diff --git a/library/x509_csr_write.c b/library/x509_csr_write.c
new file mode 100644
index 0000000..b744300
--- /dev/null
+++ b/library/x509_csr_write.c
@@ -0,0 +1,244 @@
+/*
+ *  X.509 Certificate Signing Request writing
+ *
+ *  Copyright (C) 2006-2013, 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.
+ */
+/*
+ * References:
+ * - CSRs: PKCS#10 v1.7 aka RFC 2986
+ * - attributes: PKCS#9 v2.0 aka RFC 2985
+ */
+
+#include "polarssl/config.h"
+
+#if defined(POLARSSL_X509_CSR_WRITE_C)
+
+#include "polarssl/x509_csr.h"
+#include "polarssl/oid.h"
+#include "polarssl/asn1write.h"
+
+#if defined(POLARSSL_PEM_WRITE_C)
+#include "polarssl/pem.h"
+#endif
+
+#include <string.h>
+#include <stdlib.h>
+
+void x509write_csr_init( x509write_csr *ctx )
+{
+    memset( ctx, 0, sizeof(x509write_csr) );
+}
+
+void x509write_csr_free( x509write_csr *ctx )
+{
+    asn1_free_named_data_list( &ctx->subject );
+    asn1_free_named_data_list( &ctx->extensions );
+
+    memset( ctx, 0, sizeof(x509write_csr) );
+}
+
+void x509write_csr_set_md_alg( x509write_csr *ctx, md_type_t md_alg )
+{
+    ctx->md_alg = md_alg;
+}
+
+void x509write_csr_set_key( x509write_csr *ctx, pk_context *key )
+{
+    ctx->key = key;
+}
+
+int x509write_csr_set_subject_name( x509write_csr *ctx, char *subject_name )
+{
+    return x509write_string_to_names( &ctx->subject, subject_name );
+}
+
+int x509write_csr_set_extension( x509write_csr *ctx,
+                                 const char *oid, size_t oid_len,
+                                 const unsigned char *val, size_t val_len )
+{
+    return x509_set_extension( &ctx->extensions, oid, oid_len,
+                               0, val, val_len );
+}
+
+int x509write_csr_set_key_usage( x509write_csr *ctx, unsigned char key_usage )
+{
+    unsigned char buf[4];
+    unsigned char *c;
+    int ret;
+
+    c = buf + 4;
+
+    if( ( ret = asn1_write_bitstring( &c, buf, &key_usage, 7 ) ) != 4 )
+        return( ret );
+
+    ret = x509write_csr_set_extension( ctx, OID_KEY_USAGE,
+                                       OID_SIZE( OID_KEY_USAGE ),
+                                       buf, 4 );
+    if( ret != 0 )
+        return( ret );
+
+    return( 0 );
+}
+
+int x509write_csr_set_ns_cert_type( x509write_csr *ctx,
+                                    unsigned char ns_cert_type )
+{
+    unsigned char buf[4];
+    unsigned char *c;
+    int ret;
+
+    c = buf + 4;
+
+    if( ( ret = asn1_write_bitstring( &c, buf, &ns_cert_type, 8 ) ) != 4 )
+        return( ret );
+
+    ret = x509write_csr_set_extension( ctx, OID_NS_CERT_TYPE,
+                                       OID_SIZE( OID_NS_CERT_TYPE ),
+                                       buf, 4 );
+    if( ret != 0 )
+        return( ret );
+
+    return( 0 );
+}
+
+int x509write_csr_der( x509write_csr *ctx, unsigned char *buf, size_t size,
+                       int (*f_rng)(void *, unsigned char *, size_t),
+                       void *p_rng )
+{
+    int ret;
+    const char *sig_oid;
+    size_t sig_oid_len = 0;
+    unsigned char *c, *c2;
+    unsigned char hash[64];
+    unsigned char sig[POLARSSL_MPI_MAX_SIZE];
+    unsigned char tmp_buf[2048];
+    size_t pub_len = 0, sig_and_oid_len = 0, sig_len;
+    size_t len = 0;
+    pk_type_t pk_alg;
+
+    /*
+     * Prepare data to be signed in tmp_buf
+     */
+    c = tmp_buf + sizeof( tmp_buf );
+
+    ASN1_CHK_ADD( len, x509_write_extensions( &c, tmp_buf, ctx->extensions ) );
+
+    if( len )
+    {
+        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 ) );
+
+        ASN1_CHK_ADD( len, asn1_write_len( &c, tmp_buf, len ) );
+        ASN1_CHK_ADD( len, asn1_write_tag( &c, tmp_buf, ASN1_CONSTRUCTED | ASN1_SET ) );
+
+        ASN1_CHK_ADD( len, asn1_write_oid( &c, tmp_buf, OID_PKCS9_CSR_EXT_REQ,
+                                          OID_SIZE( OID_PKCS9_CSR_EXT_REQ ) ) );
+
+        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 ) );
+    }
+
+    ASN1_CHK_ADD( len, asn1_write_len( &c, tmp_buf, len ) );
+    ASN1_CHK_ADD( len, asn1_write_tag( &c, tmp_buf, ASN1_CONSTRUCTED | ASN1_CONTEXT_SPECIFIC ) );
+
+    ASN1_CHK_ADD( pub_len, pk_write_pubkey_der( ctx->key,
+                                                tmp_buf, c - tmp_buf ) );
+    c -= pub_len;
+    len += pub_len;
+
+    /*
+     *  Subject  ::=  Name
+     */
+    ASN1_CHK_ADD( len, x509_write_names( &c, tmp_buf, ctx->subject ) );
+
+    /*
+     *  Version  ::=  INTEGER  {  v1(0), v2(1), v3(2)  }
+     */
+    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 ) );
+
+    /*
+     * Prepare signature
+     */
+    md( md_info_from_type( ctx->md_alg ), c, len, hash );
+
+    pk_alg = pk_get_type( ctx->key );
+    if( pk_alg == POLARSSL_PK_ECKEY )
+        pk_alg = POLARSSL_PK_ECDSA;
+
+    if( ( ret = pk_sign( ctx->key, ctx->md_alg, hash, 0, sig, &sig_len,
+                         f_rng, p_rng ) ) != 0 ||
+        ( ret = oid_get_oid_by_sig_alg( pk_alg, ctx->md_alg,
+                                        &sig_oid, &sig_oid_len ) ) != 0 )
+    {
+        return( ret );
+    }
+
+    /*
+     * Write data to output buffer
+     */
+    c2 = buf + size;
+    ASN1_CHK_ADD( sig_and_oid_len, x509_write_sig( &c2, buf,
+                                        sig_oid, sig_oid_len, sig, sig_len ) );
+
+    c2 -= len;
+    memcpy( c2, c, len );
+
+    len += sig_and_oid_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 );
+}
+
+#define PEM_BEGIN_CSR           "-----BEGIN CERTIFICATE REQUEST-----\n"
+#define PEM_END_CSR             "-----END CERTIFICATE REQUEST-----\n"
+
+#if defined(POLARSSL_PEM_WRITE_C)
+int x509write_csr_pem( x509write_csr *ctx, unsigned char *buf, size_t size,
+                       int (*f_rng)(void *, unsigned char *, size_t),
+                       void *p_rng )
+{
+    int ret;
+    unsigned char output_buf[4096];
+    size_t olen = 0;
+
+    if( ( ret = x509write_csr_der( ctx, output_buf, sizeof(output_buf),
+                                   f_rng, p_rng ) ) < 0 )
+    {
+        return( ret );
+    }
+
+    if( ( ret = pem_write_buffer( PEM_BEGIN_CSR, PEM_END_CSR,
+                                  output_buf + sizeof(output_buf) - ret,
+                                  ret, buf, size, &olen ) ) != 0 )
+    {
+        return( ret );
+    }
+
+    return( 0 );
+}
+#endif /* POLARSSL_PEM_WRITE_C */
+
+#endif /* POLARSSL_X509_CSR_WRITE_C */