diff --git a/src/main/java/synapticloop/b2/B2ApiClient.java b/src/main/java/synapticloop/b2/B2ApiClient.java
index dd2692f..82e7925 100644
--- a/src/main/java/synapticloop/b2/B2ApiClient.java
+++ b/src/main/java/synapticloop/b2/B2ApiClient.java
@@ -54,7 +54,7 @@
 import synapticloop.b2.response.B2GetUploadUrlResponse;
 import synapticloop.b2.response.B2HideFileResponse;
 import synapticloop.b2.response.B2ListFilesResponse;
-import synapticloop.b2.util.Helper;
+import synapticloop.b2.util.ChecksumHelper;
 
 /**
  * This is a wrapper class for the underlying calls to the request/response
@@ -327,7 +327,7 @@ public B2FileResponse uploadFile(String bucketId, String fileName, HttpEntity en
 	public B2FileResponse uploadFile(String bucketId, String fileName, File file, String mimeType, Map<String, String> fileInfo) throws B2ApiException {
 		B2GetUploadUrlResponse b2GetUploadUrlResponse = new B2GetUploadUrlRequest(client, b2AuthorizeAccountResponse, bucketId).getResponse();
 		return new B2UploadFileRequest(client, b2AuthorizeAccountResponse, b2GetUploadUrlResponse, fileName, file,
-				Helper.calculateSha1(file), mimeType, fileInfo).getResponse();
+				ChecksumHelper.calculateSha1(file), mimeType, fileInfo).getResponse();
 	}
 
 	/**
@@ -347,7 +347,7 @@ public B2FileResponse uploadFile(String bucketId, String fileName, File file, St
 	public B2FileResponse uploadFile(String bucketId, String fileName, File file, Map<String, String> fileInfo) throws B2ApiException {
 		B2GetUploadUrlResponse b2GetUploadUrlResponse = new B2GetUploadUrlRequest(client, b2AuthorizeAccountResponse, bucketId).getResponse();
 		return new B2UploadFileRequest(client, b2AuthorizeAccountResponse, b2GetUploadUrlResponse, fileName, file,
-				Helper.calculateSha1(file), fileInfo).getResponse();
+				ChecksumHelper.calculateSha1(file), fileInfo).getResponse();
 	}
 
 	/**
@@ -369,7 +369,7 @@ public B2FileResponse uploadFile(String bucketId, String fileName, File file, Ma
 	public B2FileResponse uploadFile(String bucketId, String fileName, File file, String mimeType) throws B2ApiException {
 		B2GetUploadUrlResponse b2GetUploadUrlResponse = new B2GetUploadUrlRequest(client, b2AuthorizeAccountResponse, bucketId).getResponse();
 		return new B2UploadFileRequest(client, b2AuthorizeAccountResponse, b2GetUploadUrlResponse, fileName, file,
-				Helper.calculateSha1(file), mimeType).getResponse();
+				ChecksumHelper.calculateSha1(file), mimeType).getResponse();
 	}
 
 	/**
@@ -388,7 +388,7 @@ public B2FileResponse uploadFile(String bucketId, String fileName, File file, St
 	public B2FileResponse uploadFile(String bucketId, String fileName, File file) throws B2ApiException {
 		B2GetUploadUrlResponse b2GetUploadUrlResponse = new B2GetUploadUrlRequest(client, b2AuthorizeAccountResponse, bucketId).getResponse();
 		return new B2UploadFileRequest(client, b2AuthorizeAccountResponse, b2GetUploadUrlResponse, fileName,
-				file, Helper.calculateSha1(file)).getResponse();
+				file, ChecksumHelper.calculateSha1(file)).getResponse();
 	}
 
 
diff --git a/src/test/java/synapticloop/b2/helper/B2TestHelper.java b/src/test/java/synapticloop/b2/helper/B2TestHelper.java
index 4d0b1fc..5ed1fcd 100644
--- a/src/test/java/synapticloop/b2/helper/B2TestHelper.java
+++ b/src/test/java/synapticloop/b2/helper/B2TestHelper.java
@@ -1,28 +1,18 @@
 package synapticloop.b2.helper;
 
+import org.apache.http.impl.client.HttpClients;
+import synapticloop.b2.BucketType;
+import synapticloop.b2.exception.B2ApiException;
+import synapticloop.b2.request.*;
+import synapticloop.b2.response.*;
+import synapticloop.b2.util.ChecksumHelper;
+
 import java.io.File;
 import java.io.FileWriter;
 import java.io.IOException;
 import java.util.Map;
 import java.util.UUID;
 
-import org.apache.http.impl.client.HttpClients;
-
-import synapticloop.b2.BucketType;
-import synapticloop.b2.exception.B2ApiException;
-import synapticloop.b2.request.B2AuthorizeAccountRequest;
-import synapticloop.b2.request.B2CreateBucketRequest;
-import synapticloop.b2.request.B2DeleteBucketRequest;
-import synapticloop.b2.request.B2DeleteFileVersionRequest;
-import synapticloop.b2.request.B2GetUploadUrlRequest;
-import synapticloop.b2.request.B2UploadFileRequest;
-import synapticloop.b2.response.B2AuthorizeAccountResponse;
-import synapticloop.b2.response.B2BucketResponse;
-import synapticloop.b2.response.B2DeleteFileVersionResponse;
-import synapticloop.b2.response.B2FileResponse;
-import synapticloop.b2.response.B2GetUploadUrlResponse;
-import synapticloop.b2.util.Helper;
-
 public class B2TestHelper {
 	public static final String B2_BUCKET_PREFIX = "b2api-test-";
 	public static final String B2_ACCOUNT_ID = "B2_ACCOUNT_ID";
@@ -131,7 +121,7 @@ public static B2FileResponse uploadTemporaryFileToBucket(String bucketId) throws
 			throw new B2ApiException("Could not create temporary file", ioex);
 		}
 		return(new B2UploadFileRequest(HttpClients.createDefault(), getB2AuthorizeAccountResponse(),
-				b2GetUploadUrlResponse, file.getName(), file, Helper.calculateSha1(file)).getResponse());
+				b2GetUploadUrlResponse, file.getName(), file, ChecksumHelper.calculateSha1(file)).getResponse());
 	}
 
 //	public static B2FileResponse uploadTemporaryFileToBucketWithPath(String bucketId) throws B2Exception {
@@ -173,7 +163,7 @@ public static B2FileResponse uploadTemporaryFileToBucket(String bucketId, Map<St
 			throw new B2ApiException("Could not create temporary file", ioex);
 		}
 		return(new B2UploadFileRequest(HttpClients.createDefault(), getB2AuthorizeAccountResponse(), b2GetUploadUrlResponse, file.getName(), file,
-				Helper.calculateSha1(file), fileInfo).getResponse());
+				ChecksumHelper.calculateSha1(file), fileInfo).getResponse());
 	}
 
 }
diff --git a/src/test/java/synapticloop/b2/request/B2DownloadFileRequestTest.java b/src/test/java/synapticloop/b2/request/B2DownloadFileRequestTest.java
index 5d33f4c..6229ffb 100644
--- a/src/test/java/synapticloop/b2/request/B2DownloadFileRequestTest.java
+++ b/src/test/java/synapticloop/b2/request/B2DownloadFileRequestTest.java
@@ -1,23 +1,18 @@
 package synapticloop.b2.request;
 
-import static org.junit.Assert.*;
-
-import java.io.File;
-import java.io.FileWriter;
-import java.io.IOException;
-
 import org.apache.commons.io.IOUtils;
 import org.apache.http.impl.client.HttpClients;
 import org.junit.Test;
-
 import synapticloop.b2.exception.B2ApiException;
 import synapticloop.b2.helper.B2TestHelper;
-import synapticloop.b2.response.B2BucketResponse;
-import synapticloop.b2.response.B2DeleteFileVersionResponse;
-import synapticloop.b2.response.B2DownloadFileResponse;
-import synapticloop.b2.response.B2FileResponse;
-import synapticloop.b2.response.B2GetUploadUrlResponse;
-import synapticloop.b2.util.Helper;
+import synapticloop.b2.response.*;
+import synapticloop.b2.util.ChecksumHelper;
+
+import java.io.File;
+import java.io.FileWriter;
+import java.io.IOException;
+
+import static org.junit.Assert.assertEquals;
 
 public class B2DownloadFileRequestTest {
 	private B2BucketResponse randomPrivateBucket = null;
@@ -37,7 +32,7 @@ public void testDownloadByFilePath() throws Exception {
 		B2FileResponse b2UploadFileResponse = new B2UploadFileRequest(HttpClients.createDefault(), 
 				B2TestHelper.getB2AuthorizeAccountResponse(), 
 				b2GetUploadUrlResponse, 
-				testFileName, file, Helper.calculateSha1(file)).getResponse();
+				testFileName, file, ChecksumHelper.calculateSha1(file)).getResponse();
 
 		String fileName = b2UploadFileResponse.getFileName();
 		String fileId = b2UploadFileResponse.getFileId();
diff --git a/src/test/java/synapticloop/b2/request/B2UploadAndDeleteFileRequestTest.java b/src/test/java/synapticloop/b2/request/B2UploadAndDeleteFileRequestTest.java
index 23d2021..b7459be 100644
--- a/src/test/java/synapticloop/b2/request/B2UploadAndDeleteFileRequestTest.java
+++ b/src/test/java/synapticloop/b2/request/B2UploadAndDeleteFileRequestTest.java
@@ -1,21 +1,20 @@
 package synapticloop.b2.request;
 
-import static org.junit.Assert.*;
-
-import java.io.File;
-import java.io.FileWriter;
-import java.util.HashMap;
-import java.util.Map;
-
 import org.apache.http.impl.client.HttpClients;
 import org.junit.Test;
-
 import synapticloop.b2.helper.B2TestHelper;
 import synapticloop.b2.response.B2BucketResponse;
 import synapticloop.b2.response.B2DeleteFileVersionResponse;
 import synapticloop.b2.response.B2FileResponse;
 import synapticloop.b2.response.B2GetUploadUrlResponse;
-import synapticloop.b2.util.Helper;
+import synapticloop.b2.util.ChecksumHelper;
+
+import java.io.File;
+import java.io.FileWriter;
+import java.util.HashMap;
+import java.util.Map;
+
+import static org.junit.Assert.assertEquals;
 
 
 public class B2UploadAndDeleteFileRequestTest {
@@ -31,7 +30,7 @@ public void testFileUpload() throws Exception {
 		fileWriter.close();
 		B2FileResponse b2UploadFileResponse = new B2UploadFileRequest(HttpClients.createDefault(),
 				B2TestHelper.getB2AuthorizeAccountResponse(), b2GetUploadUrlResponse, file.getName(), file,
-				Helper.calculateSha1(file)).getResponse();
+				ChecksumHelper.calculateSha1(file)).getResponse();
 
 		String fileName = b2UploadFileResponse.getFileName();
 		String fileId = b2UploadFileResponse.getFileId();
@@ -60,7 +59,7 @@ public void testFileUploadWithInfo() throws Exception {
 
 		B2FileResponse b2UploadFileResponse = new B2UploadFileRequest(HttpClients.createDefault(),
 				B2TestHelper.getB2AuthorizeAccountResponse(), b2GetUploadUrlResponse, file.getName(), file,
-				Helper.calculateSha1(file), fileInfo).getResponse();
+				ChecksumHelper.calculateSha1(file), fileInfo).getResponse();
 
 		String fileName = b2UploadFileResponse.getFileName();
 		String fileId = b2UploadFileResponse.getFileId();