Public-Key Cryptography Standards (PKCS) #8: Private-Key Information Syntax Specification Version 1.2
draft-kaliski-pkcs8-00

Network Working Group                                 Burt Kaliski, EMC 
Internet Draft                                           April 16, 2008 
Intended Status: Informational 
Expires: October 16, 2008 
 
 
                                      
             PKCS #8: Private-Key Information Syntax Standard 
                                Version 1.2 
                        draft-kaliski-pkcs8-00.txt 

Status of this Memo 

   By submitting this Internet-Draft, each author represents that any 
   applicable patent or other IPR claims of which he or she is aware 
   have been or will be disclosed, and any of which he or she becomes 
   aware will be disclosed, in accordance with Section 6 of BCP 79. 

   Internet-Drafts are working documents of the Internet Engineering 
   Task Force (IETF), its areas, and its working groups.  Note that 
   other groups may also distribute working documents as Internet-
   Drafts. 

   Internet-Drafts are draft documents valid for a maximum of six months 
   and may be updated, replaced, or obsoleted by other documents at any 
   time.  It is inappropriate to use Internet-Drafts as reference 
   material or to cite them other than as "work in progress." 

   The list of current Internet-Drafts can be accessed at 
   http://www.ietf.org/ietf/1id-abstracts.txt 

   The list of Internet-Draft Shadow Directories can be accessed at 
   http://www.ietf.org/shadow.html 

   This Internet-Draft will expire on October 16, 2008. 

Copyright Notice 

   Copyright (C) The IETF Trust (2008). 

Abstract 

   This document represents a republication of PKCS #8 v1.2 from RSA 
   Laboratories' Public Key Cryptography Standard (PKCS) series.  Change 
   control is transferred to the IETF.  The body of this document, 
   except for the security considerations section, is taken directly 
   from the PKCS #8 v1.2 specification. 

   This document describes a syntax for private-key information. 
 
 
Kaliski                Expires October 16, 2008                [Page 1] 


Internet-Draft     PKCS #8 Private Key Information           April 2008 
                         Syntax Version 1.2 

Table of Contents 

   1. Introduction...................................................2 
   2. References.....................................................2 
   3. Definitions....................................................3 
   4. Symbols and Abbreviations......................................3 
   5. General Overview...............................................3 
   6. Private Key Information Syntax.................................3 
   7. Encrypted private-key information syntax.......................4 
   8. IANA Considerations............................................5 
    
1. Introduction 

   This standard describes a syntax for private-key information. 
   Private-key information includes a private key for some public-key 
   algorithm and a set of attributes. The standard also describes a 
   syntax for encrypted private keys. A password-based encryption 
   algorithm (e.g., one of those described in PKCS #5) could be used to 
   encrypt the private-key information. 

   The intention of including a set of attributes is to provide a simple 
   way for a user to establish trust in information such as a 
   distinguished name or a top-level certification authority's public 
   key. While such trust could also be established with a digital 
   signature, encryption with a secret key known only to the user is 
   just as effective and possibly easier to implement. A non-exhaustive 
   list of attributes is given in PKCS #9. 

2. References 

   PKCS #1 RSA Laboratories. PKCS #1: RSA Encryption Standard. Version 
   1.5, November 1993. 

   PKCS #5 RSA Laboratories. PKCS #5: Password-Based Encryption 
   Standard. Version 1.5, November 1993. 

   PKCS #9 RSA Laboratories. PKCS #9: Selected Attribute Types. Version 
   1.1, November 1993. 

   X.208 CCITT. Recommendation X.208: Specification of Abstract Syntax 
   Notation One (ASN.1). 1988. 

   X.209 CCITT. Recommendation X.209: Specification of Basic Encoding 
   Rules for Abstract Syntax Notation One (ASN.1). 1988. 

   X.501 CCITT. Recommendation X.501: The Directory - Models. 1988. 

 
 
Kaliski                Expires October 16, 2008                [Page 2] 


Internet-Draft     PKCS #8 Private Key Information           April 2008 
                         Syntax Version 1.2 

   X.509 CCITT. Recommendation X.509: The Directory - Authentication 
   Framework. 1988. 

3. Definitions 

   For the purposes of this standard, the following definitions apply. 

      AlgorithmIdentifier: A type that identifies an algorithm (by 
      object identifier) and any associated parameters. This type is 
      defined in X.509. 

      ASN.1: Abstract Syntax Notation One, as defined in X.208. 

      Attribute: A type that contains an attribute type (specified by 
      object identifier) and one or more attribute values. This type is 
      defined in X.501. 

      BER: Basic Encoding Rules, as defined in X.209. 

4. Symbols and Abbreviations 

   No symbols or abbreviations are defined in this standard. 

5. General Overview 

   The next two sections specify private-key information syntax and 
   encrypted private-key information syntax. 

   This standard exports two types: PrivateKeyInfo (Section 6) and 
   EncryptedPrivateKeyInfo (Section 7). 

6. Private Key Information Syntax 

   This section gives the syntax for private-key information. 

   Private-key information shall have ASN.1 type PrivateKeyInfo: 

     PrivateKeyInfo ::= SEQUENCE { 
       version                   Version, 
       privateKeyAlgorithm       PrivateKeyAlgorithmIdentifier, 
       privateKey                PrivateKey, 
       attributes           [0]  IMPLICIT Attributes OPTIONAL } 

     Version ::= INTEGER 

     PrivateKeyAlgorithmIdentifier ::= AlgorithmIdentifier 

 
 
Kaliski                Expires October 16, 2008                [Page 3] 


Internet-Draft     PKCS #8 Private Key Information           April 2008 
                         Syntax Version 1.2 

     PrivateKey ::= OCTET STRING 

     Attributes ::= SET OF Attribute 

   The fields of type PrivateKeyInfo have the following meanings: 

      version is the syntax version number, for compatibility with 
      future revisions of this standard. It shall be 0 for this version 
      of the standard. 

      privateKeyAlgorithm identifies the private-key algorithm. One 
      example of a private-key algorithm is PKCS #1's rsaEncryption. 

      privateKey is an octet string whose contents are the value of the 
      private key. The interpretation of the contents is defined in the 
      registration of the private -key algorithm. For an RSA private 
      key, for example, the contents are a BER encoding of a value of 
      type RSAPrivateKey. 

      attributes is a set of attributes. These are the extended 
      information that is encrypted along with the private-key 
      information. 

7. Encrypted private-key information syntax 

   This section gives the syntax for encrypted private-key information. 

   Encrypted private-key information shall have ASN.1 type 
   EncryptedPrivateKeyInfo: 

     EncryptedPrivateKeyInfo ::= SEQUENCE { 
       encryptionAlgorithm  EncryptionAlgorithmIdentifier, 
       encryptedData        EncryptedData } 

     EncryptionAlgorithmIdentifier ::= AlgorithmIdentifier 

     EncryptedData ::= OCTET STRING 

   The fields of type EncryptedPrivateKeyInfo have the following 
   meanings: 

      encryptionAlgorithm identifies the algorithm under which the 
      private-key information is encrypted. Two examples are PKCS #5's 
      pbeWithMD2AndDES-CBC and pbeWithMD5AndDES-CBC. 

      encryptedData is the result of encrypting the private-key 
      information. 
 
 
Kaliski                Expires October 16, 2008                [Page 4] 


Internet-Draft     PKCS #8 Private Key Information           April 2008 
                         Syntax Version 1.2 

   The encryption process involves the following two steps: 

      1. The private-key information is BER encoded, yielding an octet 
      string. 

      2. The result of step 1 is encrypted with the secret key to give 
      an octet string, the result of the encryption process. 

8. Security Considerations 

   Protection of the private-key information is vital to public-key 
   cryptography.  Disclosure of the private-key material to another 
   entity can lead to masquerades.  The encryption algorithm used in the 
   encryption process must be as 'strong' as the key it is protecting. 

9. IANA Considerations 

   None.  Please remove this section prior to publication as an RFC. 

Revision History  

   Version 1.0 

      Version 1.0 was distributed to participants in RSA Data Security, 
      Inc.'s Public-Key Cryptography Standards meetings in February and 
      March 1991. 

   Version 1.1 

      Version 1.1 is part of the June 3, 1991 initial public release of 
      PKCS. Version 1.1 was published as NIST/OSI Implementors' 
      Workshop document SEC-SIG-91-23. 

   Version 1.2 

      Version 1.2 incorporates several editorial changes, including 
      updates to the references and the addition of a revision history. 

Author's Addresses 

   Burt Kaliski 

   174 Middlesex Turnpike 
   Bedford, MA 01730 

   kaliski_burt@emc.com 

 
 
Kaliski                Expires October 16, 2008                [Page 5] 


Internet-Draft     PKCS #8 Private Key Information           April 2008 
                         Syntax Version 1.2 

Full Copyright Statement 

   Copyright (C) The IETF Trust (2008). 

   This document is subject to the rights, licenses and restrictions 
   contained in BCP 78, and except as set forth therein, the authors 
   retain all their rights. 

   This document and the information contained herein are provided on an 
   "AS IS" basis and THE CONTRIBUTOR, THE ORGANIZATION HE/SHE REPRESENTS 
   OR IS SPONSORED BY (IF ANY), THE INTERNET SOCIETY, THE IETF TRUST AND 
   THE INTERNET ENGINEERING TASK FORCE DISCLAIM ALL WARRANTIES, EXPRESS 
   OR IMPLIED, INCLUDING BUT NOT LIMITED TO ANY WARRANTY THAT THE USE OF 
   THE INFORMATION HEREIN WILL NOT INFRINGE ANY RIGHTS OR ANY IMPLIED 
   WARRANTIES OF MERCHANTABILITY OR FITNESS FOR A PARTICULAR PURPOSE. 

Intellectual Property 

   The IETF takes no position regarding the validity or scope of any 
   Intellectual Property Rights or other rights that might be claimed to 
   pertain to the implementation or use of the technology described in 
   this document or the extent to which any license under such rights 
   might or might not be available; nor does it represent that it has 
   made any independent effort to identify any such rights.  Information 
   on the procedures with respect to rights in RFC documents can be 
   found in BCP 78 and BCP 79. 

   Copies of IPR disclosures made to the IETF Secretariat and any 
   assurances of licenses to be made available, or the result of an 
   attempt made to obtain a general license or permission for the use of 
   such proprietary rights by implementers or users of this 
   specification can be obtained from the IETF on-line IPR repository at 
   http://www.ietf.org/ipr. 

   The IETF invites any interested party to bring to its attention any 
   copyrights, patents or patent applications, or other proprietary 
   rights that may cover technology that may be required to implement 
   this standard.  Please address the information to the IETF at ietf-
   ipr@ietf.org. 

Acknowledgment 

   Funding for the RFC Editor function is provided by the IETF 
   Administrative Support Activity (IASA). 

 
 
Kaliski                Expires October 16, 2008                [Page 6]