Data.OTP

Implements HMAC-Based One-Time Password Algorithm as defined in RFC 4226 and Time-Based One-Time Password Algorithm as defined in RFC 6238.

HOTP

hotp

Arguments

:: HashAlgorithm a

=> a

Hashing algorithm from module Crypto.Hash

-> ByteString

Shared secret

-> Word64

Counter value

-> Word

Number of digits in a password

-> Word32

HOTP

Compute HOTP using secret key and counter value.

>>> hotp SHA1 "1234" 100 6
317569

>>> hotp SHA512 "1234" 100 6
134131

>>> hotp SHA512 "1234" 100 8
55134131

hotpCheck

Arguments

:: HashAlgorithm a

=> a

Hashing algorithm

-> ByteString

Shared secret

-> (Word64, Word64)

Valid counter range, before and after ideal

-> Word64

Ideal (expected) counter value

-> Word

Number of digits in a password

-> Word32

Password entered by user

-> Bool

True if password is valid

Check presented password against a valid range.

>>> hotp SHA1 "1234" 10 6
50897

>>> hotpCheck SHA1 "1234" (0,0) 10 6 50897
True

>>> hotpCheck SHA1 "1234" (0,0) 9 6 50897
False

>>> hotpCheck SHA1 "1234" (0,1) 9 6 50897
True

>>> hotpCheck SHA1 "1234" (1,0) 11 6 50897
True

>>> hotpCheck SHA1 "1234" (2,2) 8 6 50897
True

>>> hotpCheck SHA1 "1234" (2,2) 7 6 50897
False

>>> hotpCheck SHA1 "1234" (2,2) 12 6 50897
True

>>> hotpCheck SHA1 "1234" (2,2) 13 6 50897
False

TOTP

totp

Arguments

:: HashAlgorithm a

=> a

Hash algorithm to use

-> ByteString

Shared secret

-> UTCTime

Time of TOTP

-> Word64

Time period in seconds

-> Word

Number of digits in a password

-> Word32

TOTP

Compute a TOTP using secret key and time.

>>> totp SHA1 "1234" (read "2010-10-10 00:01:00 UTC") 30 6
388892

>>> totp SHA1 "1234" (read "2010-10-10 00:01:00 UTC") 30 8
43388892

>>> totp SHA1 "1234" (read "2010-10-10 00:01:15 UTC") 30 8
43388892

>>> totp SHA1 "1234" (read "2010-10-10 00:01:31 UTC") 30 8
39110359

totpCheck

Arguments

:: HashAlgorithm a

=> a

Hashing algorithm

-> ByteString

Shared secret

-> (Word64, Word64)

Valid counter range, before and after ideal

-> UTCTime

Time of TOTP

-> Word64

Period duration in seconds

-> Word

Numer of digits in a password

-> Word32

Password given by user

-> Bool

True if password is valid

Check presented password against time periods.

>>> totp SHA1 "1234" (read "2010-10-10 00:00:00 UTC") 30 6
778374

>>> totpCheck SHA1 "1234" (0, 0) (read "2010-10-10 00:00:00 UTC") 30 6 778374
True

>>> totpCheck SHA1 "1234" (0, 0) (read "2010-10-10 00:00:30 UTC") 30 6 778374
False

>>> totpCheck SHA1 "1234" (1, 0) (read "2010-10-10 00:00:30 UTC") 30 6 778374
True

>>> totpCheck SHA1 "1234" (1, 0) (read "2010-10-10 00:01:00 UTC") 30 6 778374
False

>>> totpCheck SHA1 "1234" (2, 0) (read "2010-10-10 00:01:00 UTC") 30 6 778374
True

Auxiliary

totpCounter

Arguments

:: UTCTime

Time of totp

-> Word64

Period duration in seconds

-> Word64

Resulting counter

Calculate HOTP counter using time. Starting time (T0 according to RFC6238) is 0 (begining of UNIX epoch)

>>> totpCounter (read "2010-10-10 00:00:00 UTC") 30
42888960

>>> totpCounter (read "2010-10-10 00:00:30 UTC") 30
42888961

>>> totpCounter (read "2010-10-10 00:01:00 UTC") 30
42888962

counterRange

Arguments

:: (Word64, Word64)

Number of counters before and after ideal

-> Word64

Ideal counter value

-> [Word64]

Make a sequence of acceptable counters, protected from arithmetic overflow. Maximum range is limited to 1000 due to huge counter ranges being insecure.

>>> counterRange (0, 0) 9000
[9000]

>>> counterRange (1, 0) 9000
[8999,9000]

>>> length $ counterRange (5000, 0) 9000
501

>>> length $ counterRange (5000, 5000) 9000
1000

>>> counterRange (2, 2) maxBound
[18446744073709551613,18446744073709551614,18446744073709551615]

>>> counterRange (2, 2) minBound
[0,1,2]

>>> counterRange (2, 2) (maxBound `div` 2)
[9223372036854775805,9223372036854775806,9223372036854775807,9223372036854775808,9223372036854775809]

>>> counterRange (5, 5) 9000
[8995,8996,8997,8998,8999,9000,9001,9002,9003,9004,9005]

RFC recommends avoiding excessively large values for counter ranges.

totpCounterRange :: (Word64, Word64) -> UTCTime -> Word64 -> [Word64]

Make a sequence of acceptable periods.

>>> totpCounterRange (0, 0) (read "2010-10-10 00:01:00 UTC") 30
[42888962]

>>> totpCounterRange (2, 0) (read "2010-10-10 00:01:00 UTC") 30
[42888960,42888961,42888962]

>>> totpCounterRange (0, 2) (read "2010-10-10 00:01:00 UTC") 30
[42888962,42888963,42888964]

>>> totpCounterRange (2, 2) (read "2010-10-10 00:01:00 UTC") 30
[42888960,42888961,42888962,42888963,42888964]