OathType

public enum OathType : String, CaseIterable, Codable, Sendable

Enum representing the different types of OATH credentials.

OATH (Open Authentication) supports two main types of one-time password algorithms:

  • TOTP (Time-based One-Time Password): Generates codes based on the current time
  • HOTP (HMAC-based One-Time Password): Generates codes based on a counter value

Standards Compliance

Both algorithms are standardized in RFC specifications and widely supported by authentication systems and mobile authenticator applications.

  • TOTP: Implements RFC 6238 (TOTP: Time-Based One-Time Password Algorithm)
  • HOTP: Implements RFC 4226 (HOTP: An HMAC-Based One-Time Password Algorithm)

  • Time-based One-Time Password algorithm (RFC 6238).

    TOTP generates codes that are valid for a specific time window (typically 30 seconds). The algorithm combines the current time with a shared secret to produce a unique code.

    Characteristics:

    • Codes automatically expire after the time period
    • No counter synchronization required
    • Resistant to replay attacks

    Requires

    Requires accurate time synchronization between client and server

    Declaration

    Swift

    case totp = "totp"

  • HMAC-based One-Time Password algorithm (RFC 4226).

    HOTP generates codes based on a counter value that increments with each use. The algorithm combines the counter with a shared secret to produce a unique code.

    Characteristics:

    • Codes remain valid until used or explicitly invalidated

    Requires

    Requires counter synchronization between client and server
    • No time dependency
    • Vulnerable to replay attacks if not properly managed

    Declaration

    Swift

    case hotp = "hotp"

  • Creates an OathType from a string representation.

    Throws

    OathError.invalidOathType if the string doesn’t match any known type.

    Declaration

    Swift

    public static func fromString(_ string: String) throws -> OathType

    Parameters

    string

    The string representation (case-insensitive).

    Return Value

    The corresponding OathType.