You may have noticed that your account in HashPack has a dash and five letters after the end of the numbers. Previously, the Hedera account looked like 0.0.123456, but now it displays as 0.0.123456-abcde.
Imagine the scenario: You are sending a large amount of HBAR from one account to another. A checksum is helpful in ensuring that you don't forget a digit and unintentionally send money to account 0.0.1235 rather than 0.0.12345, for instance.
Account number with checksum.
Overall, this feature aims to improve the security and accuracy of transactions on the network by helping to prevent manual data entry mistakes and address similar errors.
The added letters are completely optional. The number-only address still works without the added checksum, but we encourage using the checksum whenever possible.
TLDR: The new letters are totally safe and part of the Hedera network, added to help reduce typos and user errors.
A small caveat
Exchanges and other dApps that require you to type in your account number in their site may not support checksums. If you get an error on those sites, simply remove the dash and the five letters at the end, but make sure to double check the account to make sure there are no typos! (That’s why checksums were added in the first place.)
We encourage all platforms to add support for checksums, to take advantage of this new functionality.
A bit more in depth information
Checksums were added on the Hedera Network in HIP-15 and proposed by Dr Leemon Baird himself.
These five extra characters are a native feature on the Hedera network that we’ve added support for in Patch 5.0.0. This is a new address format to help prevent mistakes when sending transactions on the network. The new format consists of a no-checksum address, which is the normal Hedera address that you would use to send a transaction. This is followed by a 5-letter checksum, which is appended to the address after a dash.
The purpose of the checksum is to provide an additional layer of protection against errors when entering or sending an address. The checksum is calculated using a formula that takes into account the characters in the no-checksum address. If the address is entered correctly, the checksum will also be correct. However, if any characters in the address are entered incorrectly or the address is otherwise invalid, the checksum will not match and the transaction will not be processed.
By using this new addressing format, Hedera aims to reduce the number of mistakes made when sending transactions on the network and increase the overall security and reliability of the platform.
This new format is completely optional, but it is intended to help prevent manual data entry mistakes when transferring funds on the Hedera network. In the past, it was common for wallets to use a compact address identifier such as 0.0.12345, but this format is prone to errors as it is easy to leave out digits, permute them, or accidentally add extra digits. These errors can result in funds being transferred to the wrong account, potentially irreversibly.