A library for generating and verifying one-time passwords (OTP). nauthy library implements counter-based OTP (RFC4226) and time-based OTP (RFC6238). Various hash modes are supported: MD5, SHA1, SHA256 and SHA512 as well as custom hash functions.

Basic usage

Some examples to get started:

import nauthy

# Construct a new TOTP with a base-32 encoded key.
var totp = initTotp("HXDMVJECJJWSRB3HWIZR4IFUGFTMXBOZ")
# Print out the current totp value
echo totp.now()

# Construct a new TOTP from a URI.
var otp = otpFromUri(
 "otpauth://totp/ACME%20Co:john@example.com?secret=HXDMVJECJJWSRB3HWIZR4IFUGFTMXBOZ&issuer=ACME%20Co"
)
echo otp.totp.now()

# Build a URI from a TOTP
totp.uri = newUri("Example issuer", "accountname@example.com")
echo totp.buildUri()

Types

Bytes = seq[byte]: Source Edit
HashFunc = tuple[hash: proc (input: Bytes): Bytes {...}{.nimcall.}, blockSize: int, name: string]: Source Edit
Algorithm = enum MD5, SHA1, SHA256, SHA512: Source Edit
OtpValueLen = range[6 .. 10]: Source Edit
TimeInterval = range[1 .. int.high]: Source Edit
EpochSecond = BiggestUInt: Source Edit
OtpType = enum HotpT = "hotp", TotpT = "totp": Source Edit
Uri = ref object issuer: string accountname: string: Source Edit
Hotp = tuple[key: Bytes, length: OtpValueLen, hashFunc: HashFunc, initialCounter: int, uri: Uri]: Source Edit
Totp = tuple[key: Bytes, length: OtpValueLen, interval: TimeInterval, hashFunc: HashFunc, t0: EpochSecond, uri: Uri]: Source Edit
Otp = ref object case otpType*: OtpType of HotpT: hotp*: Hotp of TotpT: totp*: Totp: Source Edit

Lets

sha1Hash: HashFunc = (hash: sha1Digest, blockSize: 64, name: "SHA1"): Source Edit
md5Hash: HashFunc = (hash: md5Digest, blockSize: 64, name: "MD5"): Source Edit
sha256Hash: HashFunc = (hash: sha256Digest, blockSize: 64, name: "SHA256"): Source Edit
sha512Hash: HashFunc = (hash: sha512Digest, blockSize: 128, name: "SHA512"): Source Edit

Procs

proc `$`(u: Uri): string {...}{.raises: [ValueError], tags: [].}

Source Edit

proc initHotp(key: string | Bytes; b32Decode: bool = false; length: OtpValueLen = 6; hashFunc: HashFunc = sha1Hash): Hotp

Constructs a new HOTP. sha1Hash is the default but other hash modes are also available: md5Hash, sha256Hash and sha512Hash. Custom hash functions are also accepted. If the given key is base32-encoded, give the b32Decode argument as true. Source Edit

proc initTotp(key: string | Bytes; b32Decode: bool = true; length: OtpValueLen = 6; interval: TimeInterval = 30; hashFunc: HashFunc = sha1Hash; t0: EpochSecond = 0): Totp

Constructs a new TOTP. sha1Hash is the default but other hash modes are also available: md5Hash, sha256Hash and sha512Hash. Custom hash functions are also accepted. If the given key is base32-encoded, give the b32Decode argument as true. Source Edit

proc newUri(issuer: string; accountname: string): Uri {...}{.raises: [], tags: [].}

Constructs a new URI. Source Edit

proc getName(uri: Uri): string {...}{.raises: [], tags: [].}

Extract account name from a URI. Source Edit

proc getIssuer(uri: Uri): string {...}{.raises: [], tags: [].}

Extract issuer from a URI. Source Edit

proc otpFromUri(uri: string): Otp {...}{.raises: [ValueError, KeyError, CatchableError], tags: [].}

Initialize HOTP/TOTP from a URI.

Example:

let otp = otpFromUri(
  "otpauth://totp/ACME:john@dot.com?secret=HXDMVJECJJWSRB3HWIZR4IFUGFTMXBOZ&issuer=ACME"
  )
var totp = otp.totp
echo totp.now()

Source Edit

proc buildUri(hotp: Hotp): string {...}{.raises: [], tags: [].}

Build URI from HOTP. Source Edit

proc buildUri(totp: Totp): string {...}{.raises: [], tags: [].}

Build URI from TOTP. Source Edit

proc `$`(hotp: Hotp): string {...}{.raises: [], tags: [].}

This is the same as hotp.buildUri(). Source Edit

proc `$`(totp: Totp): string {...}{.raises: [], tags: [].}

This is the same as totp.buildUri(). Source Edit

proc at(hotp: Hotp; counter: SomeInteger): string

Get HOTP value at counter. Source Edit

proc at(totp: Totp; utime: EpochSecond): string {...}{.raises: [Exception], tags: [RootEffect].}

Get TOTP value at time utime. Source Edit

proc now(totp: Totp): string {...}{.raises: [Exception], tags: [RootEffect, TimeEffect].}

Get TOTP value at current time. Source Edit

proc verify(hotp: Hotp; value: string; counter: SomeInteger): bool

Verify that the given HOTP value is correct. Source Edit

proc verify(totp: Totp; value: string; now: EpochSecond = currentTime()): bool {...}{. raises: [Exception], tags: [RootEffect].}

Verify that the given TOTP value is correct. Source Edit

proc randomBase32(): string {...}{.raises: [], tags: [TimeEffect].}

Generates a random 16-characters Base-32 encoded string. Compatible with other OTP apps such as Google Authenticator and Authy. Source Edit