The PKCS #8 EncryptedPrivateKeyInfo Media Type
draft-seantek-pkcs8-encrypted-01

Network Working Group                                         S. Leonard
Internet-Draft                                             Penango, Inc.
Intended Status: Informational                              July 8, 2016
Expires: January 9, 2017                                                

             The PKCS #8 EncryptedPrivateKeyInfo Media Type
                    draft-seantek-pkcs8-encrypted-01

Abstract

   This document registers the application/pkcs8-encrypted media type
   for the EncryptedPrivateKeyInfo type of PKCS #8. An instance of this
   media type carries a single encrypted private key, BER-encoded as a
   single EncryptedPrivateKeyInfo value.

Status of this Memo

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1. Definitions

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

2. Registration Application

   Type name: application

   Subtype name: pkcs8-encrypted

   Required parameters: None.

   Optional parameters:

    password-mapping: The private key is encrypted with an encryption
     algorithm, which could be a password-based encryption scheme (i.e.,
     algorithm), as that term is used in PKCS #5 [RFC2898]. Such
     algorithms take a password as input. A "password" is a secret text
     value (Section 3 of PKCS #5), but for algorithmic purposes the term
     "password" refers to an octet string (Section 2 of PKCS #5).
     Therefore, there must be some mapping between the text value (which
     might be user input) and the octet string. Section 3 of PKCS #5
     recommends "that applications follow some common text encoding
     rules"; it then offers, but does not recommend, ASCII and UTF-8.

     This parameter specifies the charset (defined in Section 1.3 of
     [RFC2978]) that a recipient SHOULD attempt first when mapping to
     the octet string. This parameter is not cryptographically
     protected, so recipients SHOULD NOT rely on it as the exclusive
     mapping possibility.

     This parameter has similar semantics as the charset parameter from
     text/plain, except that it only applies to the user's input (text
     value) of a password. There is no default value.

     The following special values, which all begin with "*" to
     distinguish them from registered charsets, are defined:
     *pkcs12     = UTF-16LE with U+0000 NULL terminator (PKCS #12-style,
                   see [RFC7292])
     *precis     = PRECIS password profile, i.e., OpaqueString from
                   Section 4 of [RFC7613] (always UTF-8)
     *precis-XXX = PRECIS profile as named XXX in the IANA PRECIS
                   Profiles Registry
     *hex        = hexadecimal input: the input is mapped to 0-9, A-F,
                   and then converted directly to octets. If there are
                   an odd number of hex digits, either the final digit 0
                   is appended, or an error condition is raised. Compare
 

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                   with Annex M.4 of IEEE 802.11-2012.
     *dtmf       = The characters "0"-"9", "A"-"D", "*", and "#", which
                   map to their corresponding ASCII codes. "A"-"D" map
                   to the uppercase range 0x41 - 0x44. (This is to
                   support restricted-input devices, i.e., telephones
                   and telephone-like equipment.) User input outside of
                   these values is either ignored, or an error condition
                   is raised.

     Otherwise, the value of this parameter is a charset, from the IANA
     Character Sets Registry [CHARREG].

     This parameter is case-insensitive.

   Encoding considerations: Binary.

   Security considerations:

     Carries a cryptographic private key. See Section 6 of [RFC5958].

     EncryptedPrivateKeyInfo PKCS #8 data contains exactly one private
     key. Poor password choices, weak algorithms, or improper parameter
     selections (e.g., insufficient salting rounds) will make the
     confidential payloads much easier to compromise.

   Interoperability considerations:

     PKCS #8 is a widely recognized format for private key information
     on all modern cryptographic stacks. The contents are exactly one
     private key (with optional key attributes), so there is no
     possibility for hidden "Easter eggs" in the payload such as
     unexpected certificates or miscellaneous secrets.

     The encrypted variation in this registration,
     EncryptedPrivateKeyInfo (Section 3, Encrypted Private Key Info, of
     [RFC5958], and Section 6 of PKCS #8), is less widely used for
     exchange than PKCS #12, but it is much simpler to implement.
     Actually PKCS #12 incorporates the PKCS #8 types, so a PKCS #12
     processor ought to be able to process PKCS #8 data by embedding the
     PKCS #8 data in PKCS #12 "scaffolding".

   Published specification:

     PKCS #8 v1.2, November 1993 (republished as RFC 5208, May 2008);
     RFC 5958, August 2010

 

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   Applications that use this media type:

     Machines, applications, browsers, Internet kiosks, and so on, that
     support this standard allow a user to import, export, and exercise
     a single private key.

   Fragment identifier considerations: None.

   Additional information:

     Deprecated alias names for this type: N/A
     Magic number(s): None.
     File extension(s): .p8e
     Macintosh file type code(s):
       None. A uniform type identifier (UTI) of
       "com.rsa.pkcs-8-encrypted" is RECOMMENDED.

   Object Identifiers: 1.2.840.113549.1.12.10.1.2 (when in PKCS #12)

   Person & email address to contact for further information:

     Sean Leonard <dev+ietf@seantek.com>

   Restrictions on usage: None.

   Author/Change controller: Sean Leonard <dev+ietf@seantek.com>

   Intended usage: COMMON

   Provisional registration? No

3.  IANA Considerations

   IANA is asked to register the media type application/pkcs8-encrypted
   in the Standards tree using the applications provided in Section 1 of
   this document.

4. Security Considerations

   See the registration template.

5. Normative References

   [CHARREG]  IANA, "Character Sets",
              <http://www.iana.org/assignments/character-sets>, December
              2013.

   [RFC2119]  Bradner, S., "Key words for use in RFCs to Indicate
 

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              Requirement Levels", BCP 14, RFC 2119, March 1997.

   [RFC2898]  Kaliski, B., "PKCS #5: Password-Based Cryptography
              Specification Version 2.0", RFC 2898, September 2000.

   [RFC2978]  Freed, N. and J. Postel, "IANA Charset Registration
              Procedures", BCP 19, RFC 2978, October 2000.

   [RFC5208]  Kaliski, B., "Public-Key Cryptography Standards (PKCS) #8:
              Private-Key Information Syntax Specification Version 1.2",
              RFC 5208, May 2008.

   [RFC5958]  Turner, S., "Asymmetric Key Packages", RFC 5958, August
              2010.

   [RFC7292]  Moriarty, K., Nystrom, S., Parkinson, S., Rusch, A., and
              M. Scott, "PKCS #12: Personal Information Exchange Syntax
              v1.1", RFC 7292, July 2014.

   [RFC7613]  Saint-Andre, P. and A. Melnikov, "Preparation,
              Enforcement, and Comparison of Internationalized Strings
              Representing Usernames and Passwords", RFC 7613, August
              2015.

Author's Address

   Sean Leonard
   Penango, Inc.
   5900 Wilshire Boulevard
   21st Floor
   Los Angeles, CA  90036
   USA

   EMail: dev+ietf@seantek.com
   URI:   http://www.penango.com/

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