diff --git a/bitfinexhttp.go b/bitfinexhttp.go
index cc90dc24..df855040 100644
--- a/bitfinexhttp.go
+++ b/bitfinexhttp.go
@@ -4,7 +4,6 @@ import (
 	"fmt"
 	"log"
 	"encoding/json"
-	"crypto/sha512"
 	"errors"
 	"strings"
 	"strconv"
@@ -257,7 +256,7 @@ func (b *Bitfinex) SendAuthenticatedHTTPRequest(method, path string, params map[
 	}
 
 	PayloadBase64 := Base64Encode(PayloadJson)
-	hmac := GetHMAC(sha512.New384, []byte(PayloadBase64), []byte(b.APISecret))
+	hmac := GetHMAC(HASH_SHA512_384, []byte(PayloadBase64), []byte(b.APISecret))
 	headers := make(map[string]string)
 	headers["X-BFX-APIKEY"] = b.APIKey
 	headers["X-BFX-PAYLOAD"] = PayloadBase64
diff --git a/bitstamphttp.go b/bitstamphttp.go
index 682ec1dc..e94264d7 100644
--- a/bitstamphttp.go
+++ b/bitstamphttp.go
@@ -4,7 +4,6 @@ import (
 	"net/url"
 	"log"
 	"encoding/json"
-	"crypto/sha256"
 	"strings"
 	"strconv"
 	"errors"
@@ -268,7 +267,7 @@ func (b *Bitstamp) SendAuthenticatedHTTPRequest(path string, values url.Values,
 	nonce := strconv.FormatInt(time.Now().UnixNano(), 10)
 	values.Set("key", b.APIKey)
 	values.Set("nonce", nonce)
-	hmac := GetHMAC(sha256.New, []byte(nonce + b.ClientID + b.APIKey), []byte(b.APISecret))
+	hmac := GetHMAC(HASH_SHA256, []byte(nonce + b.ClientID + b.APIKey), []byte(b.APISecret))
 	values.Set("signature", strings.ToUpper(HexEncodeToString(hmac)))
 	path = BITSTAMP_API_URL + path
 
diff --git a/btcchinahttp.go b/btcchinahttp.go
index 1a09bdf8..b9ad6ae6 100644
--- a/btcchinahttp.go
+++ b/btcchinahttp.go
@@ -3,7 +3,6 @@ package main
 import (
 	"net/url"
 	"strconv"
-	"crypto/sha1"
 	"encoding/json"
 	"errors"
 	"strings"
@@ -676,7 +675,7 @@ func (b *BTCChina) SendAuthenticatedHTTPRequest(method string, params []interfac
 		log.Println(encoded)
 	}
 
-	hmac := GetHMAC(sha1.New, []byte(encoded), []byte(b.APISecret))
+	hmac := GetHMAC(HASH_SHA1, []byte(encoded), []byte(b.APISecret))
 	postData := make(map[string]interface{})
 	postData["method"] = method
 	postData["params"] = params
diff --git a/btcehttp.go b/btcehttp.go
index 98554eb9..d853d194 100644
--- a/btcehttp.go
+++ b/btcehttp.go
@@ -3,7 +3,6 @@ package main
 import (
 	"net/url"
 	"strconv"
-	"crypto/sha512"
 	"strings"
 	"time"
 	"fmt"
@@ -234,7 +233,7 @@ func (b *BTCE) SendAuthenticatedHTTPRequest(method string, values url.Values) (e
 	values.Set("method", method)
 
 	encoded := values.Encode()
-	hmac := GetHMAC(sha512.New, []byte(encoded), []byte(b.APISecret))
+	hmac := GetHMAC(HASH_SHA512, []byte(encoded), []byte(b.APISecret))
 
 	if b.Verbose {
 		log.Printf("Sending POST request to %s calling method %s with params %s\n", BTCE_API_PRIVATE_URL, method, encoded)
diff --git a/btcmarkets.go b/btcmarkets.go
index 78782d15..9474b764 100644
--- a/btcmarkets.go
+++ b/btcmarkets.go
@@ -2,7 +2,6 @@ package main
 
 import (
 	"strconv"
-	"crypto/sha512"
 	"strings"
 	"time"
 	"log"
@@ -101,7 +100,7 @@ func (b *BTCMarkets) SendAuthenticatedRequest(reqType, path, data string) (error
 		request = path + "\n" + nonce + "\n"
 	}
 
-	hmac := GetHMAC(sha512.New, []byte(request), []byte(b.APISecret))
+	hmac := GetHMAC(HASH_SHA512, []byte(request), []byte(b.APISecret))
 
 	if b.Verbose {
 		log.Printf("Sending %s request to %s path %s with params %s\n", reqType, BTCMARKETS_API_URL + path, path, request)
diff --git a/common.go b/common.go
index ad3a7ae7..5f4d7ab7 100644
--- a/common.go
+++ b/common.go
@@ -5,6 +5,7 @@ import (
 	"hash"
 	"crypto/md5"
 	"crypto/hmac"
+	"crypto/sha1"
 	"crypto/sha512"
 	"crypto/sha256"
 	"encoding/base64"
@@ -18,6 +19,13 @@ import (
 	"log"
 )
 
+const (
+	HASH_SHA1 = iota
+	HASH_SHA256
+	HASH_SHA512
+	HASH_SHA512_384
+)
+
 func GetMD5(input []byte) ([]byte) {
 	hash := md5.New()
 	hash.Write(input)
@@ -36,7 +44,24 @@ func GetSHA256(input []byte) ([]byte) {
 	return sha.Sum(nil)
 }
 
-func GetHMAC(hash func() hash.Hash, input, key []byte) ([]byte) {
+func GetHMAC(hashType int, input, key []byte) ([]byte) {
+	var hash func() hash.Hash
+
+	switch hashType {
+		case HASH_SHA1: {
+			hash = sha1.New
+		}
+		case HASH_SHA256: {
+			hash = sha256.New
+		}
+		case HASH_SHA512: {
+			hash = sha512.New
+		}
+		case HASH_SHA512_384: {
+			hash = sha512.New384
+		}
+	}
+
 	hmac := hmac.New(hash, []byte(key))
 	hmac.Write(input)
 	return hmac.Sum(nil)
diff --git a/itbithttp.go b/itbithttp.go
index 05dd5eed..dacfbcbb 100644
--- a/itbithttp.go
+++ b/itbithttp.go
@@ -3,7 +3,6 @@ package main
 import (
 	"net/http"
 	"strconv"
-	"crypto/sha512"
 	"errors"
 	"strings"
 	"time"
@@ -268,7 +267,7 @@ func (i *ItBit) SendAuthenticatedHTTPRequest(method string, path string, params
 		log.Printf("Request JSON: %s\n", PayloadJson)
 	}
 
-	hmac := GetHMAC(sha512.New, []byte(nonce + string(PayloadJson)), []byte(i.APISecret))
+	hmac := GetHMAC(HASH_SHA512, []byte(nonce + string(PayloadJson)), []byte(i.APISecret))
 	signature := Base64Encode([]byte(HexEncodeToString(hmac)))
 
 	headers := make(map[string]string)
diff --git a/kraken.go b/kraken.go
index d3732f1b..01aea4a7 100644
--- a/kraken.go
+++ b/kraken.go
@@ -5,7 +5,6 @@ import (
 	"fmt"
 	"strconv"
 	"encoding/json"
-	"crypto/sha512"
 	"errors"
 	"time"
 	"strings"
@@ -503,7 +502,7 @@ func (k *Kraken) SendAuthenticatedHTTPRequest(method string, values url.Values)
 	}
 
 	shasum := GetSHA256([]byte(values.Get("nonce") + values.Encode()))
-	signature := Base64Encode(GetHMAC(sha512.New, append([]byte(path), shasum...), secret))
+	signature := Base64Encode(GetHMAC(HASH_SHA512, append([]byte(path), shasum...), secret))
 
 	if k.Verbose {
 		log.Printf("Sending POST request to %s, path: %s.", KRAKEN_API_URL, path)
diff --git a/lakebtchttp.go b/lakebtchttp.go
index 33cec4e8..3cb78962 100644
--- a/lakebtchttp.go
+++ b/lakebtchttp.go
@@ -3,7 +3,6 @@ package main
 import (
 	"net/url"
 	"strconv"
-	"crypto/sha256"
 	"errors"
 	"strings"
 	"time"
@@ -174,7 +173,7 @@ func (l *LakeBTC) SendAuthenticatedHTTPRequest(method, params string) (err error
 	v.Set("params", params)
 
 	encoded := v.Encode()
-	hmac := GetHMAC(sha256.New, []byte(encoded), []byte(l.APISecret))
+	hmac := GetHMAC(HASH_SHA256, []byte(encoded), []byte(l.APISecret))
 
 	if l.Verbose {
 		log.Printf("Sending POST request to %s calling method %s with params %s\n", LAKEBTC_API_URL, method, encoded)