diff --git a/library/pkwrite.c b/library/pkwrite.c
new file mode 100644
index 0000000..741df08
--- /dev/null
+++ b/library/pkwrite.c
@@ -0,0 +1,389 @@
+/*
+ *  Public Key layer for writing key files and structures
+ *
+ *  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.
+ */
+
+#include "polarssl/config.h"
+
+#if defined(POLARSSL_PK_C)
+
+#include "polarssl/pk.h"
+#include "polarssl/asn1write.h"
+#include "polarssl/oid.h"
+
+#if defined(POLARSSL_RSA_C)
+#include "polarssl/rsa.h"
+#endif
+#if defined(POLARSSL_ECP_C)
+#include "polarssl/ecp.h"
+#endif
+#if defined(POLARSSL_ECDSA_C)
+#include "polarssl/ecdsa.h"
+#endif
+#if defined(POLARSSL_BASE64_C)
+#include "polarssl/base64.h"
+#endif
+
+#if defined(POLARSSL_MEMORY_C)
+#include "polarssl/memory.h"
+#else
+#include <stdlib.h>
+#define polarssl_malloc     malloc
+#define polarssl_free       free
+#endif
+
+#if defined(POLARSSL_RSA_C)
+/*
+ *  RSAPublicKey ::= SEQUENCE {
+ *      modulus           INTEGER,  -- n
+ *      publicExponent    INTEGER   -- e
+ *  }
+ */
+static int pk_write_rsa_pubkey( unsigned char **p, unsigned char *start,
+                                  rsa_context *rsa )
+{
+    int ret;
+    size_t len = 0;
+
+    ASN1_CHK_ADD( len, asn1_write_mpi( p, start, &rsa->E ) );
+    ASN1_CHK_ADD( len, asn1_write_mpi( p, start, &rsa->N ) );
+
+    ASN1_CHK_ADD( len, asn1_write_len( p, start, len ) );
+    ASN1_CHK_ADD( len, asn1_write_tag( p, start, ASN1_CONSTRUCTED | ASN1_SEQUENCE ) );
+
+    return( len );
+}
+#endif /* POLARSSL_RSA_C */
+
+#if defined(POLARSSL_ECP_C)
+/*
+ * EC public key is an EC point
+ */
+static int pk_write_ec_pubkey( unsigned char **p, unsigned char *start,
+                                 ecp_keypair *ec )
+{
+    int ret;
+    size_t len = 0;
+    unsigned char buf[POLARSSL_ECP_MAX_PT_LEN];
+
+    if( ( ret = ecp_point_write_binary( &ec->grp, &ec->Q,
+                                        POLARSSL_ECP_PF_UNCOMPRESSED,
+                                        &len, buf, sizeof( buf ) ) ) != 0 )
+    {
+        return( ret );
+    }
+
+    if( *p - start < (int) len )
+        return( POLARSSL_ERR_ASN1_BUF_TOO_SMALL );
+
+    *p -= len;
+    memcpy( *p, buf, len );
+
+    return( len );
+}
+
+/*
+ * ECParameters ::= CHOICE {
+ *   namedCurve         OBJECT IDENTIFIER
+ * }
+ */
+static int pk_write_ec_param( unsigned char **p, unsigned char *start,
+                                ecp_keypair *ec )
+{
+    int ret;
+    size_t len = 0;
+    const char *oid;
+    size_t oid_len;
+
+    if( ( ret = oid_get_oid_by_ec_grp( ec->grp.id, &oid, &oid_len ) ) != 0 )
+        return( ret );
+
+    ASN1_CHK_ADD( len, asn1_write_oid( p, start, oid, oid_len ) );
+
+    return( len );
+}
+#endif /* POLARSSL_ECP_C */
+
+int pk_write_pubkey( unsigned char **p, unsigned char *start,
+                     const pk_context *key )
+{
+    int ret;
+    size_t len = 0;
+
+#if defined(POLARSSL_RSA_C)
+    if( pk_get_type( key ) == POLARSSL_PK_RSA )
+        ASN1_CHK_ADD( len, pk_write_rsa_pubkey( p, start, pk_rsa( *key ) ) );
+    else
+#endif
+#if defined(POLARSSL_ECP_C)
+    if( pk_get_type( key ) == POLARSSL_PK_ECKEY )
+        ASN1_CHK_ADD( len, pk_write_ec_pubkey( p, start, pk_ec( *key ) ) );
+    else
+#endif
+        return( POLARSSL_ERR_PK_FEATURE_UNAVAILABLE );
+
+    return( len );
+}
+
+int pk_write_pubkey_der( pk_context *key, unsigned char *buf, size_t size )
+{
+    int ret;
+    unsigned char *c;
+    size_t len = 0, par_len = 0, oid_len;
+    const char *oid;
+
+    c = buf + size;
+
+    ASN1_CHK_ADD( len, pk_write_pubkey( &c, buf, key ) );
+
+    if( c - buf < 1 )
+        return( POLARSSL_ERR_ASN1_BUF_TOO_SMALL );
+
+    /*
+     *  SubjectPublicKeyInfo  ::=  SEQUENCE  {
+     *       algorithm            AlgorithmIdentifier,
+     *       subjectPublicKey     BIT STRING }
+     */
+    *--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 ) );
+
+    if( ( ret = oid_get_oid_by_pk_alg( pk_get_type( key ),
+                                       &oid, &oid_len ) ) != 0 )
+    {
+        return( ret );
+    }
+
+#if defined(POLARSSL_ECP_C)
+    if( pk_get_type( key ) == POLARSSL_PK_ECKEY )
+    {
+        ASN1_CHK_ADD( par_len, pk_write_ec_param( &c, buf, pk_ec( *key ) ) );
+    }
+#endif
+
+    ASN1_CHK_ADD( len, asn1_write_algorithm_identifier( &c, buf, oid, oid_len,
+                                                        par_len ) );
+
+    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 pk_write_key_der( pk_context *key, unsigned char *buf, size_t size )
+{
+    int ret;
+    unsigned char *c = buf + size;
+    size_t len = 0;
+
+#if defined(POLARSSL_RSA_C)
+    if( pk_get_type( key ) == POLARSSL_PK_RSA )
+    {
+        rsa_context *rsa = pk_rsa( *key );
+
+        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 ) );
+    }
+    else
+#endif
+#if defined(POLARSSL_ECP_C)
+    if( pk_get_type( key ) == POLARSSL_PK_ECKEY )
+    {
+        ecp_keypair *ec = pk_ec( *key );
+        size_t pub_len = 0, par_len = 0;
+
+        /*
+         * RFC 5915, or SEC1 Appendix C.4
+         *
+         * ECPrivateKey ::= SEQUENCE {
+         *      version        INTEGER { ecPrivkeyVer1(1) } (ecPrivkeyVer1),
+         *      privateKey     OCTET STRING,
+         *      parameters [0] ECParameters {{ NamedCurve }} OPTIONAL,
+         *      publicKey  [1] BIT STRING OPTIONAL
+         *    }
+         */
+
+        /* publicKey */
+        ASN1_CHK_ADD( pub_len, pk_write_ec_pubkey( &c, buf, ec ) );
+
+        if( c - buf < 1 )
+            return( POLARSSL_ERR_ASN1_BUF_TOO_SMALL );
+        *--c = 0;
+        pub_len += 1;
+
+        ASN1_CHK_ADD( pub_len, asn1_write_len( &c, buf, pub_len ) );
+        ASN1_CHK_ADD( pub_len, asn1_write_tag( &c, buf, ASN1_BIT_STRING ) );
+
+        ASN1_CHK_ADD( pub_len, asn1_write_len( &c, buf, pub_len ) );
+        ASN1_CHK_ADD( pub_len, asn1_write_tag( &c, buf,
+                            ASN1_CONTEXT_SPECIFIC | ASN1_CONSTRUCTED | 1 ) );
+        len += pub_len;
+
+        /* parameters */
+        ASN1_CHK_ADD( par_len, pk_write_ec_param( &c, buf, ec ) );
+
+        ASN1_CHK_ADD( par_len, asn1_write_len( &c, buf, par_len ) );
+        ASN1_CHK_ADD( par_len, asn1_write_tag( &c, buf,
+                            ASN1_CONTEXT_SPECIFIC | ASN1_CONSTRUCTED | 0 ) );
+        len += par_len;
+
+        /* privateKey: write as MPI then fix tag */
+        ASN1_CHK_ADD( len, asn1_write_mpi( &c, buf, &ec->d ) );
+        *c = ASN1_OCTET_STRING;
+
+        /* version */
+        ASN1_CHK_ADD( len, asn1_write_int( &c, buf, 1 ) );
+
+        ASN1_CHK_ADD( len, asn1_write_len( &c, buf, len ) );
+        ASN1_CHK_ADD( len, asn1_write_tag( &c, buf, ASN1_CONSTRUCTED | ASN1_SEQUENCE ) );
+    }
+    else
+#endif
+        return( POLARSSL_ERR_PK_FEATURE_UNAVAILABLE );
+
+    return( len );
+}
+
+#if defined(POLARSSL_BASE64_C)
+static int pk_write_pemify( const char *begin_str, const char *end_str,
+                             const unsigned char *der_data, size_t der_len,
+                             unsigned char *buf, size_t size )
+{
+    int ret;
+    unsigned char base_buf[4096];
+    unsigned char *c = base_buf, *p = buf;
+    size_t len = 0, olen = sizeof(base_buf);
+
+    if( ( ret = base64_encode( base_buf, &olen, der_data, der_len ) ) != 0 )
+        return( ret );
+
+    if( olen + strlen( begin_str ) + strlen( end_str ) +
+        olen / 64 > size )
+    {
+        return( POLARSSL_ERR_BASE64_BUFFER_TOO_SMALL );
+    }
+
+    memcpy( p, begin_str, strlen( begin_str ) );
+    p += strlen( begin_str );
+
+    while( olen )
+    {
+        len = ( olen > 64 ) ? 64 : olen;
+        memcpy( p, c, len );
+        olen -= len;
+        p += len;
+        c += len;
+        *p++ = '\n';
+    }
+
+    memcpy( p, end_str, strlen( end_str ) );
+    p += strlen( end_str );
+
+    *p = '\0';
+
+    return( 0 );
+}
+
+#define PEM_BEGIN_PUBLIC_KEY    "-----BEGIN PUBLIC KEY-----\n"
+#define PEM_END_PUBLIC_KEY      "-----END PUBLIC KEY-----\n"
+
+#define PEM_BEGIN_PRIVATE_KEY_RSA   "-----BEGIN RSA PRIVATE KEY-----\n"
+#define PEM_END_PRIVATE_KEY_RSA     "-----END RSA PRIVATE KEY-----\n"
+#define PEM_BEGIN_PRIVATE_KEY_EC    "-----BEGIN EC PRIVATE KEY-----\n"
+#define PEM_END_PRIVATE_KEY_EC      "-----END EC PRIVATE KEY-----\n"
+
+int pk_write_pubkey_pem( pk_context *key, unsigned char *buf, size_t size )
+{
+    int ret;
+    unsigned char output_buf[4096];
+
+    if( ( ret = pk_write_pubkey_der( key, output_buf,
+                                      sizeof(output_buf) ) ) < 0 )
+    {
+        return( ret );
+    }
+
+    if( ( ret = pk_write_pemify( PEM_BEGIN_PUBLIC_KEY, PEM_END_PUBLIC_KEY,
+                                  output_buf + sizeof(output_buf) - ret,
+                                  ret, buf, size ) ) != 0 )
+    {
+        return( ret );
+    }
+
+    return( 0 );
+}
+
+int pk_write_key_pem( pk_context *key, unsigned char *buf, size_t size )
+{
+    int ret;
+    unsigned char output_buf[4096];
+    char *begin, *end;
+
+    if( ( ret = pk_write_key_der( key, output_buf,
+                                      sizeof(output_buf) ) ) < 0 )
+    {
+        return( ret );
+    }
+
+#if defined(POLARSSL_RSA_C)
+    if( pk_get_type( key ) == POLARSSL_PK_RSA )
+    {
+        begin = PEM_BEGIN_PRIVATE_KEY_RSA;
+        end = PEM_END_PRIVATE_KEY_RSA;
+    }
+    else
+#endif
+#if defined(POLARSSL_ECP_C)
+    if( pk_get_type( key ) == POLARSSL_PK_ECKEY )
+    {
+        begin = PEM_BEGIN_PRIVATE_KEY_EC;
+        end = PEM_END_PRIVATE_KEY_EC;
+    }
+    else
+#endif
+        return( POLARSSL_ERR_PK_FEATURE_UNAVAILABLE );
+
+    if( ( ret = pk_write_pemify( begin, end,
+                                  output_buf + sizeof(output_buf) - ret,
+                                  ret, buf, size ) ) != 0 )
+    {
+        return( ret );
+    }
+
+    return( 0 );
+}
+#endif /* POLARSSL_BASE64_C */
+
+#endif /* POLARSSL_PK_C */