HOTP {otp}

HMAC based One Time Password (HOTP)

Description

An R6 class that implements the HMAC based One Time Password (HOTP) algorithm.

Initialization

HOTP$new(secret, digits = 6L, algorithm = "sha1")

Create an One Time Password object

• secret a scalar character, the base32-based secret key.

• digits an integer, the number of digits of the password.

• algorithm the hash algorithm used, possible values are "sha1", "sha256" and "sha512".

Methods

HOTP$at(counter)

Generate an one time password at counter value.

• counter a non-negative integer.

HOTP$verify(code, counter, ahead = 0L)

Verify if a given one time password is valid. Returns the matching counter value if there is a match within the ahead window. Otherwise return NULL.

• code a string of digits.

• counter a non-negative integer.

• ahead a non-negative integer, the amount of counter ticks to look ahead.

HOTP$provisioning_uri(name, issuer = NULL, counter = 0L)

Return a provisioning uri which is compatible with google authenticator format.

• name account name.

• issuer issuer name.

• counter a non-negative integer, initial counter.

See Also

https://datatracker.ietf.org/doc/html/rfc4226

Examples

p <- HOTP$new("JBSWY3DPEHPK3PXP")
p$at(8)

p$verify("964230", 8)
p$verify("964230", 7, ahead = 3)

p$provisioning_uri("Alice", issuer = "example.com", counter = 5)