Fix error reponses

Signed-off-by: Asai Neko <sugar@sne.moe>

internal/cryptography/aes.go

@@ -21,7 +21,7 @@ func normalizeKey(key []byte) ([]byte, error) {
 	case 16, 24, 32:
 		return key, nil
 	default:
-		return nil, errors.New("AES key length must be 16, 24, or 32 bytes")
+		return nil, errors.New("[Cryptography AES] AES key length must be 16, 24, or 32 bytes")
 	}
 }
 
@@ -74,7 +74,7 @@ func AESGCMDecrypt(encoded string, key []byte) ([]byte, error) {
 	}
 
 	if len(data) < gcm.NonceSize() {
-		return nil, errors.New("ciphertext too short")
+		return nil, errors.New("[Cryptography AES] ciphertext too short")
 	}
 
 	nonce := data[:gcm.NonceSize()]
@@ -92,11 +92,11 @@ func pkcs7Pad(data []byte, blockSize int) []byte {
 func pkcs7Unpad(data []byte) ([]byte, error) {
 	length := len(data)
 	if length == 0 {
-		return nil, errors.New("invalid padding")
+		return nil, errors.New("[Cryptography AES] invalid padding")
 	}
 	padding := int(data[length-1])
 	if padding == 0 || padding > length {
-		return nil, errors.New("invalid padding")
+		return nil, errors.New("[Cryptography AES] invalid padding")
 	}
 	return data[:length-padding], nil
 }
@@ -143,7 +143,7 @@ func AESCBCDecrypt(encoded string, key []byte) ([]byte, error) {
 	}
 
 	if len(data) < block.BlockSize() {
-		return nil, errors.New("ciphertext too short")
+		return nil, errors.New("[Cryptography AES] ciphertext too short")
 	}
 
 	iv := data[:block.BlockSize()]
@@ -195,7 +195,7 @@ func AESCFBDecrypt(encoded string, key []byte) ([]byte, error) {
 	}
 
 	if len(data) < block.BlockSize() {
-		return nil, errors.New("ciphertext too short")
+		return nil, errors.New("[Cryptography AES] ciphertext too short")
 	}
 
 	iv := data[:block.BlockSize()]