High Density Mail Protocol (HDMP)
is a binary network protocol designed for the exchange
of e-mail messages among computers or other devices.
is not compatible with
the current e-mail exchange standards SMTP (Standard
Mail Transfer Protocol) and POP3 (Post Office Protocol
3), since HDMP features a completely different structure
which makes it extremely efficient, fast and safe, eradicating
the main causes for SPAM, phishing (ID forgery) and
High Speed to Send and Receive
Compression: Depending on its content, this feature
may reduce e-mail size up to 10 times, which facilitates
a measurable speed increase and minimizes information
traffic across the net. This compression always takes
place internally and automatically through the method
“Normal Deflate 08” (currently used in applications
like WinZip). By contrast, the current e-mail protocol
(SMTP) requires that all binary data in the email be
converted into text format and encodes them using “Base64”,
which results in a 30% size increase!
Hand-Shaking: HDMP requires very few steps to achieve
client-server communication and send or receive e-mails.
Only 4 steps are necessary to deliver an e-mail, in
contrast to the 14 steps required by the current SMTP
standard. This speeds e-mail sending and reception.
Communication Port: Only one communication port is used
to send and receive e-mails. Thus both processes take
place in only one connection session, without having
to connect and authenticate separately for each task
(as in SMTP/POP3 standards).
Protocol: HDMP uses data transmission in binary format
instead of using Text. At present, data transmission
in Text format (as currently used in SMTP) is unnecessary,
since the user doesn’t intervene in the communication
by entering commands manually. The binary protocol accelerates
the transmissions because a great amount of unnecessary
data is eliminated. As an additional benefit, information
theft is made more difficult.
Encryption: Activating this feature protects the content
(text of the message and attached file/s) through the
use of encryption methods like AES, 3DES, etc. The AES
cipher is currently used by the FBI for “Top Secret”
level protection. The decryption can be External (provided
by the receiving user) or PDS (see below).
and decryption code “PDS Security” (Persistent
Digital Signature): This code (512-bit PDS Signature)
enables not only the user ID verification, but also
the protection of information through automatic encryption.
To achieve the automation of all these processes, the
contact list of the e-mail client application provides
a special field that permits to store this particular
code for each contact.
User ID Protection
of Recipients’ Addresses: When an e-mail has more than
one recipient, they are all treated as BCC (Blind Carbon
Copy). When sending the e-mail to each recipient, the
sending server removes all other recipients’ addresses,
so that each recipient can only know “how many other
people the email was sent to” but not their e-mail addresses.
This prevents address theft due to indiscriminate address
forwarding, which commonly occurs in “e-mail chains”,
User Authentication: User authentication to send or
receive e-mails is safely achieved by sending to the
server a 64-byte MD5 code, instead of having to send
user name, access code and the domain it belongs to;
this prevents account theft and data interception by
Protection against SPAM
Trace Verification: When sending an e-mail via HDMP,
this goes through a series of servers till it gets to
its final recipient; each intermediate server doesn’t
send the e-mail to the next server without verifying
before that the e-mail really comes from the preceding
server. This reverse connection takes place after the
primary connection, which allows a complete verification
of the trace. Finally, if it is not possible to fulfill
this verification at any point of the e-mail trajectory,
the e-mail is destroyed and doesn’t get to the receiving
user. This prevents the sending of SPAM using software
known as SPAM Pumps (software for massive SPAM forwarding).
ID: When sending an email via HDMP, the sending server
adds the information of the “sender’s e-mail” and “sender’s
name”. This feature prevents the user sending an e-mail
from changing any of their data and forging their identity;
or if they did, they would leave a trace of their accessing
the server where they registered their account.
Identity (Persistent Digital Signature): The persistent
digital signature allows the ID validation of a sending
user. This is so because every e-mail has a field known
as PDS Checksum which stores a 256-bit number created
from certain data from the email and the user’s PDS
identity. The recipient can verify this number (if they
have the sender’s PDS Signature) and in this way verify
the authenticity of the received e-mail. If it comes
to it the e-mail client application can be configured
to filter e-mails that don’t validate the sender’s ID
using the PDS; this would completely block unknown or
Open Mail Relay servers: Users who want to send an e-mail
must use the server where they opened their e-mail account
since they will have to validate their identity in it
to send the e-mail. This feature prevents servers from
being used by third parties to send SPAM without having
an account in them
IP Record: When sending an e-mail, the sending server
takes the IP number of the sending user and attaches
it to the e-mail. In this way the recipient can know
the sending user’s ID, thus providing another way to
know the e-mail’s origin and judge its validity.
these features prevent phishing as well as the most
common sources of SPAM, thus protecting the recipient.
Data Transmission Reliability
Control through CRC-32: When sending or receiving e-mails
via HDMP, controls of data validity are made using the
cyclic redundancy check CRC-32. By contrast, the Simple
Mail Transport Protocol (SMTP) doesn’t make any kind
of integrity control.
Capacity: E-mails can have more than one message body,
a feature similar to the “sheets” in Excel documents.
Attached Files: Attached files are always linked to
a message body in particular; this allows separating
the file belonging to each body and organizing more
efficiently the information within the e-mail.
E-mail Header: It enables fields like user card inlay
with photo, e-mail status, part sizes, digital signatures,
The PDS is a free digital signature
that can be used for a user’s ID validation and automatic
data encryption or decryption. This signature is a hexadecimal
number of 64 characters in its complete version, or
44 characters in the “identity only” version.
How it is created
The required data for the creation of a Persistent Digital
Signature are the person’s full name, city of residence
or birth, and a password (this password is only used
to create the signature); these are combined in a certain
way using algorithms like MD5, HMAC-SHA1 and CRC16 to
generate the final number.
Constitutive parts and nomenclatures
Signature: Complete signature of 64 hexadecimal characters.
It has a Self Integrity Checksum.
Identity: It corresponds with the first 44 signature
characters and enables a user’s identification. This
portion can be used in isolation from the full PDS and
has a self integrity checksum of the portion as well.
Security: it is found in the following 16 characters
and functions as a public key for information encryption
or decryption. This portion can’t be used in isolation
from the full PDS.
Use of PDS in the HDMP Standard
The two main functions of the Persistent Digital Signatures
are implemented in the e-mail protocol HDMP. This means
that the user that receives an e-mail has the sender’s
ID authentication through PDS Identity, and e-mail automatic
decryption through PDS Security.
It is worth noting that in no case the Persistent Digital
Signature or any of its parts is directly attached to
an e-mail or contact card, but it is simply used locally
to create a code known as PDS Checksum that is calculated
using several specific points of an e-mail and the digital
signature itself. This prevents signature theft through
You can download this description
of the protocol's features in Microsoft Word
format, by clicking