Storing private key validation parameters in PKCS#8
draft-mavrogiannopoulos-pkcs8-validated-parameters-00

Abstract

This memo describes a method of storing parameters needed for private key validation in the Private-Key Information Syntax Specification Version 1.2 [RFC5208] (PKCS#8) format.

Status of This Memo

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Copyright Notice

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1. Introduction

RSA or DSA private keys generated using the Shawe-Taylor prime generation algorithm describled in [FIPS186-4] allow for parameter validation, i.e., verify whether the primes are actually prime, and were correctly generated. That is done by generating the parameters from a known seed and a selected hash algorithm.

Storing these parameters in a private key format such as the RSA Private Key Syntax from PKCS#1 [RFC8017], or common representations for DSA private keys, does not allow attaching information on the parameters needed for validation. The purpose of the document is to describe such a method using the Private-Key Information Syntax Specification Version 1.2 [RFC5208] format.

2. Terminology

The key words "MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL NOT", "SHOULD", "SHOULD NOT", "RECOMMENDED", "MAY", and "OPTIONAL" in this document are to be interpreted as described in [RFC2119].

3. ValidationParams attribute

The information related to the validated parameters is stored as an attribute in the PrivateKeyInfo structure. The attribute is identified by the id-attr-validated-parameters object identifier and contains as AttributeValue a single ValidationParams structure.

     id-attr-validated-parameters OBJECT IDENTIFIER ::= {1 3 6 1 4 1 2312 18 8 1}

     ValidationParams ::= SEQUENCE {
         algorithm OBJECT IDENTIFIER,
         seed OCTET STRING
     }

The algorithm identifier in the ValidationParams should be a hash algorithm identifier for the [FIPS186-4] methods.

4. Example Structure

The following structure contains an RSA key generated using the [FIPS186-4] section B.3.3 algorithm with SHA2-384 hash. The seed used is '8af4328c87bebcec31e303b8f5537effcb6a91d947084d99a369823b36f01462' (hex encoded).

5. Compatibility notes

For compatibility it is RECOMMENDED that implementations following this document, support generation and validation using the SHA2-384 hash algorithm.

This document intentionally ignores [RFC5958] as it enhances PKCS#8 [RFC5208] in a way that makes new keys incompatible with old parsers.

6. Security Considerations

All the considerations in [RFC5208] apply.

7. IANA Considerations

None.

8. References

8.1. Normative References

[FIPS186-4]	Kerry, C. and P. Gallagher, "FIPS PUB 186-4: Digital Signature Standard (DSS)", FEDERAL INFORMATION PROCESSING STANDARDS PUBLICATION , July 2013.
[RFC2119]	Bradner, S., "Key words for use in RFCs to Indicate Requirement Levels", BCP 14, RFC 2119, DOI 10.17487/RFC2119, March 1997.
[RFC5208]	Kaliski, B., "Public-Key Cryptography Standards (PKCS) #8: Private-Key Information Syntax Specification Version 1.2", RFC 5208, DOI 10.17487/RFC5208, May 2008.

8.2. Informative References

[RFC5958]	Turner, S., "Asymmetric Key Packages", RFC 5958, DOI 10.17487/RFC5958, August 2010.
[RFC8017]	Moriarty, K., Kaliski, B., Jonsson, J. and A. Rusch, "PKCS #1: RSA Cryptography Specifications Version 2.2", RFC 8017, DOI 10.17487/RFC8017, November 2016.

Appendix A. Acknowledgements

None.

Author's Address

Nikos Mavrogiannopoulos Red Hat, Inc. Brno, Czech Republic EMail: nmav@redhat.com

1. Introduction
2. Terminology
3. ValidationParams attribute
4. Example Structure
5. Compatibility notes
6. Security Considerations
7. IANA Considerations
8. References

8.1. Normative References
8.2. Informative References

Appendix A. Acknowledgements
Author's Address