Time-based One-time Password (TOTP)

updated: 2023-04-14 08:07

Time-based One-time Password (TOTP)

Configuring TOTP

TOTP is not enabled in Keystone by default. To enable it add the totp authentication method to the [auth] section in keystone.conf:

[auth]
methods = external,password,token,oauth1,totp

For a user to have access to TOTP, he must have configured TOTP credentials in Keystone and a TOTP device (i.e. Google Authenticator).

TOTP uses a base32 encoded string for the secret. The secret must be at least 128 bits (16 bytes). The following python code can be used to generate a TOTP secret:

import base64
message = b'1234567890123456'
print(base64.b32encode(message).rstrip(b'='))

Example output:

GEZDGNBVGY3TQOJQGEZDGNBVGY

This generated secret can then be used to add new ‘totp’ credentials to a specific user.

Create a TOTP credential

Create totp credentials for user:

USER_ID=b7793000f8d84c79af4e215e9da78654
SECRET=GEZDGNBVGY3TQOJQGEZDGNBVGY

curl -i \
  -H "Content-Type: application/json" \
  -d '
{
    "credential": {
        "blob": "'$SECRET'",
        "type": "totp",
        "user_id": "'$USER_ID'"
    }
}' \
  http://localhost:5000/v3/credentials ; echo

Google Authenticator

On a device install Google Authenticator and inside the app click on ‘Set up account’ and then click on ‘Enter provided key’. In the input fields enter account name and secret. Optionally a QR code can be generated programmatically to avoid having to type the information.

QR code

Create TOTP QR code for device:

import qrcode

secret='GEZDGNBVGY3TQOJQGEZDGNBVGY'
uri = 'otpauth://totp/{name}?secret={secret}&issuer={issuer}'.format(
    name='name',
    secret=secret,
    issuer='Keystone')

img = qrcode.make(uri)
img.save('totp.png')

In Google Authenticator app click on ‘Set up account’ and then click on ‘Scan a barcode’, and then scan the ‘totp.png’ image. This should create a new TOTP entry in the application.

Authenticate with TOTP

Google Authenticator will generate a 6 digit PIN (passcode) every few seconds. Use the passcode and your user ID to authenticate using the totp method.

Tokens

Get a token with default scope (may be unscoped) using totp:

USER_ID=b7793000f8d84c79af4e215e9da78654
PASSCODE=012345

curl -i \
  -H "Content-Type: application/json" \
  -d '
{ "auth": {
        "identity": {
            "methods": [
                "totp"
            ],
            "totp": {
                "user": {
                    "id": "'$USER_ID'",
                    "passcode": "'$PASSCODE'"
                }
            }
        }
    }
}' \
  http://localhost:5000/v3/auth/tokens ; echo
updated: 2023-04-14 08:07
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