diff --git a/src/platform/nxp/k32w/common/OTATlvProcessor.cpp b/src/platform/nxp/k32w/common/OTATlvProcessor.cpp
index c313fd0c13989f..ed79d0c39e53ad 100644
--- a/src/platform/nxp/k32w/common/OTATlvProcessor.cpp
+++ b/src/platform/nxp/k32w/common/OTATlvProcessor.cpp
@@ -106,8 +106,8 @@ CHIP_ERROR OTADataAccumulator::Accumulate(ByteSpan & block)
 CHIP_ERROR OTATlvProcessor::vOtaProcessInternalEncryption(MutableByteSpan & block)
 {
     uint8_t iv[16];
-    uint8_t key[16];
-    uint8_t dataOut[16] = { 0 };
+    uint8_t key[kOTAEncryptionKeyLength];
+    uint8_t dataOut[16] = {0};
     uint32_t u32IVCount;
     uint32_t Offset = 0;
     uint8_t data;
@@ -119,23 +119,18 @@ CHIP_ERROR OTATlvProcessor::vOtaProcessInternalEncryption(MutableByteSpan & bloc
     u32IVCount = (((uint32_t) iv[12]) << 24) | (((uint32_t) iv[13]) << 16) | (((uint32_t) iv[14]) << 8) | (iv[15]);
     u32IVCount += (mIVOffset >> 4);
 
-    iv[12] = (uint8_t) ((u32IVCount >> 24) & 0xff);
-    iv[13] = (uint8_t) ((u32IVCount >> 16) & 0xff);
-    iv[14] = (uint8_t) ((u32IVCount >> 8) & 0xff);
-    iv[15] = (uint8_t) (u32IVCount & 0xff);
+    iv[12] = (uint8_t)((u32IVCount >> 24) &  0xff);
+    iv[13] = (uint8_t)((u32IVCount >> 16) &  0xff);
+    iv[14] = (uint8_t)((u32IVCount >> 8) &  0xff);
+    iv[15] = (uint8_t)(u32IVCount &  0xff);
 
-    size_t len = strlen(OTA_ENCRYPTION_KEY);
-
-    if (len != 32)
+    if (Encoding::HexToBytes(OTA_ENCRYPTION_KEY, strlen(OTA_ENCRYPTION_KEY),
+                             key,kOTAEncryptionKeyLength) != kOTAEncryptionKeyLength)
     {
-        return CHIP_ERROR_INVALID_ARGUMENT;
+        //Failed to convert the OTAEncryptionKey string to octstr type value
+        return CHIP_ERROR_INVALID_STRING_LENGTH;
     }
 
-    for (size_t i = 0; i < len; i += 2)
-    {
-        char hex[3] = { OTA_ENCRYPTION_KEY[i], OTA_ENCRYPTION_KEY[i + 1], '\0' };
-        key[i / 2]  = (uint8_t) strtol(hex, NULL, 16);
-    }
     ByteSpan KEY = ByteSpan(key);
     Encoding::LittleEndian::Reader reader_key(KEY.data(), KEY.size());
     ReturnErrorOnFailure(reader_key.Read32(&sKey.u32register0)
diff --git a/src/platform/nxp/k32w/common/OTATlvProcessor.h b/src/platform/nxp/k32w/common/OTATlvProcessor.h
index e412e1cdd1c5fa..13a2df115d90d9 100644
--- a/src/platform/nxp/k32w/common/OTATlvProcessor.h
+++ b/src/platform/nxp/k32w/common/OTATlvProcessor.h
@@ -127,6 +127,8 @@ class OTATlvProcessor
 #if OTA_ENCRYPTION_ENABLE
     /*ota decryption*/
     uint32_t mIVOffset = 0;
+    /* Expected byte size of the OTAEncryptionKeyLength */
+    static constexpr size_t kOTAEncryptionKeyLength = 16;
 #endif
     uint32_t mLength                             = 0;
     uint32_t mProcessedLength                    = 0;