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Document Data Documentation

This document describes the structure of the document revision data. Applies as of DMS Core version 0.12.16

Revision Data

Documentchain stores serveral hash values in transactions. Below the data is described as hex string.

Prefix

444D24000104D2

Data Size Description
444D24 6 Constant prefix, magic chars "DM$"
0001 4 Blockchain-defined data type/version
04D2 4 App-defined data type/version

Blockchain-defined Data Type 0001

Fixed order of 128 bit hash values as hex string with 32 characters each.

Start End Size Description
0 5 6 444D24
6 9 4 0001
10 13 4 App-defined type
14 45 32 Document GUID without brackets and hyphens
46 77 32 File hash
78 109 32 Attribute hash
110 141 32 (optional) any hash, such as owner hash
Example

A text file with content "Documentchain" and file name "Testfile.txt" has the following hex data:

444d2400010003a819374e9e5e4c98aeed1adc6feccc0de5ce47fb53fba975afa0060d490f4f309e0d97e0b0ef38bb22d44819dc9b6d3db048bc1a059d83d52de7dac1d0cf01c4

Blockchain-defined Data Type 0002

Any combination of individual hash values. The whole data must not exceed 600 bytes.

The first value should be an MD51) file hash. This allows the user to perform a document revision in his web browser. The MD5 hash is used to search for the corresponding blockchain transaction. In addition, another more secure file hash should be stored for the revision.

Start End Size Description
0 5 6 444D24
6 9 4 0002
10 13 4 App-defined type

Followed by one or more hash values with four-digit prefix:

Start End Size Description
0 0 1 Type: 0=compressed GUID, F=file hash, A=attribute hash , B=owner hash
1 1 1 App-defined char 0..F
2 3 2 Algorithm (see below), i.e. 22
4 .. 32-128 Hex encoding hash
Algorithm
  • 00=MD5/GUID 1)
  • 01=SHA11)
  • 21=SHA2-224 1)
  • 22=SHA2-256
  • 23=SHA2-384
  • 25=SHA2-512
  • 31=Keccak-224 1)
  • 32=Keccak-256
  • 33=Keccak-384
  • 35=Keccak-512
  • 36=SHA3-224 1)
  • 37=SHA3-256
  • 38=SHA3-384
  • 39=SHA3-512

1) These hashes are not considered collision proof and should only be used together with longer hashes. See BSI.

App Defined Data Type

Use another ID for your application. You can reserve your app ID with us.

Example Code