ISO/IEC 14776-481:2019

ISO/IEC 14776-481
Edition 1.0 2019-12
INTERNATIONAL
STANDARD
colour
inside
Information technology – Small Computer System Interface (SCSI) –
Part 481: Security features for SCSI commands (SFSC)

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ISO/IEC 14776-481
Edition 1.0 2019-12
INTERNATIONAL
STANDARD
colour
inside
Information technology – Small Computer System Interface (SCSI) –

Part 481: Security features for SCSI commands (SFSC)

INTERNATIONAL
ELECTROTECHNICAL
COMMISSION
ICS 35.200 ISBN 978-2-8322-7663-1

ISO/IEC
14776-481
Information technology -
Small Computer System Interface (SCSI) -
Part 481: Security features for SCSI commands (SFSC)
Reference
ISO/IEC 14776-481
Contents
Page
FOREWORD. 9
INTRODUCTION. 11
1 Scope. 12
2 Normative references. 12
3 Terms and definitions, symbols, abbreviations, and conventions . 14
3.1 Terms and definitions . 14
3.2 Abbreviations and symbols. 24
3.2.1 Abbreviations. 24
3.2.2 Symbols. 25
3.2.3 Mathematical operators . 25
3.3 Keywords. 25
3.4 Editorial conventions . 27
3.5 Numeric and character conventions . 27
3.5.1 Numeric conventions . 27
3.5.2 Units of measure . 28
3.5.3 Byte encoded character strings conventions. 29
3.6 Bit and byte ordering . 29
4 Security features model common to all device types. 31
4.1 Security features for SCSI devices. 31
4.1.1 Security associations. 31
4.1.1.1 Principles of SAs . 31
4.1.1.2 SA parameters. 32
4.1.1.3 Creating an SA . 34
4.1.2 Key derivation functions . 35
4.1.2.1 KDFs overview . 35
4.1.2.2 IKEv2-based iterative KDF . 36
4.1.2.3 HMAC-based KDFs . 36
4.1.2.4 AES-XCBC-PRF-128 IKEv2-based iterative KDF . 38
4.1.3 Using IKEv2-SCSI to create an SA . 38
4.1.3.1 Overview. 38
4.1.3.2 IKEv2-SCSI Protocol summary . 42
4.1.3.3 IKEv2-SCSI Authentication. 44
4.1.3.3.1 Overview. 44
4.1.3.3.2 Pre-shared key authentication. 45
4.1.3.3.3 Digital signature authentication . 46
4.1.3.3.3.1 Overview. 46
4.1.3.3.3.2 Certificates and digital signature authentication . 46
4.1.3.3.3.3 Example of certificate use for digital signature authentication. 47
4.1.3.3.3.4 Handling of the Certificate Request payload and the Certificate payload . 47
4.1.3.3.4 Constraints on skipping the Authentication step. 47
4.1.3.4 Summary of IKEv2-SCSI shared keys nomenclature and shared key sizes . 49
4.1.3.5 Device Server Capabilities step. 50
4.1.3.6 IKEv2-SCSI Key Exchange step . 52
4.1.3.6.1 Overview. 52
4.1.3.6.2 Key Exchange step SECURITY PROTOCOL OUT command. 52
4.1.3.6.3 Key Exchange step SECURITY PROTOCOL IN command. 53
4.1.3.6.4 Key Exchange step completion . 54
4.1.3.6.5 After the Key Exchange step . 54
4.1.3.7 IKEv2-SCSI Authentication step. 54

4.1.3.7.1 Overview. 54
4.1.3.7.2 Authentication step SECURITY PROTOCOL OUT command . 55
4.1.3.7.3 Authentication step SECURITY PROTOCOL IN command . 56
4.1.3.8 Generating shared keys . 57
4.1.3.8.1 Overview. 57
4.1.3.8.2 Generating shared keys when the Authentication step is skipped . 58
4.1.3.8.3 Generating shared keys when the Authentication step is processed . 58
4.1.3.8.4 Initializing shared key generation . 58
4.1.3.8.4.1 Initializing for SA creation shared key generation . 58
4.1.3.8.4.2 Initializing for generation of shared keys used by the created SA. 59
4.1.3.8.5 Generating shared keys used for SA management. 59
4.1.3.8.6 Generating shared keys for use by the created SA. 60
4.1.3.9 IKEv2-SCSI SA generation. 61
4.1.3.10 Abandoning an IKEv2-SCSI CCS. 62
4.1.3.11 Deleting an IKEv2-SCSI SA . 63
4.1.4 Security progress indication . 63
4.1.5 ESP-SCSI encapsulations for parameter data . 64
4.1.5.1 Overview. 64
4.1.5.2 ESP-SCSI required inputs . 64
4.1.5.3 ESP-SCSI data format before encryption and after decryption . 65
4.1.5.4 ESP-SCSI outbound data descriptors . 66
4.1.5.4.1 Overview. 66
4.1.5.4.2 ESP-SCSI CDBs or Data-Out Buffer parameter lists including a descriptor length. 67
4.1.5.4.2.1 Initialization vector absent . 67
4.1.5.4.2.2 Initialization vector present . 68
4.1.5.4.3 ESP-SCSI Data-Out Buffer parameter lists for externally specified descriptor length. 70
4.1.5.4.3.1 Initialization vector absent . 70
4.1.5.4.3.2 Initialization vector present . 71
4.1.5.5 ESP-SCSI Data-In Buffer parameter data descriptors . 71
4.1.5.5.1 Overview. 71
4.1.5.5.2 ESP-SCSI Data-In Buffer parameter data including a descriptor length . 72
4.1.5.5.2.1 Initialization vector absent . 72
4.1.5.5.2.2 Initialization vector present . 74
4.1.5.5.3 ESP-SCSI Data-In Buffer parameter data for externally specified descriptor length. 75
4.1.5.5.3.1 Initialization vector absent . 75
4.1.5.5.3.2 Initialization vector present . 76
4.1.6 Security algorithm codes . 77
4.2 Secure random numbers . 79
5 Security protocol parameters for all device types . 80
5.1 Security protocol information description. 80
5.1.1 Overview. 80
5.1.2 CDB description. 80
5.1.3 Supported security protocols list description . 81
5.1.4 Certificate data description . 82
5.1.4.1 Certificate overview . 82
5.1.4.2 Public Key certificate description. 82
5.1.4.3 Attribute certificate description . 82
5.1.5 Security compliance information description . 83
5.1.5.1 Security compliance information overview . 83
5.1.5.2 Compliance descriptor overview. 84
5.1.5.3 FIPS 140 compliance descriptor. 85
5.2 SA creation capabilities . 86
5.2.1 Overview. 86
5.2.2 SA creation capabilities CDB description . 86
5.2.3 SA creation capabilities parameter data formats. 87
5.2.3.1 Supported device server capabilities formats parameter data format . 87

5.2.3.2 IKEv2-SCSI device server capabilities parameter data format. 88
5.3 IKEv2-SCSI . 88
5.3.1 Overview. 88
5.3.2 IKEv2-SCSI SECURITY PROTOCOL IN CDB description . 89
5.3.3 IKEv2-SCSI SECURITY PROTOCOL OUT CDB description . 90
5.3.4 IKEv2-SCSI parameter data format. 91
5.3.5 IKEv2-SCSI payloads . 98
5.3.5.1 IKEv2-SCSI payload format. 98
5.3.5.2 No Next payload . 99
5.3.5.3 Key Exchange payload. 100
5.3.5.4 Identification – Application Client payload and Identification – Device Server payload. 101
5.3.5.5 Certificate payload. 102
5.3.5.6 Certificate Request payload . 103
5.3.5.7 Authentication payload . 104
5.3.5.8 Nonce payload. 106
5.3.5.9 Notify payload. 107
5.3.5.10 Delete payload. 108
5.3.5.11 Encrypted payload. 109
5.3.5.11.1 Combined mode encryption. 109
5.3.5.11.2 Encrypted payload introduction . 110
5.3.5.11.3 IKEv2-SCSI AAD . 112
5.3.5.11.4 Processing a received Encrypted payload . 113
5.3.5.12 IKEv2-SCSI SA Creation Capabilities payload. 115
5.3.5.13 IKEv2-SCSI SA Cryptographic Algorithms payload. 116
5.3.5.14 IKEv2-SCSI SAUT Cryptographic Algorithms payload. 118
5.3.5.15 IKEv2-SCSI Timeout Values payload. 119
5.3.6 IKEv2-SCSI cryptographic algorithm descriptors . 120
5.3.6.1 Overview. 120
5.3.6.2 ENCR IKEv2-SCSI cryptographic algorithm descriptor . 122
5.3.6.3 PRF IKEv2-SCSI cryptographic algorithm descriptor . 124
5.3.6.4 INTEG IKEv2-SCSI cryptographic algorithm descriptor . 126
5.3.6.5 D-H IKEv2-SCSI cryptographic algorithm descriptor. 127
5.3.6.6 IKEv2-SCSI authentication algorithm IKEv2-SCSI cryptographic algorithm descriptor. 129
5.3.7 Errors in IKEv2-SCSI security protocol commands . 131
5.3.8 Errors in IKEv2-SCSI security protocol parameter data . 133
5.3.8.1 Overview. 133
5.3.8.2 Errors with high denial of service attack potential . 133
5.3.8.3 Errors with low denial of service attack potential. 134
5.3.9 Translating IKEv2 errors. 134
Annex A (informative) Security goals and threat model. 136
A.1 Overview . 136
A.2 Security goals. 136
A.3 Threat model . 137
A.4 Types of attacks . 137
A.5 SCSI security considerations . 138
Annex B (informative) Variations between this document and equivalent security protocols . 139
B.1 IKEv2 protocol details and variations for IKEv2-SCSI. 139
B.2 ESP protocol details and variations for ESP-SCSI . 142
BIBLIOGRAPHY . 143

Figures
Page
Figure 1 — SCSI document structure . 11
Figure 2 — SA relationships . 31
Figure 3 — IKEv2-SCSI Device Server Capabilities step . 42
Figure 4 — IKEv2-SCSI Key Exchange step . 42
Figure 5 — IKEv2-SCSI Authentication step. 43
Figure 6 — IKEv2-SCSI Delete operation. 44

Tables
Page
Table 1 — Numbering conventions examples . 28
Table 2 — Comparison of decimal prefixes and binary prefixes. 29
Table 3 — Minimum SA parameters. 32
Table 4 — USAGE_TYPE SA parameter . 34
Table 5 — Security protocols that create SAs . 35
Table 6 — KDFs summary. 36
Table 7 — HMAC-based KDFs. 37
Table 8 — Hash functions used by HMAC based on KDF_ID. 37
Table 9 — RFC 3566 parameter translations for the KDF based on AES-XCBC-PRF-128 . 38
Table 10 — IKEv2-SCSI shared key names and SA shared key names. 49
Table 11 — Shared key size determination . 50
Table 12 — Device Server Capabilities step parameter data requirements . 51
Table 13 — IKEv2-SCSI command terminations that do not abandon the CCS . 62
Table 14 — ESP-SCSI data format before encryption and after decryption. 65
Table 15 — ESP-SCSI outbound data descriptors . 66
Table 16 — ESP-SCSI CDBs or Data-Out Buffer parameter list descriptor without initialization vector. 67
Table 17 — ESP-SCSI CDBs or Data-Out Buffer full parameter list descriptor. 69
Table 18 — ESP-SCSI Data-Out Buffer parameter list descriptor without length and initialization vector . 70
Table 19 — ESP-SCSI Data-Out Buffer parameter list descriptor without length. 71
Table 20 — ESP-SCSI Data-In Buffer parameter data descriptors . 72
Table 21 — ESP-SCSI Data-In Buffer parameter data descriptor without initialization vector . 72
Table 22 — ESP-SCSI Data-In Buffer full parameter data descriptor. 74
Table 23 — ESP-SCSI Data-In Buffer parameter data descriptor without length and initialization vector. 75
Table 24 — ESP-SCSI Data-In Buffer parameter data descriptor without length. 76
Table 25 — Security algorithm codes . 77
Table 26 — SECURITY PROTOCOL SPECIFIC field for SECURITY PROTOCOL IN protocol 00h. 80
Table 27 — Supported security protocols SECURITY PROTOCOL IN parameter data. 81
Table 28 — Certificate data SECURITY PROTOCOL IN parameter data. 82
Table 29 — Security compliance information SECURITY PROTOCOL IN parameter data . 83
Table 30 — Compliance descriptor format. 84
Table 31 — COMPLIANCE DESCRIPTOR TYPE field . 84
Table 32 — FIPS 140 compliance descriptor. 85
Table 33 — RELATED STANDARD field. 85
Table 34 — SECURITY PROTOCOL SPECIFIC field for the SA creation capabilities . 87
Table 35 — Supported device server capabilities formats parameter data . 87
Table 36 — IKEv2-SCSI device server capabilities parameter data. 88
Table 37 — SECURITY PROTOCOL SPECIFIC field as defined by the IKEv2-SCSI SECURITY PROTOCOL
IN command. 89
Table 38 — SECURITY PROTOCOL SPECIFIC field as defined by the IKEv2-SCSI SECURITY PROTOCOL
OUT command . 90
Table 39 — IKEv2-SCSI SECURITY PROTOCOL OUT command and SECURITY PROTOCOL IN
command parameter data . 91
Table 40 — IKEv2-SCSI header checking of SAIs . 93
Table 41 — NEXT PAYLOAD field. 94
Table 42 — MESSAGE ID field. 95
Table 43 — Next payload values in SECURITY PROTOCOL OUT/IN parameter data . 96
Table 44 — IKEv2-SCSI payload format. 98
Table 45 — Key Exchange payload format. 100
Table 46 — Identification payload format. 101
Table 47 — ID TYPE field. 101
Table 48 — Certificate payload format. 102
Table 49 — CERTIFICATE ENCODING field. 102
Table 50 — Certificate Request payload format . 103
Table 51 — Authentication payload format. 104
Table 52 — Nonce payload format . 106

Table 53 — Notify payload format. 107
Table 54 — Delete payload format . 108
Table 55 — Encrypted payload format. 110
Table 56 — Plaintext format for Encrypted payload CIPHERTEXT field. 112
Table 57 — IKEv2-SCSI SA Creation Capabilities payload format. 115
Table 58 — IKEv2-SCSI SA Cryptographic Algorithms payload format . 116
Table 59 — IKEv2-SCSI SAUT Cryptographic Algorithms payload format. 118
Table 60 — IKEv2-SCSI Timeout Values payload format. 119
Table 61 — IKEv2-SCSI cryptographic algorithm descriptor format. 120
Table 62 — ALGORITHM TYPE field . 121
Table 63 — ENCR IKEv2-SCSI cryptographic algorithm descriptor format. 122
Table 64 — ENCR ALGORITHM IDENTIFIER field. 123
Table 65 — PRF IKEv2-SCSI cryptographic algorithm descriptor format. 124
Table 66 — PRF ALGORITHM IDENTIFIER field. 125
Table 67 — INTEG IKEv2-SCSI cryptographic algorithm descriptor format. 126
Table 68 — INTEG ALGORITHM IDENTIFIER field. 126
Table 69 — D-H IKEv2-SCSI cryptographic algorithm descriptor format. 127
Table 70 — D-H ALGORITHM IDENTIFIER field . 128
Table 71 — SA_AUTH_OUT and SA_AUTH_IN IKEv2-SCSI cryptographic algorithm descriptor format. 129
Table 72 — SA_AUTH_OUT and SA_AUTH_IN ALGORITHM IDENTIFIER field . 130
Table 73 — IKEv2-SCSI command order processing requirements on a single I_T_L nexus. 132
Table 74 — IKEv2-SCSI parameter error categories. 133
Table 75 — IKEv2 Notify payload error translations for IKEv2-SCSI. 135
Table B.1 — IKE payload names shorthand. 141

INFORMATION TECHNOLOGY –
SMALL COMPUTER SYSTEM INTERFACE (SCSI) –
Part 481: Security features for SCSI commands (SFSC)
FOREWORD
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Commission) form the specialized system for worldwide standardization. National bodies that are
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all such patent rights.
International Standard ISO/IEC 14776-481 was prepared by subcommittee 25: Interconnection of information
technology equipment, of ISO/IEC joint technical committee 1: Information technology.
The list of all currently available parts of the ISO/IEC 14776 series, under the general title Information
technology – Small computer system interface (SCSI), can be found on the IEC and ISO web sites.

The text of this standard is based on the following documents:
CDV Report on voting
JTC1-SC25/2845/CDV JTC1-SC25/2871/RVC
Full information on the voting for the approval of this standard can be found in the report on voting indicated in
the above table.
This publication has been drafted in accordance with the ISO/IEC Directives, Part 2, except as described in
3.4 and 3.5.
A bilingual version of this publication may be issued at a later date.
IMPORTANT - The 'colour inside' logo on the cover page of this publication indicates that
it contains colours which are considered to be useful for the correct understanding of its
contents. Users should therefore print this document using a colour printer.

INTRODUCTION
ISO/IEC 14776 (all parts) provides for many different commands that define device models and commands for
different SCSI devices. This document defines security features for use by all SCSI devices. This document
defines the security model that is basic to every device model and the parameter data that may apply to any
device model.
Figure 1 shows the relationship of this document to the other documents and related projects in the SCSI
family of standards.
(shared for all device types)
Device type specific command sets
Primary command set
(e.g., SBC-4, SSC-4)
Security features
(this standard)
SCSI transport protocols
(e.g., SPL-3, FCP-4)
Interconnects
(e.g., SAS-3, Fibre Channel)
Figure 1 — SCSI document structure
The SCSI document structure in figure 1 shows the general applicability of the documents to one another.
Figure 1 is not intended to imply a relationship such as a hierarchy, protocol stack, or system architecture.
The term SCSI is used to refer to ISO/IEC 14776 (all parts).
These documents specify the interfaces, functions and operations necessary to ensure interoperability
between conforming implementations. This document contains a functional description. Conforming
implementations employ any design technique that does not violate interoperability.
SCSI Architecture Model
(SAM-5)
INFORMATION TECHNOLOGY –
SMALL COMPUTER SYSTEM INTERFACE (SCSI) –
Part 481: Security features for SCSI commands (SFSC)
1 Scope
ISO/IEC 14776 (all parts) provides for many different types of SCSI devices (e.g., disks, tapes, media
changers). This part of ISO/IEC 14776 defines a device model that is applicable to all SCSI devices. Other
command standards expand on the general SCSI device model in ways appropriate to specific types of SCSI
devices.
ISO/IEC 14776 (all parts) specifies the interfaces, functions, and operations necessary to ensure
interoperability between conforming SCSI implementations. This document is a functional description.
Conforming implementations employ any design technique that does not violate interoperability.
This document defines security features for use by all SCSI devices. This document defines the security
model that is basic to every device model and the parameter data that applies to any device model. For
additional information on the security goals and threat model discussed in this document see Annex A.
2 Normative references
The following documents are referred to in the text in such a way that some or all of their content constitutes
requirements of this document. For dated references, only the edition cited applies. For undated references,
the latest edition of the referenced document (including any amendments) applies.
ISO/IEC 14776-415, Information Technology – Small computer system interface (SCSI) - Part 415: SCSI
Architecture Model - 5 (SAM-5)
ISO/IEC 10646:2017, Information technology - Universal Coded Character Set (UCS)
INCITS 496-2012, Information Technology - Fibre Channel - Security Protocols - 2 (FC-SP-2)
INCITS 496-2012/AM1-2015, Information Technology - Fibre Channel - Security Protocols - 2/Amendment 1
-(FC-SP-2/AM1)
INCITS 502, Information technology – SCSI Primary Commands - 5 (SPC-5)
INCITS 516, Infor
...