[ANN][GRS] Groestlcoin | 1st to activate Segwit & Taproot

[jackielove4u]

Finished the GRS Vanitygen modifications - Windows binaries here (signed):

https://ottrbutt.com/grs-vanitygen/grs-vanitygen.zip
https://ottrbutt.com/grs-vanitygen/grs-vanitygen.zip.sig

Thanks for this, nice release!

[1714845906]

1714845906

[TagBot]

Hi developers! The project is alive?

[jackielove4u]

Hi developers! The project is alive?

Next release will be during Christmas if that is what you are asking.

[jackielove4u]

Finished the GRS Vanitygen modifications - Windows binaries here (signed):

https://ottrbutt.com/grs-vanitygen/grs-vanitygen.zip
https://ottrbutt.com/grs-vanitygen/grs-vanitygen.zip.sig

Great release 
Lets make some personalized addresses

Did you make some nice personalized addresses? Care to share?

[crackfoo]

I just built the wallet from source and when I try to start it, it just segfaults... any ideas?

It's on Ubuntu Server 15.10 ... anyone else have problems?

[crackfoo]

I just built the wallet from source and when I try to start it, it just segfaults... any ideas?

It's on Ubuntu Server 15.10 ... anyone else have problems?

Seems the issue is with the new libdb version being 5.3. I've recompiled including DB 4.8 and it's started fine now.

Might be something for the dev to look at so newer OS's will be supported.

[jackielove4u]

I just built the wallet from source and when I try to start it, it just segfaults... any ideas?

It's on Ubuntu Server 15.10 ... anyone else have problems?

Seems the issue is with the new libdb version being 5.3. I've recompiled including DB 4.8 and it's started fine now.

Might be something for the dev to look at so newer OS's will be supported.

Thanks for the update!

[LTEX]

Finished the GRS Vanitygen modifications - Windows binaries here (signed):

https://ottrbutt.com/grs-vanitygen/grs-vanitygen.zip
https://ottrbutt.com/grs-vanitygen/grs-vanitygen.zip.sig

Great release 
Lets make some personalized addresses

Did you make some nice personalized addresses? Care to share?

Ah, another great feature to make use of my obsolete GPU's 

I have been in contact with Jackie on several developments here, but man, I must say I'm impressed with the progress and development done here! Will follow (and participate) more active here from now on 

[LTEX]

Besides awesome technical development, what's the marketing plan behind Groestl? Anybody in here been involved with that part of development already?

[jackielove4u]

Besides awesome technical development, what's the marketing plan behind Groestl? Anybody in here been involved with that part of development already?

Besides technical developments there is nothing else. No marketing plans, we need help from the community for this. You got idea's?

[The Frisian]

Besides awesome technical development, what's the marketing plan behind Groestl? Anybody in here been involved with that part of development already?

Besides technical developments there is nothing else. No marketing plans, we need help from the community for this. You got idea's?

I'm still waiting going to the moon......
What can be the problem with this altcoin?
Nice developments, many owners but price almost below zero.
What do we need for the unique coin?

[jackielove4u]

Reminder:
All users still using old 2.1.0.6 wallet please upgrade to 2.11.0

BIP66 soft fork
Version 2.11.0 of Groestlcoin core fixes very important common vulnerabilities and exposures (classified as CVE-2015-3641) and all users MUST upgrade to this version as soon as possible. Deamons and QT wallets that are derived from Bitcoin and have a codebase prior to Bitcoin 0.10.2 needs to address this CVE as soon as possible.
To address this CVE, Groestlcoin used the BIP66 soft fork. The majority of the Groestlcoin miners have already upgraded to the latest version of Groestlcoin Core which activated the new BIP66 consensus rule. This soft fork was a two stage process where certain thresholds have been reached, consisting of the following conditions:

• Once 75% of the last 1000 blocks are version 3, strict DER encoding for signatures will be enforced when new blocks are generated, preventing non-standard transactions from being included in them.
• Once 95% of the last 1000 blocks are version 3, propagation of version 112 (aka 1) and version 2 blocks will be rejected from the network entirely.

Users
From a users perspective, the change will be seamless and is purely a backed change. Older version (v2.1.0.6) is still compatible with the network, however it is extremely important that you upgrade to version 2.11.0 (link) if you haven't done so already due to the security fixes, new features and privacy enhancements.

Miners
If you're a miner, below you will find a list of the pools who have upgraded and the ones who haven't. If you're a miner on a pool which hasn't upgraded yet, please temporarily move your hashing power to another pool until they have upgraded otherwise mining version 112 (aka 1) blocks will be orphaned and you will generate no revenue.

The following pools have upgraded and enforce the new rules:
Coinmine.pl
Dwarfpool
Miningpoolhub
Suprnova

The following pools have not yet upgraded:
Coin-base
Please note that we will update this list as soon as any there are any updates.

The 75% threshold value was reached in approximately 6 days. The 95% threshold value was reached in approximately 10 days. As of last week the Groestlcoin network BIP66 soft fork is completed.

Bitcoin BIP66 Fork Incident
Bitcoin's BIP66 enforcement lead to a fork of the network once the 95% threshold had been reached. This was caused by mining pools representing half the hashing power of the network not validating blocks properly due to SPV mining, despite publishing v3 blocks and building on top of an invalid block leading to a 6 block deep fork. After the issue was identified, the miners corrected the issue and a block reorgonisation took place, orphaning the invalid fork.
We have discussed this issue with various pools and have confirmed that full validation nodes are being used. Despite this, we have been monitoring the network to make sure any issues were promptly dealt with. More details about the incident can be found here.

[jackielove4u]

Besides awesome technical development, what's the marketing plan behind Groestl? Anybody in here been involved with that part of development already?

Besides technical developments there is nothing else. No marketing plans, we need help from the community for this. You got idea's?

I'm still waiting going to the moon......
What can be the problem with this altcoin?
Nice developments, many owners but price almost below zero.
What do we need for the unique coin?

below zero? price can have a negative value also?

[jackielove4u]

Reminder to upgrade the core wallet.

A new major Groestlcoin Core version 2.11.0 is now available for download bringing both new features and bug fixes, so it is recommended to upgrade to it if you are running a full Groestlcoin node or a local Groestlcoin Core wallet.

v2.11.0 is now the official release version of Groestlcoin Core. On top of the new features, this update contains very important security fixes and all users MUST upgrade to this version as soon as possible. Pool operators, P2Pool and solo miners especially, as once BIP 66 is enforced, blockversion 112 (aka 1) and blockversion 2 will be rejected from the network entirely and only blockversion 3 will be accepted.

What's new in version v2.11.0?
This is a major release of Groestlcoin Core, featuring the technical equivalent of Bitcoin v0.11.0 but with Groestlcoin specific patches. On a general level, most of what is new is is hidden where block synchronization and various internals are considerably faster and more efficient, and it has several major privacy improvements.  The most significant changes include:
• Qt dependency changed. Version upgraded to 5.5.
• OpenSSL dependency changed. Version upgraded to 1.0.2a (19 March 2015).
• BerkeleyDB dependency changed. Version for Windows and MAC upgraded to 5.3.21 (11 May 2012).
• Protocolversion changed to 70002
• Blockversion 112 interpreted as version 1. All new blocks will have blockversion 3, but v2.11.0 clients will also accept blockversion 1 (v112) and blockversion 2 blocks until 95% of all blocks will be blockversion 3. After this moment all blockversion 1 and blockversion 2 will be rejected.
• All possible languages added.
• New alert keys added.
• Canonical name for .GroestlCoin in UNIX changed to use all lowercase: .groestlcoin.
• Extra main seeds added.
• New testnet created.
• Comes now with a installer.
• Transaction-URL support of third parties blockexplorers.
• Coin control support.
• Ability to open Groestlcoin URI or payment request.
• Ability to spent unconfirmed coins.
• Ability to see receive and send addresses.
• Groestlcoin-cli. Another change in the v2.11.0 release is moving away from the groestlcoind executable functioning both as a server and as a RPC client. The RPC client functionality (“tell the running groestlcoin daemon to do THIS”) was split into a separate executable, ‘groestlcoin-cli’.
• Transaction malleability-related fixes
• Autotools build system. For v2.11.0 we switched to an autotools-based build system instead of individual makefiles. Using the standard “./autogen.sh; ./configure; make” to build Groestlcoin-Qt and Groestlcoind makes it easier for experienced open source developers to contribute to the project.
• Rebranding to Groestlcoin Core. To reduce confusion between Groestlcoin-the-network and Groestlcoin-the-software we have renamed the reference client to Groestlcoin Core.
• OP_RETURN and data in the block chain support.
• Standard script rules relaxed for P2SH addresses.
• Watch-only wallet support. This allows the wallet to track transactions to and form wallets for which you know the address of but do not have the private key to.
• Memory usage optimization. There have been many changes in this release to reduce the default memory usage of a node.
• Experimental support for big-endian CPU architectures was added in this release.
• Privacy: Stream isolation for Tor. This release adds functionality to create a new circuit for every peer connection, when the software is used with Tor.
• Privacy: Disable wallet transaction broadcast
• Block file pruning for nodes (without wallet). This release supports running a fully validating node without maintaining a copy of the raw block and undo data on disk. Pruning is disabled by default.
• Faster blockchain synchronization due to headers-first synchronization and support for downloading blocks in parallel. Downloading the blockchain is now much quicker and can be completed within a half hour instead of taking hours for some users.
• A REST interface which allows unauthenticated access to public node data when the -rest flag is specified.
• RPC Server “Warm-Up” Mode which starts earlier than previous versions. This helps users or services relying on it know that the server has already started and will be available soon.
• Improved signing security. This is due to using the libsecp256k1 library for signing instead of OpenSSL. libsecp256k1 is a cryptographic library optimized for elliptic curve uses which Groestlcoin relies on and was created by Bitcoin Core developer Pieter Wuille. Featuring better security, via hardening against timing leaks and derandomization, this library is believed to be better tested and more thoroughly reviewed than the implementation in OpenSSL.
• Improved algorithm used for fee estimation. This release automatically estimates how high a transaction fee (or how high a priority) transactions require to be confirmed quickly.
• Consensus library. Starting from v2.11.0, the Groestlcoin Core distribution includes a consensus library. The purpose of this library is to make the verification functionality that is critical to Groestlcoin’s consensus available to other applications, e.g. alternative node implementations.
• New utility applications including groestlcoin-tx for transaction related functionality and groestlcoin-cli for RPC command line functionality as groestlcoind no longer accepts them.
• Strict DER encoding for signatures (BIP 66). This introduces block version 3 and a new consensus rule which prevents non-standard transactions from being included in blocks. This also removes the dependency on OpenSSL’s signature parsing. Eventually, libsecp256k1 will be used for all consensus related tasks, depreciating the need for OpenSSL entirely.
• RPC Access Changes. RPC access now supports binary network addresses. This means that you can specify a single IP address, a CIDR network address or a netmask for accessing the RPC service. Please note, wildcard string matching no longer works and will display an error in the debug.log file when you attempt to use use a wildcard string in the rpcallowip= variable, either as a config setting or launch parameter. Note: IPv6 addresses can also be used.
• Added option -alerts’ to opt out of the network alert system. Please note that disabling network alerts should only be used by power users as this system is used for network emergencies and important security releases. The default behavior is that network alerts are enabled.
• Detect and reject LibreSSL. This prevents a non-approved SSL library being used for compiling Groestlcoin Core, preventing potential consensus compatibility issues.
• Improved getbalance RPC functionality to allow the user to display zero confirmation transactions (this works with watch-only addresses as well).

It is appreciated if feedback of the following is provided:
1. Can you receive coins? (small amounts to avoid losing them)
2. Can you send coins?
3. Can you view your transaction on a third party blockexplorer (restart the client after entering the url of the blockexplorer) ?
4. Can you use the wallet with TOR?
5. Are you able to backup your wallet (wallet.dat) file?
6. Are you able to encrypt your wallet (wallet.dat) file?
7. Are you able to use watch-only function?
8. How long does it take to fully synchronize?
9. Are you able to sign/verify messages?
10. Are you able to see you send/receive addresses?
11. Are you able to use the wallet in your local language?

The application may have unfound bugs and problems. Please report using the issue tracker at github:
https://github.com/groestlcoin/groestlcoin/issues

Important:
• There is no warranty and no party shall be made liable to you for damages. If you lose coins due to this app, no compensation will be given. Use this app solely at your own risk.
• Encrypt your wallet. This can be done by clicking the settings menu from inside the wallet. Make sure your password is secure and do not forget it.
• Make a copy your wallet.dat file as a backup and move it to a secure location:
Location Windows: Navigate to C:\Users\Username\AppData\Roaming\groestlCoin\wallet.dat (or open windows explorer and enter %appdata%\Groestlcoin\wallet.dat)
Location Mac: Finder -> Go {Hold Option] -> Library -> groestlcoin -> wallet.dat (~/Library/Application Support/groestlcoin/wallet.dat)

WARNING:
While this branch has been extensively tested to be compatible with the existing Groestlcoin v2.1.0.6 network there is the possibility that we missed something. BACKUP YOUR GROESTLCOIN DATA DIRECTORY and wallet.dat because after you run v2.11.0 the old v2.1.0.6 version is no longer compatible with your on-disk data. Without this your node will need start syncing (or importing from bootstrap.dat) anew afterwards. It is possible that the data from a completely synchronised v2.11.0 node may be usable in older versions as-is, but this is not supported and may break as soon as the older version attempts to reindex. Because release v2.11.0 makes use of headers-first synchronization and parallel block download, the block files and databases are not backwards-compatible with older versions of Groestlcoin Core or other software:
• Blocks will be stored on disk out of order (in the order they are received), which makes it incompatible with some tools or other programs. Reindexing using earlier versions will also not work anymore as a result of this.
• The block index database will now hold headers for which no block is stored on disk, which earlier versions won’t support.

How to Upgrade?
If you are running an older version, shut it down. Wait until it has completely shut down (which might take a few minutes for older versions), then run the installer (on Windows) or just copy over /Applications/Groestlcoin-Qt (on Mac).
Linux users: Canonical name for .GroestlCoin in Linux is changed to use all lowercase: .groestlcoin. Please make a link as a solution: ln .GroestlCoin .groestlcoin and rename the GroestlCoin.conf to groestlcoin.conf.  And copy over groestlcoind/Groestlcoin-qt.

Download the Windows Wallet (64 bit) here: https://github.com/GroestlCoin/groestlcoin/releases/download/v2.11.0/groestlcoin_x64.msi
Download the Windows Wallet (32 bit) here: https://github.com/GroestlCoin/groestlcoin/releases/download/v2.11.0/groestlcoin_x86.msi
Download the MAC Wallet here: https://github.com/GroestlCoin/groestlcoin/releases/download/v2.11.0/Groestlcoin-Qt.dmg

Source code:
https://github.com/Groestlcoin/groestlcoin
Build instructions for Linux can be found here: https://github.com/GroestlCoin/groestlcoin/blob/master/doc/build-unix.md
Build instructions for OSX can be found here: https://github.com/GroestlCoin/groestlcoin/blob/master/doc/build-osx.md
Build instructions for Windows can be found here: https://github.com/GroestlCoin/groestlcoin/blob/master/doc/build-windows.md

[cryptonit]

i can see lot activity in area utility of GRS
good job of our brothers in algo

in case storage of wealth and a zero energy waste POS income
or the total new unique ultra rare crypto assets are also interesing to u
i wana shameless point u towards a project that was prepared whole 2015 by DMD Diamond
(as a big GRS stakeholder myself i think i can post a few lines here about this)

in case the opportunity is to big for u
u can get at least 150 DMD by find someone who can take it



https://bit.diamonds/auction.html


(first round only two legendary10 are avaiable and both have a bid already!)

(The Allnatt Diamond: Unique Crypto Asset)is at 2.6 BTC

and other /The Moussaieff Red Diamond: Unique Crypto Asset) at 3.5 BTC already

so in fact both stones of phase 1 are above starting bid of phase 2 already

[bhokor]

Ẁell the new upgrade is really great DEV, technically this coin is showing his reliability and with the updates of the code people knows it is being actively  worked, i would like to know  if we have actually some Dice site working?

thanks

[jackielove4u]

(as a big GRS stakeholder myself i think i can post a few lines here about this)

It's ok to cross promote but did u say few lines?  Wondering what your perception is of many lines then 
Good luck with your auction!

[jackielove4u]

Merry Christmas everyone! Warmest wishes. Thank you for your support throughout the entire year. Happy holidays!

[gruve_p]

Electrum-grs is a lightweight "thin client" groestlcoin wallet Windows, MacOS and Linux based on a client-server protocol. Its main advantages over the original Groestlcoin client include support for multi-signature wallets and not requiring the download of the entire block chain.

If you are an ordinary user of Groestlcoin and simply want the convenience of a web wallet with the security of a real application and support for multi-signature, then Elecrum-GRS is the right choice for you.

Changelog Electrum-GRS 2.5.4:
• Linux binary file included
• Fixed sweeping private keys
• Fixed signing/verifying messages
• Electrum-GRS servers updated to 2.5.4
• Installwizard: do not allow direct copy-paste of the seed
• The QT GUI supports multiple windows in the same process. When a new Electrum-GRS instance is started, it checks for an already running Electrum-GRS process, and connects to it.
• The network layer uses select(), so all server communication is handled by a single thread. Moreover, the synchronizer, verifier, and exchange rate plugin now run as separate jobs within the networking thread instead of as their own threads.
• Plugins are revamped
• Simplified Chinese wordlist
• Dynamic Fees: using estimatefee value returned by server
• Various GUI improvements
• Arbitrary m-of-n multisig wallets are supported (n<=15).
• Transaction fees set manually in the GUI are retained, including when the user uses the '!' shortcut.
• New 'email' plugin, that enables sending and receiving payment requests by email.
• improvements to the transaction dialog:
    - request password after showing transaction
    - show change addresses in yellow color
• Improved logic for the network layer.
• More efficient coin selection. Spend oldest coins first, and minimize the number of transaction inputs.
• The command line accepts the '!' syntax to send the maximum amount available. It can be combined with the '--from' option. Example: 'payto <destination> ! --from <from_address>'
• The command line also accepts a '?' shortcut for private keys arguments, that triggers a prompt.
• Payment requests can be signed with a SSL certificate, and published as bip70 files in a public web directory.
• Show amounts (thousands separators and decimal point) according to locale in GUI
• Show unmatured coins in balance
• Faster startup, thanks to the following optimizations:
   1. Transaction input/outputs are cached in the wallet file
   2. Fast X509 certificate parser, not using pyasn1 anymore.
• The 'Invoices' and 'Send' tabs have been merged.
• Contacts are stored in a separate file, shared between wallets.
• A Search Box is available in the GUI (Ctrl-S)
• Own addresses are shown in green in the Transaction dialog.
• Address History dialog.
• The password dialog will ask for password again if the user enters a wrong password
• The Master Public Key dialog displays which keys belong to the wallet, and which are cosigners
• The transaction dialog will ask to save unsaved transaction received from cosigner pool, when user clicks on 'Close'
• The multisig restore dialog accepts xprv keys.

Features
• Encrypted wallet - the file that contains your groestlcoins is protected with a password. You are protected from thieves.
• Deterministic key generation - If you lose your wallet, you can recover it from its seed. You are protected from your own mistakes.
• Instant on - the client does not download the blockchain, it requests that information from a server. No delays, always up-to-date.
• Freedom and Privacy - The server does not store user accounts. You are not tied to a particular server, and the server does not need to know you.
• No scripts - Electrum-GRS does not download any script. A compromised server cannot send you arbitrary code and steal your groestlcoins.
• No single point of failure - The server code is open source, anyone can run a server.
• Transactions are signed locally - Your private keys are not shared with the server. You do not have to trust the server with your money.
• Firewall friendly - The client does not need to open a port, it simply polls the server for updates.
• Free software - Gnu GPL v3. Anyone can audit the code.
• Written in Python - The code is short, and easy to review.
• User Friendly - Support for Groestlcoin URIs, signed URIs and Groestlcoin aliases
• No Lock-In - You can export your private keys and use them in other groestlcoin clients.
• No Downtimes - Electrum-GRS servers are decentralized and redundant. Your wallet is never down.
• Proof Checking - Electrum-GRS Wallet verifies all the transactions in your history using SPV.
• Cold Storage - Keep your private keys offline, and go online with a watching-only wallet. Sign transactions from a computer taht is always offline. Broadcast them from a machine that does not have your keys.
• Multisign - Split the permission to spend your coins between several wallets using parallel BIP32 derivations and P2SH addresses ("2 of 2", "2 of 3"). Compact serialization format for unsigned or partially signed transactions, that includes the BIP32 master public key and derivation needed to sign inputs. Serialized transactions can be sent to cosigners or to cold storage using QR codes
• Cosigner Pool plugin - encrypted communication channel for multisign wallets, to send and receive partially signed transactions.
• Get noticed - Run a public Electrum-GRS server, publish your message and reach thousands of Groestlcoin users

It is appreciated if feedback of the following is provided:
1. Can you receive coins? (small amounts to avoid losing them)
2. Can you send coins?
3. Does the cosigner pool work when using a multi-signature wallet?
4. Does the virtual keyboard work when it asks to enter your wallet password?
5. Does it automatically detect electrum1.groestlcoin.org and electrum2.groestlcoin.org under Tools - Network?
6. Are you able to sweep private keys?
7. Are you able to sign/verify messages?
8. Are you able to encrypt/decrypt messages?

This application is licensed under the GPL version 3. There is no warranty and no party shall be made liable to you for damages. If you lose coins due to this app, no compensation will be given. Use this app solely at your own risk.

The application may have unfound bugs and problems. To leave feedback: 
1. PM me
2. Email: groestlcoin@gmail.com
3. Post reports of erros in this topic.

Important:
Store your secret phrase somewhere safe!
The multi-signature addresses starts with a "3" and not with a "F".
Electrum-GRS creates an encrypted filename default_wallet instead of wallet.dat (like in Groestlcoin Core)
• Location Windows: Navigate to C:\Users\USER NAME\AppData\Roaming\Electrum-grs\wallets (or open windows explorer and enter %appdata%\Electryum-grs\wallets) and back up your default_wallet file by making a copy of it and moving it to a secure location.
• Location Mac: Navigate to ~/Libarary/Application Support/Electrum-grs/wallets and back up your default_wallet file by making a copy of it and moving it to a secure location.

You can download it using the links below and be up and running with Groestlcoin in 5 minutes.

Download the Linux wallet here: https://github.com/GroestlCoin/electrum-grs/releases/download/v2.5.4/Electrum-GRS-2.5.4_Linux_x86_64-Installer.bin
Download the OSX PKG wallet here: https://github.com/GroestlCoin/electrum-grs/releases/download/v2.5.4/Electrum-GRS-2.5.4-Installer.pkg
Download Windows wallet here: https://github.com/GroestlCoin/electrum-grs/releases/download/v2.5.4/Electrum-grs-2.5.4-Windows-setup.exe
Note: The QR code scanner is not supported in Windows and OSX binaries

Source code:
GitHub Source server: https://github.com/Groestlcoin/electrum-grs-server
Github Source client: https://github.com/Groestlcoin/electrum-grs

[gruve_p]

Groestlcoin Vanitygen: Vanity groestlcoin address generator . Vanitygen is a command-line vanity groestlcoin address generator. Add unique flair when you tell people to send groestlcoins to FXSLUT2zcZPnhJ7J3BqGUCQMj5cEUyN31V.  Alternatively, vanitygen can be used to generate random addresses offline.

If you're tired of the random, cryptic addresses generated by regular groestlcoin clients, then vanitygen is the right choice for you to create a more personalized address.

Features
• Vanitygen accepts as input a pattern, or list of patterns to search for, and produces a list of addresses and private keys.
• Vanitygen's search is probabilistic, and the amount of time required to find a given pattern depends on how complex the pattern is, the speed of your computer, and whether you get lucky.
• Vanitygen includes components to perform address searching on your CPU (vanitygen) and your OpenCL-compatible GPU (oclvanitygen). Both can be built from source, and both are included in the Windows binary package.
• Upon finding a match for a given pattern, vanitygen will stop searching for additional matches for that pattern. To search for multiple matches for each pattern, use the -k option
• Prefixes are exact strings that must appear at the beginning of the address. When searching for prefixes, vanitygen will ensure that the prefix is possible, and will provide a difficulty estimate.  Exact prefixes are case-sensitive by default, but may be searched case-insensitively using the -i option
• The percentage displayed just shows how probable it is that a match would be found in the session so far. If it finds your address with 5% on the display, you are extremely lucky.  If it finds your address with 92% on the display, you are unlucky.  If you stop vanitygen with 90% on the display, restart it, and it finds your address with 2% on the display, your first session was unlucky, but your second session was lucky.
• Vanitygen uses the OpenSSL random number generator. This is the same RNG used by groestlcoin and a good number of HTTPS servers. It is regarded as well-scrutinized. On Linux, the RNG will be seeded from /dev/urandom. Guessing the private key of an address found by vanitygen will be no easier than guessing a private key created by groestlcoin itself. Nonetheless, if you feel the default RNG is unable to provide numbers that are sufficiently difficult to guess, vanitygen can be directed to seed the RNG from an external file using the -s option.
• To speed up address generation, vanitygen uses the RNG to choose a private key, and literally increments the private key in a loop searching for a match. As long as the starting point is not disclosed, if a match is found, the private key will not be any easier to guess than if every private key tested were taken from the RNG. Vanitygen will also reload the private key from the RNG after 10,000,000 unsuccessful searches (100M for oclvanitygen), or when a match is found and multiple patterns are being searched for.
• Free software - Gnu GPL v3. Anyone can audit the code.
• Written in C - The code is short, and easy to review.

To use vanitygen, you need to open a command line window and change to the directory where you extracted the vanitygen program.  An easy way to do this in Windows 7, hold down the shift key, right-click on the folder where you unzipped vanitygen, and select "Open command window here."  Then, you can type the vanitygen command at the prompt. Example how to use:
vanitygen -G FXSLUT
Difficulty: 264104224
Pattern: FXSLUT                                                               
Address: FXSLUT2zcZPnhJ7J3BqGUCQMj5cEUyN31V
Privkey: 5KNtRRpMfpYXVuSv86GF2pKhS4TDvVGy4c2L6psSLRkPikFbzUf

Note: Groestlcoin addresses consist of random digits and uppercase and lowercase letters, with the exception that the uppercase letter "O", uppercase letter "I", lowercase letter "l", and the number "0" are never used to prevent visual ambiguity.

It is appreciated if feedback of the following is provided:
1. Are you able to create vanity addresses for Groestlcoin?
2. Are you able to sweep the private keys (using any of our clients)?
3. Are you able to imprt the private keys (using any of our clients)?

This application is licensed under the GPL version 3. There is no warranty and no party shall be made liable to you for damages. If you lose coins due to this app, no compensation will be given. Use this app solely at your own risk.

The application may have unfound bugs and problems. To leave feedback: 
1.  PM Wolf on bitcointalk: https://bitcointalk.org/index.php?action=profile;u=80740
2.  Email: groestlcoin@gmail.com
3.  Reports of errors can also be posted in this topic.

Download the Groestlcoin vanitygen here: https://github.com/GroestlCoin/vanitygen/releases/download/1.0/grs-vanitygen.zip

Source code: https://github.com/GroestlCoin/vanitygen