diff --git a/lib/util/string.ts b/lib/util/string.ts
index 1c0cfaedde477869f55c94fc6059a0ceed54cc2e..f3a10e5163e32c9b86df8c7e3595dd611d0a0c2c 100644
--- a/lib/util/string.ts
+++ b/lib/util/string.ts
@@ -30,12 +30,16 @@ export function nonEmptyStringAndNotWhitespace(input: unknown): boolean {
   return is.nonEmptyString(input) && !is.emptyStringOrWhitespace(input);
 }
 
-// Converts from ascii string to base64-encoded string
+/**
+ * Converts from utf-8 string to base64-encoded string
+ */
 export function toBase64(input: string): string {
   return Buffer.from(input).toString('base64');
 }
 
-// Converts from base64-encoded string to ascii string
+/**
+ * Converts from base64-encoded string to utf-8 string
+ */
 export function fromBase64(input: string): string {
   return Buffer.from(input, 'base64').toString();
 }