MultiChain Developer Q&A - Recent questions tagged files

File Handling Question

Wed, 05 Nov 2025 16:34:15 +0000

What is the best way to store files or should we really store file on the blockchain? if not, what are the best practices?

Offchain storage of files

Tue, 19 Mar 2019 08:51:17 +0000

Hi,

How can we add a file to the offchain and the process to retrieve the original file from another node.

Do we need to convert the file to Hex format and append it using append binarycache. (Im getting error is Hex value of file is large as "Data should be hexadecimal string")

Or we can just copy the file contents to the cache file as mentioned in below link. (In this case file is in raw format and not binary)

https://www.multichain.com/qa/12710/adding-file-into-a-stream

Any detailed steps would be helpful to every users.

Thanks.

Storing files MC vs IPFS

Tue, 19 Mar 2019 08:16:00 +0000

Hi,

I would like to know whats the difference and advantage of storing files on Multichain than in IPFS.

And to store a file on multichain could you help me with the steps.

Thanks.

Store and retrieve huge binary files in off-chain

Mon, 21 Jan 2019 16:39:05 +0000

Hi,

In Multichain 2.0, when you use the binary cache, you can directly append large binary files and then publish them off-chain from the cache.

However, when you want to retrieve them back, you get a huge HEX string which simply cannot be handled in memory, so how do you convert back to the original binary file?

Thanks!

Publishing files in streams

Fri, 02 Nov 2018 13:27:48 +0000

hi Dears,

I used streams in blockchain, but i want to know if it is possible to publish file in stream and read it , if ok how how can it be done technically using the commands for publishing and reading. thank you so much
cordially

Why the explorer is not running ?

Thu, 04 Oct 2018 13:38:10 +0000

nohup python -m Mce.abe --config Buybit.conf &

afer doing this , i get

[1] 5773
root@buybitcoin:~/.multichain# nohup: ignoring input and appending output to 'nohup.out'

chain is running bit blocks are not increasing

Tue, 17 Jul 2018 06:04:20 +0000

Hi Team

pl guide

we are using MC2-3 veriosn

we had changed three paramters to increase the file size in params.dat,

chains starts well after that and blcoks keep increasing

later we installed web exploere and web demo

though it was working fine for few days, but then we observed that blcoks has stopped inceasing the count where as intercative mode is working fine, and tx are going fine, files kept uploading, > we dont know which block they were going as the Blcoks count was static.

1) is there any way to restart the stuck blcoks count

Then later Block explorer stopped responding >

2) does it need any supersiver it keep it running behind the scene.

3) thereafter with 3-4 days it stopped taking files upload, giving error of large file size.

here are the params and Interactive mode has stopped responding details

chain-protocol = multichain
chain-description = MultiChain dibs

root-stream-name = root
root-stream-open = true                 #
chain-is-testnet = false                #
target-block-time = 15                  #
maximum-block-size = 20097500
maximum-chunk-size = 1048576            #
maximum-chunk-count = 1024

# Global permissions

anyone-can-connect = false              # Anyone can connect, i.e. a publicly readable blockchain.
anyone-can-send = false                 # Anyone can send, i.e. transaction signing not restricted by address.
anyone-can-receive = false              # Anyone can receive, i.e. transaction outputs not restricted by address.
anyone-can-receive-empty = true         # Anyone can receive empty output, i.e. without permission grants, asset transfers and zero native currency.
anyone-can-create = false               # Anyone can create new streams.
anyone-can-issue = false                # Anyone can issue new native assets.
anyone-can-mine = false                 # Anyone can mine blocks (confirm transactions).
anyone-can-activate = false             # Anyone can grant or revoke connect, send and receive permissions.
anyone-can-admin = false                # Anyone can grant or revoke all permissions.
support-miner-precheck = true           # Require special metadata output with cached scriptPubKey for input, to support advanced miner checks.
allow-arbitrary-outputs = false         # Allow arbitrary (without clear destination) scripts.
allow-p2sh-outputs = true               # Allow pay-to-scripthash (P2SH) scripts, often used for multisig. Ignored if allow-arbitrary-outputs=true.
allow-multisig-outputs = true           # Allow bare multisignature scripts, rarely used but still supported. Ignored if allow-arbitrary-outputs=true.

# Consensus requirements

setup-first-blocks = 60                 # Length of initial setup phase in blocks, in which mining-diversity,
                                        # admin-consensus-* and mining-requires-peers are not applied. (1 - 31536000)
mining-diversity = 0.3                  # Miners must wait <mining-diversity>*<active miners> between blocks. (0 - 1)
admin-consensus-upgrade = 0.5           # <admin-consensus-upgrade>*<active admins> needed to upgrade the chain. (0 - 1)
admin-consensus-admin = 0.5             # <admin-consensus-admin>*<active admins> needed to change admin perms. (0 - 1)
admin-consensus-activate = 0.5          # <admin-consensus-activate>*<active admins> to change activate perms. (0 - 1)
admin-consensus-mine = 0.5              # <admin-consensus-mine>*<active admins> to change mining permissions. (0 - 1)
admin-consensus-create = 0.0            # <admin-consensus-create>*<active admins> to change create permissions. (0 - 1)
admin-consensus-issue = 0.0             # <admin-consensus-issue>*<active admins> to change issue permissions. (0 - 1)

# Defaults for node runtime parameters

lock-admin-mine-rounds = 10             # Ignore forks that reverse changes in admin or mine permissions after this many mining rounds have passed. Integer only. (0 - 10000)
mining-requires-peers = true            # Nodes only mine blocks if connected to other nodes (ignored if only one permitted miner).
mine-empty-rounds = 10                  # Mine this many rounds of empty blocks before pausing to wait for new transactions. If negative, continue indefinitely (ignored if target-adjust-freq>0). Non-integer allowed. (-1 - 1000)
mining-turnover = 0.5                   # Prefer pure round robin between a subset of active miners to minimize forks (0.0) or random equal participation for all permitted miners (1.0). (0 - 1)

# Native blockchain currency (likely not required)

initial-block-reward = 0                # Initial block mining reward in raw native currency units. (0 - 1000000000000000000)
first-block-reward = -1                 # Different mining reward for first block only, ignored if negative. (-1 - 1000000000000000000)
reward-halving-interval = 52560000      # Interval for halving of mining rewards, in blocks. (60 - 1000000000)
reward-spendable-delay = 1              # Delay before mining reward can be spent, in blocks. (1 - 100000)
minimum-per-output = 0                  # Minimum native currency per output (anti-dust), in raw units.
                                        # If set to -1, this is calculated from minimum-relay-fee. (-1 - 1000000000)
maximum-per-output = 100000000000000    # Maximum native currency per output, in raw units. (0 - 1000000000000000000)
minimum-offchain-fee = 0                # Minimum fee for publishing off-chain data items, per 1000 bytes, in raw units of native currency. (0 - 1000000000)
minimum-relay-fee = 0                   # Minimum transaction fee, per 1000 bytes, in raw units of native currency. (0 - 1000000000)
native-currency-multiple = 100000000    # Number of raw units of native currency per display unit. (0 - 1000000000)

# Advanced mining parameters

skip-pow-check = false                  # Skip checking whether block hashes demonstrate proof of work.
pow-minimum-bits = 8                    # Initial and minimum proof of work difficulty, in leading zero bits. (1 - 32)
target-adjust-freq = -1                 # Interval between proof of work difficulty adjustments, in seconds, if negative - never adjusted. (-1 - 4294967295)
allow-min-difficulty-blocks = false     # Allow lower difficulty blocks if none after 2*<target-block-time>.

# Standard transaction definitions

only-accept-std-txs = true              #
max-std-tx-size = 20097500              #

max-std-op-returns-count = 32           # )
max-std-op-return-size = 20097152

max-std-op-drops-count = 5

max-std-element-size = 40000            # M

default-network-port = 4245             #.
default-rpc-port = 4244                 # Default
chain-name = dibs                       # Chain name
protocol-version = 20003                #

network-message-start = f1cad3fc        #
address-pubkeyhash-version = 00f1aa15   #

address-scripthash-version = 058c522c   # Version bytes used for pay-to-scripthash addresses.
private-key-version = 803d9492          # Version bytes used for exporting private keys.
address-checksum-value = 2fbe08b4       # Bytes used for XOR in address checksum calculation.

# The following parameters were generated by multichaind.
# They SHOULD NOT BE EDITED.

genesis-pubkey = 0201153ad6bad99fbceb4a9f024054dcdd325dd3d6594965c32a3f50e37aadc277 # Gene...

Can files stored in the Blockchain be deleted or replaced, or are they immutably stored forever?

Thu, 08 Mar 2018 14:33:41 +0000

Storing hashes or files in Multichain

Wed, 07 Mar 2018 05:23:01 +0000

Hello,

I'm totally new to blockchain. I've setup a 2 node blockchain, and setup a web explorer on both nodes.

I've setup a stream as well. I'm trying to build a proof of concept where 5 different users, are able to store documents on the blockchain and would appreciate some guidance/help.

My blockchain nodes are running on linux and these users are windows users, so would that be done with curl?

Thanks.

Can large files (over 64MB) be stored in the blockchain employing multiple assocaited streams?

Tue, 27 Feb 2018 13:36:54 +0000

Configuration files

Mon, 22 Jan 2018 12:43:01 +0000

Hi, I'm super new to Multichain. This question may seem a bit dumb but what's the difference between params.dat and multichain.conf? Both of them set configuration params for the blockchain you want to create but I can't really find out what's the difference between them.

User authentication and file sharing in multichain

Wed, 17 Jan 2018 19:57:55 +0000

I am a newbie in multichain development and I am going through the documentation with multichain-node wrapper for json-rpc api. I have two use cases which I am unable to understand and implement it on multichain. I have following scenarios.

1. User authentication: How can we create user login signup module on multichain such that user can register and login to see and perform different functions on blockchain like file transfer, message transfer etc ?

2. How to send file in such a way that only the recipient can read the contents of that file.

Multichain 1.0.2: Attaching files to the blockchain

Sat, 06 Jan 2018 20:00:35 +0000

I have a question regarding Multichain 1.0.2.

I would like to be able to add files to the blockchain only from one specific address. The other addresses can not be possible.

It should be possible to read these attached files by any person.

Does Multichain 1.0.2 offer such functionality?
Are there any restrictions?

Hello everybody :), I have 2 PC connected in Local Area Network. How can i send documents using Multichain.

Thu, 11 May 2017 15:40:56 +0000

How to send a document between 2 PC in LAN ?

- Linux (CentOs)

- Using a switch with RJ45.

I want to push just a PDF on the blockchain.

Thanks :)

Files inside MultiChain

Wed, 21 Sep 2016 03:01:57 +0000

Hi,

When the multichain is initialized, there are alot files store inside like permissions.dat, wallet.dat, entities.dat, etc. May i know whats the purpose of each file?

Thank You