refactor verification logic to be case-insensitive

captcha.go

@@ -50,7 +50,7 @@ func (c *Captcha) Generate() (id, b64s, answer string, err error) {
 // You may want to call `store.Verify` method instead.
 func (c *Captcha) Verify(id, answer string, clear bool) (match bool) {
 	vv := c.Store.Get(id, clear)
-	//fix issue for some redis key-value string value
-	vv = strings.TrimSpace(vv)
-	return vv == strings.TrimSpace(answer)
+    vv = strings.TrimSpace(vv)
+    answer = strings.TrimSpace(answer)
+    return strings.EqualFold(vv, answer)
 }

store_memory.go

@@ -16,6 +16,7 @@ package base64Captcha
 
 import (
 	"container/list"
+	"strings"
 	"sync"
 	"time"
 )
@@ -70,7 +71,7 @@ func (s *memoryStore) Verify(id, answer string, clear bool) bool {
 		return false
 	}
 	v := s.Get(id, clear)
-	return v != "" && v == answer
+	return strings.EqualFold(v, answer)
 }
 
 func (s *memoryStore) Get(id string, clear bool) (value string) {

store_sync_map.go

@@ -1,6 +1,7 @@
 package base64Captcha
 
 import (
+	"strings"
 	"sync"
 	"time"
 )
@@ -59,5 +60,6 @@ func (s StoreSyncMap) Get(id string, clear bool) string {
 
 // Verify check a string value
 func (s StoreSyncMap) Verify(id, answer string, clear bool) bool {
-	return s.Get(id, clear) == answer
+	vv := s.Get(id, clear)
+    return strings.EqualFold(vv, answer)
 }