diff --git a/library/x509_create.c b/library/x509_create.c
new file mode 100644
index 0000000..546e8fa
--- /dev/null
+++ b/library/x509_create.c
@@ -0,0 +1,379 @@
+/*
+ *  X.509 base functions for creating certificates / CSRs
+ *
+ *  Copyright (C) 2006-2015, ARM Limited, All Rights Reserved
+ *  SPDX-License-Identifier: Apache-2.0
+ *
+ *  Licensed under the Apache License, Version 2.0 (the "License"); you may
+ *  not use this file except in compliance with the License.
+ *  You may obtain a copy of the License at
+ *
+ *  http://www.apache.org/licenses/LICENSE-2.0
+ *
+ *  Unless required by applicable law or agreed to in writing, software
+ *  distributed under the License is distributed on an "AS IS" BASIS, WITHOUT
+ *  WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ *  See the License for the specific language governing permissions and
+ *  limitations under the License.
+ *
+ *  This file is part of mbed TLS (https://tls.mbed.org)
+ */
+
+#if !defined(MBEDTLS_CONFIG_FILE)
+#include "mbedtls/config.h"
+#else
+#include MBEDTLS_CONFIG_FILE
+#endif
+
+#if defined(MBEDTLS_X509_CREATE_C)
+
+#include "mbedtls/x509.h"
+#include "mbedtls/asn1write.h"
+#include "mbedtls/oid.h"
+
+#include <string.h>
+
+/* Structure linking OIDs for X.509 DN AttributeTypes to their
+ * string representations and default string encodings used by Mbed TLS. */
+typedef struct {
+   const char *name; /* String representation of AttributeType, e.g.
+                      * "CN" or "emailAddress". */
+   size_t name_len;  /* Length of 'name', without trailing 0 byte. */
+   const char *oid;  /* String representation of OID of AttributeType,
+                      * as per RFC 5280, Appendix A.1. */
+   int default_tag;  /* The default character encoding used for the
+                      * given attribute type, e.g.
+                      * MBEDTLS_ASN1_UTF8_STRING for UTF-8. */
+} x509_attr_descriptor_t;
+
+#define ADD_STRLEN( s )     s, sizeof( s ) - 1
+
+/* X.509 DN attributes from RFC 5280, Appendix A.1. */
+static const x509_attr_descriptor_t x509_attrs[] =
+{
+    { ADD_STRLEN( "CN" ),
+      MBEDTLS_OID_AT_CN, MBEDTLS_ASN1_UTF8_STRING },
+    { ADD_STRLEN( "commonName" ),
+      MBEDTLS_OID_AT_CN, MBEDTLS_ASN1_UTF8_STRING },
+    { ADD_STRLEN( "C" ),
+      MBEDTLS_OID_AT_COUNTRY, MBEDTLS_ASN1_PRINTABLE_STRING },
+    { ADD_STRLEN( "countryName" ),
+      MBEDTLS_OID_AT_COUNTRY, MBEDTLS_ASN1_PRINTABLE_STRING },
+    { ADD_STRLEN( "O" ),
+      MBEDTLS_OID_AT_ORGANIZATION, MBEDTLS_ASN1_UTF8_STRING },
+    { ADD_STRLEN( "organizationName" ),
+      MBEDTLS_OID_AT_ORGANIZATION, MBEDTLS_ASN1_UTF8_STRING },
+    { ADD_STRLEN( "L" ),
+      MBEDTLS_OID_AT_LOCALITY, MBEDTLS_ASN1_UTF8_STRING },
+    { ADD_STRLEN( "locality" ),
+      MBEDTLS_OID_AT_LOCALITY, MBEDTLS_ASN1_UTF8_STRING },
+    { ADD_STRLEN( "R" ),
+      MBEDTLS_OID_PKCS9_EMAIL, MBEDTLS_ASN1_IA5_STRING },
+    { ADD_STRLEN( "OU" ),
+      MBEDTLS_OID_AT_ORG_UNIT, MBEDTLS_ASN1_UTF8_STRING },
+    { ADD_STRLEN( "organizationalUnitName" ),
+      MBEDTLS_OID_AT_ORG_UNIT, MBEDTLS_ASN1_UTF8_STRING },
+    { ADD_STRLEN( "ST" ),
+      MBEDTLS_OID_AT_STATE, MBEDTLS_ASN1_UTF8_STRING },
+    { ADD_STRLEN( "stateOrProvinceName" ),
+      MBEDTLS_OID_AT_STATE, MBEDTLS_ASN1_UTF8_STRING },
+    { ADD_STRLEN( "emailAddress" ),
+      MBEDTLS_OID_PKCS9_EMAIL, MBEDTLS_ASN1_IA5_STRING },
+    { ADD_STRLEN( "serialNumber" ),
+      MBEDTLS_OID_AT_SERIAL_NUMBER, MBEDTLS_ASN1_PRINTABLE_STRING },
+    { ADD_STRLEN( "postalAddress" ),
+      MBEDTLS_OID_AT_POSTAL_ADDRESS, MBEDTLS_ASN1_PRINTABLE_STRING },
+    { ADD_STRLEN( "postalCode" ),
+      MBEDTLS_OID_AT_POSTAL_CODE, MBEDTLS_ASN1_PRINTABLE_STRING },
+    { ADD_STRLEN( "dnQualifier" ),
+      MBEDTLS_OID_AT_DN_QUALIFIER, MBEDTLS_ASN1_PRINTABLE_STRING },
+    { ADD_STRLEN( "title" ),
+      MBEDTLS_OID_AT_TITLE, MBEDTLS_ASN1_UTF8_STRING },
+    { ADD_STRLEN( "surName" ),
+      MBEDTLS_OID_AT_SUR_NAME, MBEDTLS_ASN1_UTF8_STRING },
+    { ADD_STRLEN( "SN" ),
+      MBEDTLS_OID_AT_SUR_NAME, MBEDTLS_ASN1_UTF8_STRING },
+    { ADD_STRLEN( "givenName" ),
+      MBEDTLS_OID_AT_GIVEN_NAME, MBEDTLS_ASN1_UTF8_STRING },
+    { ADD_STRLEN( "GN" ),
+      MBEDTLS_OID_AT_GIVEN_NAME, MBEDTLS_ASN1_UTF8_STRING },
+    { ADD_STRLEN( "initials" ),
+      MBEDTLS_OID_AT_INITIALS, MBEDTLS_ASN1_UTF8_STRING },
+    { ADD_STRLEN( "pseudonym" ),
+      MBEDTLS_OID_AT_PSEUDONYM, MBEDTLS_ASN1_UTF8_STRING },
+    { ADD_STRLEN( "generationQualifier" ),
+      MBEDTLS_OID_AT_GENERATION_QUALIFIER, MBEDTLS_ASN1_UTF8_STRING },
+    { ADD_STRLEN( "domainComponent" ),
+      MBEDTLS_OID_DOMAIN_COMPONENT, MBEDTLS_ASN1_IA5_STRING },
+    { ADD_STRLEN( "DC" ),
+      MBEDTLS_OID_DOMAIN_COMPONENT,   MBEDTLS_ASN1_IA5_STRING },
+    { NULL, 0, NULL, MBEDTLS_ASN1_NULL }
+};
+
+static const x509_attr_descriptor_t *x509_attr_descr_from_name( const char *name, size_t name_len )
+{
+    const x509_attr_descriptor_t *cur;
+
+    for( cur = x509_attrs; cur->name != NULL; cur++ )
+        if( cur->name_len == name_len &&
+            strncmp( cur->name, name, name_len ) == 0 )
+            break;
+
+    if ( cur->name == NULL )
+        return( NULL );
+
+    return( cur );
+}
+
+int mbedtls_x509_string_to_names( mbedtls_asn1_named_data **head, const char *name )
+{
+    int ret = 0;
+    const char *s = name, *c = s;
+    const char *end = s + strlen( s );
+    const char *oid = NULL;
+    const x509_attr_descriptor_t* attr_descr = NULL;
+    int in_tag = 1;
+    char data[MBEDTLS_X509_MAX_DN_NAME_SIZE];
+    char *d = data;
+
+    /* Clear existing chain if present */
+    mbedtls_asn1_free_named_data_list( head );
+
+    while( c <= end )
+    {
+        if( in_tag && *c == '=' )
+        {
+            if( ( attr_descr = x509_attr_descr_from_name( s, c - s ) ) == NULL )
+            {
+                ret = MBEDTLS_ERR_X509_UNKNOWN_OID;
+                goto exit;
+            }
+
+            oid = attr_descr->oid;
+            s = c + 1;
+            in_tag = 0;
+            d = data;
+        }
+
+        if( !in_tag && *c == '\\' && c != end )
+        {
+            c++;
+
+            /* Check for valid escaped characters */
+            if( c == end || *c != ',' )
+            {
+                ret = MBEDTLS_ERR_X509_INVALID_NAME;
+                goto exit;
+            }
+        }
+        else if( !in_tag && ( *c == ',' || c == end ) )
+        {
+            mbedtls_asn1_named_data* cur =
+                mbedtls_asn1_store_named_data( head, oid, strlen( oid ),
+                                               (unsigned char *) data,
+                                               d - data );
+
+            if(cur == NULL )
+            {
+                return( MBEDTLS_ERR_X509_ALLOC_FAILED );
+            }
+
+            // set tagType
+            cur->val.tag = attr_descr->default_tag;
+
+            while( c < end && *(c + 1) == ' ' )
+                c++;
+
+            s = c + 1;
+            in_tag = 1;
+        }
+
+        if( !in_tag && s != c + 1 )
+        {
+            *(d++) = *c;
+
+            if( d - data == MBEDTLS_X509_MAX_DN_NAME_SIZE )
+            {
+                ret = MBEDTLS_ERR_X509_INVALID_NAME;
+                goto exit;
+            }
+        }
+
+        c++;
+    }
+
+exit:
+
+    return( ret );
+}
+
+/* The first byte of the value in the mbedtls_asn1_named_data structure is reserved
+ * to store the critical boolean for us
+ */
+int mbedtls_x509_set_extension( mbedtls_asn1_named_data **head, const char *oid, size_t oid_len,
+                        int critical, const unsigned char *val, size_t val_len )
+{
+    mbedtls_asn1_named_data *cur;
+
+    if( ( cur = mbedtls_asn1_store_named_data( head, oid, oid_len,
+                                       NULL, val_len + 1 ) ) == NULL )
+    {
+        return( MBEDTLS_ERR_X509_ALLOC_FAILED );
+    }
+
+    cur->val.p[0] = critical;
+    memcpy( cur->val.p + 1, val, val_len );
+
+    return( 0 );
+}
+
+/*
+ *  RelativeDistinguishedName ::=
+ *    SET OF AttributeTypeAndValue
+ *
+ *  AttributeTypeAndValue ::= SEQUENCE {
+ *    type     AttributeType,
+ *    value    AttributeValue }
+ *
+ *  AttributeType ::= OBJECT IDENTIFIER
+ *
+ *  AttributeValue ::= ANY DEFINED BY AttributeType
+ */
+static int x509_write_name( unsigned char **p, unsigned char *start, mbedtls_asn1_named_data* cur_name)
+{
+    int ret;
+    size_t len = 0;
+    const char *oid             = (const char*)cur_name->oid.p;
+    size_t oid_len              = cur_name->oid.len;
+    const unsigned char *name   = cur_name->val.p;
+    size_t name_len             = cur_name->val.len;
+
+    // Write correct string tag and value
+    MBEDTLS_ASN1_CHK_ADD( len, mbedtls_asn1_write_tagged_string( p, start,
+                                                       cur_name->val.tag,
+                                                       (const char *) name,
+                                                       name_len ) );
+    // Write OID
+    //
+    MBEDTLS_ASN1_CHK_ADD( len, mbedtls_asn1_write_oid( p, start, oid,
+                                                       oid_len ) );
+
+    MBEDTLS_ASN1_CHK_ADD( len, mbedtls_asn1_write_len( p, start, len ) );
+    MBEDTLS_ASN1_CHK_ADD( len, mbedtls_asn1_write_tag( p, start,
+                                                    MBEDTLS_ASN1_CONSTRUCTED |
+                                                    MBEDTLS_ASN1_SEQUENCE ) );
+
+    MBEDTLS_ASN1_CHK_ADD( len, mbedtls_asn1_write_len( p, start, len ) );
+    MBEDTLS_ASN1_CHK_ADD( len, mbedtls_asn1_write_tag( p, start,
+                                                 MBEDTLS_ASN1_CONSTRUCTED |
+                                                 MBEDTLS_ASN1_SET ) );
+
+    return( (int) len );
+}
+
+int mbedtls_x509_write_names( unsigned char **p, unsigned char *start,
+                              mbedtls_asn1_named_data *first )
+{
+    int ret;
+    size_t len = 0;
+    mbedtls_asn1_named_data *cur = first;
+
+    while( cur != NULL )
+    {
+        MBEDTLS_ASN1_CHK_ADD( len, x509_write_name( p, start, cur ) );
+        cur = cur->next;
+    }
+
+    MBEDTLS_ASN1_CHK_ADD( len, mbedtls_asn1_write_len( p, start, len ) );
+    MBEDTLS_ASN1_CHK_ADD( len, mbedtls_asn1_write_tag( p, start, MBEDTLS_ASN1_CONSTRUCTED |
+                                                 MBEDTLS_ASN1_SEQUENCE ) );
+
+    return( (int) len );
+}
+
+int mbedtls_x509_write_sig( unsigned char **p, unsigned char *start,
+                    const char *oid, size_t oid_len,
+                    unsigned char *sig, size_t size )
+{
+    int ret;
+    size_t len = 0;
+
+    if( *p < start || (size_t)( *p - start ) < size )
+        return( MBEDTLS_ERR_ASN1_BUF_TOO_SMALL );
+
+    len = size;
+    (*p) -= len;
+    memcpy( *p, sig, len );
+
+    if( *p - start < 1 )
+        return( MBEDTLS_ERR_ASN1_BUF_TOO_SMALL );
+
+    *--(*p) = 0;
+    len += 1;
+
+    MBEDTLS_ASN1_CHK_ADD( len, mbedtls_asn1_write_len( p, start, len ) );
+    MBEDTLS_ASN1_CHK_ADD( len, mbedtls_asn1_write_tag( p, start, MBEDTLS_ASN1_BIT_STRING ) );
+
+    // Write OID
+    //
+    MBEDTLS_ASN1_CHK_ADD( len, mbedtls_asn1_write_algorithm_identifier( p, start, oid,
+                                                        oid_len, 0 ) );
+
+    return( (int) len );
+}
+
+static int x509_write_extension( unsigned char **p, unsigned char *start,
+                                 mbedtls_asn1_named_data *ext )
+{
+    int ret;
+    size_t len = 0;
+
+    MBEDTLS_ASN1_CHK_ADD( len, mbedtls_asn1_write_raw_buffer( p, start, ext->val.p + 1,
+                                              ext->val.len - 1 ) );
+    MBEDTLS_ASN1_CHK_ADD( len, mbedtls_asn1_write_len( p, start, ext->val.len - 1 ) );
+    MBEDTLS_ASN1_CHK_ADD( len, mbedtls_asn1_write_tag( p, start, MBEDTLS_ASN1_OCTET_STRING ) );
+
+    if( ext->val.p[0] != 0 )
+    {
+        MBEDTLS_ASN1_CHK_ADD( len, mbedtls_asn1_write_bool( p, start, 1 ) );
+    }
+
+    MBEDTLS_ASN1_CHK_ADD( len, mbedtls_asn1_write_raw_buffer( p, start, ext->oid.p,
+                                              ext->oid.len ) );
+    MBEDTLS_ASN1_CHK_ADD( len, mbedtls_asn1_write_len( p, start, ext->oid.len ) );
+    MBEDTLS_ASN1_CHK_ADD( len, mbedtls_asn1_write_tag( p, start, MBEDTLS_ASN1_OID ) );
+
+    MBEDTLS_ASN1_CHK_ADD( len, mbedtls_asn1_write_len( p, start, len ) );
+    MBEDTLS_ASN1_CHK_ADD( len, mbedtls_asn1_write_tag( p, start, MBEDTLS_ASN1_CONSTRUCTED |
+                                                 MBEDTLS_ASN1_SEQUENCE ) );
+
+    return( (int) len );
+}
+
+/*
+ * Extension  ::=  SEQUENCE  {
+ *     extnID      OBJECT IDENTIFIER,
+ *     critical    BOOLEAN DEFAULT FALSE,
+ *     extnValue   OCTET STRING
+ *                 -- contains the DER encoding of an ASN.1 value
+ *                 -- corresponding to the extension type identified
+ *                 -- by extnID
+ *     }
+ */
+int mbedtls_x509_write_extensions( unsigned char **p, unsigned char *start,
+                           mbedtls_asn1_named_data *first )
+{
+    int ret;
+    size_t len = 0;
+    mbedtls_asn1_named_data *cur_ext = first;
+
+    while( cur_ext != NULL )
+    {
+        MBEDTLS_ASN1_CHK_ADD( len, x509_write_extension( p, start, cur_ext ) );
+        cur_ext = cur_ext->next;
+    }
+
+    return( (int) len );
+}
+
+#endif /* MBEDTLS_X509_CREATE_C */