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

The information below is for an old version of the document that is already published as an RFC
Document Type RFC Internet-Draft (individual in gen area)
Author Burt Kaliski 
Last updated 2020-01-21 (latest revision 2008-04-16)
Stream Internet Engineering Task Force (IETF)
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Send notices to turners@ieca.com
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 

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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. 
 
 
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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. 

 
 
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   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 

 
 
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     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. 
 
 
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   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 

 
 
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Acknowledgment 

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

 
 
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