Documentation ¶
Overview ¶
Package totp implement Time-Based One-Time Password Algorithm based on RFC 6238 [1].
Index ¶
Examples ¶
Constants ¶
const ( // DefCodeDigits default digits generated when verifying or generating // OTP. DefCodeDigits = 6 DefTimeStep = 30 // DefStepsBack maximum value for stepsBack parameter on Verify. // The value 20 means the Verify() method will check maximum 20 TOTP // tokens or 10 minutes to the past. DefStepsBack = 20 )
Variables ¶
This section is empty.
Functions ¶
This section is empty.
Types ¶
type Protocol ¶
type Protocol struct {
// contains filtered or unexported fields
}
Protocol contain methods to work with TOTP using the number of digits and time steps defined from New().
func New ¶
New create TOTP protocol for prover or verifier using "fnHash" as the hmac-sha hash function, "codeDigits" as the number of digits to be generated and/or verified, and "timeStep" as the time divisor.
func (*Protocol) GenerateN ¶ added in v0.22.0
GenerateN generate n number of passwords from (current time - N*timeStep) until the curent time.
func (*Protocol) Verify ¶
Verify the token based on the prover secret key. It will return true if the token matched, otherwise it will return false.
The stepsBack parameter define number of steps in the pass to be checked for valid OTP. For example, if stepsBack = 2 and timeStep = 30, the time range to checking OTP is in between
(current_timestamp - (2*30)) ... current_timestamp
For security reason, the maximum stepsBack is limited to DefStepsBack.
Example ¶
secretHex := "3132333435363738393031323334353637383930" secret, err := hex.DecodeString(secretHex) if err != nil { log.Fatal(err) } p := New(sha1.New, DefCodeDigits, DefTimeStep) otp, _ := p.Generate(secret) if p.Verify(secret, otp, 1) { fmt.Printf("Generated token is valid.\n") } else { fmt.Printf("Generated token is not valid.\n") }
Output: Generated token is valid.