diff --git a/library/psa_crypto_rsa.c b/library/psa_crypto_rsa.c
new file mode 100644
index 0000000..b4ea86a
--- /dev/null
+++ b/library/psa_crypto_rsa.c
@@ -0,0 +1,128 @@
+/*
+ *  PSA RSA layer on top of Mbed TLS crypto
+ */
+/*
+ *  Copyright The Mbed TLS Contributors
+ *  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.
+ */
+
+#include "common.h"
+
+#if defined(MBEDTLS_PSA_CRYPTO_C)
+
+#include <psa/crypto.h>
+#include "psa_crypto_core.h"
+#include "psa_crypto_rsa.h"
+
+#include <stdlib.h>
+#include <string.h>
+#include "mbedtls/platform.h"
+#if !defined(MBEDTLS_PLATFORM_C)
+#define mbedtls_calloc calloc
+#define mbedtls_free   free
+#endif
+
+#include <mbedtls/rsa.h>
+#include <mbedtls/error.h>
+#include <mbedtls/pk.h>
+#include <mbedtls/pk_internal.h>
+
+#if defined(MBEDTLS_PSA_BUILTIN_ALG_RSA_PKCS1V15_CRYPT) || \
+    defined(MBEDTLS_PSA_BUILTIN_ALG_RSA_PKCS1V15_SIGN) || \
+    defined(MBEDTLS_PSA_BUILTIN_ALG_RSA_OAEP) || \
+    defined(MBEDTLS_PSA_BUILTIN_ALG_RSA_PSS) || \
+    defined(MBEDTLS_PSA_BUILTIN_KEY_TYPE_RSA_KEY_PAIR) || \
+    defined(MBEDTLS_PSA_BUILTIN_KEY_TYPE_RSA_PUBLIC_KEY)
+
+/* Mbed TLS doesn't support non-byte-aligned key sizes (i.e. key sizes
+ * that are not a multiple of 8) well. For example, there is only
+ * mbedtls_rsa_get_len(), which returns a number of bytes, and no
+ * way to return the exact bit size of a key.
+ * To keep things simple, reject non-byte-aligned key sizes. */
+static psa_status_t psa_check_rsa_key_byte_aligned(
+    const mbedtls_rsa_context *rsa )
+{
+    mbedtls_mpi n;
+    psa_status_t status;
+    mbedtls_mpi_init( &n );
+    status = mbedtls_to_psa_error(
+        mbedtls_rsa_export( rsa, &n, NULL, NULL, NULL, NULL ) );
+    if( status == PSA_SUCCESS )
+    {
+        if( mbedtls_mpi_bitlen( &n ) % 8 != 0 )
+            status = PSA_ERROR_NOT_SUPPORTED;
+    }
+    mbedtls_mpi_free( &n );
+    return( status );
+}
+
+psa_status_t mbedtls_psa_rsa_load_representation(
+    psa_key_type_t type, const uint8_t *data, size_t data_length,
+    mbedtls_rsa_context **p_rsa )
+{
+    psa_status_t status;
+    mbedtls_pk_context ctx;
+    size_t bits;
+    mbedtls_pk_init( &ctx );
+
+    /* Parse the data. */
+    if( PSA_KEY_TYPE_IS_KEY_PAIR( type ) )
+        status = mbedtls_to_psa_error(
+            mbedtls_pk_parse_key( &ctx, data, data_length, NULL, 0 ) );
+    else
+        status = mbedtls_to_psa_error(
+            mbedtls_pk_parse_public_key( &ctx, data, data_length ) );
+    if( status != PSA_SUCCESS )
+        goto exit;
+
+    /* We have something that the pkparse module recognizes. If it is a
+     * valid RSA key, store it. */
+    if( mbedtls_pk_get_type( &ctx ) != MBEDTLS_PK_RSA )
+    {
+        status = PSA_ERROR_INVALID_ARGUMENT;
+        goto exit;
+    }
+
+    /* The size of an RSA key doesn't have to be a multiple of 8. Mbed TLS
+     * supports non-byte-aligned key sizes, but not well. For example,
+     * mbedtls_rsa_get_len() returns the key size in bytes, not in bits. */
+    bits = PSA_BYTES_TO_BITS( mbedtls_rsa_get_len( mbedtls_pk_rsa( ctx ) ) );
+    if( bits > PSA_VENDOR_RSA_MAX_KEY_BITS )
+    {
+        status = PSA_ERROR_NOT_SUPPORTED;
+        goto exit;
+    }
+    status = psa_check_rsa_key_byte_aligned( mbedtls_pk_rsa( ctx ) );
+    if( status != PSA_SUCCESS )
+        goto exit;
+
+    /* Copy out the pointer to the RSA context, and reset the PK context
+     * such that pk_free doesn't free the RSA context we just grabbed. */
+    *p_rsa = mbedtls_pk_rsa( ctx );
+    ctx.pk_info = NULL;
+
+exit:
+    mbedtls_pk_free( &ctx );
+    return( status );
+}
+
+#endif /* defined(MBEDTLS_PSA_BUILTIN_ALG_RSA_PKCS1V15_CRYPT) ||
+        * defined(MBEDTLS_PSA_BUILTIN_ALG_RSA_PKCS1V15_SIGN) ||
+        * defined(MBEDTLS_PSA_BUILTIN_ALG_RSA_OAEP) ||
+        * defined(MBEDTLS_PSA_BUILTIN_ALG_RSA_PSS) ||
+        * defined(MBEDTLS_PSA_BUILTIN_KEY_TYPE_RSA_KEY_PAIR) ||
+        * defined(MBEDTLS_PSA_BUILTIN_KEY_TYPE_RSA_PUBLIC_KEY) */
+
+#endif /* MBEDTLS_PSA_CRYPTO_C */