Working with a byte array in WCF service

I am working with a byte array input to a WCF REST service. Request and Response format is json. I am facing issue when the service tries to deserialize byte array. At client side I am using NewtonSoft to serialize and at server side it is default DataContract Serializer. If I encode byte array to Base64String then service works fine. Problem is with byte array. Can someone help me if there is any special treatment required while working with byte array in WCF.