/
generator.go
58 lines (48 loc) · 1.31 KB
/
generator.go
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// Copyright © 2023 Ory Corp
// SPDX-License-Identifier: Apache-2.0
package totp
import (
"bytes"
"context"
"encoding/base64"
"image/png"
"github.com/pkg/errors"
"github.com/pquerna/otp"
stdtotp "github.com/pquerna/otp/totp"
"github.com/ory/kratos/driver/config"
)
// rfc4226 recommends:
//
// The algorithm MUST use a strong shared secret. The length of
// the shared secret MUST be at least 128 bits. This document
// RECOMMENDs a shared secret length of 160 bits.
//
// So we need 160/8 = 20 key length. stdtotp.Generate uses the key
// length for reading from crypto.Rand.
const secretSize = 160 / 8
func NewKey(ctx context.Context, accountName string, d interface {
config.Provider
}) (*otp.Key, error) {
key, err := stdtotp.Generate(stdtotp.GenerateOpts{
Issuer: d.Config().TOTPIssuer(ctx),
AccountName: accountName,
SecretSize: secretSize,
Digits: otp.DigitsSix,
Period: 30,
})
if err != nil {
return nil, errors.WithStack(err)
}
return key, err
}
func KeyToHTMLImage(key *otp.Key) (string, error) {
var buf bytes.Buffer
img, err := key.Image(256, 256)
if err != nil {
return "", errors.WithStack(err)
}
if err := png.Encode(&buf, img); err != nil {
return "", errors.WithStack(err)
}
return "data:image/png;base64," + base64.StdEncoding.EncodeToString(buf.Bytes()), nil
}