diff --git a/index.ts b/index.ts
index c6690b2..cc48fad 100644
--- a/index.ts
+++ b/index.ts
@@ -1,10 +1,16 @@
 import {Result} from 'result'
+import logger from 'log'
+
+const log = logger('misc')
 
 export function a2str(buf: Uint8Array) : string {
+    log.debug('a2str')
     // @ts-ignore
     return String.fromCharCode.apply(null, buf)
 }
 export function str2a(str: string) : Uint8Array {
+    log.debug('str2a')
+
     const buf = new Uint8Array(str.length)
 
     for (let i= 0, strLen = str.length; i < strLen; i++) {
@@ -15,12 +21,18 @@ export function str2a(str: string) : Uint8Array {
 }
 
 export function a2b64(buf: Uint8Array) : string {
+    log.debug('a2b64')
     return btoa(a2str(buf))
 }
 export function b642a(b64: string) : Result<Uint8Array> {
+    log.debug('b642a')
+
     try {
         return Result.ok(str2a(atob(b64)))
-    } catch (e) {}
+    } catch (e) {
+        log.warn('b64 decode failed')
+        log.debug(`error : ${e}`)
+    }
 
     return Result.error([])
 }
diff --git a/package.json b/package.json
index f953f8e..1e2c787 100644
--- a/package.json
+++ b/package.json
@@ -6,6 +6,7 @@
   "files": ["index.ts"],
   
   "dependencies": {
+    "log": "git+git@git.pband.ch:typescript/log",
     "result": "git+git@git.pband.ch/typescript/result"
   },
   "devDependencies": {