|
+3.1.4.1 Single-Factor OTP Authenticators |
3.1.4.1 Single-Factor OTP AuthenticatorsSingle-factor OTP authenticators and verifiers contain two persistent values: 1) a symmetric key that persists for the authenticator’s lifetime and 2) a nonce that is either changed each time the authenticator is used or is based on a real-time clock. The secret key and its algorithm SHALL provide at least the minimum security strength specified in the latest revision of [SP800-131A] (i.e., 112 bits as of the date of this publication). The nonce SHALL be of sufficient length to ensure that it is unique for each operation of the authenticator over its lifetime. If a subscriber needs to change the device on which a software-based OTP authenticator resides, they SHOULD bind the authenticator application on the new device to their subscriber account, as described in Sec. 4.1.2, and invalidate the authenticator application that will no longer be used. Alternatively, the subscriber MAY export the secret key and store it in a sync fabric that meets the requirements in Appendix B.2 and then retrieve the key with their new device. The authenticator output is obtained using an approved block cipher or hash function to securely combine the key and nonce. In coordination with the verifier, the authenticator MAY truncate its output to as few as six decimal digits (or an equivalent representation). If the nonce used to generate the authenticator output is based on a real-time clock, the nonce SHALL be changed at least once every two minutes. 1. Přehled
1.1 Odkazy1.2 Identifikované požadavky1.3 Související regulace2. Identifikované požadavky
3. Související regulace
|