diff --git a/library/asn1parse.c b/library/asn1parse.c
new file mode 100644
index 0000000..1375614
--- /dev/null
+++ b/library/asn1parse.c
@@ -0,0 +1,389 @@
+/*
+ *  Generic ASN.1 parsing
+ *
+ *  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 Crypto (https://tls.mbed.org)
+ */
+
+#if !defined(MBEDCRYPTO_CONFIG_FILE)
+#include "mbedcrypto/config.h"
+#else
+#include MBEDCRYPTO_CONFIG_FILE
+#endif
+
+#if defined(MBEDCRYPTO_ASN1_PARSE_C)
+
+#include "mbedcrypto/asn1.h"
+#include "mbedcrypto/platform_util.h"
+
+#include <string.h>
+
+#if defined(MBEDCRYPTO_BIGNUM_C)
+#include "mbedcrypto/bignum.h"
+#endif
+
+#if defined(MBEDCRYPTO_PLATFORM_C)
+#include "mbedcrypto/platform.h"
+#else
+#include <stdlib.h>
+#define mbedcrypto_calloc    calloc
+#define mbedcrypto_free       free
+#endif
+
+/*
+ * ASN.1 DER decoding routines
+ */
+int mbedcrypto_asn1_get_len( unsigned char **p,
+                  const unsigned char *end,
+                  size_t *len )
+{
+    if( ( end - *p ) < 1 )
+        return( MBEDCRYPTO_ERR_ASN1_OUT_OF_DATA );
+
+    if( ( **p & 0x80 ) == 0 )
+        *len = *(*p)++;
+    else
+    {
+        switch( **p & 0x7F )
+        {
+        case 1:
+            if( ( end - *p ) < 2 )
+                return( MBEDCRYPTO_ERR_ASN1_OUT_OF_DATA );
+
+            *len = (*p)[1];
+            (*p) += 2;
+            break;
+
+        case 2:
+            if( ( end - *p ) < 3 )
+                return( MBEDCRYPTO_ERR_ASN1_OUT_OF_DATA );
+
+            *len = ( (size_t)(*p)[1] << 8 ) | (*p)[2];
+            (*p) += 3;
+            break;
+
+        case 3:
+            if( ( end - *p ) < 4 )
+                return( MBEDCRYPTO_ERR_ASN1_OUT_OF_DATA );
+
+            *len = ( (size_t)(*p)[1] << 16 ) |
+                   ( (size_t)(*p)[2] << 8  ) | (*p)[3];
+            (*p) += 4;
+            break;
+
+        case 4:
+            if( ( end - *p ) < 5 )
+                return( MBEDCRYPTO_ERR_ASN1_OUT_OF_DATA );
+
+            *len = ( (size_t)(*p)[1] << 24 ) | ( (size_t)(*p)[2] << 16 ) |
+                   ( (size_t)(*p)[3] << 8  ) |           (*p)[4];
+            (*p) += 5;
+            break;
+
+        default:
+            return( MBEDCRYPTO_ERR_ASN1_INVALID_LENGTH );
+        }
+    }
+
+    if( *len > (size_t) ( end - *p ) )
+        return( MBEDCRYPTO_ERR_ASN1_OUT_OF_DATA );
+
+    return( 0 );
+}
+
+int mbedcrypto_asn1_get_tag( unsigned char **p,
+                  const unsigned char *end,
+                  size_t *len, int tag )
+{
+    if( ( end - *p ) < 1 )
+        return( MBEDCRYPTO_ERR_ASN1_OUT_OF_DATA );
+
+    if( **p != tag )
+        return( MBEDCRYPTO_ERR_ASN1_UNEXPECTED_TAG );
+
+    (*p)++;
+
+    return( mbedcrypto_asn1_get_len( p, end, len ) );
+}
+
+int mbedcrypto_asn1_get_bool( unsigned char **p,
+                   const unsigned char *end,
+                   int *val )
+{
+    int ret;
+    size_t len;
+
+    if( ( ret = mbedcrypto_asn1_get_tag( p, end, &len, MBEDCRYPTO_ASN1_BOOLEAN ) ) != 0 )
+        return( ret );
+
+    if( len != 1 )
+        return( MBEDCRYPTO_ERR_ASN1_INVALID_LENGTH );
+
+    *val = ( **p != 0 ) ? 1 : 0;
+    (*p)++;
+
+    return( 0 );
+}
+
+int mbedcrypto_asn1_get_int( unsigned char **p,
+                  const unsigned char *end,
+                  int *val )
+{
+    int ret;
+    size_t len;
+
+    if( ( ret = mbedcrypto_asn1_get_tag( p, end, &len, MBEDCRYPTO_ASN1_INTEGER ) ) != 0 )
+        return( ret );
+
+    if( len == 0 || len > sizeof( int ) || ( **p & 0x80 ) != 0 )
+        return( MBEDCRYPTO_ERR_ASN1_INVALID_LENGTH );
+
+    *val = 0;
+
+    while( len-- > 0 )
+    {
+        *val = ( *val << 8 ) | **p;
+        (*p)++;
+    }
+
+    return( 0 );
+}
+
+#if defined(MBEDCRYPTO_BIGNUM_C)
+int mbedcrypto_asn1_get_mpi( unsigned char **p,
+                  const unsigned char *end,
+                  mbedcrypto_mpi *X )
+{
+    int ret;
+    size_t len;
+
+    if( ( ret = mbedcrypto_asn1_get_tag( p, end, &len, MBEDCRYPTO_ASN1_INTEGER ) ) != 0 )
+        return( ret );
+
+    ret = mbedcrypto_mpi_read_binary( X, *p, len );
+
+    *p += len;
+
+    return( ret );
+}
+#endif /* MBEDCRYPTO_BIGNUM_C */
+
+int mbedcrypto_asn1_get_bitstring( unsigned char **p, const unsigned char *end,
+                        mbedcrypto_asn1_bitstring *bs)
+{
+    int ret;
+
+    /* Certificate type is a single byte bitstring */
+    if( ( ret = mbedcrypto_asn1_get_tag( p, end, &bs->len, MBEDCRYPTO_ASN1_BIT_STRING ) ) != 0 )
+        return( ret );
+
+    /* Check length, subtract one for actual bit string length */
+    if( bs->len < 1 )
+        return( MBEDCRYPTO_ERR_ASN1_OUT_OF_DATA );
+    bs->len -= 1;
+
+    /* Get number of unused bits, ensure unused bits <= 7 */
+    bs->unused_bits = **p;
+    if( bs->unused_bits > 7 )
+        return( MBEDCRYPTO_ERR_ASN1_INVALID_LENGTH );
+    (*p)++;
+
+    /* Get actual bitstring */
+    bs->p = *p;
+    *p += bs->len;
+
+    if( *p != end )
+        return( MBEDCRYPTO_ERR_ASN1_LENGTH_MISMATCH );
+
+    return( 0 );
+}
+
+/*
+ * Get a bit string without unused bits
+ */
+int mbedcrypto_asn1_get_bitstring_null( unsigned char **p, const unsigned char *end,
+                             size_t *len )
+{
+    int ret;
+
+    if( ( ret = mbedcrypto_asn1_get_tag( p, end, len, MBEDCRYPTO_ASN1_BIT_STRING ) ) != 0 )
+        return( ret );
+
+    if( (*len)-- < 2 || *(*p)++ != 0 )
+        return( MBEDCRYPTO_ERR_ASN1_INVALID_DATA );
+
+    return( 0 );
+}
+
+
+
+/*
+ *  Parses and splits an ASN.1 "SEQUENCE OF <tag>"
+ */
+int mbedcrypto_asn1_get_sequence_of( unsigned char **p,
+                          const unsigned char *end,
+                          mbedcrypto_asn1_sequence *cur,
+                          int tag)
+{
+    int ret;
+    size_t len;
+    mbedcrypto_asn1_buf *buf;
+
+    /* Get main sequence tag */
+    if( ( ret = mbedcrypto_asn1_get_tag( p, end, &len,
+            MBEDCRYPTO_ASN1_CONSTRUCTED | MBEDCRYPTO_ASN1_SEQUENCE ) ) != 0 )
+        return( ret );
+
+    if( *p + len != end )
+        return( MBEDCRYPTO_ERR_ASN1_LENGTH_MISMATCH );
+
+    while( *p < end )
+    {
+        buf = &(cur->buf);
+        buf->tag = **p;
+
+        if( ( ret = mbedcrypto_asn1_get_tag( p, end, &buf->len, tag ) ) != 0 )
+            return( ret );
+
+        buf->p = *p;
+        *p += buf->len;
+
+        /* Allocate and assign next pointer */
+        if( *p < end )
+        {
+            cur->next = (mbedcrypto_asn1_sequence*)mbedcrypto_calloc( 1,
+                                            sizeof( mbedcrypto_asn1_sequence ) );
+
+            if( cur->next == NULL )
+                return( MBEDCRYPTO_ERR_ASN1_ALLOC_FAILED );
+
+            cur = cur->next;
+        }
+    }
+
+    /* Set final sequence entry's next pointer to NULL */
+    cur->next = NULL;
+
+    if( *p != end )
+        return( MBEDCRYPTO_ERR_ASN1_LENGTH_MISMATCH );
+
+    return( 0 );
+}
+
+int mbedcrypto_asn1_get_alg( unsigned char **p,
+                  const unsigned char *end,
+                  mbedcrypto_asn1_buf *alg, mbedcrypto_asn1_buf *params )
+{
+    int ret;
+    size_t len;
+
+    if( ( ret = mbedcrypto_asn1_get_tag( p, end, &len,
+            MBEDCRYPTO_ASN1_CONSTRUCTED | MBEDCRYPTO_ASN1_SEQUENCE ) ) != 0 )
+        return( ret );
+
+    if( ( end - *p ) < 1 )
+        return( MBEDCRYPTO_ERR_ASN1_OUT_OF_DATA );
+
+    alg->tag = **p;
+    end = *p + len;
+
+    if( ( ret = mbedcrypto_asn1_get_tag( p, end, &alg->len, MBEDCRYPTO_ASN1_OID ) ) != 0 )
+        return( ret );
+
+    alg->p = *p;
+    *p += alg->len;
+
+    if( *p == end )
+    {
+        mbedcrypto_platform_zeroize( params, sizeof(mbedcrypto_asn1_buf) );
+        return( 0 );
+    }
+
+    params->tag = **p;
+    (*p)++;
+
+    if( ( ret = mbedcrypto_asn1_get_len( p, end, &params->len ) ) != 0 )
+        return( ret );
+
+    params->p = *p;
+    *p += params->len;
+
+    if( *p != end )
+        return( MBEDCRYPTO_ERR_ASN1_LENGTH_MISMATCH );
+
+    return( 0 );
+}
+
+int mbedcrypto_asn1_get_alg_null( unsigned char **p,
+                       const unsigned char *end,
+                       mbedcrypto_asn1_buf *alg )
+{
+    int ret;
+    mbedcrypto_asn1_buf params;
+
+    memset( &params, 0, sizeof(mbedcrypto_asn1_buf) );
+
+    if( ( ret = mbedcrypto_asn1_get_alg( p, end, alg, &params ) ) != 0 )
+        return( ret );
+
+    if( ( params.tag != MBEDCRYPTO_ASN1_NULL && params.tag != 0 ) || params.len != 0 )
+        return( MBEDCRYPTO_ERR_ASN1_INVALID_DATA );
+
+    return( 0 );
+}
+
+void mbedcrypto_asn1_free_named_data( mbedcrypto_asn1_named_data *cur )
+{
+    if( cur == NULL )
+        return;
+
+    mbedcrypto_free( cur->oid.p );
+    mbedcrypto_free( cur->val.p );
+
+    mbedcrypto_platform_zeroize( cur, sizeof( mbedcrypto_asn1_named_data ) );
+}
+
+void mbedcrypto_asn1_free_named_data_list( mbedcrypto_asn1_named_data **head )
+{
+    mbedcrypto_asn1_named_data *cur;
+
+    while( ( cur = *head ) != NULL )
+    {
+        *head = cur->next;
+        mbedcrypto_asn1_free_named_data( cur );
+        mbedcrypto_free( cur );
+    }
+}
+
+mbedcrypto_asn1_named_data *mbedcrypto_asn1_find_named_data( mbedcrypto_asn1_named_data *list,
+                                       const char *oid, size_t len )
+{
+    while( list != NULL )
+    {
+        if( list->oid.len == len &&
+            memcmp( list->oid.p, oid, len ) == 0 )
+        {
+            break;
+        }
+
+        list = list->next;
+    }
+
+    return( list );
+}
+
+#endif /* MBEDCRYPTO_ASN1_PARSE_C */