From 69c81ec8e9062eb8c47012967a283d84b8b7b084 Mon Sep 17 00:00:00 2001
From: Ugljesa Jovanovic <ionspinf@gmail.com>
Date: Mon, 23 Sep 2019 22:14:42 +0200
Subject: [PATCH] Working ctr decryption

---
 .../kotlin/com/ionspin/kotlin/crypto/symmetric/AesCtr.kt  | 8 ++++++--
 1 file changed, 6 insertions(+), 2 deletions(-)

diff --git a/multiplatform-crypto/src/commonMain/kotlin/com/ionspin/kotlin/crypto/symmetric/AesCtr.kt b/multiplatform-crypto/src/commonMain/kotlin/com/ionspin/kotlin/crypto/symmetric/AesCtr.kt
index 30806c1..23e63df 100644
--- a/multiplatform-crypto/src/commonMain/kotlin/com/ionspin/kotlin/crypto/symmetric/AesCtr.kt
+++ b/multiplatform-crypto/src/commonMain/kotlin/com/ionspin/kotlin/crypto/symmetric/AesCtr.kt
@@ -133,7 +133,11 @@ class AesCtr internal constructor(val aesKey: AesKey, val mode: Mode, initialCou
 
     fun decrypt(): Array<UByte> {
         val removePaddingCount = output.last().last()
-        val removedPadding = output.last().dropLast(removePaddingCount.toInt() and 0x7F)
+        val removedPadding = if (removePaddingCount > 0U && removePaddingCount < 16U) {
+            output.last().dropLast(removePaddingCount.toInt() and 0x7F)
+        } else {
+            output.last().toList()
+        }
         val preparedOutput = output.dropLast(1).toTypedArray() + removedPadding.toTypedArray()
         //JS compiler freaks out here if we don't supply exact type
         val reversed : List<Array<UByte>> = preparedOutput.reversed() as List<Array<UByte>>
@@ -153,7 +157,7 @@ class AesCtr internal constructor(val aesKey: AesKey, val mode: Mode, initialCou
                 Aes.encrypt(aesKey, blockCount.toUByteArray(Endianness.BIG)) xor data
             }
             Mode.DECRYPT -> {
-                Aes.decrypt(aesKey, blockCount.toUByteArray(Endianness.BIG)) xor data
+                Aes.encrypt(aesKey, blockCount.toUByteArray(Endianness.BIG)) xor data
             }
         }