diff --git a/cmd/signature-v4.go b/cmd/signature-v4.go
index b66bdc9b9..007a66922 100644
--- a/cmd/signature-v4.go
+++ b/cmd/signature-v4.go
@@ -289,7 +289,7 @@ func doesPresignedSignatureMatch(hashedPayload string, r *http.Request, region s
 	/// Verify finally if signature is same.
 
 	// Get canonical request.
-	presignedCanonicalReq := getCanonicalRequest(extractedSignedHeaders, unsignedPayload, encodedQuery, req.URL.Path, req.Method)
+	presignedCanonicalReq := getCanonicalRequest(extractedSignedHeaders, hashedPayload, encodedQuery, req.URL.Path, req.Method)
 
 	// Get string to sign from canonical request.
 	presignedStringToSign := getStringToSign(presignedCanonicalReq, t, pSignValues.Credential.getScope())
diff --git a/pkg/hash/reader.go b/pkg/hash/reader.go
index a38ea6e42..c0b569db3 100644
--- a/pkg/hash/reader.go
+++ b/pkg/hash/reader.go
@@ -26,6 +26,8 @@ import (
 	"io"
 )
 
+var errNestedReader = errors.New("Nesting of Reader detected, not allowed")
+
 // Reader writes what it reads from an io.Reader to an MD5 and SHA256 hash.Hash.
 // Reader verifies that the content of the io.Reader matches the expected checksums.
 type Reader struct {
@@ -40,17 +42,17 @@ type Reader struct {
 // SHA256 sum (if set) of the provided io.Reader at EOF.
 func NewReader(src io.Reader, size int64, md5Hex, sha256Hex string) (*Reader, error) {
 	if _, ok := src.(*Reader); ok {
-		return nil, errors.New("Nesting of Reader detected, not allowed")
+		return nil, errNestedReader
 	}
 
 	sha256sum, err := hex.DecodeString(sha256Hex)
 	if err != nil {
-		return nil, err
+		return nil, SHA256Mismatch{}
 	}
 
 	md5sum, err := hex.DecodeString(md5Hex)
 	if err != nil {
-		return nil, err
+		return nil, BadDigest{}
 	}
 
 	var sha256Hash hash.Hash
diff --git a/pkg/hash/reader_test.go b/pkg/hash/reader_test.go
index 8d53a6227..40e5018a1 100644
--- a/pkg/hash/reader_test.go
+++ b/pkg/hash/reader_test.go
@@ -114,26 +114,30 @@ func TestHashReaderInvalidArguments(t *testing.T) {
 		size              int64
 		md5hex, sha256hex string
 		success           bool
+		expectedErr       error
 	}{
 		// Invalid md5sum NewReader() will fail.
 		{
-			src:     bytes.NewReader([]byte("abcd")),
-			size:    4,
-			md5hex:  "invalid-md5",
-			success: false,
+			src:         bytes.NewReader([]byte("abcd")),
+			size:        4,
+			md5hex:      "invalid-md5",
+			success:     false,
+			expectedErr: BadDigest{},
 		},
 		// Invalid sha256 NewReader() will fail.
 		{
-			src:       bytes.NewReader([]byte("abcd")),
-			size:      4,
-			sha256hex: "invalid-sha256",
-			success:   false,
+			src:         bytes.NewReader([]byte("abcd")),
+			size:        4,
+			sha256hex:   "invalid-sha256",
+			success:     false,
+			expectedErr: SHA256Mismatch{},
 		},
 		// Nested hash reader NewReader() will fail.
 		{
-			src:     &Reader{src: bytes.NewReader([]byte("abcd"))},
-			size:    4,
-			success: false,
+			src:         &Reader{src: bytes.NewReader([]byte("abcd"))},
+			size:        4,
+			success:     false,
+			expectedErr: errNestedReader,
 		},
 		// Expected inputs, NewReader() will succeed.
 		{
@@ -151,5 +155,8 @@ func TestHashReaderInvalidArguments(t *testing.T) {
 		if err == nil && !testCase.success {
 			t.Errorf("Test %d: Expected error, but got success", i+1)
 		}
+		if err != testCase.expectedErr {
+			t.Errorf("Test %d: Expected error %v, but got %v", i+1, testCase.expectedErr, err)
+		}
 	}
 }