HOTP and TOTP-SHA-1 working.

why the frak aren't the SHA-256 and SHA-512 variants working

hotp.go

@@ -3,6 +3,10 @@ package twofactor
 import (
 	"crypto"
 	"crypto/sha1"
+	"encoding/base32"
+	"io"
+	"net/url"
+	"strconv"
 )
 
 type HOTP struct {
@@ -38,3 +42,50 @@ func (otp *HOTP) URL(label string) string {
 func (otp *HOTP) SetProvider(provider string) {
 	otp.provider = provider
 }
+
+func GenerateGoogleHOTP() *HOTP {
+	key := make([]byte, sha1.Size)
+	if _, err := io.ReadFull(PRNG, key); err != nil {
+		return nil
+	}
+	return NewHOTP(key, 0, 6)
+}
+
+func hotpFromURL(u *url.URL) (*HOTP, string, error) {
+	label := u.Path[1:]
+	v := u.Query()
+
+	secret := v.Get("secret")
+	if secret == "" {
+		return nil, "", ErrInvalidURL
+	}
+
+	var digits = 6
+	if sdigit := v.Get("digits"); sdigit != "" {
+		tmpDigits, err := strconv.ParseInt(sdigit, 10, 8)
+		if err != nil {
+			return nil, "", err
+		}
+		digits = int(tmpDigits)
+	}
+
+	var counter uint64 = 0
+	if scounter := v.Get("counter"); scounter != "" {
+		var err error
+		counter, err = strconv.ParseUint(scounter, 10, 64)
+		if err != nil {
+			return nil, "", err
+		}
+	}
+
+	key, err := base32.StdEncoding.DecodeString(secret)
+	if err != nil {
+		return nil, "", err
+	}
+	otp := NewHOTP(key, counter, digits)
+	return otp, label, nil
+}
+
+func (otp *HOTP) QR(label string) ([]byte, error) {
+	return otp.oath.QR(otp.Type(), label)
+}