wdiff rfc8351.original rfc8351.txt

Network Working Group
Independent Submission S. Leonard
Internet-Draft
Request for Comments: 8351 Penango, Inc.
Intended Status:
Category: Informational November 14, 2017
Expires: May 18, June 2018
ISSN: 2070-1721

The PKCS #8 EncryptedPrivateKeyInfo Media Type
draft-seantek-pkcs8-encrypted-03

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 This Memo

This Internet-Draft document is submitted in full conformance with not an Internet Standards Track specification; it is
published for informational purposes.

This is a contribution to the
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https://www.rfc-editor.org/info/rfc8351.

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Table of
the Trust Legal Provisions and are provided without warranty as
described in the Simplified BSD License. Contents

1. Definitions Introduction . . . . . . . . . . . . . . . . . . . . . . . . 2
2. Registration Application . . . . . . . . . . . . . . . . . . 2
3. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 6
4. Security Considerations . . . . . . . . . . . . . . . . . . . 6
5. Normative References . . . . . . . . . . . . . . . . . . . . 6
Author's Address . . . . . . . . . . . . . . . . . . . . . . . . 7

1. Introduction

The private key words "SHOULD", "SHOULD NOT", and "RECOMMENDED" in this
document are to is encrypted with an encryption algorithm, which
could be interpreted a password-based encryption scheme as that term is used in
PKCS #5: Password-Based Cryptography Specification Version 2.1 as
published in [RFC2898] and updated by [RFC8018]. This document
registers the application/pkcs8-encrypted media type for the
EncryptedPrivateKeyInfo type of PKCS #8 (as originally described in [RFC2119].
[RFC5208], which was obsoleted by [RFC5958]). An instance of this
media type carries a single encrypted private key [RFC5958] BER-
encoded as a single EncryptedPrivateKeyInfo value.

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 as
that term is used in PKCS #5 [RFC2898]. ([RFC2898] and [RFC8018]). Such
algorithms take a password as input. A "password" is a secret
text value (Section (see Section 3 of PKCS #5), [RFC2898] and [RFC8018]), but for
algorithmic purposes the term "password" refers to an octet
string (Section (see Section 2 of PKCS #5). [RFC2898] and [RFC8018]). Therefore,
there must be some mapping between the text value (which might
be user input) and the octet string. Section 3 of PKCS #5 [RFC2898]
(which was replaced by [RFC8018]) recommends "that applications
follow some common text encoding rules"; it then offers, but
does not recommend, ASCII and UTF-8.

While many modern applications support Unicode and Unicode-based
encodings such as UTF-8 and UTF-16, interchange is still needed
with private key artifacts that are encrypted with passwords in
other encodings. Therefore, this parameter specifies the
charset (see Section 1.3 of [RFC2978]) that a recipient SHOULD should
attempt first, in "reverse", when mapping from a sequence of
characters to an octet string. This parameter is not
cryptographically protected, so recipients SHOULD NOT cannot rely on it as
the exclusive mapping possibility.

This parameter has similar semantics to 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, #12
style, see [RFC7292] [RFC7292].

*precis = PRECIS Preparation, Enforcement, and Comparison of
Internationalized Strings (PRECIS) password
profile, i.e., OpaqueString from Section 4 of
[RFC7613]: always UTF-8 in Normalization Form C (NFC)
(NFC).

*precis-XXX = PRECIS Any profile from the IANA "PRECIS Profiles"
registry where "XXX" is replaced by the profile
name as named XXX shown in the IANA PRECIS
Profiles Registry 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, appended or an error condition is
raised. Compare with Annex M.4 of IEEE 802.11-2012.
[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, ignored or
an error condition is raised.

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

This parameter is case-insensitive. 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 "Encrypted Private Key Info, Info",
of [RFC5958], and Section 6 of PKCS #8), #8 as originally described in
[RFC5208], which was obsoleted by [RFC5958]), is less widely used
for exchange than PKCS #12, but it is much simpler to implement.
Actually
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".

The password-mapping parameter aids in interoperability when the
creator (who encrypted the keying material) and the user (who is
attempting to decrypt the keying material) are not operating in
the same character encoding character-encoding environment. An anticipated scenario
is that the creator may have created the keying material with a
password in a Shift-JIS environment a long time ago, while the
user is in a UTF-8 environment. There are potentially many
Unicode sequences that code for the same abstract character, such
as precomposed and decomposed forms; yet, such an abstract
character (however coded in Unicode) will tend to map to one
coding in the legacy charset, if it can be represented at all.
Therefore, the password-mapping parameter will almost never be
ambiguous when mapping to legacy encodings. When mapping from one
Unicode form to another (such as an internal Unicode
representation to *pkcs12), code sequences are either preserved, preserved or
folded deterministically to common Unicode code points or
sequences, producing the same holistic result as mapping to legacy
encodings.

It is possible that an abstract character might map to multiple
legacy encodings under the same charset. However, the possibility
is sufficiently remote as to be ignored in this media type
registration. One possible workaround is to set the user's
(decrypting party's) local operating environment to the password-
mapping legacy encoding parameter for the purpose of generating
the password octet string from user input. Another possibility is
to generate all possible legacy encoding combinations from the
abstract text (i.e., Unicode text), attempting decryption with
them. Customized behavior can be defined by updating this media
type registration with a new password-mapping special value,
prefixed with *.

Published specification:

RSA Laboratories PKCS #8 v1.2, v1.2 RSA Encryption Standard, November
1993 (republished as RFC 5208, [RFC5208], May 2008); 2008, and updated as
[RFC5958], August 2010); RFC 5958, August 2010

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. 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>

Intended usage: COMMON

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 has registered the media type application/pkcs8-encrypted in the
Standards tree using the applications information provided in Section 1 2 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 2013,
<http://www.iana.org/assignments/character-sets>.

[IEEE.802.11-2012]
IEEE, "IEEE Standard for use in RFCs to Indicate
Requirement Levels", BCP 14, RFC 2119, March 1997. Information technology--
Telecommunications and information exchange between
systems Local and metropolitan area networks--Specific
requirements Part 11: Wireless LAN Medium Access Control
(MAC) and Physical Layer (PHY) Specifications",
IEEE 802.11-2012, DOI 10.1109/ieeestd.2012.6178212,
<http://ieeexplore.ieee.org/document/6178212/>.

[RFC2898] Kaliski, B., "PKCS #5: Password-Based Cryptography
Specification Version 2.0", RFC 2898,
DOI 10.17487/RFC2898, September 2000. 2000,
<https://www.rfc-editor.org/info/rfc2898>.

[RFC2978] Freed, N. and J. Postel, "IANA Charset Registration
Procedures", BCP 19, RFC 2978, DOI 10.17487/RFC2978,
October 2000. 2000, <https://www.rfc-editor.org/info/rfc2978>.

[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. 2008,
<https://www.rfc-editor.org/info/rfc5208>.

[RFC5958] Turner, S., "Asymmetric Key Packages", RFC 5958,
DOI 10.17487/RFC5958, August
2010. 2010,
<https://www.rfc-editor.org/info/rfc5958>.

[RFC7292] Moriarty, K., Ed., Nystrom, S., M., Parkinson, S., Rusch, A.,
and M. Scott, "PKCS #12: Personal Information Exchange
Syntax v1.1", RFC 7292, DOI 10.17487/RFC7292, July 2014. 2014,
<https://www.rfc-editor.org/info/rfc7292>.

[RFC7613] Saint-Andre, P. and A. Melnikov, "Preparation,
Enforcement, and Comparison of Internationalized Strings
Representing Usernames and Passwords", RFC 7613,
DOI 10.17487/RFC7613, August
2015. 2015,
<https://www.rfc-editor.org/info/rfc7613>.

[RFC8018] Moriarty, K., Ed., Kaliski, B., and A. Rusch, "PKCS #5:
Password-Based Cryptography Specification Version 2.1",
RFC 8018, DOI 10.17487/RFC8018, January 2017,
<https://www.rfc-editor.org/info/rfc8018>.

Author's Address

Sean Leonard
Penango, Inc.
5900 Wilshire Blvd
Ste 2600
Los Angeles, CA 90036
USA

EMail:
United States of America

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

Appendix A. Changes from -02 to -03

Updated the document based on discussions. Added much more
explanatory text about the password-mapping parameter.