diff --git a/ChangeLog b/ChangeLog
index 973d18f..99c0ff2 100644
--- a/ChangeLog
+++ b/ChangeLog
@@ -35,6 +35,16 @@
      Guido Vranken. #756
    * Include configuration file in md.h, to fix compilation warnings.
      Reported by aaronmdjones in #1001
+   * Correct extraction of signature-type from PK instance in X.509 CRT and CSR
+     writing routines that prevented these functions to work with alternative
+     RSA implementations. Raised by J.B. in the Mbed TLS forum. Fixes #1011.
+   * Don't print X.509 version tag for v1 CRT's, and omit extensions for
+     non-v3 CRT's.
+
+Changes
+   * Extend cert_write example program by options to set the CRT version
+     and the message digest. Further, allow enabling/disabling of authority
+     identifier, subject identifier and basic constraints extensions.
 
 = mbed TLS 2.1.9 branch released 2017-08-10
 
diff --git a/library/x509write_crt.c b/library/x509write_crt.c
index 4d674ab..0af23d7 100644
--- a/library/x509write_crt.c
+++ b/library/x509write_crt.c
@@ -51,7 +51,7 @@
 
 void mbedtls_x509write_crt_init( mbedtls_x509write_cert *ctx )
 {
-    memset( ctx, 0, sizeof(mbedtls_x509write_cert) );
+    memset( ctx, 0, sizeof( mbedtls_x509write_cert ) );
 
     mbedtls_mpi_init( &ctx->serial );
     ctx->version = MBEDTLS_X509_CRT_VERSION_3;
@@ -65,7 +65,7 @@
     mbedtls_asn1_free_named_data_list( &ctx->issuer );
     mbedtls_asn1_free_named_data_list( &ctx->extensions );
 
-    mbedtls_zeroize( ctx, sizeof(mbedtls_x509write_cert) );
+    mbedtls_zeroize( ctx, sizeof( mbedtls_x509write_cert ) );
 }
 
 void mbedtls_x509write_crt_set_version( mbedtls_x509write_cert *ctx, int version )
@@ -193,14 +193,14 @@
 {
     int ret;
     unsigned char buf[MBEDTLS_MPI_MAX_SIZE * 2 + 20]; /* tag, length + 2xMPI */
-    unsigned char *c = buf + sizeof(buf);
+    unsigned char *c = buf + sizeof( buf );
     size_t len = 0;
 
     memset( buf, 0, sizeof(buf) );
     MBEDTLS_ASN1_CHK_ADD( len, mbedtls_pk_write_pubkey( &c, buf, ctx->issuer_key ) );
 
-    mbedtls_sha1( buf + sizeof(buf) - len, len, buf + sizeof(buf) - 20 );
-    c = buf + sizeof(buf) - 20;
+    mbedtls_sha1( buf + sizeof( buf ) - len, len, buf + sizeof( buf ) - 20 );
+    c = buf + sizeof( buf ) - 20;
     len = 20;
 
     MBEDTLS_ASN1_CHK_ADD( len, mbedtls_asn1_write_len( &c, buf, len ) );
@@ -212,7 +212,7 @@
 
     return mbedtls_x509write_crt_set_extension( ctx, MBEDTLS_OID_AUTHORITY_KEY_IDENTIFIER,
                                    MBEDTLS_OID_SIZE( MBEDTLS_OID_AUTHORITY_KEY_IDENTIFIER ),
-                                   0, buf + sizeof(buf) - len, len );
+                                   0, buf + sizeof( buf ) - len, len );
 }
 #endif /* MBEDTLS_SHA1_C */
 
@@ -313,12 +313,18 @@
     c = tmp_buf + sizeof( tmp_buf );
 
     /* Signature algorithm needed in TBS, and later for actual signature */
-    pk_alg = mbedtls_pk_get_type( ctx->issuer_key );
-    if( pk_alg == MBEDTLS_PK_ECKEY )
+
+    /* There's no direct way of extracting a signature algorithm
+     * (represented as an element of mbedtls_pk_type_t) from a PK instance. */
+    if( mbedtls_pk_can_do( ctx->issuer_key, MBEDTLS_PK_RSA ) )
+        pk_alg = MBEDTLS_PK_RSA;
+    else if( mbedtls_pk_can_do( ctx->issuer_key, MBEDTLS_PK_ECDSA ) )
         pk_alg = MBEDTLS_PK_ECDSA;
+    else
+        return( MBEDTLS_ERR_X509_INVALID_ALG );
 
     if( ( ret = mbedtls_oid_get_oid_by_sig_alg( pk_alg, ctx->md_alg,
-                                        &sig_oid, &sig_oid_len ) ) != 0 )
+                                          &sig_oid, &sig_oid_len ) ) != 0 )
     {
         return( ret );
     }
@@ -326,13 +332,18 @@
     /*
      *  Extensions  ::=  SEQUENCE SIZE (1..MAX) OF Extension
      */
-    MBEDTLS_ASN1_CHK_ADD( len, mbedtls_x509_write_extensions( &c, tmp_buf, ctx->extensions ) );
-    MBEDTLS_ASN1_CHK_ADD( len, mbedtls_asn1_write_len( &c, tmp_buf, len ) );
-    MBEDTLS_ASN1_CHK_ADD( len, mbedtls_asn1_write_tag( &c, tmp_buf, MBEDTLS_ASN1_CONSTRUCTED |
-                                                    MBEDTLS_ASN1_SEQUENCE ) );
-    MBEDTLS_ASN1_CHK_ADD( len, mbedtls_asn1_write_len( &c, tmp_buf, len ) );
-    MBEDTLS_ASN1_CHK_ADD( len, mbedtls_asn1_write_tag( &c, tmp_buf, MBEDTLS_ASN1_CONTEXT_SPECIFIC |
-                                                    MBEDTLS_ASN1_CONSTRUCTED | 3 ) );
+
+    /* Only for v3 */
+    if( ctx->version == MBEDTLS_X509_CRT_VERSION_3 )
+    {
+        MBEDTLS_ASN1_CHK_ADD( len, mbedtls_x509_write_extensions( &c, tmp_buf, ctx->extensions ) );
+        MBEDTLS_ASN1_CHK_ADD( len, mbedtls_asn1_write_len( &c, tmp_buf, len ) );
+        MBEDTLS_ASN1_CHK_ADD( len, mbedtls_asn1_write_tag( &c, tmp_buf, MBEDTLS_ASN1_CONSTRUCTED |
+                                                           MBEDTLS_ASN1_SEQUENCE ) );
+        MBEDTLS_ASN1_CHK_ADD( len, mbedtls_asn1_write_len( &c, tmp_buf, len ) );
+        MBEDTLS_ASN1_CHK_ADD( len, mbedtls_asn1_write_tag( &c, tmp_buf, MBEDTLS_ASN1_CONTEXT_SPECIFIC |
+                                                           MBEDTLS_ASN1_CONSTRUCTED | 3 ) );
+    }
 
     /*
      *  SubjectPublicKeyInfo
@@ -384,16 +395,21 @@
     /*
      *  Version  ::=  INTEGER  {  v1(0), v2(1), v3(2)  }
      */
-    sub_len = 0;
-    MBEDTLS_ASN1_CHK_ADD( sub_len, mbedtls_asn1_write_int( &c, tmp_buf, ctx->version ) );
-    len += sub_len;
-    MBEDTLS_ASN1_CHK_ADD( len, mbedtls_asn1_write_len( &c, tmp_buf, sub_len ) );
-    MBEDTLS_ASN1_CHK_ADD( len, mbedtls_asn1_write_tag( &c, tmp_buf, MBEDTLS_ASN1_CONTEXT_SPECIFIC |
-                                                    MBEDTLS_ASN1_CONSTRUCTED | 0 ) );
+
+    /* Can be omitted for v1 */
+    if( ctx->version != MBEDTLS_X509_CRT_VERSION_1 )
+    {
+        sub_len = 0;
+        MBEDTLS_ASN1_CHK_ADD( sub_len, mbedtls_asn1_write_int( &c, tmp_buf, ctx->version ) );
+        len += sub_len;
+        MBEDTLS_ASN1_CHK_ADD( len, mbedtls_asn1_write_len( &c, tmp_buf, sub_len ) );
+        MBEDTLS_ASN1_CHK_ADD( len, mbedtls_asn1_write_tag( &c, tmp_buf, MBEDTLS_ASN1_CONTEXT_SPECIFIC |
+                                                           MBEDTLS_ASN1_CONSTRUCTED | 0 ) );
+    }
 
     MBEDTLS_ASN1_CHK_ADD( len, mbedtls_asn1_write_len( &c, tmp_buf, len ) );
     MBEDTLS_ASN1_CHK_ADD( len, mbedtls_asn1_write_tag( &c, tmp_buf, MBEDTLS_ASN1_CONSTRUCTED |
-                                                    MBEDTLS_ASN1_SEQUENCE ) );
+                                                       MBEDTLS_ASN1_SEQUENCE ) );
 
     /*
      * Make signature
diff --git a/library/x509write_csr.c b/library/x509write_csr.c
index 8fd856b..2c91608 100644
--- a/library/x509write_csr.c
+++ b/library/x509write_csr.c
@@ -50,7 +50,7 @@
 
 void mbedtls_x509write_csr_init( mbedtls_x509write_csr *ctx )
 {
-    memset( ctx, 0, sizeof(mbedtls_x509write_csr) );
+    memset( ctx, 0, sizeof( mbedtls_x509write_csr ) );
 }
 
 void mbedtls_x509write_csr_free( mbedtls_x509write_csr *ctx )
@@ -58,7 +58,7 @@
     mbedtls_asn1_free_named_data_list( &ctx->subject );
     mbedtls_asn1_free_named_data_list( &ctx->extensions );
 
-    mbedtls_zeroize( ctx, sizeof(mbedtls_x509write_csr) );
+    mbedtls_zeroize( ctx, sizeof( mbedtls_x509write_csr ) );
 }
 
 void mbedtls_x509write_csr_set_md_alg( mbedtls_x509write_csr *ctx, mbedtls_md_type_t md_alg )
@@ -194,14 +194,21 @@
      */
     mbedtls_md( mbedtls_md_info_from_type( ctx->md_alg ), c, len, hash );
 
-    pk_alg = mbedtls_pk_get_type( ctx->key );
-    if( pk_alg == MBEDTLS_PK_ECKEY )
-        pk_alg = MBEDTLS_PK_ECDSA;
-
     if( ( ret = mbedtls_pk_sign( ctx->key, ctx->md_alg, hash, 0, sig, &sig_len,
-                         f_rng, p_rng ) ) != 0 ||
-        ( ret = mbedtls_oid_get_oid_by_sig_alg( pk_alg, ctx->md_alg,
-                                        &sig_oid, &sig_oid_len ) ) != 0 )
+                                 f_rng, p_rng ) ) != 0 )
+    {
+        return( ret );
+    }
+
+    if( mbedtls_pk_can_do( ctx->key, MBEDTLS_PK_RSA ) )
+        pk_alg = MBEDTLS_PK_RSA;
+    else if( mbedtls_pk_can_do( ctx->key, MBEDTLS_PK_ECDSA ) )
+        pk_alg = MBEDTLS_PK_ECDSA;
+    else
+        return( MBEDTLS_ERR_X509_INVALID_ALG );
+
+    if( ( ret = mbedtls_oid_get_oid_by_sig_alg( pk_alg, ctx->md_alg,
+                                            &sig_oid, &sig_oid_len ) ) != 0 )
     {
         return( ret );
     }
diff --git a/programs/x509/cert_write.c b/programs/x509/cert_write.c
index 66e5f1d..9cc582d 100644
--- a/programs/x509/cert_write.c
+++ b/programs/x509/cert_write.c
@@ -51,6 +51,7 @@
 #include "mbedtls/x509_csr.h"
 #include "mbedtls/entropy.h"
 #include "mbedtls/ctr_drbg.h"
+#include "mbedtls/md.h"
 #include "mbedtls/error.h"
 
 #include <stdio.h>
@@ -59,9 +60,9 @@
 
 #if defined(MBEDTLS_X509_CSR_PARSE_C)
 #define USAGE_CSR                                                           \
-    "    request_file=%%s     default: (empty)\n"                           \
-    "                        If request_file is specified, subject_key,\n"  \
-    "                        subject_pwd and subject_name are ignored!\n"
+    "    request_file=%%s         default: (empty)\n"                           \
+    "                            If request_file is specified, subject_key,\n"  \
+    "                            subject_pwd and subject_name are ignored!\n"
 #else
 #define USAGE_CSR ""
 #endif /* MBEDTLS_X509_CSR_PARSE_C */
@@ -83,50 +84,70 @@
 #define DFL_MAX_PATHLEN         -1
 #define DFL_KEY_USAGE           0
 #define DFL_NS_CERT_TYPE        0
+#define DFL_VERSION             3
+#define DFL_AUTH_IDENT          1
+#define DFL_SUBJ_IDENT          1
+#define DFL_CONSTRAINTS         1
+#define DFL_DIGEST              MBEDTLS_MD_SHA256
 
 #define USAGE \
     "\n usage: cert_write param=<>...\n"                \
     "\n acceptable parameters:\n"                       \
     USAGE_CSR                                           \
-    "    subject_key=%%s      default: subject.key\n"   \
-    "    subject_pwd=%%s      default: (empty)\n"       \
-    "    subject_name=%%s     default: CN=Cert,O=mbed TLS,C=UK\n"   \
+    "    subject_key=%%s          default: subject.key\n"   \
+    "    subject_pwd=%%s          default: (empty)\n"       \
+    "    subject_name=%%s         default: CN=Cert,O=mbed TLS,C=UK\n"   \
     "\n"                                                \
-    "    issuer_crt=%%s       default: (empty)\n"       \
-    "                        If issuer_crt is specified, issuer_name is\n"  \
-    "                        ignored!\n"                \
-    "    issuer_name=%%s      default: CN=CA,O=mbed TLS,C=UK\n"     \
+    "    issuer_crt=%%s           default: (empty)\n"       \
+    "                            If issuer_crt is specified, issuer_name is\n"  \
+    "                            ignored!\n"                \
+    "    issuer_name=%%s          default: CN=CA,O=mbed TLS,C=UK\n"     \
     "\n"                                                \
-    "    selfsign=%%d         default: 0 (false)\n"     \
-    "                        If selfsign is enabled, issuer_name and\n" \
-    "                        issuer_key are required (issuer_crt and\n" \
-    "                        subject_* are ignored\n"   \
-    "    issuer_key=%%s       default: ca.key\n"        \
-    "    issuer_pwd=%%s       default: (empty)\n"       \
-    "    output_file=%%s      default: cert.crt\n"      \
-    "    serial=%%s           default: 1\n"             \
-    "    not_before=%%s       default: 20010101000000\n"\
-    "    not_after=%%s        default: 20301231235959\n"\
-    "    is_ca=%%d            default: 0 (disabled)\n"  \
-    "    max_pathlen=%%d      default: -1 (none)\n"     \
-    "    key_usage=%%s        default: (empty)\n"       \
-    "                        Comma-separated-list of values:\n"     \
-    "                          digital_signature\n"     \
-    "                          non_repudiation\n"       \
-    "                          key_encipherment\n"      \
-    "                          data_encipherment\n"     \
-    "                          key_agreement\n"         \
-    "                          key_cert_sign\n"  \
-    "                          crl_sign\n"              \
-    "    ns_cert_type=%%s     default: (empty)\n"       \
-    "                        Comma-separated-list of values:\n"     \
-    "                          ssl_client\n"            \
-    "                          ssl_server\n"            \
-    "                          email\n"                 \
-    "                          object_signing\n"        \
-    "                          ssl_ca\n"                \
-    "                          email_ca\n"              \
-    "                          object_signing_ca\n"     \
+    "    selfsign=%%d             default: 0 (false)\n"     \
+    "                            If selfsign is enabled, issuer_name and\n" \
+    "                            issuer_key are required (issuer_crt and\n" \
+    "                            subject_* are ignored\n"   \
+    "    issuer_key=%%s           default: ca.key\n"        \
+    "    issuer_pwd=%%s           default: (empty)\n"       \
+    "    output_file=%%s          default: cert.crt\n"      \
+    "    serial=%%s               default: 1\n"             \
+    "    not_before=%%s           default: 20010101000000\n"\
+    "    not_after=%%s            default: 20301231235959\n"\
+    "    is_ca=%%d                default: 0 (disabled)\n"  \
+    "    max_pathlen=%%d          default: -1 (none)\n"     \
+    "    md=%%s                   default: SHA256\n"        \
+    "                            Supported values:\n"       \
+    "                            MD5, SHA1, SHA256, SHA512\n"\
+    "    version=%%d              default: 3\n"            \
+    "                            Possible values: 1, 2, 3\n"\
+    "    subject_identifier=%%s   default: 1\n"             \
+    "                            Possible values: 0, 1\n"   \
+    "                            (Considered for v3 only)\n"\
+    "    authority_identifier=%%s default: 1\n"             \
+    "                            Possible values: 0, 1\n"   \
+    "                            (Considered for v3 only)\n"\
+    "    basic_constraints=%%d    default: 1\n"             \
+    "                            Possible values: 0, 1\n"   \
+    "                            (Considered for v3 only)\n"\
+    "    key_usage=%%s            default: (empty)\n"       \
+    "                            Comma-separated-list of values:\n"     \
+    "                            digital_signature\n"     \
+    "                            non_repudiation\n"       \
+    "                            key_encipherment\n"      \
+    "                            data_encipherment\n"     \
+    "                            key_agreement\n"         \
+    "                            key_cert_sign\n"  \
+    "                            crl_sign\n"              \
+    "                            (Considered for v3 only)\n"\
+    "    ns_cert_type=%%s         default: (empty)\n"       \
+    "                            Comma-separated-list of values:\n"     \
+    "                            ssl_client\n"            \
+    "                            ssl_server\n"            \
+    "                            email\n"                 \
+    "                            object_signing\n"        \
+    "                            ssl_ca\n"                \
+    "                            email_ca\n"              \
+    "                            object_signing_ca\n"     \
     "\n"
 
 /*
@@ -149,6 +170,11 @@
     int selfsign;               /* selfsign the certificate             */
     int is_ca;                  /* is a CA certificate                  */
     int max_pathlen;            /* maximum CA path length               */
+    int authority_identifier;   /* add authority identifier to CRT      */
+    int subject_identifier;     /* add subject identifier to CRT        */
+    int basic_constraints;      /* add basic constraints ext to CRT     */
+    int version;                /* CRT version                          */
+    mbedtls_md_type_t md;       /* Hash used for signing                */
     unsigned char key_usage;    /* key usage flags                      */
     unsigned char ns_cert_type; /* NS cert type                         */
 } opt;
@@ -163,7 +189,8 @@
     size_t len = 0;
 
     memset( output_buf, 0, 4096 );
-    if( ( ret = mbedtls_x509write_crt_pem( crt, output_buf, 4096, f_rng, p_rng ) ) < 0 )
+    if( ( ret = mbedtls_x509write_crt_pem( crt, output_buf, 4096,
+                                           f_rng, p_rng ) ) < 0 )
         return( ret );
 
     len = strlen( (char *) output_buf );
@@ -207,7 +234,6 @@
      * Set to sane values
      */
     mbedtls_x509write_crt_init( &crt );
-    mbedtls_x509write_crt_set_md_alg( &crt, MBEDTLS_MD_SHA256 );
     mbedtls_pk_init( &loaded_issuer_key );
     mbedtls_pk_init( &loaded_subject_key );
     mbedtls_mpi_init( &serial );
@@ -243,6 +269,11 @@
     opt.max_pathlen         = DFL_MAX_PATHLEN;
     opt.key_usage           = DFL_KEY_USAGE;
     opt.ns_cert_type        = DFL_NS_CERT_TYPE;
+    opt.version             = DFL_VERSION - 1;
+    opt.md                  = DFL_DIGEST;
+    opt.subject_identifier   = DFL_SUBJ_IDENT;
+    opt.authority_identifier = DFL_AUTH_IDENT;
+    opt.basic_constraints    = DFL_CONSTRAINTS;
 
     for( i = 1; i < argc; i++ )
     {
@@ -286,23 +317,88 @@
         {
             opt.serial = q;
         }
+        else if( strcmp( p, "authority_identifier" ) == 0 )
+        {
+            opt.authority_identifier = atoi( q );
+            if( opt.authority_identifier != 0 &&
+                opt.authority_identifier != 1 )
+            {
+                mbedtls_printf( "Invalid argument for option %s\n", p );
+                goto usage;
+            }
+        }
+        else if( strcmp( p, "subject_identifier" ) == 0 )
+        {
+            opt.subject_identifier = atoi( q );
+            if( opt.subject_identifier != 0 &&
+                opt.subject_identifier != 1 )
+            {
+                mbedtls_printf( "Invalid argument for option %s\n", p );
+                goto usage;
+            }
+        }
+        else if( strcmp( p, "basic_constraints" ) == 0 )
+        {
+            opt.basic_constraints = atoi( q );
+            if( opt.basic_constraints != 0 &&
+                opt.basic_constraints != 1 )
+            {
+                mbedtls_printf( "Invalid argument for option %s\n", p );
+                goto usage;
+            }
+        }
+        else if( strcmp( p, "md" ) == 0 )
+        {
+            if( strcmp( q, "SHA1" ) == 0 )
+                opt.md = MBEDTLS_MD_SHA1;
+            else if( strcmp( q, "SHA256" ) == 0 )
+                opt.md = MBEDTLS_MD_SHA256;
+            else if( strcmp( q, "SHA512" ) == 0 )
+                opt.md = MBEDTLS_MD_SHA512;
+            else if( strcmp( q, "MD5" ) == 0 )
+                opt.md = MBEDTLS_MD_MD5;
+            else
+            {
+                mbedtls_printf( "Invalid argument for option %s\n", p );
+                goto usage;
+            }
+        }
+        else if( strcmp( p, "version" ) == 0 )
+        {
+            opt.version = atoi( q );
+            if( opt.version < 1 || opt.version > 3 )
+            {
+                mbedtls_printf( "Invalid argument for option %s\n", p );
+                goto usage;
+            }
+            opt.version--;
+        }
         else if( strcmp( p, "selfsign" ) == 0 )
         {
             opt.selfsign = atoi( q );
             if( opt.selfsign < 0 || opt.selfsign > 1 )
+            {
+                mbedtls_printf( "Invalid argument for option %s\n", p );
                 goto usage;
+            }
         }
         else if( strcmp( p, "is_ca" ) == 0 )
         {
             opt.is_ca = atoi( q );
             if( opt.is_ca < 0 || opt.is_ca > 1 )
+            {
+                mbedtls_printf( "Invalid argument for option %s\n", p );
                 goto usage;
+            }
         }
         else if( strcmp( p, "max_pathlen" ) == 0 )
         {
             opt.max_pathlen = atoi( q );
             if( opt.max_pathlen < -1 || opt.max_pathlen > 127 )
+            {
+                mbedtls_printf( "Invalid argument for option %s\n", p );
                 goto usage;
+            }
         }
         else if( strcmp( p, "key_usage" ) == 0 )
         {
@@ -326,7 +422,10 @@
                 else if( strcmp( q, "crl_sign" ) == 0 )
                     opt.key_usage |= MBEDTLS_X509_KU_CRL_SIGN;
                 else
+                {
+                    mbedtls_printf( "Invalid argument for option %s\n", p );
                     goto usage;
+                }
 
                 q = r;
             }
@@ -353,7 +452,10 @@
                 else if( strcmp( q, "object_signing_ca" ) == 0 )
                     opt.ns_cert_type |= MBEDTLS_X509_NS_CERT_TYPE_OBJECT_SIGNING_CA;
                 else
+                {
+                    mbedtls_printf( "Invalid argument for option %s\n", p );
                     goto usage;
+                }
 
                 q = r;
             }
@@ -376,7 +478,8 @@
                                strlen( pers ) ) ) != 0 )
     {
         mbedtls_strerror( ret, buf, 1024 );
-        mbedtls_printf( " failed\n  !  mbedtls_ctr_drbg_seed returned %d - %s\n", ret, buf );
+        mbedtls_printf( " failed\n  !  mbedtls_ctr_drbg_seed returned %d - %s\n",
+                        ret, buf );
         goto exit;
     }
 
@@ -390,7 +493,8 @@
     if( ( ret = mbedtls_mpi_read_string( &serial, 10, opt.serial ) ) != 0 )
     {
         mbedtls_strerror( ret, buf, 1024 );
-        mbedtls_printf( " failed\n  !  mbedtls_mpi_read_string returned -0x%02x - %s\n\n", -ret, buf );
+        mbedtls_printf( " failed\n  !  mbedtls_mpi_read_string "
+                        "returned -0x%04x - %s\n\n", -ret, buf );
         goto exit;
     }
 
@@ -409,7 +513,8 @@
         if( ( ret = mbedtls_x509_crt_parse_file( &issuer_crt, opt.issuer_crt ) ) != 0 )
         {
             mbedtls_strerror( ret, buf, 1024 );
-            mbedtls_printf( " failed\n  !  mbedtls_x509_crt_parse_file returned -0x%02x - %s\n\n", -ret, buf );
+            mbedtls_printf( " failed\n  !  mbedtls_x509_crt_parse_file "
+                            "returned -0x%04x - %s\n\n", -ret, buf );
             goto exit;
         }
 
@@ -418,7 +523,8 @@
         if( ret < 0 )
         {
             mbedtls_strerror( ret, buf, 1024 );
-            mbedtls_printf( " failed\n  !  mbedtls_x509_dn_gets returned -0x%02x - %s\n\n", -ret, buf );
+            mbedtls_printf( " failed\n  !  mbedtls_x509_dn_gets "
+                            "returned -0x%04x - %s\n\n", -ret, buf );
             goto exit;
         }
 
@@ -441,7 +547,8 @@
         if( ( ret = mbedtls_x509_csr_parse_file( &csr, opt.request_file ) ) != 0 )
         {
             mbedtls_strerror( ret, buf, 1024 );
-            mbedtls_printf( " failed\n  !  mbedtls_x509_csr_parse_file returned -0x%02x - %s\n\n", -ret, buf );
+            mbedtls_printf( " failed\n  !  mbedtls_x509_csr_parse_file "
+                            "returned -0x%04x - %s\n\n", -ret, buf );
             goto exit;
         }
 
@@ -450,7 +557,8 @@
         if( ret < 0 )
         {
             mbedtls_strerror( ret, buf, 1024 );
-            mbedtls_printf( " failed\n  !  mbedtls_x509_dn_gets returned -0x%02x - %s\n\n", -ret, buf );
+            mbedtls_printf( " failed\n  !  mbedtls_x509_dn_gets "
+                            "returned -0x%04x - %s\n\n", -ret, buf );
             goto exit;
         }
 
@@ -474,7 +582,8 @@
         if( ret != 0 )
         {
             mbedtls_strerror( ret, buf, 1024 );
-            mbedtls_printf( " failed\n  !  mbedtls_pk_parse_keyfile returned -0x%02x - %s\n\n", -ret, buf );
+            mbedtls_printf( " failed\n  !  mbedtls_pk_parse_keyfile "
+                            "returned -0x%04x - %s\n\n", -ret, buf );
             goto exit;
         }
 
@@ -489,7 +598,8 @@
     if( ret != 0 )
     {
         mbedtls_strerror( ret, buf, 1024 );
-        mbedtls_printf( " failed\n  !  mbedtls_pk_parse_keyfile returned -x%02x - %s\n\n", -ret, buf );
+        mbedtls_printf( " failed\n  !  mbedtls_pk_parse_keyfile "
+                        "returned -x%02x - %s\n\n", -ret, buf );
         goto exit;
     }
 
@@ -503,7 +613,8 @@
             mbedtls_mpi_cmp_mpi( &mbedtls_pk_rsa( issuer_crt.pk )->E,
                          &mbedtls_pk_rsa( *issuer_key )->E ) != 0 )
         {
-            mbedtls_printf( " failed\n  !  issuer_key does not match issuer certificate\n\n" );
+            mbedtls_printf( " failed\n  !  issuer_key does not match "
+                            "issuer certificate\n\n" );
             ret = -1;
             goto exit;
         }
@@ -526,25 +637,31 @@
     if( ( ret = mbedtls_x509write_crt_set_subject_name( &crt, opt.subject_name ) ) != 0 )
     {
         mbedtls_strerror( ret, buf, 1024 );
-        mbedtls_printf( " failed\n  !  mbedtls_x509write_crt_set_subject_name returned -0x%02x - %s\n\n", -ret, buf );
+        mbedtls_printf( " failed\n  !  mbedtls_x509write_crt_set_subject_name "
+                        "returned -0x%04x - %s\n\n", -ret, buf );
         goto exit;
     }
 
     if( ( ret = mbedtls_x509write_crt_set_issuer_name( &crt, opt.issuer_name ) ) != 0 )
     {
         mbedtls_strerror( ret, buf, 1024 );
-        mbedtls_printf( " failed\n  !  mbedtls_x509write_crt_set_issuer_name returned -0x%02x - %s\n\n", -ret, buf );
+        mbedtls_printf( " failed\n  !  mbedtls_x509write_crt_set_issuer_name "
+                        "returned -0x%04x - %s\n\n", -ret, buf );
         goto exit;
     }
 
     mbedtls_printf( "  . Setting certificate values ..." );
     fflush( stdout );
 
+    mbedtls_x509write_crt_set_version( &crt, opt.version );
+    mbedtls_x509write_crt_set_md_alg( &crt, opt.md );
+
     ret = mbedtls_x509write_crt_set_serial( &crt, &serial );
     if( ret != 0 )
     {
         mbedtls_strerror( ret, buf, 1024 );
-        mbedtls_printf( " failed\n  !  mbedtls_x509write_crt_set_serial returned -0x%02x - %s\n\n", -ret, buf );
+        mbedtls_printf( " failed\n  !  mbedtls_x509write_crt_set_serial "
+                        "returned -0x%04x - %s\n\n", -ret, buf );
         goto exit;
     }
 
@@ -552,55 +669,74 @@
     if( ret != 0 )
     {
         mbedtls_strerror( ret, buf, 1024 );
-        mbedtls_printf( " failed\n  !  mbedtls_x509write_crt_set_validity returned -0x%02x - %s\n\n", -ret, buf );
+        mbedtls_printf( " failed\n  !  mbedtls_x509write_crt_set_validity "
+                        "returned -0x%04x - %s\n\n", -ret, buf );
         goto exit;
     }
 
     mbedtls_printf( " ok\n" );
 
-    mbedtls_printf( "  . Adding the Basic Constraints extension ..." );
-    fflush( stdout );
-
-    ret = mbedtls_x509write_crt_set_basic_constraints( &crt, opt.is_ca,
-                                               opt.max_pathlen );
-    if( ret != 0 )
+    if( opt.version == MBEDTLS_X509_CRT_VERSION_3 &&
+        opt.basic_constraints != 0 )
     {
-        mbedtls_strerror( ret, buf, 1024 );
-        mbedtls_printf( " failed\n  !  x509write_crt_set_basic_contraints returned -0x%02x - %s\n\n", -ret, buf );
-        goto exit;
-    }
+        mbedtls_printf( "  . Adding the Basic Constraints extension ..." );
+        fflush( stdout );
 
-    mbedtls_printf( " ok\n" );
+        ret = mbedtls_x509write_crt_set_basic_constraints( &crt, opt.is_ca,
+                                                           opt.max_pathlen );
+        if( ret != 0 )
+        {
+            mbedtls_strerror( ret, buf, 1024 );
+            mbedtls_printf( " failed\n  !  x509write_crt_set_basic_contraints "
+                            "returned -0x%04x - %s\n\n", -ret, buf );
+            goto exit;
+        }
+
+        mbedtls_printf( " ok\n" );
+    }
 
 #if defined(MBEDTLS_SHA1_C)
-    mbedtls_printf( "  . Adding the Subject Key Identifier ..." );
-    fflush( stdout );
-
-    ret = mbedtls_x509write_crt_set_subject_key_identifier( &crt );
-    if( ret != 0 )
+    if( opt.version == MBEDTLS_X509_CRT_VERSION_3 &&
+        opt.subject_identifier != 0 )
     {
-        mbedtls_strerror( ret, buf, 1024 );
-        mbedtls_printf( " failed\n  !  mbedtls_x509write_crt_set_subject_key_identifier returned -0x%02x - %s\n\n", -ret, buf );
-        goto exit;
+        mbedtls_printf( "  . Adding the Subject Key Identifier ..." );
+        fflush( stdout );
+
+        ret = mbedtls_x509write_crt_set_subject_key_identifier( &crt );
+        if( ret != 0 )
+        {
+            mbedtls_strerror( ret, buf, 1024 );
+            mbedtls_printf( " failed\n  !  mbedtls_x509write_crt_set_subject"
+                            "_key_identifier returned -0x%04x - %s\n\n",
+                            -ret, buf );
+            goto exit;
+        }
+
+        mbedtls_printf( " ok\n" );
     }
 
-    mbedtls_printf( " ok\n" );
-
-    mbedtls_printf( "  . Adding the Authority Key Identifier ..." );
-    fflush( stdout );
-
-    ret = mbedtls_x509write_crt_set_authority_key_identifier( &crt );
-    if( ret != 0 )
+    if( opt.version == MBEDTLS_X509_CRT_VERSION_3 &&
+        opt.authority_identifier != 0 )
     {
-        mbedtls_strerror( ret, buf, 1024 );
-        mbedtls_printf( " failed\n  !  mbedtls_x509write_crt_set_authority_key_identifier returned -0x%02x - %s\n\n", -ret, buf );
-        goto exit;
-    }
+        mbedtls_printf( "  . Adding the Authority Key Identifier ..." );
+        fflush( stdout );
 
-    mbedtls_printf( " ok\n" );
+        ret = mbedtls_x509write_crt_set_authority_key_identifier( &crt );
+        if( ret != 0 )
+        {
+            mbedtls_strerror( ret, buf, 1024 );
+            mbedtls_printf( " failed\n  !  mbedtls_x509write_crt_set_authority_"
+                            "key_identifier returned -0x%04x - %s\n\n",
+                            -ret, buf );
+            goto exit;
+        }
+
+        mbedtls_printf( " ok\n" );
+    }
 #endif /* MBEDTLS_SHA1_C */
 
-    if( opt.key_usage )
+    if( opt.version == MBEDTLS_X509_CRT_VERSION_3 &&
+        opt.key_usage != 0 )
     {
         mbedtls_printf( "  . Adding the Key Usage extension ..." );
         fflush( stdout );
@@ -609,14 +745,16 @@
         if( ret != 0 )
         {
             mbedtls_strerror( ret, buf, 1024 );
-            mbedtls_printf( " failed\n  !  mbedtls_x509write_crt_set_key_usage returned -0x%02x - %s\n\n", -ret, buf );
+            mbedtls_printf( " failed\n  !  mbedtls_x509write_crt_set_key_usage "
+                            "returned -0x%04x - %s\n\n", -ret, buf );
             goto exit;
         }
 
         mbedtls_printf( " ok\n" );
     }
 
-    if( opt.ns_cert_type )
+    if( opt.version == MBEDTLS_X509_CRT_VERSION_3 &&
+        opt.ns_cert_type != 0 )
     {
         mbedtls_printf( "  . Adding the NS Cert Type extension ..." );
         fflush( stdout );
@@ -625,7 +763,8 @@
         if( ret != 0 )
         {
             mbedtls_strerror( ret, buf, 1024 );
-            mbedtls_printf( " failed\n  !  mbedtls_x509write_crt_set_ns_cert_type returned -0x%02x - %s\n\n", -ret, buf );
+            mbedtls_printf( " failed\n  !  mbedtls_x509write_crt_set_ns_cert_type "
+                            "returned -0x%04x - %s\n\n", -ret, buf );
             goto exit;
         }
 
@@ -642,7 +781,8 @@
                                    mbedtls_ctr_drbg_random, &ctr_drbg ) ) != 0 )
     {
         mbedtls_strerror( ret, buf, 1024 );
-        mbedtls_printf( " failed\n  !  write_certifcate -0x%02x - %s\n\n", -ret, buf );
+        mbedtls_printf( " failed\n  !  write_certificate -0x%04x - %s\n\n",
+                        -ret, buf );
         goto exit;
     }
 
diff --git a/tests/data_files/Makefile b/tests/data_files/Makefile
index e963f49..d4aed67 100644
--- a/tests/data_files/Makefile
+++ b/tests/data_files/Makefile
@@ -12,6 +12,7 @@
 
 ## Tools
 OPENSSL ?= openssl
+MBEDTLS_CERT_WRITE ?= $(PWD)/../../programs/x509/cert_write
 
 ## Build the generated test data. Note that since the final outputs
 ## are committed to the repository, this target should do nothing on a
@@ -30,6 +31,7 @@
 #### Generate certificates from existing keys
 ################################################################
 
+test_ca_crt = test-ca.crt
 test_ca_key_file_rsa = test-ca.key
 test_ca_pwd_rsa = PolarSSLTest
 test_ca_config_file = test-ca.opensslconf
@@ -64,6 +66,8 @@
 	$(OPENSSL) x509 -req -extfile $(cli_crt_extensions_file) -extensions cli-rsa -CA test-ca-sha256.crt -CAkey $(test_ca_key_file_rsa) -passin "pass:$(test_ca_pwd_rsa)" -set_serial 4 -days 3653 -sha256 -in server2-rsa.csr -out $@
 all_final += server2-sha256.crt
 
+
+
 ################################################################
 #### Generate various RSA keys
 ################################################################
@@ -309,6 +313,85 @@
 ### Generate all RSA keys
 keys_rsa_all: keys_rsa_unenc keys_rsa_enc_basic keys_rsa_enc_pkcs8_v1 keys_rsa_enc_pkcs8_v2
 
+
+
+################################################################
+### Generate certificates for CRT write check tests
+################################################################
+
+### The test files use the Mbed TLS generated certificates server1*.crt,
+### but for comparison with OpenSSL also rules for OpenSSL-generated
+### certificates server1*.crt.openssl are offered.
+###
+### Known differences:
+### * OpenSSL encodes trailing zero-bits in bit-strings occurring in X.509 extension
+###   as unused bits, while Mbed TLS doesn't.
+
+test_ca_server1_db = test-ca.server1.db
+test_ca_server1_serial = test-ca.server1.serial
+test_ca_server1_config_file = test-ca.server1.opensslconf
+
+server1.csr: server1.key server1_csr.opensslconf
+	$(OPENSSL) req -keyform PEM -key server1.key -config server1_csr.opensslconf -out $@ -new
+all_final += server1.csr
+
+server1.crt: server1.key server1.csr $(test_ca_crt) $(test_ca_key_file_rsa)
+	$(MBEDTLS_CERT_WRITE) request_file=server1.csr issuer_crt=$(test_ca_crt) issuer_key=$(test_ca_key_file_rsa) issuer_pwd=$(test_ca_pwd_rsa) version=1 not_before=20110212144406 not_after=20210212144406 md=SHA1 version=3 output_file=$@
+server1.noauthid.crt: server1.key server1.csr $(test_ca_crt) $(test_ca_key_file_rsa)
+	$(MBEDTLS_CERT_WRITE) request_file=server1.csr issuer_crt=$(test_ca_crt) issuer_key=$(test_ca_key_file_rsa) issuer_pwd=$(test_ca_pwd_rsa) not_before=20110212144406 not_after=20210212144406 md=SHA1 authority_identifier=0 version=3 output_file=$@
+server1.der: server1.crt
+	$(OPENSSL) x509 -inform PEM -in $< -outform DER -out $@
+all_final += server1.crt server1.noauthid.crt server1.der
+
+server1.key_usage.crt: server1.key server1.csr $(test_ca_crt) $(test_ca_key_file_rsa)
+	$(MBEDTLS_CERT_WRITE) request_file=server1.csr issuer_crt=$(test_ca_crt) issuer_key=$(test_ca_key_file_rsa) issuer_pwd=$(test_ca_pwd_rsa) version=1 not_before=20110212144406 not_after=20210212144406 md=SHA1 key_usage=digital_signature,non_repudiation,key_encipherment version=3 output_file=$@
+server1.key_usage_noauthid.crt: server1.key server1.csr $(test_ca_crt) $(test_ca_key_file_rsa)
+	$(MBEDTLS_CERT_WRITE) request_file=server1.csr issuer_crt=$(test_ca_crt) issuer_key=$(test_ca_key_file_rsa) issuer_pwd=$(test_ca_pwd_rsa) version=1 not_before=20110212144406 not_after=20210212144406 md=SHA1 key_usage=digital_signature,non_repudiation,key_encipherment authority_identifier=0 version=3 output_file=$@
+server1.key_usage.der: server1.key_usage.crt
+	$(OPENSSL) x509 -inform PEM -in $< -outform DER -out $@
+all_final += server1.key_usage.crt server1.key_usage_noauthid.crt server1.key_usage.der
+
+server1.cert_type.crt: server1.key server1.csr $(test_ca_crt) $(test_ca_key_file_rsa)
+	$(MBEDTLS_CERT_WRITE) request_file=server1.csr issuer_crt=$(test_ca_crt) issuer_key=$(test_ca_key_file_rsa) issuer_pwd=$(test_ca_pwd_rsa) version=1 not_before=20110212144406 not_after=20210212144406 md=SHA1 ns_cert_type=ssl_server version=3 output_file=$@
+server1.cert_type_noauthid.crt: server1.key server1.csr $(test_ca_crt) $(test_ca_key_file_rsa)
+	$(MBEDTLS_CERT_WRITE) request_file=server1.csr issuer_crt=$(test_ca_crt) issuer_key=$(test_ca_key_file_rsa) issuer_pwd=$(test_ca_pwd_rsa) version=1 not_before=20110212144406 not_after=20210212144406 md=SHA1 ns_cert_type=ssl_server authority_identifier=0 version=3 output_file=$@
+server1.cert_type.der: server1.cert_type.crt
+	$(OPENSSL) x509 -inform PEM -in $< -outform DER -out $@
+all_final += server1.cert_type.crt server1.cert_type_noauthid.crt server1.cert_type.der
+
+server1.v1.crt: server1.key server1.csr $(test_ca_crt) $(test_ca_key_file_rsa)
+	$(MBEDTLS_CERT_WRITE) request_file=server1.csr issuer_crt=$(test_ca_crt) issuer_key=$(test_ca_key_file_rsa) issuer_pwd=$(test_ca_pwd_rsa) version=1 not_before=20110212144406 not_after=20210212144406 md=SHA1 version=1 output_file=$@
+server1.v1.der: server1.v1.crt
+	$(OPENSSL) x509 -inform PEM -in $< -outform DER -out $@
+all_final += server1.v1.crt server1.v1.der
+
+# OpenSSL-generated certificates for comparison
+# Also provide certificates in DER format to allow
+# direct binary comparison using e.g. dumpasn1
+server1.crt.openssl server1.key_usage.crt.openssl server1.cert_type.crt.openssl: server1.key server1.csr $(test_ca_crt) $(test_ca_key_file_rsa) $(test_ca_server1_config_file)
+	echo "01" > $(test_ca_server1_serial)
+	rm -f $(test_ca_server1_db)
+	touch $(test_ca_server1_db)
+	$(OPENSSL) ca -batch -passin "pass:$(test_ca_pwd_rsa)" -config $(test_ca_server1_config_file) -in server1.csr -extensions v3_ext -extfile $@.v3_ext -out $@
+server1.der.openssl: server1.crt.openssl
+	$(OPENSSL) x509 -inform PEM -in $< -outform DER -out $@
+server1.key_usage.der.openssl: server1.key_usage.crt.openssl
+	$(OPENSSL) x509 -inform PEM -in $< -outform DER -out $@
+server1.cert_type.der.openssl: server1.cert_type.crt.openssl
+	$(OPENSSL) x509 -inform PEM -in $< -outform DER -out $@
+
+server1.v1.crt.openssl: server1.key server1.csr $(test_ca_crt) $(test_ca_key_file_rsa) $(test_ca_server1_config_file)
+	echo "01" > $(test_ca_server1_serial)
+	rm -f $(test_ca_server1_db)
+	touch $(test_ca_server1_db)
+	$(OPENSSL) ca -batch -passin "pass:$(test_ca_pwd_rsa)" -config $(test_ca_server1_config_file) -in server1.csr -out $@
+server1.v1.der.openssl: server1.v1.crt.openssl
+	$(OPENSSL) x509 -inform PEM -in $< -outform DER -out $@
+
+server1_all: server1.csr server1.crt server1.noauthid.crt server1.crt.openssl server1.v1.crt server1.v1.crt.openssl server1.key_usage.crt server1.key_usage_noauthid.crt server1.key_usage.crt.openssl server1.cert_type.crt server1.cert_type_noauthid.crt server1.cert_type.crt.openssl server1.der server1.der.openssl server1.v1.der server1.v1.der.openssl server1.key_usage.der server1.key_usage.der.openssl server1.cert_type.der server1.cert_type.der.openssl
+
+
+
 ################################################################
 #### Meta targets
 ################################################################
@@ -316,10 +399,15 @@
 all_final: $(all_final)
 all: $(all_intermediate) $(all_final)
 
-.PHONY: default all_final all keys_rsa_unenc keys_rsa_enc_basic keys_rsa_enc_pkcs8_v1 keys_rsa_enc_pkcs8_v2 keys_rsa_all \
-	keys_rsa_enc_basic_1024 keys_rsa_enc_basic_2048 keys_rsa_enc_basic_4096 keys_rsa_enc_pkcs8_v1_1024		 \
-	keys_rsa_enc_pkcs8_v1_2048 keys_rsa_enc_pkcs8_v1_4096 keys_rsa_enc_pkcs8_v2_1024				 \
-	keys_rsa_enc_pkcs8_v2_2048 keys_rsa_enc_pkcs8_v2_4096
+.PHONY: default all_final all
+.PHONY: keys_rsa_all
+.PHONY: keys_rsa_unenc keys_rsa_enc_basic
+.PHONY: keys_rsa_enc_pkcs8_v1 keys_rsa_enc_pkcs8_v2
+.PHONY: keys_rsa_enc_basic_1024 keys_rsa_enc_basic_2048 keys_rsa_enc_basic_4096
+.PHONY: keys_rsa_enc_pkcs8_v1_1024 keys_rsa_enc_pkcs8_v2_1024
+.PHONY: keys_rsa_enc_pkcs8_v1_2048 keys_rsa_enc_pkcs8_v2_2048
+.PHONY: keys_rsa_enc_pkcs8_v1_4096 keys_rsa_enc_pkcs8_v2_4096
+.PHONY: server1_all
 
 # These files should not be committed to the repository.
 list_intermediate:
diff --git a/tests/data_files/server1.cert_type.crt.openssl.v3_ext b/tests/data_files/server1.cert_type.crt.openssl.v3_ext
new file mode 100644
index 0000000..bd225ff
--- /dev/null
+++ b/tests/data_files/server1.cert_type.crt.openssl.v3_ext
@@ -0,0 +1,5 @@
+[v3_ext]
+basicConstraints = CA:false
+subjectKeyIdentifier=hash
+authorityKeyIdentifier=keyid
+nsCertType=server
diff --git a/tests/data_files/server1.cert_type_noauthid.crt b/tests/data_files/server1.cert_type_noauthid.crt
new file mode 100644
index 0000000..ed8b80b
--- /dev/null
+++ b/tests/data_files/server1.cert_type_noauthid.crt
@@ -0,0 +1,20 @@
+-----BEGIN CERTIFICATE-----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+-----END CERTIFICATE-----
diff --git a/tests/data_files/server1.crt.openssl.v3_ext b/tests/data_files/server1.crt.openssl.v3_ext
new file mode 100644
index 0000000..239d56a
--- /dev/null
+++ b/tests/data_files/server1.crt.openssl.v3_ext
@@ -0,0 +1,4 @@
+[v3_ext]
+basicConstraints = CA:false
+subjectKeyIdentifier=hash
+authorityKeyIdentifier=keyid
diff --git a/tests/data_files/server1.csr b/tests/data_files/server1.csr
new file mode 100644
index 0000000..804c4a5
--- /dev/null
+++ b/tests/data_files/server1.csr
@@ -0,0 +1,16 @@
+-----BEGIN CERTIFICATE REQUEST-----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+-----END CERTIFICATE REQUEST-----
diff --git a/tests/data_files/server1.key_usage.crt.openssl.v3_ext b/tests/data_files/server1.key_usage.crt.openssl.v3_ext
new file mode 100644
index 0000000..e255027
--- /dev/null
+++ b/tests/data_files/server1.key_usage.crt.openssl.v3_ext
@@ -0,0 +1,5 @@
+[v3_ext]
+basicConstraints = CA:false
+subjectKeyIdentifier=hash
+authorityKeyIdentifier=keyid
+keyUsage=critical, digitalSignature, nonRepudiation, keyEncipherment
diff --git a/tests/data_files/server1.key_usage_noauthid.crt b/tests/data_files/server1.key_usage_noauthid.crt
new file mode 100644
index 0000000..d66e515
--- /dev/null
+++ b/tests/data_files/server1.key_usage_noauthid.crt
@@ -0,0 +1,20 @@
+-----BEGIN CERTIFICATE-----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+-----END CERTIFICATE-----
diff --git a/tests/data_files/server1.noauthid.crt b/tests/data_files/server1.noauthid.crt
new file mode 100644
index 0000000..99c004f
--- /dev/null
+++ b/tests/data_files/server1.noauthid.crt
@@ -0,0 +1,19 @@
+-----BEGIN CERTIFICATE-----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+-----END CERTIFICATE-----
diff --git a/tests/data_files/server1.v1.crt b/tests/data_files/server1.v1.crt
index 0a4b2a5..b13be43 100644
--- a/tests/data_files/server1.v1.crt
+++ b/tests/data_files/server1.v1.crt
@@ -1,18 +1,18 @@
 -----BEGIN CERTIFICATE-----
-MIIC9DCCAdygAwIBAAIBATANBgkqhkiG9w0BAQUFADA7MQswCQYDVQQGEwJOTDER
-MA8GA1UEChMIUG9sYXJTU0wxGTAXBgNVBAMTEFBvbGFyU1NMIFRlc3QgQ0EwHhcN
-MTEwMjEyMTQ0NDA2WhcNMjEwMjEyMTQ0NDA2WjA8MQswCQYDVQQGEwJOTDERMA8G
-A1UEChMIUG9sYXJTU0wxGjAYBgNVBAMTEVBvbGFyU1NMIFNlcnZlciAxMIIBIjAN
-BgkqhkiG9w0BAQEFAAOCAQ8AMIIBCgKCAQEAqQIfPUBq1VVTi/027oJlLhVhXom/
-uOhFkNvuiBZS0/FDUEeWEllkh2v9K+BG+XO+3c+S4ZFb7Wagb4kpeUWA0INq1UFD
-d185fAkER4KwVzlw7aPsFRkeqDMIR8EFQqn9TMO0390GH00QUUBncxMPQPhtgSVf
-CrFTxjB+FTms+Vruf5KepgVb5xOXhbUjktnUJAbVCSWJdQfdphqPPwkZvq1lLGTr
-lZvc/kFeF6babFtpzAK6FCwWJJxK3M3Q91Jnc/EtoCP9fvQxyi1wyokLBNsupk9w
-bp7OvViJ4lNZnm5akmXiiD8MlBmj3eXonZUT7Snbq3AS3FrKaxerUoJUsQIDAQAB
-owIwADANBgkqhkiG9w0BAQUFAAOCAQEAoZVuVi7bIslKgMJhejSFXiO+ICMz1fmK
-b0tPN68mRYhI/gsjRT0cmX6GUNrg+U5mcBWhMwHgyvx1CARU4YToKZxcXGNL0DPd
-Z1hF8nCrJCZBQvNuWE7s0ufw92xz5ZfuKkVxi94RYR529F6gzgl4rpX8UQVu2ym/
-9pTlHKr4MKi9LNppyJMS89uRcb2FJFMdhAKbhNtbIjI9qGZ7x//0belAaWhq389u
-6XWFnZt35PU6Zz6YbAQ5pjZYsTaohuufgrpOlFPUuc4uR+RfGHIQ6id12lZaQC2m
-OFIBDcU0x1cFfPfMgVdBLf6klPt/v/tD77mwx0eztSp28NIf+ACw8A==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 -----END CERTIFICATE-----
diff --git a/tests/data_files/server1_csr.opensslconf b/tests/data_files/server1_csr.opensslconf
new file mode 100644
index 0000000..6e7075e
--- /dev/null
+++ b/tests/data_files/server1_csr.opensslconf
@@ -0,0 +1,10 @@
+[ req ]
+distinguished_name = req_distinguished_name
+prompt             = no
+# Restrict to non-UTF8 PrintableStrings.
+string_mask        = nombstr
+
+[ req_distinguished_name ]
+C  = NL
+O  = PolarSSL
+CN = PolarSSL Server 1
diff --git a/tests/data_files/test-ca.server1.opensslconf b/tests/data_files/test-ca.server1.opensslconf
new file mode 100644
index 0000000..4a5072e
--- /dev/null
+++ b/tests/data_files/test-ca.server1.opensslconf
@@ -0,0 +1,18 @@
+ [ ca ]
+ default_ca             = test-ca
+ 
+ [ test-ca ]
+ certificate            = test-ca.crt
+ private_key            = test-ca.key
+ serial                 = test-ca.server1.serial
+ default_md             = sha1
+ default_startdate      = 110212144406Z
+ default_enddate        = 210212144406Z
+ new_certs_dir          = ./
+ database               = ./test-ca.server1.db
+ policy                 = policy_match
+
+ [policy_match]
+ countryName            = supplied
+ organizationName       = supplied
+ commonName             = supplied
diff --git a/tests/suites/test_suite_x509write.data b/tests/suites/test_suite_x509write.data
index d4d2a98..5b54d85 100644
--- a/tests/suites/test_suite_x509write.data
+++ b/tests/suites/test_suite_x509write.data
@@ -44,19 +44,35 @@
 
 Certificate write check Server1 SHA1
 depends_on:MBEDTLS_SHA1_C:MBEDTLS_RSA_C:MBEDTLS_PKCS1_V15:MBEDTLS_DES_C:MBEDTLS_CIPHER_MODE_CBC:MBEDTLS_MD5_C
-x509_crt_check:"data_files/server1.key":"":"C=NL,O=PolarSSL,CN=PolarSSL Server 1":"data_files/test-ca.key":"PolarSSLTest":"C=NL,O=PolarSSL,CN=PolarSSL Test CA":"1":"20110212144406":"20210212144406":MBEDTLS_MD_SHA1:0:0:-1:"data_files/server1.crt"
+x509_crt_check:"data_files/server1.key":"":"C=NL,O=PolarSSL,CN=PolarSSL Server 1":"data_files/test-ca.key":"PolarSSLTest":"C=NL,O=PolarSSL,CN=PolarSSL Test CA":"1":"20110212144406":"20210212144406":MBEDTLS_MD_SHA1:0:0:1:-1:"data_files/server1.crt":0
 
 Certificate write check Server1 SHA1, key_usage
 depends_on:MBEDTLS_SHA1_C:MBEDTLS_RSA_C:MBEDTLS_PKCS1_V15:MBEDTLS_DES_C:MBEDTLS_CIPHER_MODE_CBC:MBEDTLS_MD5_C
-x509_crt_check:"data_files/server1.key":"":"C=NL,O=PolarSSL,CN=PolarSSL Server 1":"data_files/test-ca.key":"PolarSSLTest":"C=NL,O=PolarSSL,CN=PolarSSL Test CA":"1":"20110212144406":"20210212144406":MBEDTLS_MD_SHA1:MBEDTLS_X509_KU_DIGITAL_SIGNATURE | MBEDTLS_X509_KU_NON_REPUDIATION | MBEDTLS_X509_KU_KEY_ENCIPHERMENT:0:-1:"data_files/server1.key_usage.crt"
+x509_crt_check:"data_files/server1.key":"":"C=NL,O=PolarSSL,CN=PolarSSL Server 1":"data_files/test-ca.key":"PolarSSLTest":"C=NL,O=PolarSSL,CN=PolarSSL Test CA":"1":"20110212144406":"20210212144406":MBEDTLS_MD_SHA1:MBEDTLS_X509_KU_DIGITAL_SIGNATURE | MBEDTLS_X509_KU_NON_REPUDIATION | MBEDTLS_X509_KU_KEY_ENCIPHERMENT:0:1:-1:"data_files/server1.key_usage.crt":0
 
 Certificate write check Server1 SHA1, ns_cert_type
 depends_on:MBEDTLS_SHA1_C:MBEDTLS_RSA_C:MBEDTLS_PKCS1_V15:MBEDTLS_DES_C:MBEDTLS_CIPHER_MODE_CBC:MBEDTLS_MD5_C
-x509_crt_check:"data_files/server1.key":"":"C=NL,O=PolarSSL,CN=PolarSSL Server 1":"data_files/test-ca.key":"PolarSSLTest":"C=NL,O=PolarSSL,CN=PolarSSL Test CA":"1":"20110212144406":"20210212144406":MBEDTLS_MD_SHA1:0:MBEDTLS_X509_NS_CERT_TYPE_SSL_SERVER:-1:"data_files/server1.cert_type.crt"
+x509_crt_check:"data_files/server1.key":"":"C=NL,O=PolarSSL,CN=PolarSSL Server 1":"data_files/test-ca.key":"PolarSSLTest":"C=NL,O=PolarSSL,CN=PolarSSL Test CA":"1":"20110212144406":"20210212144406":MBEDTLS_MD_SHA1:0:MBEDTLS_X509_NS_CERT_TYPE_SSL_SERVER:1:-1:"data_files/server1.cert_type.crt":0
 
 Certificate write check Server1 SHA1, version 1
 depends_on:MBEDTLS_SHA1_C:MBEDTLS_RSA_C:MBEDTLS_PKCS1_V15:MBEDTLS_DES_C:MBEDTLS_CIPHER_MODE_CBC:MBEDTLS_MD5_C
-x509_crt_check:"data_files/server1.key":"":"C=NL,O=PolarSSL,CN=PolarSSL Server 1":"data_files/test-ca.key":"PolarSSLTest":"C=NL,O=PolarSSL,CN=PolarSSL Test CA":"1":"20110212144406":"20210212144406":MBEDTLS_MD_SHA1:0:0:MBEDTLS_X509_CRT_VERSION_1:"data_files/server1.v1.crt"
+x509_crt_check:"data_files/server1.key":"":"C=NL,O=PolarSSL,CN=PolarSSL Server 1":"data_files/test-ca.key":"PolarSSLTest":"C=NL,O=PolarSSL,CN=PolarSSL Test CA":"1":"20110212144406":"20210212144406":MBEDTLS_MD_SHA1:0:0:1:MBEDTLS_X509_CRT_VERSION_1:"data_files/server1.v1.crt":0
+
+Certificate write check Server1 SHA1, RSA_ALT
+depends_on:MBEDTLS_SHA1_C:MBEDTLS_RSA_C:MBEDTLS_PKCS1_V15:MBEDTLS_DES_C:MBEDTLS_CIPHER_MODE_CBC:MBEDTLS_MD5_C
+x509_crt_check:"data_files/server1.key":"":"C=NL,O=PolarSSL,CN=PolarSSL Server 1":"data_files/test-ca.key":"PolarSSLTest":"C=NL,O=PolarSSL,CN=PolarSSL Test CA":"1":"20110212144406":"20210212144406":MBEDTLS_MD_SHA1:0:0:0:-1:"data_files/server1.noauthid.crt":1
+
+Certificate write check Server1 SHA1, RSA_ALT, key_usage
+depends_on:MBEDTLS_SHA1_C:MBEDTLS_RSA_C:MBEDTLS_PKCS1_V15:MBEDTLS_DES_C:MBEDTLS_CIPHER_MODE_CBC:MBEDTLS_MD5_C
+x509_crt_check:"data_files/server1.key":"":"C=NL,O=PolarSSL,CN=PolarSSL Server 1":"data_files/test-ca.key":"PolarSSLTest":"C=NL,O=PolarSSL,CN=PolarSSL Test CA":"1":"20110212144406":"20210212144406":MBEDTLS_MD_SHA1:MBEDTLS_X509_KU_DIGITAL_SIGNATURE | MBEDTLS_X509_KU_NON_REPUDIATION | MBEDTLS_X509_KU_KEY_ENCIPHERMENT:0:0:-1:"data_files/server1.key_usage_noauthid.crt":1
+
+Certificate write check Server1 SHA1, RSA_ALT, ns_cert_type
+depends_on:MBEDTLS_SHA1_C:MBEDTLS_RSA_C:MBEDTLS_PKCS1_V15:MBEDTLS_DES_C:MBEDTLS_CIPHER_MODE_CBC:MBEDTLS_MD5_C
+x509_crt_check:"data_files/server1.key":"":"C=NL,O=PolarSSL,CN=PolarSSL Server 1":"data_files/test-ca.key":"PolarSSLTest":"C=NL,O=PolarSSL,CN=PolarSSL Test CA":"1":"20110212144406":"20210212144406":MBEDTLS_MD_SHA1:0:MBEDTLS_X509_NS_CERT_TYPE_SSL_SERVER:0:-1:"data_files/server1.cert_type_noauthid.crt":1
+
+Certificate write check Server1 SHA1, RSA_ALT, version 1
+depends_on:MBEDTLS_SHA1_C:MBEDTLS_RSA_C:MBEDTLS_PKCS1_V15:MBEDTLS_DES_C:MBEDTLS_CIPHER_MODE_CBC:MBEDTLS_MD5_C
+x509_crt_check:"data_files/server1.key":"":"C=NL,O=PolarSSL,CN=PolarSSL Server 1":"data_files/test-ca.key":"PolarSSLTest":"C=NL,O=PolarSSL,CN=PolarSSL Test CA":"1":"20110212144406":"20210212144406":MBEDTLS_MD_SHA1:0:0:0:MBEDTLS_X509_CRT_VERSION_1:"data_files/server1.v1.crt":1
 
 X509 String to Names #1
 mbedtls_x509_string_to_names:"C=NL,O=Offspark\, Inc., OU=PolarSSL":"C=NL, O=Offspark, Inc., OU=PolarSSL":0
diff --git a/tests/suites/test_suite_x509write.function b/tests/suites/test_suite_x509write.function
index 5120837..6a66b2f 100644
--- a/tests/suites/test_suite_x509write.function
+++ b/tests/suites/test_suite_x509write.function
@@ -3,6 +3,30 @@
 #include "mbedtls/x509_csr.h"
 #include "mbedtls/pem.h"
 #include "mbedtls/oid.h"
+#include "mbedtls/rsa.h"
+
+#if defined(MBEDTLS_RSA_C)
+int mbedtls_rsa_decrypt_func( void *ctx, int mode, size_t *olen,
+                       const unsigned char *input, unsigned char *output,
+                       size_t output_max_len )
+{
+    return( mbedtls_rsa_pkcs1_decrypt( (mbedtls_rsa_context *) ctx, NULL, NULL, mode, olen,
+                               input, output, output_max_len ) );
+}
+int mbedtls_rsa_sign_func( void *ctx,
+                   int (*f_rng)(void *, unsigned char *, size_t), void *p_rng,
+                   int mode, mbedtls_md_type_t md_alg, unsigned int hashlen,
+                   const unsigned char *hash, unsigned char *sig )
+{
+    return( mbedtls_rsa_pkcs1_sign( (mbedtls_rsa_context *) ctx, f_rng, p_rng, mode,
+                            md_alg, hashlen, hash, sig ) );
+}
+size_t mbedtls_rsa_key_len_func( void *ctx )
+{
+    return( ((const mbedtls_rsa_context *) ctx)->len );
+}
+#endif /* MBEDTLS_RSA_C */
+
 /* END_HEADER */
 
 /* BEGIN_DEPENDENCIES
@@ -38,7 +62,7 @@
     if( cert_type != 0 )
         TEST_ASSERT( mbedtls_x509write_csr_set_ns_cert_type( &req, cert_type ) == 0 );
 
-    ret = mbedtls_x509write_csr_pem( &req, buf, sizeof(buf),
+    ret = mbedtls_x509write_csr_pem( &req, buf, sizeof( buf ),
                              rnd_pseudo_rand, &rnd_info );
     TEST_ASSERT( ret == 0 );
 
@@ -67,10 +91,12 @@
                      char *subject_name, char *issuer_key_file,
                      char *issuer_pwd, char *issuer_name,
                      char *serial_str, char *not_before, char *not_after,
-                     int md_type, int key_usage, int cert_type, int ver,
-                     char *cert_check_file )
+                     int md_type, int key_usage, int cert_type, int auth_ident,
+                     int ver, char *cert_check_file, int rsa_alt )
 {
-    mbedtls_pk_context subject_key, issuer_key;
+    mbedtls_pk_context subject_key, issuer_key, issuer_key_alt;
+    mbedtls_pk_context *key = &issuer_key;
+
     mbedtls_x509write_cert crt;
     unsigned char buf[4000];
     unsigned char check_buf[5000];
@@ -82,61 +108,83 @@
 
     memset( &rnd_info, 0x2a, sizeof( rnd_pseudo_info ) );
     mbedtls_mpi_init( &serial );
+
     mbedtls_pk_init( &subject_key );
-    mbedtls_pk_init( &issuer_key );
+    mbedtls_pk_init( &issuer_key  );
+    mbedtls_pk_init( &issuer_key_alt );
+
+    mbedtls_x509write_crt_init( &crt );
 
     TEST_ASSERT( mbedtls_pk_parse_keyfile( &subject_key, subject_key_file,
                                          subject_pwd ) == 0 );
+
     TEST_ASSERT( mbedtls_pk_parse_keyfile( &issuer_key, issuer_key_file,
                                          issuer_pwd ) == 0 );
+
+    /* For RSA PK contexts, create a copy as an alternative RSA context. */
+    if( rsa_alt == 1 && mbedtls_pk_get_type( &issuer_key ) == MBEDTLS_PK_RSA )
+    {
+        TEST_ASSERT( mbedtls_pk_setup_rsa_alt( &issuer_key_alt,
+                                            mbedtls_pk_rsa( issuer_key ),
+                                            mbedtls_rsa_decrypt_func,
+                                            mbedtls_rsa_sign_func,
+                                            mbedtls_rsa_key_len_func ) == 0 );
+
+        key = &issuer_key_alt;
+    }
+
     TEST_ASSERT( mbedtls_mpi_read_string( &serial, 10, serial_str ) == 0 );
 
-    mbedtls_x509write_crt_init( &crt );
     if( ver != -1 )
         mbedtls_x509write_crt_set_version( &crt, ver );
+
     TEST_ASSERT( mbedtls_x509write_crt_set_serial( &crt, &serial ) == 0 );
     TEST_ASSERT( mbedtls_x509write_crt_set_validity( &crt, not_before,
-                                                   not_after ) == 0 );
+                                                     not_after ) == 0 );
     mbedtls_x509write_crt_set_md_alg( &crt, md_type );
     TEST_ASSERT( mbedtls_x509write_crt_set_issuer_name( &crt, issuer_name ) == 0 );
     TEST_ASSERT( mbedtls_x509write_crt_set_subject_name( &crt, subject_name ) == 0 );
     mbedtls_x509write_crt_set_subject_key( &crt, &subject_key );
-    mbedtls_x509write_crt_set_issuer_key( &crt, &issuer_key );
+
+    mbedtls_x509write_crt_set_issuer_key( &crt, key );
 
     if( crt.version >= MBEDTLS_X509_CRT_VERSION_3 )
     {
         TEST_ASSERT( mbedtls_x509write_crt_set_basic_constraints( &crt, 0, 0 ) == 0 );
         TEST_ASSERT( mbedtls_x509write_crt_set_subject_key_identifier( &crt ) == 0 );
-        TEST_ASSERT( mbedtls_x509write_crt_set_authority_key_identifier( &crt ) == 0 );
+        if( auth_ident )
+            TEST_ASSERT( mbedtls_x509write_crt_set_authority_key_identifier( &crt ) == 0 );
         if( key_usage != 0 )
             TEST_ASSERT( mbedtls_x509write_crt_set_key_usage( &crt, key_usage ) == 0 );
         if( cert_type != 0 )
             TEST_ASSERT( mbedtls_x509write_crt_set_ns_cert_type( &crt, cert_type ) == 0 );
     }
 
-    ret = mbedtls_x509write_crt_pem( &crt, buf, sizeof(buf),
-                             rnd_pseudo_rand, &rnd_info );
+    ret = mbedtls_x509write_crt_pem( &crt, buf, sizeof( buf ),
+                                     rnd_pseudo_rand, &rnd_info );
     TEST_ASSERT( ret == 0 );
 
     pem_len = strlen( (char *) buf );
 
     f = fopen( cert_check_file, "r" );
     TEST_ASSERT( f != NULL );
-    olen = fread( check_buf, 1, sizeof(check_buf), f );
+    olen = fread( check_buf, 1, sizeof( check_buf ), f );
     fclose( f );
-    TEST_ASSERT( olen < sizeof(check_buf) );
+    TEST_ASSERT( olen < sizeof( check_buf ) );
 
     TEST_ASSERT( olen >= pem_len - 1 );
     TEST_ASSERT( memcmp( buf, check_buf, pem_len - 1 ) == 0 );
 
     ret = mbedtls_x509write_crt_der( &crt, buf, pem_len / 2,
                             rnd_pseudo_rand, &rnd_info );
+
     TEST_ASSERT( ret == MBEDTLS_ERR_ASN1_BUF_TOO_SMALL );
 
 exit:
     mbedtls_x509write_crt_free( &crt );
-    mbedtls_pk_free( &issuer_key );
+    mbedtls_pk_free( &issuer_key_alt );
     mbedtls_pk_free( &subject_key );
+    mbedtls_pk_free( &issuer_key );
     mbedtls_mpi_free( &serial );
 }
 /* END_CASE */