feat: validate mnemonic

Author: Benzbeeb

bip39/bip39.go

@@ -0,0 +1,30 @@
+package bip39
+
+import (
+	"strings"
+)
+
+// IsMnemonicValid attempts to verify that the provided mnemonic is valid.
+// Validity is determined by both the number of words being appropriate,
+// and that all the words in the mnemonic are present in the word list.
+func IsMnemonicValid(mnemonic string) bool {
+	// Create a list of all the words in the mnemonic sentence
+	words := strings.Fields(mnemonic)
+
+	//Get num of words
+	numOfWords := len(words)
+
+	// The number of words should be 12, 15, 18, 21 or 24
+	if numOfWords < 12 || numOfWords > 24 || numOfWords%3 != 0 {
+		return false
+	}
+
+	// Check if all words belong in the wordlist
+	for i := 0; i < numOfWords; i++ {
+		if _, ok := ReverseWordMap[words[i]]; !ok {
+			return false
+		}
+	}
+
+	return true
+}