Fix hashing sum bug for digests

digest.go

@@ -61,7 +61,8 @@ func addDigest(r *http.Request, algo DigestAlgorithm, b []byte) (err error) {
 	if err != nil {
 		return
 	}
-	sum := h.Sum(b)
+	h.Write(b)
+	sum := h.Sum(nil)
 	r.Header.Add(digestHeader,
 		fmt.Sprintf("%s%s%s",
 			a,
@@ -82,7 +83,8 @@ func addDigestResponse(r http.ResponseWriter, algo DigestAlgorithm, b []byte) (e
 	if err != nil {
 		return
 	}
-	sum := h.Sum(b)
+	h.Write(b)
+	sum := h.Sum(nil)
 	r.Header().Add(digestHeader,
 		fmt.Sprintf("%s%s%s",
 			a,
@@ -107,7 +109,8 @@ func verifyDigest(r *http.Request, body *bytes.Buffer) (err error) {
 	if err != nil {
 		return
 	}
-	sum := h.Sum(body.Bytes())
+	h.Write(body.Bytes())
+	sum := h.Sum(nil)
 	encSum := base64.StdEncoding.EncodeToString(sum[:])
 	if encSum != elem[1] {
 		err = fmt.Errorf("cannot verify Digest: header Digest does not match the digest of the request body")

digest_test.go

@@ -23,7 +23,7 @@ func TestAddDigest(t *testing.T) {
 			},
 			algo:           "SHA-256",
 			body:           []byte("johnny grab your gun"),
-			expectedDigest: "SHA-256=am9obm55IGdyYWIgeW91ciBndW7jsMRCmPwcFJr79MiZb7kkJ65B5GSbk0yklZkbeFK4VQ==",
+			expectedDigest: "SHA-256=RYiuVuVdRpU+BWcNUUg3sf0EbJjQ9LDj9tUqR546hhk=",
 		},
 		{
 			name: "adds sha512 digest",
@@ -33,7 +33,7 @@ func TestAddDigest(t *testing.T) {
 			},
 			algo:           "SHA-512",
 			body:           []byte("yours is the drill that will pierce the heavens"),
-			expectedDigest: "SHA-512=eW91cnMgaXMgdGhlIGRyaWxsIHRoYXQgd2lsbCBwaWVyY2UgdGhlIGhlYXZlbnPPg+E1fu+4vfFUKFDWbYAH1iDkBQtXFdyD9Kkh02zpzkfQ0TxdhfKw/4MY0od+7C9juTG9R0F6gaU4Mnr5J9o+",
+			expectedDigest: "SHA-512=bM0eBRnZkuiOTsejYNb/UpvFozde+Do1ZqlXfRTS39aGmoEzoXBpjmIIuznPslc3kaprUtI/VXH8/5HsD+thGg==",
 		},
 		{
 			name: "digest already set",
@@ -90,7 +90,7 @@ func TestVerifyDigest(t *testing.T) {
 			name: "verify sha256",
 			r: func() *http.Request {
 				r, _ := http.NewRequest("POST", "example.com", nil)
-				r.Header.Set("Digest", "SHA-256=am9obm55IGdyYWIgeW91ciBndW7jsMRCmPwcFJr79MiZb7kkJ65B5GSbk0yklZkbeFK4VQ==")
+				r.Header.Set("Digest", "SHA-256=RYiuVuVdRpU+BWcNUUg3sf0EbJjQ9LDj9tUqR546hhk=")
 				return r
 			},
 			body: []byte("johnny grab your gun"),
@@ -99,7 +99,7 @@ func TestVerifyDigest(t *testing.T) {
 			name: "verify sha512",
 			r: func() *http.Request {
 				r, _ := http.NewRequest("POST", "example.com", nil)
-				r.Header.Set("Digest", "SHA-512=eW91cnMgaXMgdGhlIGRyaWxsIHRoYXQgd2lsbCBwaWVyY2UgdGhlIGhlYXZlbnPPg+E1fu+4vfFUKFDWbYAH1iDkBQtXFdyD9Kkh02zpzkfQ0TxdhfKw/4MY0od+7C9juTG9R0F6gaU4Mnr5J9o+")
+				r.Header.Set("Digest", "SHA-512=bM0eBRnZkuiOTsejYNb/UpvFozde+Do1ZqlXfRTS39aGmoEzoXBpjmIIuznPslc3kaprUtI/VXH8/5HsD+thGg==")
 				return r
 			},
 			body: []byte("yours is the drill that will pierce the heavens"),

httpsig_test.go

@@ -84,7 +84,7 @@ func init() {
 			pubKey:            privKey.Public(),
 			pubKeyId:          "pubKeyId",
 			expectedAlgorithm: RSA_SHA512,
-			expectedDigest:    "SHA-256=TGFzdCBuaWdodCBhcyBJIGxheSBkcmVhbWluZyBUaGlzIHN0cmFuZ2VzdCBraW5kIG9mIGZlZWxpbmcgUmV2ZWFsZWQgaXRzIHNlY3JldCBtZWFuaW5nIEFuZCBub3cgSSBrbm93Li4u47DEQpj8HBSa+/TImW+5JCeuQeRkm5NMpJWZG3hSuFU=",
+			expectedDigest:    "SHA-256=07PJQngqg8+BlomdI6zM7ieOxhINWI+iivJxBDSm3Dg=",
 		},
 		{
 			name:              "hmac signature",
@@ -108,7 +108,7 @@ func init() {
 			pubKey:            macKey,
 			pubKeyId:          "pubKeyId",
 			expectedAlgorithm: HMAC_SHA256,
-			expectedDigest:    "SHA-256=SSd2ZSBuZXZlciBldmVyIGJlZW4gdG8gcGFyYWRpc2UgSSd2ZSBuZXZlciBldmVyIHNlZW4gbm8gYW5nZWwncyBleWVzIFlvdSdsbCBuZXZlciBldmVyIGxldCB0aGlzIG1hZ2ljIGRpZSBObyBtYXR0ZXIgd2hlcmUgeW91IGFyZSwgeW91IGFyZSBteSBsdWNreSBzdGFyLuOwxEKY/BwUmvv0yJlvuSQnrkHkZJuTTKSVmRt4UrhV",
+			expectedDigest:    "SHA-256=d0JoDjbDZRZF7/gUdgrazZCdKCJ9z9uUcMd6n1YKWRU=",
 		},
 		{
 			name:              "rsa authorization",