.o	cipher_wrap.o	\
 		ctr_drbg.o	debug.o		des.o			\
@@ -34,7 +35,7 @@
 		rsa.o		sha1.o		sha2.o			\
 		sha4.o		ssl_cli.o	ssl_srv.o		\
 		ssl_tls.o	timing.o	version.o		\
-		x509parse.o	xtea.o
+		x509parse.o	x509write.o	xtea.o
 	
 
 .SILENT:
diff --git a/library/asn1write.c b/library/asn1write.c
new file mode 100644
index 0000000..0c1d18b
--- /dev/null
+++ b/library/asn1write.c
@@ -0,0 +1,218 @@
+/*
+ * ASN.1 buffer writing functionality
+ *
+ *  Copyright (C) 2006-2012, Brainspark B.V.
+ *
+ *  This file is part of PolarSSL (http://www.polarssl.org)
+ *  Lead Maintainer: Paul Bakker <polarssl_maintainer at polarssl.org>
+ *
+ *  All rights reserved.
+ *
+ *  This program is free software; you can redistribute it and/or modify
+ *  it under the terms of the GNU General Public License as published by
+ *  the Free Software Foundation; either version 2 of the License, or
+ *  (at your option) any later version.
+ *
+ *  This program is distributed in the hope that it will be useful,
+ *  but WITHOUT ANY WARRANTY; without even the implied warranty of
+ *  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ *  GNU General Public License for more details.
+ *
+ *  You should have received a copy of the GNU General Public License along
+ *  with this program; if not, write to the Free Software Foundation, Inc.,
+ *  51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA.
+ */
+
+#include "polarssl/config.h"
+
+#if defined(POLARSSL_ASN1_WRITE_C)
+
+#include "polarssl/asn1write.h"
+
+int asn1_write_len( unsigned char **p, unsigned char *start, size_t len )
+{
+    if( len < 0x80 )
+    {
+        if( *p - start < 1 )
+            return( POLARSSL_ERR_ASN1_BUF_TOO_SMALL );
+
+        *--(*p) = len;
+        return( 1 );
+    }
+
+    if( len <= 0xFF )
+    {
+        if( *p - start < 2 )
+            return( POLARSSL_ERR_ASN1_BUF_TOO_SMALL );
+
+        *--(*p) = len;
+        *--(*p) = 0x81;
+        return( 2 );
+    }
+
+    if( *p - start < 3 )
+        return( POLARSSL_ERR_ASN1_BUF_TOO_SMALL );
+
+    // We assume we never have lengths larger than 65535 bytes
+    //
+    *--(*p) = len % 256;
+    *--(*p) = ( len / 256 ) % 256;
+    *--(*p) = 0x82;
+
+    return( 3 );
+}
+
+int asn1_write_tag( unsigned char **p, unsigned char *start, unsigned char tag )
+{
+    if( *p - start < 1 )
+        return( POLARSSL_ERR_ASN1_BUF_TOO_SMALL );
+
+    *--(*p) = tag;
+
+    return( 1 );
+}
+
+int asn1_write_mpi( unsigned char **p, unsigned char *start, mpi *X )
+{
+    int ret;
+    size_t len = 0;
+
+    // Write the MPI
+    //
+    len = mpi_size( X );
+
+    if( *p - start < (int) len )
+        return( POLARSSL_ERR_ASN1_BUF_TOO_SMALL );
+
+    (*p) -= len;
+    mpi_write_binary( X, *p, len );
+
+    // DER format assumes 2s complement for numbers, so the leftmost bit
+    // should be 0 for positive numbers and 1 for negative numbers.
+    //
+    if ( X->s ==1 && **p & 0x80 )
+    {
+        if( *p - start < 1 )
+            return( POLARSSL_ERR_ASN1_BUF_TOO_SMALL );
+
+        *--(*p) = 0x00;
+        len += 1;
+    }
+
+    ASN1_CHK_ADD( len, asn1_write_len( p, start, len ) );
+    ASN1_CHK_ADD( len, asn1_write_tag( p, start, ASN1_INTEGER ) );
+
+    return( len );
+}
+    
+int asn1_write_null( unsigned char **p, unsigned char *start )
+{
+    int ret;
+    size_t len = 0;
+
+    // Write NULL
+    //
+    ASN1_CHK_ADD( len, asn1_write_len( p, start, 0) );
+    ASN1_CHK_ADD( len, asn1_write_tag( p, start, ASN1_NULL ) );
+
+    return( len );
+}
+
+int asn1_write_oid( unsigned char **p, unsigned char *start, char *oid )
+{
+    int ret;
+    size_t len = 0;
+
+    // Write OID
+    //
+    len = strlen( oid );
+
+    if( *p - start < (int) len )
+        return( POLARSSL_ERR_ASN1_BUF_TOO_SMALL );
+
+    (*p) -= len;
+    memcpy( *p, oid, len );
+
+    ASN1_CHK_ADD( len , asn1_write_len( p, start, len ) );
+    ASN1_CHK_ADD( len , asn1_write_tag( p, start, ASN1_OID ) );
+
+    return( len );
+}
+
+int asn1_write_algorithm_identifier( unsigned char **p, unsigned char *start,
+                                     char *algorithm_oid )
+{
+    int ret;
+    size_t null_len = 0;
+    size_t oid_len = 0;
+    size_t len = 0;
+
+    // Write NULL
+    //
+    ASN1_CHK_ADD( null_len, asn1_write_null( p, start ) );
+
+    // Write OID
+    //
+    ASN1_CHK_ADD( oid_len, asn1_write_oid( p, start, algorithm_oid ) );
+
+    len = oid_len + null_len;
+    ASN1_CHK_ADD( len, asn1_write_len( p, start, oid_len + null_len ) );
+    ASN1_CHK_ADD( len, asn1_write_tag( p, start,
+                                       ASN1_CONSTRUCTED | ASN1_SEQUENCE ) );
+
+    return( len );
+}
+
+int asn1_write_int( unsigned char **p, unsigned char *start, int val )
+{
+    int ret;
+    size_t len = 0;
+
+    // TODO negative values and values larger than 128
+    // DER format assumes 2s complement for numbers, so the leftmost bit
+    // should be 0 for positive numbers and 1 for negative numbers.
+    //
+    if( *p - start < 1 )
+        return( POLARSSL_ERR_ASN1_BUF_TOO_SMALL );
+
+    len += 1;
+    *--(*p) = val;
+
+    if ( val > 0 && **p & 0x80 )
+    {
+        if( *p - start < 1 )
+            return( POLARSSL_ERR_ASN1_BUF_TOO_SMALL );
+
+        *--(*p) = 0x00;
+        len += 1;
+    }
+
+    ASN1_CHK_ADD( len, asn1_write_len( p, start, len ) );
+    ASN1_CHK_ADD( len, asn1_write_tag( p, start, ASN1_INTEGER ) );
+
+    return( len );
+}
+
+int asn1_write_printable_string( unsigned char **p, unsigned char *start,
+                                 char *text )
+{
+    int ret;
+    size_t len = 0;
+
+    // Write string
+    //
+    len = strlen( text );
+
+    if( *p - start < (int) len )
+        return( POLARSSL_ERR_ASN1_BUF_TOO_SMALL );
+
+    (*p) -= len;
+    memcpy( *p, text, len );
+
+    ASN1_CHK_ADD( len, asn1_write_len( p, start, len ) );
+    ASN1_CHK_ADD( len, asn1_write_tag( p, start, ASN1_PRINTABLE_STRING ) );
+
+    return( len );
+}
+    
+#endif
diff --git a/library/error.c b/library/error.c
index 9bc5034..195ae20 100644
--- a/library/error.c
+++ b/library/error.c
@@ -378,6 +378,8 @@
         snprintf( buf, buflen, "ASN1 - Data is invalid. (not used)" );
     if( use_ret == -(POLARSSL_ERR_ASN1_MALLOC_FAILED) )
         snprintf( buf, buflen, "ASN1 - Memory allocation failed" );
+    if( use_ret == -(POLARSSL_ERR_ASN1_BUF_TOO_SMALL) )
+        snprintf( buf, buflen, "ASN1 - Buffer too small when writing ASN.1 data structure" );
 #endif /* POLARSSL_ASN1_PARSE_C */
 
 #if defined(POLARSSL_BASE64_C)
diff --git a/library/x509write.c b/library/x509write.c
new file mode 100644
index 0000000..b114e70
--- /dev/null
+++ b/library/x509write.c
@@ -0,0 +1,233 @@
+/*
+ * X509 buffer writing functionality
+ *
+ *  Copyright (C) 2006-2012, Brainspark B.V.
+ *
+ *  This file is part of PolarSSL (http://www.polarssl.org)
+ *  Lead Maintainer: Paul Bakker <polarssl_maintainer at polarssl.org>
+ *
+ *  All rights reserved.
+ *
+ *  This program is free software; you can redistribute it and/or modify
+ *  it under the terms of the GNU General Public License as published by
+ *  the Free Software Foundation; either version 2 of the License, or
+ *  (at your option) any later version.
+ *
+ *  This program is distributed in the hope that it will be useful,
+ *  but WITHOUT ANY WARRANTY; without even the implied warranty of
+ *  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ *  GNU General Public License for more details.
+ *
+ *  You should have received a copy of the GNU General Public License along
+ *  with this program; if not, write to the Free Software Foundation, Inc.,
+ *  51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA.
+ */
+
+#include "polarssl/config.h"
+
+#if defined(POLARSSL_X509_WRITE_C)
+
+#include "polarssl/asn1write.h"
+#include "polarssl/x509write.h"
+#include "polarssl/x509.h"
+#include "polarssl/sha1.h"
+
+int x509_write_pubkey_der( unsigned char *buf, size_t size, rsa_context *rsa )
+{
+    int ret;
+    unsigned char *c;
+    size_t len = 0;
+
+    c = buf + size - 1;
+
+    ASN1_CHK_ADD( len, asn1_write_mpi( &c, buf, &rsa->E ) );
+    ASN1_CHK_ADD( len, asn1_write_mpi( &c, buf, &rsa->N ) );
+
+    ASN1_CHK_ADD( len, asn1_write_len( &c, buf, len ) );
+    ASN1_CHK_ADD( len, asn1_write_tag( &c, buf, ASN1_CONSTRUCTED | ASN1_SEQUENCE ) );
+
+    if( c - buf < 1 )
+        return( POLARSSL_ERR_ASN1_BUF_TOO_SMALL );
+
+    *--c = 0;
+    len += 1;
+
+    ASN1_CHK_ADD( len, asn1_write_len( &c, buf, len ) );
+    ASN1_CHK_ADD( len, asn1_write_tag( &c, buf, ASN1_BIT_STRING ) );
+
+    ASN1_CHK_ADD( len, asn1_write_algorithm_identifier( &c, buf, OID_PKCS1_RSA ) );
+
+    ASN1_CHK_ADD( len, asn1_write_len( &c, buf, len ) );
+    ASN1_CHK_ADD( len, asn1_write_tag( &c, buf, ASN1_CONSTRUCTED | ASN1_SEQUENCE ) );
+
+    return( len );
+}
+
+int x509_write_key_der( unsigned char *buf, size_t size, rsa_context *rsa )
+{
+    int ret;
+    unsigned char *c;
+    size_t len = 0;
+
+    c = buf + size - 1;
+
+    ASN1_CHK_ADD( len, asn1_write_mpi( &c, buf, &rsa->QP ) );
+    ASN1_CHK_ADD( len, asn1_write_mpi( &c, buf, &rsa->DQ ) );
+    ASN1_CHK_ADD( len, asn1_write_mpi( &c, buf, &rsa->DP ) );
+    ASN1_CHK_ADD( len, asn1_write_mpi( &c, buf, &rsa->Q ) );
+    ASN1_CHK_ADD( len, asn1_write_mpi( &c, buf, &rsa->P ) );
+    ASN1_CHK_ADD( len, asn1_write_mpi( &c, buf, &rsa->D ) );
+    ASN1_CHK_ADD( len, asn1_write_mpi( &c, buf, &rsa->E ) );
+    ASN1_CHK_ADD( len, asn1_write_mpi( &c, buf, &rsa->N ) );
+    ASN1_CHK_ADD( len, asn1_write_int( &c, buf, 0 ) );
+
+    ASN1_CHK_ADD( len, asn1_write_len( &c, buf, len ) );
+    ASN1_CHK_ADD( len, asn1_write_tag( &c, buf, ASN1_CONSTRUCTED | ASN1_SEQUENCE ) );
+
+    // TODO: Make NON RSA Specific variant later on
+/*    *--c = 0;
+    len += 1;
+
+    len += asn1_write_len( &c, len);
+    len += asn1_write_tag( &c, ASN1_BIT_STRING );
+
+    len += asn1_write_oid( &c, OID_PKCS1_RSA );
+
+    len += asn1_write_int( &c, 0 );
+
+    len += asn1_write_len( &c, len);
+    len += asn1_write_tag( &c, ASN1_CONSTRUCTED | ASN1_SEQUENCE );*/
+
+/*    for(i = 0; i < len; ++i)
+    {
+        if (i % 16 == 0 ) printf("\n");
+        printf("%02x ", c[i]);
+    }
+    printf("\n");*/
+
+    return( len );
+}
+
+int x509_write_name( unsigned char **p, unsigned char *start, char *oid,
+                     char *name )
+{
+    int ret;
+    size_t string_len = 0;
+    size_t oid_len = 0;
+    size_t len = 0;
+
+    // Write PrintableString
+    //
+    ASN1_CHK_ADD( string_len, asn1_write_printable_string( p, start, name ) );
+
+    // Write OID
+    //
+    ASN1_CHK_ADD( oid_len, asn1_write_oid( p, start, oid ) );
+
+    len = oid_len + string_len;
+    ASN1_CHK_ADD( len, asn1_write_len( p, start, oid_len + string_len ) );
+    ASN1_CHK_ADD( len, asn1_write_tag( p, start, ASN1_CONSTRUCTED | ASN1_SEQUENCE ) );
+
+    ASN1_CHK_ADD( len, asn1_write_len( p, start, len ) );
+    ASN1_CHK_ADD( len, asn1_write_tag( p, start, ASN1_CONSTRUCTED | ASN1_SET ) );
+
+    return( len );
+}
+
+int x509_write_sig( unsigned char **p, unsigned char *start, char *oid,
+                    unsigned char *sig, size_t size )
+{
+    int ret;
+    size_t len = 0;
+
+    if( *p - start < (int) size + 1 )
+        return( POLARSSL_ERR_ASN1_BUF_TOO_SMALL );
+
+    len = size;
+    (*p) -= len;
+    memcpy( *p, sig, len );
+
+    *--(*p) = 0;
+    len += 1;
+
+    ASN1_CHK_ADD( len, asn1_write_len( p, start, len ) );
+    ASN1_CHK_ADD( len, asn1_write_tag( p, start, ASN1_BIT_STRING ) );
+
+    // Write OID
+    //
+    ASN1_CHK_ADD( len, asn1_write_algorithm_identifier( p, start, oid ) );
+
+    return( len );
+}
+
+int x509_write_cert_req( unsigned char *buf, size_t size, rsa_context *rsa,
+                         x509_req_name *req_name )
+{
+    int ret;
+    unsigned char *c, *c2;
+    unsigned char hash[20];
+    unsigned char sig[512];
+    unsigned char tmp_buf[2048];
+    size_t sub_len = 0, pub_len = 0, sig_len = 0;
+    size_t len = 0;
+    x509_req_name *cur = req_name;
+
+    c = tmp_buf + 2048 - 1;
+
+    ASN1_CHK_ADD( len, asn1_write_len( &c, tmp_buf, 0 ) );
+    ASN1_CHK_ADD( len, asn1_write_tag( &c, tmp_buf, ASN1_CONSTRUCTED | ASN1_CONTEXT_SPECIFIC ) );
+
+    ASN1_CHK_ADD( pub_len, asn1_write_mpi( &c, tmp_buf, &rsa->E ) );
+    ASN1_CHK_ADD( pub_len, asn1_write_mpi( &c, tmp_buf, &rsa->N ) );
+
+    ASN1_CHK_ADD( pub_len, asn1_write_len( &c, tmp_buf, pub_len ) );
+    ASN1_CHK_ADD( pub_len, asn1_write_tag( &c, tmp_buf, ASN1_CONSTRUCTED | ASN1_SEQUENCE ) );
+
+    if( c - tmp_buf < 1 )
+        return( POLARSSL_ERR_ASN1_BUF_TOO_SMALL );
+
+    *--c = 0;
+    pub_len += 1;
+
+    ASN1_CHK_ADD( pub_len, asn1_write_len( &c, tmp_buf, pub_len ) );
+    ASN1_CHK_ADD( pub_len, asn1_write_tag( &c, tmp_buf, ASN1_BIT_STRING ) );
+
+    ASN1_CHK_ADD( pub_len, asn1_write_algorithm_identifier( &c, tmp_buf, OID_PKCS1_RSA ) );
+
+    len += pub_len;
+    ASN1_CHK_ADD( len, asn1_write_len( &c, tmp_buf, pub_len ) );
+    ASN1_CHK_ADD( len, asn1_write_tag( &c, tmp_buf, ASN1_CONSTRUCTED | ASN1_SEQUENCE ) );
+
+    while( cur != NULL )
+    {
+        ASN1_CHK_ADD( sub_len, x509_write_name( &c, tmp_buf, cur->oid, cur->name ) );
+        
+        cur = cur->next;
+    }
+
+    len += sub_len;
+    ASN1_CHK_ADD( len, asn1_write_len( &c, tmp_buf, sub_len ) );
+    ASN1_CHK_ADD( len, asn1_write_tag( &c, tmp_buf, ASN1_CONSTRUCTED | ASN1_SEQUENCE ) );
+
+    ASN1_CHK_ADD( len, asn1_write_int( &c, tmp_buf, 0 ) );
+
+    ASN1_CHK_ADD( len, asn1_write_len( &c, tmp_buf, len ) );
+    ASN1_CHK_ADD( len, asn1_write_tag( &c, tmp_buf, ASN1_CONSTRUCTED | ASN1_SEQUENCE ) );
+    
+    sha1( c, len, hash );
+    rsa_pkcs1_sign( rsa, NULL, NULL, RSA_PRIVATE, SIG_RSA_SHA1, 0, hash, sig );
+
+    c2 = buf + size - 1;
+    ASN1_CHK_ADD( sig_len, x509_write_sig( &c2, buf, OID_PKCS1_SHA1, sig, rsa->len ) );
+    
+    c2 -= len;
+    memcpy( c2, c, len ); 
+    
+    len += sig_len;
+    ASN1_CHK_ADD( len, asn1_write_len( &c2, buf, len ) );
+    ASN1_CHK_ADD( len, asn1_write_tag( &c2, buf, ASN1_CONSTRUCTED | ASN1_SEQUENCE ) );
+
+    return( len );
+}
+
+#endif
diff --git a/programs/Makefile b/programs/Makefile
index c8b6def..7027743 100644
--- a/programs/Makefile
+++ b/programs/Makefile
@@ -12,7 +12,7 @@
 	hash/md5sum			hash/sha1sum		\
 	hash/sha2sum		pkey/dh_client		\
 	pkey/dh_genprime	pkey/dh_server		\
-	pkey/key_app							\
+	pkey/key_app		pkey/key_app_writer	\
 	pkey/mpi_demo		pkey/rsa_genkey		\
 	pkey/rsa_decrypt	pkey/rsa_encrypt	\
 	pkey/rsa_sign		pkey/rsa_verify		\
@@ -24,7 +24,8 @@
 	random/gen_random_ctr_drbg				\
 	test/ssl_cert_test	test/benchmark		\
 	test/selftest		test/ssl_test		\
-	x509/cert_app		x509/crl_app
+	x509/cert_app		x509/crl_app		\
+	x509/cert_req
 
 .SILENT:
 
@@ -74,6 +75,10 @@
 	echo   "  CC    pkey/key_app.c"
 	$(CC) $(CFLAGS) $(OFLAGS) pkey/key_app.c   $(LDFLAGS) -o $@
 
+pkey/key_app_writer: pkey/key_app_writer.c ../library/libpolarssl.a
+	echo   "  CC    pkey/key_app_writer.c"
+	$(CC) $(CFLAGS) $(OFLAGS) pkey/key_app_writer.c   $(LDFLAGS) -o $@
+
 pkey/mpi_demo: pkey/mpi_demo.c ../library/libpolarssl.a
 	echo   "  CC    pkey/mpi_demo.c"
 	$(CC) $(CFLAGS) $(OFLAGS) pkey/mpi_demo.c    $(LDFLAGS) -o $@
@@ -162,6 +167,10 @@
 	echo   "  CC    x509/crl_app.c"
 	$(CC) $(CFLAGS) $(OFLAGS) x509/crl_app.c    $(LDFLAGS) -o $@
 
+x509/cert_req: x509/cert_req.c ../library/libpolarssl.a
+	echo   "  CC    x509/cert_req.c"
+	$(CC) $(CFLAGS) $(OFLAGS) x509/cert_req.c    $(LDFLAGS) -o $@
+
 clean:
 	rm -f $(APPS)
 
diff --git a/programs/pkey/key_app_writer.c b/programs/pkey/key_app_writer.c
new file mode 100644
index 0000000..af508d2
--- /dev/null
+++ b/programs/pkey/key_app_writer.c
@@ -0,0 +1,347 @@
+/*
+ *  Key reading application
+ *
+ *  Copyright (C) 2006-2011, Brainspark B.V.
+ *
+ *  This file is part of PolarSSL (http://www.polarssl.org)
+ *  Lead Maintainer: Paul Bakker <polarssl_maintainer at polarssl.org>
+ *
+ *  All rights reserved.
+ *
+ *  This program is free software; you can redistribute it and/or modify
+ *  it under the terms of the GNU General Public License as published by
+ *  the Free Software Foundation; either version 2 of the License, or
+ *  (at your option) any later version.
+ *
+ *  This program is distributed in the hope that it will be useful,
+ *  but WITHOUT ANY WARRANTY; without even the implied warranty of
+ *  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ *  GNU General Public License for more details.
+ *
+ *  You should have received a copy of the GNU General Public License along
+ *  with this program; if not, write to the Free Software Foundation, Inc.,
+ *  51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA.
+ */
+
+#ifndef _CRT_SECURE_NO_DEPRECATE
+#define _CRT_SECURE_NO_DEPRECATE 1
+#endif
+
+#include <string.h>
+#include <stdlib.h>
+#include <stdio.h>
+
+#include "polarssl/config.h"
+
+#include "polarssl/error.h"
+#include "polarssl/rsa.h"
+#include "polarssl/x509.h"
+#include "polarssl/base64.h"
+#include "polarssl/x509write.h"
+
+#define MODE_NONE               0
+#define MODE_PRIVATE            1
+#define MODE_PUBLIC             2
+
+#define OUTPUT_MODE_NONE               0
+#define OUTPUT_MODE_PRIVATE            1
+#define OUTPUT_MODE_PUBLIC             2
+
+#define DFL_MODE                MODE_NONE
+#define DFL_FILENAME            "keyfile.key"
+#define DFL_DEBUG_LEVEL         0
+#define DFL_OUTPUT_MODE          OUTPUT_MODE_NONE
+#define DFL_OUTPUT_FILENAME     "keyfile.pem"
+
+/*
+ * global options
+ */
+struct options
+{
+    int mode;                   /* the mode to run the application in   */
+    char *filename;             /* filename of the key file             */
+    int debug_level;            /* level of debugging                   */
+    int output_mode;            /* the output mode to use               */
+    char *output_file;          /* where to store the constructed key file  */
+} opt;
+
+void my_debug( void *ctx, int level, const char *str )
+{
+    if( level < opt.debug_level )
+    {
+        fprintf( (FILE *) ctx, "%s", str );
+        fflush(  (FILE *) ctx  );
+    }
+}
+
+void write_public_key( rsa_context *rsa, char *output_file )
+{
+    FILE *f;
+    unsigned char output_buf[4096];
+    unsigned char base_buf[4096];
+    unsigned char *c;
+    int ret;
+    size_t len = 0, olen = 4096;
+
+    memset(output_buf, 0, 4096);
+    ret = x509_write_pubkey_der( output_buf, 4096, rsa );
+
+    if( ret < 0 )
+        return;
+
+    len = ret;
+    c = output_buf + 4095 - len;
+
+    base64_encode( base_buf, &olen, c, len );
+
+    c = base_buf;
+
+    f = fopen( output_file, "w" );
+    fprintf(f, "-----BEGIN PUBLIC KEY-----\n");
+    while (olen)
+    {
+        int use_len = olen;
+        if (use_len > 64) use_len = 64;
+        fwrite( c, 1, use_len, f );
+        olen -= use_len;
+        c += use_len;
+        fprintf(f, "\n");
+    }
+    fprintf(f, "-----END PUBLIC KEY-----\n");
+    fclose(f);
+}
+
+void write_private_key( rsa_context *rsa, char *output_file )
+{
+    FILE *f;
+    unsigned char output_buf[4096];
+    unsigned char base_buf[4096];
+    unsigned char *c;
+    int ret;
+    size_t len = 0, olen = 4096;
+
+    memset(output_buf, 0, 4096);
+    ret = x509_write_key_der( output_buf, 4096, rsa );
+    if( ret < 0 )
+        return;
+
+    len = ret;
+    c = output_buf + 4095 - len;
+
+    base64_encode( base_buf, &olen, c, len );
+
+    c = base_buf;
+
+    f = fopen( output_file, "w" );
+    fprintf(f, "-----BEGIN RSA PRIVATE KEY-----\n");
+    while (olen)
+    {
+        int use_len = olen;
+        if (use_len > 64) use_len = 64;
+        fwrite( c, 1, use_len, f );
+        olen -= use_len;
+        c += use_len;
+        fprintf(f, "\n");
+    }
+    fprintf(f, "-----END RSA PRIVATE KEY-----\n");
+    fclose(f);
+}
+
+#define USAGE \
+    "\n usage: key_app param=<>...\n"                   \
+    "\n acceptable parameters:\n"                       \
+    "    mode=private|public default: none\n"           \
+    "    filename=%%s         default: keyfile.key\n"   \
+    "    debug_level=%%d      default: 0 (disabled)\n"  \
+    "    output_mode=private|public default: none\n"    \
+    "    output_file=%%s      defeult: keyfile.pem\n"   \
+    "\n"
+
+#if !defined(POLARSSL_BIGNUM_C) || !defined(POLARSSL_RSA_C) ||         \
+    !defined(POLARSSL_X509_PARSE_C) || !defined(POLARSSL_FS_IO)
+int main( int argc, char *argv[] )
+{
+    ((void) argc);
+    ((void) argv);
+
+    printf("POLARSSL_BIGNUM_C and/or POLARSSL_RSA_C and/or "
+           "POLARSSL_X509_PARSE_C and/or POLARSSL_FS_IO not defined.\n");
+    return( 0 );
+}
+#else
+int main( int argc, char *argv[] )
+{
+    int ret = 0;
+    rsa_context rsa;
+    char buf[1024];
+    int i, j, n;
+    char *p, *q;
+
+    /*
+     * Set to sane values
+     */
+    memset( &rsa, 0, sizeof( rsa_context ) );
+    memset( buf, 0, 1024 );
+
+    if( argc == 0 )
+    {
+    usage:
+        printf( USAGE );
+        goto exit;
+    }
+
+    opt.mode                = DFL_MODE;
+    opt.filename            = DFL_FILENAME;
+    opt.debug_level         = DFL_DEBUG_LEVEL;
+    opt.output_mode         = DFL_OUTPUT_MODE;
+    opt.output_file         = DFL_OUTPUT_FILENAME;
+
+    for( i = 1; i < argc; i++ )
+    {
+        n = strlen( argv[i] );
+
+        for( j = 0; j < n; j++ )
+        {
+            if( argv[i][j] >= 'A' && argv[i][j] <= 'Z' )
+                argv[i][j] |= 0x20;
+        }
+
+        p = argv[i];
+        if( ( q = strchr( p, '=' ) ) == NULL )
+            goto usage;
+        *q++ = '\0';
+
+        if( strcmp( p, "mode" ) == 0 )
+        {
+            if( strcmp( q, "private" ) == 0 )
+                opt.mode = MODE_PRIVATE;
+            else if( strcmp( q, "public" ) == 0 )
+                opt.mode = MODE_PUBLIC;
+            else
+                goto usage;
+        }
+        else if( strcmp( p, "output_mode" ) == 0 )
+        {
+            if( strcmp( q, "private" ) == 0 )
+                opt.output_mode = OUTPUT_MODE_PRIVATE;
+            else if( strcmp( q, "public" ) == 0 )
+                opt.output_mode = OUTPUT_MODE_PUBLIC;
+            else
+                goto usage;
+        }
+        else if( strcmp( p, "filename" ) == 0 )
+            opt.filename = q;
+        else if( strcmp( p, "output_file" ) == 0 )
+            opt.output_file = q;
+        else if( strcmp( p, "debug_level" ) == 0 )
+        {
+            opt.debug_level = atoi( q );
+            if( opt.debug_level < 0 || opt.debug_level > 65535 )
+                goto usage;
+        }
+        else
+            goto usage;
+    }
+
+    if( opt.mode == MODE_NONE && opt.output_mode != OUTPUT_MODE_NONE )
+    {
+        printf( "\nCannot output a key without reading one.\n");
+        goto exit;
+    }
+
+    if( opt.mode == MODE_PUBLIC && opt.output_mode == OUTPUT_MODE_PRIVATE )
+    {
+        printf( "\nCannot output a private key from a public key.\n");
+        goto exit;
+    }
+
+    if( opt.mode == MODE_PRIVATE )
+    {
+        /*
+         * 1.1. Load the key
+         */
+        printf( "\n  . Loading the private key ..." );
+        fflush( stdout );
+
+        ret = x509parse_keyfile( &rsa, opt.filename, NULL );
+
+        if( ret != 0 )
+        {
+#ifdef POLARSSL_ERROR_C
+            error_strerror( ret, buf, 1024 );
+#endif
+            printf( " failed\n  !  x509parse_key returned %d - %s\n\n", ret, buf );
+            rsa_free( &rsa );
+            goto exit;
+        }
+
+        printf( " ok\n" );
+
+        /*
+         * 1.2 Print the key
+         */
+        printf( "  . Key information    ...\n" );
+        mpi_write_file( "N:  ", &rsa.N, 16, NULL );
+        mpi_write_file( "E:  ", &rsa.E, 16, NULL );
+        mpi_write_file( "D:  ", &rsa.D, 16, NULL );
+        mpi_write_file( "P:  ", &rsa.P, 16, NULL );
+        mpi_write_file( "Q:  ", &rsa.Q, 16, NULL );
+        mpi_write_file( "DP: ", &rsa.DP, 16, NULL );
+        mpi_write_file( "DQ:  ", &rsa.DQ, 16, NULL );
+        mpi_write_file( "QP:  ", &rsa.QP, 16, NULL );
+
+    }
+    else if( opt.mode == MODE_PUBLIC )
+    {
+        /*
+         * 1.1. Load the key
+         */
+        printf( "\n  . Loading the public key ..." );
+        fflush( stdout );
+
+        ret = x509parse_public_keyfile( &rsa, opt.filename );
+
+        if( ret != 0 )
+        {
+#ifdef POLARSSL_ERROR_C
+            error_strerror( ret, buf, 1024 );
+#endif
+            printf( " failed\n  !  x509parse_public_key returned %d - %s\n\n", ret, buf );
+            rsa_free( &rsa );
+            goto exit;
+        }
+
+        printf( " ok\n" );
+
+        /*
+         * 1.2 Print the key
+         */
+        printf( "  . Key information    ...\n" );
+        mpi_write_file( "N: ", &rsa.N, 16, NULL );
+        mpi_write_file( "E:  ", &rsa.E, 16, NULL );
+    }
+    else
+        goto usage;
+
+    if( opt.output_mode == OUTPUT_MODE_PUBLIC )
+    {
+        write_public_key( &rsa, opt.output_file );
+    }
+    if( opt.output_mode == OUTPUT_MODE_PRIVATE )
+    {
+        write_private_key( &rsa, opt.output_file );
+    }
+
+exit:
+
+    rsa_free( &rsa );
+
+#if defined(_WIN32)
+    printf( "  + Press Enter to exit this program.\n" );
+    fflush( stdout ); getchar();
+#endif
+
+    return( ret );
+}
+#endif /* POLARSSL_BIGNUM_C && POLARSSL_RSA_C &&
+          POLARSSL_X509_PARSE_C && POLARSSL_FS_IO */
diff --git a/programs/x509/cert_req.c b/programs/x509/cert_req.c
new file mode 100644
index 0000000..4bcfbbe
--- /dev/null
+++ b/programs/x509/cert_req.c
@@ -0,0 +1,298 @@
+/*
+ *  Certificate request generation
+ *
+ *  Copyright (C) 2006-2011, Brainspark B.V.
+ *
+ *  This file is part of PolarSSL (http://www.polarssl.org)
+ *  Lead Maintainer: Paul Bakker <polarssl_maintainer at polarssl.org>
+ *
+ *  All rights reserved.
+ *
+ *  This program is free software; you can redistribute it and/or modify
+ *  it under the terms of the GNU General Public License as published by
+ *  the Free Software Foundation; either version 2 of the License, or
+ *  (at your option) any later version.
+ *
+ *  This program is distributed in the hope that it will be useful,
+ *  but WITHOUT ANY WARRANTY; without even the implied warranty of
+ *  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ *  GNU General Public License for more details.
+ *
+ *  You should have received a copy of the GNU General Public License along
+ *  with this program; if not, write to the Free Software Foundation, Inc.,
+ *  51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA.
+ */
+
+#ifndef _CRT_SECURE_NO_DEPRECATE
+#define _CRT_SECURE_NO_DEPRECATE 1
+#endif
+
+#include <string.h>
+#include <stdlib.h>
+#include <stdio.h>
+
+#include "polarssl/config.h"
+
+#include "polarssl/error.h"
+#include "polarssl/rsa.h"
+#include "polarssl/x509.h"
+#include "polarssl/base64.h"
+#include "polarssl/x509write.h"
+
+#define DFL_FILENAME            "keyfile.key"
+#define DFL_DEBUG_LEVEL         0
+#define DFL_OUTPUT_FILENAME     "cert.req"
+#define DFL_SUBJECT_NAME        "CN=Cert,O=PolarSSL,C=NL"
+
+/*
+ * global options
+ */
+struct options
+{
+    char *filename;             /* filename of the key file             */
+    int debug_level;            /* level of debugging                   */
+    char *output_file;          /* where to store the constructed key file  */
+    char *subject_name;         /* subject name for certificate request */
+} opt;
+
+void my_debug( void *ctx, int level, const char *str )
+{
+    if( level < opt.debug_level )
+    {
+        fprintf( (FILE *) ctx, "%s", str );
+        fflush(  (FILE *) ctx  );
+    }
+}
+
+void write_certificate_request( rsa_context *rsa, x509_req_name *req_name,
+                                char *output_file )
+{
+    FILE *f;
+    unsigned char output_buf[4096];
+    unsigned char base_buf[4096];
+    unsigned char *c;
+    int ret;
+    size_t len = 0, olen = 4096;
+
+    memset(output_buf, 0, 4096);
+    ret = x509_write_cert_req( output_buf, 4096, rsa, req_name );
+
+    if( ret < 0 )
+        return;
+
+    len = ret;
+    c = output_buf + 4095 - len;
+
+    base64_encode( base_buf, &olen, c, len );
+
+    c = base_buf;
+
+    f = fopen( output_file, "w" );
+    fprintf(f, "-----BEGIN CERTIFICATE REQUEST-----\n");
+    while (olen)
+    {
+        int use_len = olen;
+        if (use_len > 64) use_len = 64;
+        fwrite( c, 1, use_len, f );
+        olen -= use_len;
+        c += use_len;
+        fprintf(f, "\n");
+    }
+    fprintf(f, "-----END CERTIFICATE REQUEST-----\n");
+    fclose(f);
+}
+
+#define USAGE \
+    "\n usage: key_app param=<>...\n"                   \
+    "\n acceptable parameters:\n"                       \
+    "    filename=%%s         default: keyfile.key\n"   \
+    "    debug_level=%%d      default: 0 (disabled)\n"  \
+    "    output_file=%%s      default: cert.req\n"      \
+    "    subject_name=%%s     default: CN=Cert,O=PolarSSL,C=NL\n"   \
+    "\n"
+
+#if !defined(POLARSSL_BIGNUM_C) || !defined(POLARSSL_RSA_C) ||         \
+    !defined(POLARSSL_X509_PARSE_C) || !defined(POLARSSL_FS_IO)
+int main( int argc, char *argv[] )
+{
+    ((void) argc);
+    ((void) argv);
+
+    printf("POLARSSL_BIGNUM_C and/or POLARSSL_RSA_C and/or "
+           "POLARSSL_X509_PARSE_C and/or POLARSSL_FS_IO not defined.\n");
+    return( 0 );
+}
+#else
+int main( int argc, char *argv[] )
+{
+    int ret = 0;
+    rsa_context rsa;
+    char buf[1024];
+    int i, j, n;
+    char *p, *q;
+    char *s, *c, *end;
+    int in_tag;
+    char *oid = NULL;
+    x509_req_name *req_name = NULL;
+    x509_req_name *cur = req_name;
+
+    /*
+     * Set to sane values
+     */
+    memset( &rsa, 0, sizeof( rsa_context ) );
+    memset( buf, 0, 1024 );
+
+    if( argc == 0 )
+    {
+    usage:
+        printf( USAGE );
+        goto exit;
+    }
+
+    opt.filename            = DFL_FILENAME;
+    opt.debug_level         = DFL_DEBUG_LEVEL;
+    opt.output_file         = DFL_OUTPUT_FILENAME;
+    opt.subject_name        = DFL_SUBJECT_NAME;
+
+    for( i = 1; i < argc; i++ )
+    {
+
+        p = argv[i];
+        if( ( q = strchr( p, '=' ) ) == NULL )
+            goto usage;
+        *q++ = '\0';
+
+        n = strlen( p );
+        for( j = 0; j < n; j++ )
+        {
+            if( argv[i][j] >= 'A' && argv[i][j] <= 'Z' )
+                argv[i][j] |= 0x20;
+        }
+
+        if( strcmp( p, "filename" ) == 0 )
+            opt.filename = q;
+        else if( strcmp( p, "output_file" ) == 0 )
+            opt.output_file = q;
+        else if( strcmp( p, "debug_level" ) == 0 )
+        {
+            opt.debug_level = atoi( q );
+            if( opt.debug_level < 0 || opt.debug_level > 65535 )
+                goto usage;
+        }
+        else if( strcmp( p, "subject_name" ) == 0 )
+        {
+            printf("p: '%s', q: '%s'\n", p, q);
+            opt.subject_name = q;
+        }
+        else
+            goto usage;
+    }
+
+    /*
+     * 1.0. Check the subject name for validity
+     */
+    s = opt.subject_name;
+    end = s + strlen( s );
+
+    c = s;
+
+    in_tag = 1;
+    while( c <= end )
+    {
+        if( in_tag && *c == '=' )
+        {
+            if( memcmp( s, "CN", 2 ) == 0 && c - s == 2 )
+                oid = OID_CN;
+            else if( memcmp( s, "C", 1 ) == 0 && c - s == 1 )
+                oid = OID_COUNTRY;
+            else if( memcmp( s, "O", 1 ) == 0 && c - s == 1 )
+                oid = OID_ORGANIZATION;
+            else if( memcmp( s, "L", 1 ) == 0 && c - s == 1 )
+                oid = OID_LOCALITY;
+            else if( memcmp( s, "R", 1 ) == 0 && c - s == 1 )
+                oid = OID_PKCS9_EMAIL;
+            else if( memcmp( s, "OU", 2 ) == 0 && c - s == 2 )
+                oid = OID_ORG_UNIT;
+            else if( memcmp( s, "ST", 2 ) == 0 && c - s == 2 )
+                oid = OID_STATE;
+            else
+            {
+                printf("Failed to parse subject name.\n");
+                goto exit;
+            }
+
+            s = c + 1;
+            in_tag = 0;
+        }
+        
+        if( !in_tag && ( *c == ',' || c == end ) )
+        {
+            if( c - s > 127 )
+            {
+                printf("Name too large for buffer.\n");
+                goto exit;
+            }
+
+            if( cur == NULL )
+            {
+                req_name = malloc( sizeof(x509_req_name) );
+                cur = req_name;
+            }
+            else
+            {
+                cur->next = malloc( sizeof(x509_req_name) );
+                cur = cur->next;
+            }
+
+            if( cur == NULL )
+            {
+                printf( "Failed to allocate memory.\n" );
+                goto exit;
+            }
+
+            memset( cur, 0, sizeof(x509_req_name) );
+
+            strncpy( cur->oid, oid, strlen( oid ) );
+            strncpy( cur->name, s, c - s );
+
+            s = c + 1;
+            in_tag = 1;
+        }
+        c++;
+    }
+
+    /*
+     * 1.1. Load the key
+     */
+    printf( "\n  . Loading the private key ..." );
+    fflush( stdout );
+
+    ret = x509parse_keyfile( &rsa, opt.filename, NULL );
+
+    if( ret != 0 )
+    {
+#ifdef POLARSSL_ERROR_C
+        error_strerror( ret, buf, 1024 );
+#endif
+        printf( " failed\n  !  x509parse_key returned %d - %s\n\n", ret, buf );
+        rsa_free( &rsa );
+        goto exit;
+    }
+
+    printf( " ok\n" );
+
+    write_certificate_request( &rsa, req_name, opt.output_file );
+
+exit:
+
+    rsa_free( &rsa );
+
+#if defined(_WIN32)
+    printf( "  + Press Enter to exit this program.\n" );
+    fflush( stdout ); getchar();
+#endif
+
+    return( ret );
+}
+#endif /* POLARSSL_BIGNUM_C && POLARSSL_RSA_C &&
+          POLARSSL_X509_PARSE_C && POLARSSL_FS_IO */