Initial import.

Basic HOTP functionality.

hotp.go

@@ -0,0 +1,40 @@
+package twofactor
+
+import (
+	"crypto"
+	"crypto/sha1"
+)
+
+type HOTP struct {
+	*oath
+}
+
+func (otp *HOTP) Type() Type {
+	return OATH_HOTP
+}
+
+func NewHOTP(key []byte, counter uint64, digits int) *HOTP {
+	return &HOTP{
+		oath: &oath{
+			key:     key,
+			counter: counter,
+			size:    digits,
+			hash:    sha1.New,
+			algo:    crypto.SHA1,
+		},
+	}
+}
+
+func (otp *HOTP) OTP() string {
+	code := otp.oath.OTP(otp.counter)
+	otp.counter++
+	return code
+}
+
+func (otp *HOTP) URL(label string) string {
+	return otp.oath.URL(otp.Type(), label)
+}
+
+func (otp *HOTP) SetProvider(provider string) {
+	otp.provider = provider
+}