Cleanup some doc files

ACKNOWLEDGEMENTS is now spelled correctly :)
README.ASN1 talked about 0.9.6, so it's deleted.
I turned doc/standards.txt into a set of one-line summaries of RFCs, and
also updated the pointers to original sources (to be web links)

Reviewed-by: Richard Levitte <levitte@openssl.org>
This commit is contained in:
Rich Salz 2015-03-01 20:46:38 -05:00
parent a258afaf7c
commit 9f7f8eced5
3 changed files with 81 additions and 385 deletions

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@ -12,16 +12,16 @@ or current significant support of the OpenSSL project:
Major support:
Qualys http://www.qualys.com/
Qualys http://www.qualys.com/
Very significant support:
OpenGear: http://www.opengear.com/
OpenGear: http://www.opengear.com/
Significant support:
PSW Group: http://www.psw.net/
Acano Ltd. http://acano.com/
PSW Group: http://www.psw.net/
Acano Ltd. http://acano.com/
Please note that we ask permission to identify sponsors and that some sponsors
we consider eligible for inclusion here have requested to remain anonymous.

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@ -1,187 +0,0 @@
OpenSSL ASN1 Revision
=====================
This document describes some of the issues relating to the new ASN1 code.
Previous OpenSSL ASN1 problems
=============================
OK why did the OpenSSL ASN1 code need revising in the first place? Well
there are lots of reasons some of which are included below...
1. The code is difficult to read and write. For every single ASN1 structure
(e.g. SEQUENCE) four functions need to be written for new, free, encode and
decode operations. This is a very painful and error prone operation. Very few
people have ever written any OpenSSL ASN1 and those that have usually wish
they hadn't.
2. Partly because of 1. the code is bloated and takes up a disproportionate
amount of space. The SEQUENCE encoder is particularly bad: it essentially
contains two copies of the same operation, one to compute the SEQUENCE length
and the other to encode it.
3. The code is memory based: that is it expects to be able to read the whole
structure from memory. This is fine for small structures but if you have a
(say) 1Gb PKCS#7 signedData structure it isn't such a good idea...
4. The code for the ASN1 IMPLICIT tag is evil. It is handled by temporarily
changing the tag to the expected one, attempting to read it, then changing it
back again. This means that decode buffers have to be writable even though they
are ultimately unchanged. This gets in the way of constification.
5. The handling of EXPLICIT isn't much better. It adds a chunk of code into
the decoder and encoder for every EXPLICIT tag.
6. APPLICATION and PRIVATE tags aren't even supported at all.
7. Even IMPLICIT isn't complete: there is no support for implicitly tagged
types that are not OPTIONAL.
8. Much of the code assumes that a tag will fit in a single octet. This is
only true if the tag is 30 or less (mercifully tags over 30 are rare).
9. The ASN1 CHOICE type has to be largely handled manually, there aren't any
macros that properly support it.
10. Encoders have no concept of OPTIONAL and have no error checking. If the
passed structure contains a NULL in a mandatory field it will not be encoded,
resulting in an invalid structure.
11. It is tricky to add ASN1 encoders and decoders to external applications.
Template model
==============
One of the major problems with revision is the sheer volume of the ASN1 code.
Attempts to change (for example) the IMPLICIT behaviour would result in a
modification of *every* single decode function.
I decided to adopt a template based approach. I'm using the term 'template'
in a manner similar to SNACC templates: it has nothing to do with C++
templates.
A template is a description of an ASN1 module as several constant C structures.
It describes in a machine readable way exactly how the ASN1 structure should
behave. If this template contains enough detail then it is possible to write
versions of new, free, encode, decode (and possibly others operations) that
operate on templates.
Instead of having to write code to handle each operation only a single
template needs to be written. If new operations are needed (such as a 'print'
operation) only a single new template based function needs to be written
which will then automatically handle all existing templates.
Plans for revision
==================
The revision will consist of the following steps. Other than the first two
these can be handled in any order.
o Design and write template new, free, encode and decode operations, initially
memory based. *DONE*
o Convert existing ASN1 code to template form. *IN PROGRESS*
o Convert an existing ASN1 compiler (probably SNACC) to output templates
in OpenSSL form.
o Add support for BIO based ASN1 encoders and decoders to handle large
structures, initially blocking I/O.
o Add support for non blocking I/O: this is quite a bit harder than blocking
I/O.
o Add new ASN1 structures, such as OCSP, CRMF, S/MIME v3 (CMS), attribute
certificates etc etc.
Description of major changes
============================
The BOOLEAN type now takes three values. 0xff is TRUE, 0 is FALSE and -1 is
absent. The meaning of absent depends on the context. If for example the
boolean type is DEFAULT FALSE (as in the case of the critical flag for
certificate extensions) then -1 is FALSE, if DEFAULT TRUE then -1 is TRUE.
Usually the value will only ever be read via an API which will hide this from
an application.
There is an evil bug in the old ASN1 code that mishandles OPTIONAL with
SEQUENCE OF or SET OF. These are both implemented as a STACK structure. The
old code would omit the structure if the STACK was NULL (which is fine) or if
it had zero elements (which is NOT OK). This causes problems because an empty
SEQUENCE OF or SET OF will result in an empty STACK when it is decoded but when
it is encoded it will be omitted resulting in different encodings. The new code
only omits the encoding if the STACK is NULL, if it contains zero elements it
is encoded and empty. There is an additional problem though: because an empty
STACK was omitted, sometimes the corresponding *_new() function would
initialize the STACK to empty so an application could immediately use it, if
this is done with the new code (i.e. a NULL) it wont work. Therefore a new
STACK should be allocated first. One instance of this is the X509_CRL list of
revoked certificates: a helper function X509_CRL_add0_revoked() has been added
for this purpose.
The X509_ATTRIBUTE structure used to have an element called 'set' which took
the value 1 if the attribute value was a SET OF or 0 if it was a single. Due
to the behaviour of CHOICE in the new code this has been changed to a field
called 'single' which is 0 for a SET OF and 1 for single. The old field has
been deleted to deliberately break source compatibility. Since this structure
is normally accessed via higher level functions this shouldn't break too much.
The X509_REQ_INFO certificate request info structure no longer has a field
called 'req_kludge'. This used to be set to 1 if the attributes field was
(incorrectly) omitted. You can check to see if the field is omitted now by
checking if the attributes field is NULL. Similarly if you need to omit
the field then free attributes and set it to NULL.
The top level 'detached' field in the PKCS7 structure is no longer set when
a PKCS#7 structure is read in. PKCS7_is_detached() should be called instead.
The behaviour of PKCS7_get_detached() is unaffected.
The values of 'type' in the GENERAL_NAME structure have changed. This is
because the old code use the ASN1 initial octet as the selector. The new
code uses the index in the ASN1_CHOICE template.
The DIST_POINT_NAME structure has changed to be a true CHOICE type.
typedef struct DIST_POINT_NAME_st {
int type;
union {
STACK_OF(GENERAL_NAME) *fullname;
STACK_OF(X509_NAME_ENTRY) *relativename;
} name;
} DIST_POINT_NAME;
This means that name.fullname or name.relativename should be set
and type reflects the option. That is if name.fullname is set then
type is 0 and if name.relativename is set type is 1.
With the old code using the i2d functions would typically involve:
unsigned char *buf, *p;
int len;
/* Find length of encoding */
len = i2d_SOMETHING(x, NULL);
/* Allocate buffer */
buf = OPENSSL_malloc(len);
if(buf == NULL) {
/* Malloc error */
}
/* Use temp variable because &p gets updated to point to end of
* encoding.
*/
p = buf;
i2d_SOMETHING(x, &p);
Using the new i2d you can also do:
unsigned char *buf = NULL;
int len;
len = i2d_SOMETHING(x, &buf);
if(len < 0) {
/* Malloc error */
}
and it will automatically allocate and populate a buffer with the
encoding. After this call 'buf' will point to the start of the
encoding which is len bytes long.

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@ -1,285 +1,168 @@
Standards related to OpenSSL
============================
[Please, this is currently a draft. I made a first try at finding
documents that describe parts of what OpenSSL implements. There are
big gaps, and I've most certainly done something wrong. Please
correct whatever is... Also, this note should be removed when this
file is reaching a somewhat correct state. -- Richard Levitte]
This is a work in progress. These are documents that describe things that
are implemented (in whole or at least great parts) in OpenSSL.
To search for RFCs, you can start at http://www.ietf.org/rfc.html
To search for internet-drafts, you can start at http://www.ietf.org/id-info/
Many PKCS standards are now RFC's; PKCS#11 is now at Oasis and can be
found at https://www.oasis-open.org/committees/tc_home.php?wg_abbrev=pkcs11
All pointers in here will be either URL's or blobs of text borrowed
from miscellaneous indexes, like rfc-index.txt (index of RFCs),
1id-index.txt (index of Internet drafts) and the like.
To find the latest possible RFCs, it's recommended to either browse
ftp://ftp.isi.edu/in-notes/ or go to http://www.rfc-editor.org/ and
use the search mechanism found there.
To find the latest possible Internet drafts, it's recommended to
browse ftp://ftp.isi.edu/internet-drafts/.
To find the latest possible PKCS, it's recommended to browse
http://www.rsasecurity.com/rsalabs/pkcs/.
Implemented:
------------
These are documents that describe things that are implemented (in
whole or at least great parts) in OpenSSL.
1319 The MD2 Message-Digest Algorithm. B. Kaliski. April 1992.
(Format: TXT=25661 bytes) (Status: INFORMATIONAL)
1320 The MD4 Message-Digest Algorithm. R. Rivest. April 1992. (Format:
TXT=32407 bytes) (Status: INFORMATIONAL)
1321 The MD5 Message-Digest Algorithm. R. Rivest. April 1992. (Format:
TXT=35222 bytes) (Status: INFORMATIONAL)
2246 The TLS Protocol Version 1.0. T. Dierks, C. Allen. January 1999.
(Format: TXT=170401 bytes) (Status: PROPOSED STANDARD)
2268 A Description of the RC2(r) Encryption Algorithm. R. Rivest.
January 1998. (Format: TXT=19048 bytes) (Status: INFORMATIONAL)
2315 PKCS 7: Cryptographic Message Syntax Version 1.5. B. Kaliski.
March 1998. (Format: TXT=69679 bytes) (Status: INFORMATIONAL)
Implemented
-----------
PKCS#8: Private-Key Information Syntax Standard
PKCS#12: Personal Information Exchange Syntax Standard, version 1.0.
1319 The MD2 Message-Digest Algorithm
1320 The MD4 Message-Digest Algorithm
1321 The MD5 Message-Digest Algorithm
2246 The TLS Protocol Version 1
2268 A Description of the RC2(r) Encryption Algorithm
2315 PKCS 7: Cryptographic Message Syntax Version 1.5
2560 X.509 Internet Public Key Infrastructure Online Certificate
Status Protocol - OCSP. M. Myers, R. Ankney, A. Malpani, S. Galperin,
C. Adams. June 1999. (Format: TXT=43243 bytes) (Status: PROPOSED
STANDARD)
Status Protocol - OCSP
2712 Addition of Kerberos Cipher Suites to Transport Layer Security
(TLS). A. Medvinsky, M. Hur. October 1999. (Format: TXT=13763 bytes)
(Status: PROPOSED STANDARD)
(TLS)
2898 PKCS #5: Password-Based Cryptography Specification Version 2.0.
B. Kaliski. September 2000. (Format: TXT=68692 bytes) (Status:
INFORMATIONAL)
2898 PKCS #5: Password-Based Cryptography Specification Version 2.0
2986 PKCS #10: Certification Request Syntax Specification Version 1.7.
M. Nystrom, B. Kaliski. November 2000. (Format: TXT=27794 bytes)
(Obsoletes RFC2314) (Status: INFORMATIONAL)
3174 US Secure Hash Algorithm 1 (SHA1). D. Eastlake 3rd, P. Jones.
September 2001. (Format: TXT=35525 bytes) (Status: INFORMATIONAL)
2986 PKCS #10: Certification Request Syntax Specification Version 1.7
3161 Internet X.509 Public Key Infrastructure, Time-Stamp Protocol (TSP)
C. Adams, P. Cain, D. Pinkas, R. Zuccherato. August 2001
(Status: PROPOSED STANDARD)
3174 US Secure Hash Algorithm 1 (SHA1)
3268 Advanced Encryption Standard (AES) Ciphersuites for Transport
Layer Security (TLS). P. Chown. June 2002. (Format: TXT=13530 bytes)
(Status: PROPOSED STANDARD)
Layer Security (TLS)
3279 Algorithms and Identifiers for the Internet X.509 Public Key
Infrastructure Certificate and Certificate Revocation List (CRL)
Profile. L. Bassham, W. Polk, R. Housley. April 2002. (Format:
TXT=53833 bytes) (Status: PROPOSED STANDARD)
Profile
3280 Internet X.509 Public Key Infrastructure Certificate and
Certificate Revocation List (CRL) Profile. R. Housley, W. Polk, W.
Ford, D. Solo. April 2002. (Format: TXT=295556 bytes) (Obsoletes
RFC2459) (Status: PROPOSED STANDARD)
Certificate Revocation List (CRL) Profile
3447 Public-Key Cryptography Standards (PKCS) #1: RSA Cryptography
Specifications Version 2.1. J. Jonsson, B. Kaliski. February 2003.
(Format: TXT=143173 bytes) (Obsoletes RFC2437) (Status:
INFORMATIONAL)
Specifications Version 2.1
3713 A Description of the Camellia Encryption Algorithm. M. Matsui,
J. Nakajima, S. Moriai. April 2004. (Format: TXT=25031 bytes)
(Status: INFORMATIONAL)
3713 A Description of the Camellia Encryption Algorithm
3820 Internet X.509 Public Key Infrastructure (PKI) Proxy Certificate
Profile. S. Tuecke, V. Welch, D. Engert, L. Pearlman, M. Thompson.
June 2004. (Format: TXT=86374 bytes) (Status: PROPOSED STANDARD)
Profile
4132 Addition of Camellia Cipher Suites to Transport Layer Security
(TLS). S. Moriai, A. Kato, M. Kanda. July 2005. (Format: TXT=13590
bytes) (Status: PROPOSED STANDARD)
(TLS)
4162 Addition of SEED Cipher Suites to Transport Layer Security (TLS).
H.J. Lee, J.H. Yoon, J.I. Lee. August 2005. (Format: TXT=10578 bytes)
(Status: PROPOSED STANDARD)
4162 Addition of SEED Cipher Suites to Transport Layer Security (TLS)
4269 The SEED Encryption Algorithm. H.J. Lee, S.J. Lee, J.H. Yoon,
D.H. Cheon, J.I. Lee. December 2005. (Format: TXT=34390 bytes)
(Obsoletes RFC4009) (Status: INFORMATIONAL)
4269 The SEED Encryption Algorithm
Related:
--------
Related
-------
These are documents that are close to OpenSSL, for example the
STARTTLS documents.
1421 Privacy Enhancement for Internet Electronic Mail: Part I: Message
Encryption and Authentication Procedures. J. Linn. February 1993.
(Format: TXT=103894 bytes) (Obsoletes RFC1113) (Status: PROPOSED
STANDARD)
Encryption and Authentication Procedures
1422 Privacy Enhancement for Internet Electronic Mail: Part II:
Certificate-Based Key Management. S. Kent. February 1993. (Format:
TXT=86085 bytes) (Obsoletes RFC1114) (Status: PROPOSED STANDARD)
Certificate-Based Key Management
1423 Privacy Enhancement for Internet Electronic Mail: Part III:
Algorithms, Modes, and Identifiers. D. Balenson. February 1993.
(Format: TXT=33277 bytes) (Obsoletes RFC1115) (Status: PROPOSED
STANDARD)
Algorithms, Modes, and Identifiers
1424 Privacy Enhancement for Internet Electronic Mail: Part IV: Key
Certification and Related Services. B. Kaliski. February 1993.
(Format: TXT=17537 bytes) (Status: PROPOSED STANDARD)
Certification and Related Services
2025 The Simple Public-Key GSS-API Mechanism (SPKM). C. Adams. October
1996. (Format: TXT=101692 bytes) (Status: PROPOSED STANDARD)
2025 The Simple Public-Key GSS-API Mechanism (SPKM)
2510 Internet X.509 Public Key Infrastructure Certificate Management
Protocols. C. Adams, S. Farrell. March 1999. (Format: TXT=158178
bytes) (Status: PROPOSED STANDARD)
Protocols
2511 Internet X.509 Certificate Request Message Format. M. Myers, C.
Adams, D. Solo, D. Kemp. March 1999. (Format: TXT=48278 bytes)
(Status: PROPOSED STANDARD)
2511 Internet X.509 Certificate Request Message Format
2527 Internet X.509 Public Key Infrastructure Certificate Policy and
Certification Practices Framework. S. Chokhani, W. Ford. March 1999.
(Format: TXT=91860 bytes) (Status: INFORMATIONAL)
Certification Practices Framework
2538 Storing Certificates in the Domain Name System (DNS). D. Eastlake
3rd, O. Gudmundsson. March 1999. (Format: TXT=19857 bytes) (Status:
PROPOSED STANDARD)
2538 Storing Certificates in the Domain Name System (DNS)
2539 Storage of Diffie-Hellman Keys in the Domain Name System (DNS).
D. Eastlake 3rd. March 1999. (Format: TXT=21049 bytes) (Status:
PROPOSED STANDARD)
2539 Storage of Diffie-Hellman Keys in the Domain Name System (DNS)
2559 Internet X.509 Public Key Infrastructure Operational Protocols -
LDAPv2. S. Boeyen, T. Howes, P. Richard. April 1999. (Format:
TXT=22889 bytes) (Updates RFC1778) (Status: PROPOSED STANDARD)
LDAPv2
2585 Internet X.509 Public Key Infrastructure Operational Protocols:
FTP and HTTP. R. Housley, P. Hoffman. May 1999. (Format: TXT=14813
bytes) (Status: PROPOSED STANDARD)
FTP and HTTP
2587 Internet X.509 Public Key Infrastructure LDAPv2 Schema. S.
Boeyen, T. Howes, P. Richard. June 1999. (Format: TXT=15102 bytes)
(Status: PROPOSED STANDARD)
2587 Internet X.509 Public Key Infrastructure LDAPv2 Schema
2595 Using TLS with IMAP, POP3 and ACAP. C. Newman. June 1999.
(Format: TXT=32440 bytes) (Status: PROPOSED STANDARD)
2595 Using TLS with IMAP, POP3 and ACAP
2631 Diffie-Hellman Key Agreement Method. E. Rescorla. June 1999.
(Format: TXT=25932 bytes) (Status: PROPOSED STANDARD)
2631 Diffie-Hellman Key Agreement Method
2632 S/MIME Version 3 Certificate Handling. B. Ramsdell, Ed.. June
1999. (Format: TXT=27925 bytes) (Status: PROPOSED STANDARD)
2632 S/MIME Version 3 Certificate Handling
2716 PPP EAP TLS Authentication Protocol. B. Aboba, D. Simon. October
1999. (Format: TXT=50108 bytes) (Status: EXPERIMENTAL)
2716 PPP EAP TLS Authentication Protocol
2773 Encryption using KEA and SKIPJACK. R. Housley, P. Yee, W. Nace.
February 2000. (Format: TXT=20008 bytes) (Updates RFC0959) (Status:
EXPERIMENTAL)
2797 Certificate Management Messages over CMS
2797 Certificate Management Messages over CMS. M. Myers, X. Liu, J.
Schaad, J. Weinstein. April 2000. (Format: TXT=103357 bytes) (Status:
PROPOSED STANDARD)
2817 Upgrading to TLS Within HTTP/1.1
2817 Upgrading to TLS Within HTTP/1.1. R. Khare, S. Lawrence. May
2000. (Format: TXT=27598 bytes) (Updates RFC2616) (Status: PROPOSED
STANDARD)
2818 HTTP Over TLS
2818 HTTP Over TLS. E. Rescorla. May 2000. (Format: TXT=15170 bytes)
(Status: INFORMATIONAL)
2984 Use of the CAST-128 Encryption Algorithm in CMS
2876 Use of the KEA and SKIPJACK Algorithms in CMS. J. Pawling. July
2000. (Format: TXT=29265 bytes) (Status: INFORMATIONAL)
2984 Use of the CAST-128 Encryption Algorithm in CMS. C. Adams.
October 2000. (Format: TXT=11591 bytes) (Status: PROPOSED STANDARD)
2985 PKCS #9: Selected Object Classes and Attribute Types Version 2.0.
M. Nystrom, B. Kaliski. November 2000. (Format: TXT=70703 bytes)
(Status: INFORMATIONAL)
2985 PKCS #9: Selected Object Classes and Attribute Types Version 2.0
3029 Internet X.509 Public Key Infrastructure Data Validation and
Certification Server Protocols. C. Adams, P. Sylvester, M. Zolotarev,
R. Zuccherato. February 2001. (Format: TXT=107347 bytes) (Status:
EXPERIMENTAL)
Certification Server Protocols
3039 Internet X.509 Public Key Infrastructure Qualified Certificates
Profile. S. Santesson, W. Polk, P. Barzin, M. Nystrom. January 2001.
(Format: TXT=67619 bytes) (Status: PROPOSED STANDARD)
Profile
3058 Use of the IDEA Encryption Algorithm in CMS. S. Teiwes, P.
Hartmann, D. Kuenzi. February 2001. (Format: TXT=17257 bytes)
(Status: INFORMATIONAL)
3058 Use of the IDEA Encryption Algorithm in CMS
3161 Internet X.509 Public Key Infrastructure Time-Stamp Protocol
(TSP). C. Adams, P. Cain, D. Pinkas, R. Zuccherato. August 2001.
(Format: TXT=54585 bytes) (Status: PROPOSED STANDARD)
(TSP)
3185 Reuse of CMS Content Encryption Keys. S. Farrell, S. Turner.
October 2001. (Format: TXT=20404 bytes) (Status: PROPOSED STANDARD)
3185 Reuse of CMS Content Encryption Keys
3207 SMTP Service Extension for Secure SMTP over Transport Layer
Security. P. Hoffman. February 2002. (Format: TXT=18679 bytes)
(Obsoletes RFC2487) (Status: PROPOSED STANDARD)
Security
3217 Triple-DES and RC2 Key Wrapping. R. Housley. December 2001.
(Format: TXT=19855 bytes) (Status: INFORMATIONAL)
3217 Triple-DES and RC2 Key Wrapping
3274 Compressed Data Content Type for Cryptographic Message Syntax
(CMS). P. Gutmann. June 2002. (Format: TXT=11276 bytes) (Status:
PROPOSED STANDARD)
(CMS)
3278 Use of Elliptic Curve Cryptography (ECC) Algorithms in
Cryptographic Message Syntax (CMS). S. Blake-Wilson, D. Brown, P.
Lambert. April 2002. (Format: TXT=33779 bytes) (Status:
INFORMATIONAL)
Cryptographic Message Syntax (CMS)
3281 An Internet Attribute Certificate Profile for Authorization. S.
Farrell, R. Housley. April 2002. (Format: TXT=90580 bytes) (Status:
PROPOSED STANDARD)
3281 An Internet Attribute Certificate Profile for Authorization
3369 Cryptographic Message Syntax (CMS). R. Housley. August 2002.
(Format: TXT=113975 bytes) (Obsoletes RFC2630, RFC3211) (Status:
PROPOSED STANDARD)
3369 Cryptographic Message Syntax (CMS)
3370 Cryptographic Message Syntax (CMS) Algorithms. R. Housley. August
2002. (Format: TXT=51001 bytes) (Obsoletes RFC2630, RFC3211) (Status:
PROPOSED STANDARD)
3370 Cryptographic Message Syntax (CMS) Algorithms
3377 Lightweight Directory Access Protocol (v3): Technical
Specification. J. Hodges, R. Morgan. September 2002. (Format:
TXT=9981 bytes) (Updates RFC2251, RFC2252, RFC2253, RFC2254, RFC2255,
RFC2256, RFC2829, RFC2830) (Status: PROPOSED STANDARD)
3394 Advanced Encryption Standard (AES) Key Wrap Algorithm. J. Schaad,
R. Housley. September 2002. (Format: TXT=73072 bytes) (Status:
INFORMATIONAL)
3394 Advanced Encryption Standard (AES) Key Wrap Algorithm
3436 Transport Layer Security over Stream Control Transmission
Protocol. A. Jungmaier, E. Rescorla, M. Tuexen. December 2002.
(Format: TXT=16333 bytes) (Status: PROPOSED STANDARD)
Protocol
3657 Use of the Camellia Encryption Algorithm in Cryptographic
Message Syntax (CMS). S. Moriai, A. Kato. January 2004.
(Format: TXT=26282 bytes) (Status: PROPOSED STANDARD)
"Securing FTP with TLS", 01/27/2000, <draft-murray-auth-ftp-ssl-05.txt>
To be implemented:
------------------
These are documents that describe things that are planed to be
implemented in the hopefully short future.
Message Syntax (CMS)