diff --git a/include/lib/psa/rss_crypto_defs.h b/include/lib/psa/rss_crypto_defs.h
new file mode 100644
index 0000000..b8c7426
--- /dev/null
+++ b/include/lib/psa/rss_crypto_defs.h
@@ -0,0 +1,58 @@
+/*
+ * Copyright (c) 2023, Arm Limited. All rights reserved.
+ *
+ * SPDX-License-Identifier: BSD-3-Clause
+ *
+ */
+
+#ifndef RSS_CRYPTO_DEFS_H
+#define RSS_CRYPTO_DEFS_H
+
+/* Declares types that encode errors, algorithms, key types, policies, etc. */
+#include "psa/crypto_types.h"
+
+/*
+ * Value identifying export public key function API, used to dispatch the request
+ * to the corresponding API implementation in the Crypto service backend.
+ *
+ */
+#define RSS_CRYPTO_EXPORT_PUBLIC_KEY_SID	(uint16_t)(0x701)
+
+/*
+ * The persistent key identifiers for RSS builtin keys.
+ */
+enum rss_key_id_builtin_t {
+	RSS_BUILTIN_KEY_ID_HOST_S_ROTPK = 0x7FFF816Cu,
+	RSS_BUILTIN_KEY_ID_HOST_NS_ROTPK,
+	RSS_BUILTIN_KEY_ID_HOST_CCA_ROTPK,
+};
+
+/*
+ * This type is used to overcome a limitation within RSS firmware in the number of maximum
+ * IOVECs it can use especially in psa_aead_encrypt and psa_aead_decrypt.
+ */
+#define RSS_CRYPTO_MAX_NONCE_LENGTH (16u)
+struct rss_crypto_aead_pack_input {
+	uint8_t nonce[RSS_CRYPTO_MAX_NONCE_LENGTH];
+	uint32_t nonce_length;
+};
+
+/*
+ * Structure used to pack non-pointer types in a call
+ */
+struct rss_crypto_pack_iovec {
+	psa_key_id_t key_id;	/* Key id */
+	psa_algorithm_t alg;	/* Algorithm */
+	uint32_t op_handle;	/* Frontend context handle associated
+				   to a multipart operation */
+	uint32_t capacity;	/* Key derivation capacity */
+	uint32_t ad_length;	/* Additional Data length for multipart AEAD */
+	uint32_t plaintext_length;	/* Plaintext length for multipart AEAD */
+	struct rss_crypto_aead_pack_input aead_in;	/* Packs AEAD-related inputs */
+	uint16_t function_id;	/* Used to identify the function in the API dispatcher
+				   to the service backend. See rss_crypto_func_sid for
+				   detail */
+	uint16_t step;		/* Key derivation step */
+};
+
+#endif /* RSS_CRYPTO_DEFS_H */