PSA Certified
Secure Storage API 1.0

Document number:	IHI 0087
Release Quality:	Final
Issue Number:	4
Confidentiality:	Non-confidential
Date of Issue:	23/09/2025

Abstract

This document is part of the PSA Certified API specifications. It defines interfaces to provide secure storage services.

Contents

• About this document
  • Release information
  • License
  • References
  • Terms and abbreviations
  • Potential for change
  • Conventions
  • Feedback

• 1 Introduction
  • 1.1 About Platform Security Architecture
  • 1.2 About the Secure Storage API
• 2 Architecture
  • 2.1 Use Cases and Rationale
  • 2.2 Technical Background
  • 2.3 The Protected Storage API
  • 2.4 The Internal Trusted Storage API
  • 2.5 UIDs
  • 2.6 Atomicity of Operations
  • 2.7 Components
• 3 Requirements
  • 3.1 Protected Storage requirements
  • 3.2 Internal Trusted Storage requirements
• 4 Theory of Operation
  • 4.1 Internal Trusted Storage API
  • 4.2 Memory access errors
• 5 API Reference
  • 5.1 Status codes
  • 5.2 General Definitions
    • 5.2.1 psa_storage_info_t (struct)
    • 5.2.2 psa_storage_create_flags_t (typedef)
    • 5.2.3 psa_storage_uid_t (typedef)
    • 5.2.4 PSA_STORAGE_FLAG_NONE (macro)
    • 5.2.5 PSA_STORAGE_FLAG_WRITE_ONCE (macro)
    • 5.2.6 PSA_STORAGE_FLAG_NO_CONFIDENTIALITY (macro)
    • 5.2.7 PSA_STORAGE_FLAG_NO_REPLAY_PROTECTION (macro)
    • 5.2.8 PSA_STORAGE_SUPPORT_SET_EXTENDED (macro)
  • 5.3 Internal Trusted Storage API
    • 5.3.1 PSA_ITS_API_VERSION_MAJOR (macro)
    • 5.3.2 PSA_ITS_API_VERSION_MINOR (macro)
    • 5.3.3 psa_its_set (function)
    • 5.3.4 psa_its_get (function)
    • 5.3.5 psa_its_get_info (function)
    • 5.3.6 psa_its_remove (function)
  • 5.4 Protected Storage API
    • 5.4.1 PSA_PS_API_VERSION_MAJOR (macro)
    • 5.4.2 PSA_PS_API_VERSION_MINOR (macro)
    • 5.4.3 psa_ps_set (function)
    • 5.4.4 psa_ps_get (function)
    • 5.4.5 psa_ps_get_info (function)
    • 5.4.6 psa_ps_remove (function)
    • 5.4.7 psa_ps_create (function)
    • 5.4.8 psa_ps_set_extended (function)
    • 5.4.9 psa_ps_get_support (function)

• A Example header files
  • A.1 psa/storage_common.h
  • A.2 psa/internal_trusted_storage.h
  • A.3 psa/protected_storage.h
• B Security Risk Assessment
  • B.1 About this assessment
    • B.1.1 Subject and scope
    • B.1.2 Risk assessment methodology
  • B.2 Feature definition
    • B.2.1 Introduction
    • B.2.2 Lifecycle
    • B.2.3 Operation and trust boundaries
    • B.2.4 Deployment models
    • B.2.5 Assumptions, constraints, and interacting entities
    • B.2.6 Stakeholders and Assets
    • B.2.7 Goals
    • B.2.8 Adversarial models
  • B.3 Threats
    • B.3.1 T.INTERFACE_ABUSE: Illegal inputs to the API
    • B.3.2 T.SPOOF_READ: Use the API to read another caller’s data
    • B.3.3 T.SPOOF_WRITE: Use the API to modify another caller’s data
    • B.3.4 T.EAVESDROPPING: Eavesdropping
    • B.3.5 T.MITM: Man In The Middle
    • B.3.6 T.DIRECT_READ: Bypassing the API to directly read data
    • B.3.7 T.DIRECT_WRITE: Bypassing the API to directly modify data
    • B.3.8 T.REPLACE: Physical replacement of the storage medium
    • B.3.9 T.GLITCH_READ: Glitching during a read
    • B.3.10 T.GLITCH_WRITE: Glitching during a write
  • B.4 Mitigation Summary
    • B.4.1 Architecture level mitigations
    • B.4.2 Implementation-level mitigations
    • B.4.3 User-level mitigations
    • B.4.4 Mitigations required by each deployment model
• C Document history