Groestlcoin Address Utility

Groestlcoin Address Utility allows a user to do various useful functions with Groestlcoin addresses, such as convert them between various formats, encrypt and decrypt them, and print them as paper wallets.

This program is written in C# and is based on Microsoft's .NET / Visual Studio toolchain. Groestlcoin Address Utility runs natively for Windows, and also runs on Linux and Mac using Mono.

If you need a utility to do all kind of conversions between Groestlcoin hex/address and public/private keys Groestlcoin Address Utility is the right choice for you!

Features:
• Ability to copy Qr code graphic into the clipboard for use with other programs.
• Base58 Calculator allows arbitrary conversions of base58 values to hexadecimal and vice versa, regardless of length.  Add a "?" to the end of any base58 string to suspend verification of the checksum.
• Support for compressed public keys and the ability to convert between compressed and uncompressed.
• A calculator that lets you convert between private and public keys, hex and base58 Groestlcoin addresses.
• Bulk Groestlcoin address generator
• Paper wallet printer
• Decrypter for encrypted private keys
• Self-escrow utility
• Intermediate code generator (used for creating encrypted paper wallets)
• Physical Groestlcoin insert printer (the small round private key paper found in physical Bitcoins)

Groestlcoin Address utility screen:
Create new Groestlcoin addresses with corresponding minikey and standard private key formats
Copy Groestlcoin addresses and private keys to the clipboard as QR code images
Convert minikeys to WIF/hexadecimal private key formats
Create private keys from text strings via groestl hash ("brainwallet")
Convert between hexadecimal and WIF private key formats
Decrypt/encrypt private keys per BIP 0038
Calculate public key from private key
Calculate compressed/uncompressed equivalents for public keys
Confirm that public keys are valid (i.e. that they represent a valid EC curve point)
Calculate Hash160 from public key
Calculate Groestlcoin address
View balance on block explorer

Base 58 Calculator screen:
The Base58 calculator screen allows quick conversions between the Base58 encoding commonly used in Groestlcoin-related objects and the encoded hexadecimal equivalent. This screen is especially useful for discovering what hexadecimal prefix is required to create Base58 strings with a specific prefix, or for seeing what is encoded in non-standard Base58 strings generated by service providers.
The 32-bit checksum is verified on all Base58 entries, and "invalid" is displayed in the hex box if the checksum is incorrect. However, verification of the checksum can be skipped simply by appending a question mark (?) to the end of the Base58 string. Once the hexadecimal equivalent is known, simply making an insignificant change to the hex box (such as adding a space to the end) will result in the correct checksum being recomputed and displayed.
If "invalid" is still shown after adding a question mark to the Base58 string, it probably contains invalid characters such as 0, O, I, or l.

Key Combiner screen:
The Key Combiner screen allows elliptic-curve arithmetic on Groestlcoin public and private keys. Specifically, multiplication can be used for creating two-factor Groestlcoin addresses, and addition can be used for secure vanity address generation.
The two boxes accept either a public or private key in any recognized format (hexadecimal, WIF, minikey, etc.).
Multiplying or adding two private keys yields a new private key, as well as its corresponding public key and Groestlcoin address.
Multiplying or adding a private key and public key yields a combined public key and Groestlcoin address, but no private key. When the public key input is replaced by the matching private key, then calculating the resulting private key becomes possible.

Two-Factor Groestlcoin Tools:
When you order a 2-factor item, you can protect it with a passphrase which you can convert to an intermediate code. The Intermediate Code preserves enough information about the passphrase to be able to create a public key and 2-factor groestlcoin address from it, but not the private key. The 2-factor system ensures that nobody can redeem the value from the item unless they have the passphrase.

Escrow tools:
Escrow allows two people to transact in Groestlcoin while leaving their funds visible to everybody and accessible to nobody until somebody releases them. It allows the payer or the payee to release funds to one another, and also lets a third person decide for them if the two can't agree.  The third person never has access to take the funds, and is only needed to release the funds if the original two can't agree who gets them.  Whoever gets a copy of all three "invitations" gets access to the funds.

Vanity private keys:
Generate a random address, and then add a question mark to the WIF private key (turns off checksum). Substitute characters. Convert to hex and then back to WIF (which will replace the checksum with a valid one). Once you have a working vanity private key that stays the same no matter which way you convert it, then generate the public key and groestlcoin address from it.

This application is licensed under the GPLv3 license. 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.

Important:
Save all your private keys before closing the program by copying it and moving it to a secure location. Otherwise all the information will be gone!

Windows:

Linux:

OS X:

Note: ZIP archive contains 3 files: GrsAddress.exe BouncyCastle.Crypto.dll ThoughtWorks.QRCode.dll

Source code:
https://github.com/GroestlCoin/Groestlcoin-Address-Utility