Bip39 decoder http://www.mediafire.com/file/uilrjfajg2ami24/pdf-14673-57158.pdf Checksum creation: A checksum is produced from this entropy making use of SHA-256 hashing, which allows verify the mnemonic's integrity later on. For words that have only 3 letters, there's no 4th letter. Such as Together with the word “add”, there won't be any more letters afterwards https://thebookmarknight.com/story20467432/bip39-app-what-does-bip39-generator-mean-https-t-me-bip39-chat