sha512

Pure Haskell SHA-512, HMAC-SHA512 (docs.ppad.tech/sha512).
git clone git://git.ppad.tech/sha512.git
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SHA512.hs (21174B)


      1 {-# OPTIONS_GHC -funbox-small-strict-fields #-}
      2 {-# LANGUAGE BangPatterns #-}
      3 {-# LANGUAGE RecordWildCards #-}
      4 {-# LANGUAGE ViewPatterns #-}
      5 
      6 -- |
      7 -- Module: Crypto.Hash.SHA512
      8 -- Copyright: (c) 2024 Jared Tobin
      9 -- License: MIT
     10 -- Maintainer: Jared Tobin <jared@ppad.tech>
     11 --
     12 -- Pure SHA-512 and HMAC-SHA512 implementations for
     13 -- strict and lazy ByteStrings, as specified by RFC's
     14 -- [6234](https://datatracker.ietf.org/doc/html/rfc6234) and
     15 -- [2104](https://datatracker.ietf.org/doc/html/rfc2104).
     16 
     17 module Crypto.Hash.SHA512 (
     18   -- * SHA-512 message digest functions
     19     hash
     20   , hash_lazy
     21 
     22   -- * SHA512-based MAC functions
     23   , hmac
     24   , hmac_lazy
     25   ) where
     26 
     27 import qualified Data.Bits as B
     28 import Data.Bits ((.|.), (.&.))
     29 import qualified Data.ByteString as BS
     30 import qualified Data.ByteString.Builder as BSB
     31 import qualified Data.ByteString.Builder.Extra as BE
     32 import qualified Data.ByteString.Internal as BI
     33 import qualified Data.ByteString.Lazy as BL
     34 import qualified Data.ByteString.Lazy.Internal as BLI
     35 import qualified Data.ByteString.Unsafe as BU
     36 import Data.Word (Word64)
     37 import Foreign.ForeignPtr (plusForeignPtr)
     38 
     39 -- preliminary utils ----------------------------------------------------------
     40 
     41 -- keystroke saver
     42 fi :: (Integral a, Num b) => a -> b
     43 fi = fromIntegral
     44 {-# INLINE fi #-}
     45 
     46 -- parse strict ByteString in BE order to Word64 (verbatim from
     47 -- Data.Binary)
     48 --
     49 -- invariant:
     50 --   the input bytestring is at least 64 bits in length
     51 unsafe_word64be :: BS.ByteString -> Word64
     52 unsafe_word64be s =
     53   (fi (s `BU.unsafeIndex` 0) `B.unsafeShiftL` 56) .|.
     54   (fi (s `BU.unsafeIndex` 1) `B.unsafeShiftL` 48) .|.
     55   (fi (s `BU.unsafeIndex` 2) `B.unsafeShiftL` 40) .|.
     56   (fi (s `BU.unsafeIndex` 3) `B.unsafeShiftL` 32) .|.
     57   (fi (s `BU.unsafeIndex` 4) `B.unsafeShiftL` 24) .|.
     58   (fi (s `BU.unsafeIndex` 5) `B.unsafeShiftL` 16) .|.
     59   (fi (s `BU.unsafeIndex` 6) `B.unsafeShiftL`  8) .|.
     60   (fi (s `BU.unsafeIndex` 7) )
     61 {-# INLINE unsafe_word64be #-}
     62 
     63 -- utility types for more efficient ByteString management
     64 
     65 data SSPair = SSPair
     66   {-# UNPACK #-} !BS.ByteString
     67   {-# UNPACK #-} !BS.ByteString
     68 
     69 data SLPair = SLPair {-# UNPACK #-} !BS.ByteString !BL.ByteString
     70 
     71 data WSPair = WSPair {-# UNPACK #-} !Word64 {-# UNPACK #-} !BS.ByteString
     72 
     73 -- unsafe version of splitAt that does no bounds checking
     74 --
     75 -- invariant:
     76 --   0 <= n <= l
     77 unsafe_splitAt :: Int -> BS.ByteString -> SSPair
     78 unsafe_splitAt n (BI.BS x l) =
     79   SSPair (BI.BS x n) (BI.BS (plusForeignPtr x n) (l - n))
     80 
     81 -- variant of Data.ByteString.Lazy.splitAt that returns the initial
     82 -- component as a strict, unboxed ByteString
     83 splitAt128 :: BL.ByteString -> SLPair
     84 splitAt128 = splitAt' (128 :: Int) where
     85   splitAt' _ BLI.Empty        = SLPair mempty BLI.Empty
     86   splitAt' n (BLI.Chunk c cs) =
     87     if    n < BS.length c
     88     then
     89       -- n < BS.length c, so unsafe_splitAt is safe
     90       let !(SSPair c0 c1) = unsafe_splitAt n c
     91       in  SLPair c0 (BLI.Chunk c1 cs)
     92     else
     93       let SLPair cs' cs'' = splitAt' (n - BS.length c) cs
     94       in  SLPair (c <> cs') cs''
     95 
     96 -- variant of Data.ByteString.splitAt that behaves like an incremental
     97 -- Word64 parser
     98 --
     99 -- invariant:
    100 --   the input bytestring is at least 64 bits in length
    101 unsafe_parseWsPair :: BS.ByteString -> WSPair
    102 unsafe_parseWsPair (BI.BS x l) =
    103   WSPair (unsafe_word64be (BI.BS x 8)) (BI.BS (plusForeignPtr x 8) (l - 8))
    104 {-# INLINE unsafe_parseWsPair #-}
    105 
    106 -- message padding and parsing ------------------------------------------------
    107 -- https://datatracker.ietf.org/doc/html/rfc6234#section-4.1
    108 
    109 -- k such that (l + 1 + k) mod 128 = 112
    110 sol :: Word64 -> Word64
    111 sol l =
    112   let r = 112 - fi l `mod` 128 - 1 :: Integer -- fi prevents underflow
    113   in  fi (if r < 0 then r + 128 else r)
    114 
    115 -- XX doesn't properly handle (> maxBound :: Word64) length
    116 
    117 -- RFC 6234 4.1 (strict)
    118 pad :: BS.ByteString -> BS.ByteString
    119 pad m = BL.toStrict . BSB.toLazyByteString $ padded where
    120   l = fi (BS.length m)
    121   padded = BSB.byteString m <> fill (sol l) (BSB.word8 0x80)
    122 
    123   fill j !acc
    124     | j == 0 = acc <> BSB.word64BE 0x00 <> BSB.word64BE (l * 8)
    125     | otherwise = fill (pred j) (acc <> BSB.word8 0x00)
    126 
    127 -- RFC 6234 4.1 (lazy)
    128 pad_lazy :: BL.ByteString -> BL.ByteString
    129 pad_lazy (BL.toChunks -> m) = BL.fromChunks (walk 0 m) where
    130   walk !l bs = case bs of
    131     (c:cs) -> c : walk (l + fi (BS.length c)) cs
    132     [] -> padding l (sol l) (BSB.word8 0x80)
    133 
    134   padding l k bs
    135     | k == 0 =
    136           pure
    137         . BL.toStrict
    138           -- more efficient for small builder
    139         . BE.toLazyByteStringWith
    140             (BE.safeStrategy 128 BE.smallChunkSize) mempty
    141         $ bs <> BSB.word64BE 0x00 <> BSB.word64BE (l * 8)
    142     | otherwise =
    143         let nacc = bs <> BSB.word8 0x00
    144         in  padding l (pred k) nacc
    145 
    146 -- functions and constants used -----------------------------------------------
    147 -- https://datatracker.ietf.org/doc/html/rfc6234#section-5.1
    148 
    149 ch :: Word64 -> Word64 -> Word64 -> Word64
    150 ch x y z = (x .&. y) `B.xor` (B.complement x .&. z)
    151 {-# INLINE ch #-}
    152 
    153 -- credit to SHA authors for the following optimisation. their text:
    154 --
    155 -- > note:
    156 -- >   the original functions is (x & y) ^ (x & z) ^ (y & z)
    157 -- >   if you fire off truth tables, this is equivalent to
    158 -- >     (x & y) | (x & z) | (y & z)
    159 -- >   which you can the use distribution on:
    160 -- >     (x & (y | z)) | (y & z)
    161 -- >   which saves us one operation.
    162 maj :: Word64 -> Word64 -> Word64 -> Word64
    163 maj x y z = (x .&. (y .|. z)) .|. (y .&. z)
    164 {-# INLINE maj #-}
    165 
    166 bsig0 :: Word64 -> Word64
    167 bsig0 x = B.rotateR x 28 `B.xor` B.rotateR x 34 `B.xor` B.rotateR x 39
    168 {-# INLINE bsig0 #-}
    169 
    170 bsig1 :: Word64 -> Word64
    171 bsig1 x = B.rotateR x 14 `B.xor` B.rotateR x 18 `B.xor` B.rotateR x 41
    172 {-# INLINE bsig1 #-}
    173 
    174 ssig0 :: Word64 -> Word64
    175 ssig0 x = B.rotateR x 1 `B.xor` B.rotateR x 8 `B.xor` B.unsafeShiftR x 7
    176 {-# INLINE ssig0 #-}
    177 
    178 ssig1 :: Word64 -> Word64
    179 ssig1 x = B.rotateR x 19 `B.xor` B.rotateR x 61 `B.xor` B.unsafeShiftR x 6
    180 {-# INLINE ssig1 #-}
    181 
    182 data Schedule = Schedule {
    183     w00 :: !Word64, w01 :: !Word64, w02 :: !Word64, w03 :: !Word64
    184   , w04 :: !Word64, w05 :: !Word64, w06 :: !Word64, w07 :: !Word64
    185   , w08 :: !Word64, w09 :: !Word64, w10 :: !Word64, w11 :: !Word64
    186   , w12 :: !Word64, w13 :: !Word64, w14 :: !Word64, w15 :: !Word64
    187   , w16 :: !Word64, w17 :: !Word64, w18 :: !Word64, w19 :: !Word64
    188   , w20 :: !Word64, w21 :: !Word64, w22 :: !Word64, w23 :: !Word64
    189   , w24 :: !Word64, w25 :: !Word64, w26 :: !Word64, w27 :: !Word64
    190   , w28 :: !Word64, w29 :: !Word64, w30 :: !Word64, w31 :: !Word64
    191   , w32 :: !Word64, w33 :: !Word64, w34 :: !Word64, w35 :: !Word64
    192   , w36 :: !Word64, w37 :: !Word64, w38 :: !Word64, w39 :: !Word64
    193   , w40 :: !Word64, w41 :: !Word64, w42 :: !Word64, w43 :: !Word64
    194   , w44 :: !Word64, w45 :: !Word64, w46 :: !Word64, w47 :: !Word64
    195   , w48 :: !Word64, w49 :: !Word64, w50 :: !Word64, w51 :: !Word64
    196   , w52 :: !Word64, w53 :: !Word64, w54 :: !Word64, w55 :: !Word64
    197   , w56 :: !Word64, w57 :: !Word64, w58 :: !Word64, w59 :: !Word64
    198   , w60 :: !Word64, w61 :: !Word64, w62 :: !Word64, w63 :: !Word64
    199   , w64 :: !Word64, w65 :: !Word64, w66 :: !Word64, w67 :: !Word64
    200   , w68 :: !Word64, w69 :: !Word64, w70 :: !Word64, w71 :: !Word64
    201   , w72 :: !Word64, w73 :: !Word64, w74 :: !Word64, w75 :: !Word64
    202   , w76 :: !Word64, w77 :: !Word64, w78 :: !Word64, w79 :: !Word64
    203   }
    204 
    205 -- initialization -------------------------------------------------------------
    206 -- https://datatracker.ietf.org/doc/html/rfc6234#section-6.1
    207 
    208 data Registers = Registers {
    209     h0 :: !Word64, h1 :: !Word64, h2 :: !Word64, h3 :: !Word64
    210   , h4 :: !Word64, h5 :: !Word64, h6 :: !Word64, h7 :: !Word64
    211   }
    212 
    213 -- first 64 bits of the fractional parts of the square roots of the
    214 -- first eight primes
    215 iv :: Registers
    216 iv = Registers
    217   0x6a09e667f3bcc908 0xbb67ae8584caa73b 0x3c6ef372fe94f82b 0xa54ff53a5f1d36f1
    218   0x510e527fade682d1 0x9b05688c2b3e6c1f 0x1f83d9abfb41bd6b 0x5be0cd19137e2179
    219 
    220 -- processing -----------------------------------------------------------------
    221 -- https://datatracker.ietf.org/doc/html/rfc6234#section-6.2
    222 
    223 data Block = Block {
    224     m00 :: !Word64, m01 :: !Word64, m02 :: !Word64, m03 :: !Word64
    225   , m04 :: !Word64, m05 :: !Word64, m06 :: !Word64, m07 :: !Word64
    226   , m08 :: !Word64, m09 :: !Word64, m10 :: !Word64, m11 :: !Word64
    227   , m12 :: !Word64, m13 :: !Word64, m14 :: !Word64, m15 :: !Word64
    228   }
    229 
    230 -- parse strict bytestring to block
    231 --
    232 -- invariant:
    233 --   the input bytestring is exactly 1024 bits long
    234 unsafe_parse :: BS.ByteString -> Block
    235 unsafe_parse bs =
    236   let !(WSPair m00 t00) = unsafe_parseWsPair bs
    237       !(WSPair m01 t01) = unsafe_parseWsPair t00
    238       !(WSPair m02 t02) = unsafe_parseWsPair t01
    239       !(WSPair m03 t03) = unsafe_parseWsPair t02
    240       !(WSPair m04 t04) = unsafe_parseWsPair t03
    241       !(WSPair m05 t05) = unsafe_parseWsPair t04
    242       !(WSPair m06 t06) = unsafe_parseWsPair t05
    243       !(WSPair m07 t07) = unsafe_parseWsPair t06
    244       !(WSPair m08 t08) = unsafe_parseWsPair t07
    245       !(WSPair m09 t09) = unsafe_parseWsPair t08
    246       !(WSPair m10 t10) = unsafe_parseWsPair t09
    247       !(WSPair m11 t11) = unsafe_parseWsPair t10
    248       !(WSPair m12 t12) = unsafe_parseWsPair t11
    249       !(WSPair m13 t13) = unsafe_parseWsPair t12
    250       !(WSPair m14 t14) = unsafe_parseWsPair t13
    251       !(WSPair m15 t15) = unsafe_parseWsPair t14
    252   in  if   BS.null t15
    253       then Block {..}
    254       else error "ppad-sha512: internal error (bytes remaining)"
    255 
    256 -- RFC 6234 6.2 step 1
    257 prepare_schedule :: Block -> Schedule
    258 prepare_schedule Block {..} = Schedule {..} where
    259   w00 = m00; w01 = m01; w02 = m02; w03 = m03
    260   w04 = m04; w05 = m05; w06 = m06; w07 = m07
    261   w08 = m08; w09 = m09; w10 = m10; w11 = m11
    262   w12 = m12; w13 = m13; w14 = m14; w15 = m15
    263   w16 = ssig1 w14 + w09 + ssig0 w01 + w00
    264   w17 = ssig1 w15 + w10 + ssig0 w02 + w01
    265   w18 = ssig1 w16 + w11 + ssig0 w03 + w02
    266   w19 = ssig1 w17 + w12 + ssig0 w04 + w03
    267   w20 = ssig1 w18 + w13 + ssig0 w05 + w04
    268   w21 = ssig1 w19 + w14 + ssig0 w06 + w05
    269   w22 = ssig1 w20 + w15 + ssig0 w07 + w06
    270   w23 = ssig1 w21 + w16 + ssig0 w08 + w07
    271   w24 = ssig1 w22 + w17 + ssig0 w09 + w08
    272   w25 = ssig1 w23 + w18 + ssig0 w10 + w09
    273   w26 = ssig1 w24 + w19 + ssig0 w11 + w10
    274   w27 = ssig1 w25 + w20 + ssig0 w12 + w11
    275   w28 = ssig1 w26 + w21 + ssig0 w13 + w12
    276   w29 = ssig1 w27 + w22 + ssig0 w14 + w13
    277   w30 = ssig1 w28 + w23 + ssig0 w15 + w14
    278   w31 = ssig1 w29 + w24 + ssig0 w16 + w15
    279   w32 = ssig1 w30 + w25 + ssig0 w17 + w16
    280   w33 = ssig1 w31 + w26 + ssig0 w18 + w17
    281   w34 = ssig1 w32 + w27 + ssig0 w19 + w18
    282   w35 = ssig1 w33 + w28 + ssig0 w20 + w19
    283   w36 = ssig1 w34 + w29 + ssig0 w21 + w20
    284   w37 = ssig1 w35 + w30 + ssig0 w22 + w21
    285   w38 = ssig1 w36 + w31 + ssig0 w23 + w22
    286   w39 = ssig1 w37 + w32 + ssig0 w24 + w23
    287   w40 = ssig1 w38 + w33 + ssig0 w25 + w24
    288   w41 = ssig1 w39 + w34 + ssig0 w26 + w25
    289   w42 = ssig1 w40 + w35 + ssig0 w27 + w26
    290   w43 = ssig1 w41 + w36 + ssig0 w28 + w27
    291   w44 = ssig1 w42 + w37 + ssig0 w29 + w28
    292   w45 = ssig1 w43 + w38 + ssig0 w30 + w29
    293   w46 = ssig1 w44 + w39 + ssig0 w31 + w30
    294   w47 = ssig1 w45 + w40 + ssig0 w32 + w31
    295   w48 = ssig1 w46 + w41 + ssig0 w33 + w32
    296   w49 = ssig1 w47 + w42 + ssig0 w34 + w33
    297   w50 = ssig1 w48 + w43 + ssig0 w35 + w34
    298   w51 = ssig1 w49 + w44 + ssig0 w36 + w35
    299   w52 = ssig1 w50 + w45 + ssig0 w37 + w36
    300   w53 = ssig1 w51 + w46 + ssig0 w38 + w37
    301   w54 = ssig1 w52 + w47 + ssig0 w39 + w38
    302   w55 = ssig1 w53 + w48 + ssig0 w40 + w39
    303   w56 = ssig1 w54 + w49 + ssig0 w41 + w40
    304   w57 = ssig1 w55 + w50 + ssig0 w42 + w41
    305   w58 = ssig1 w56 + w51 + ssig0 w43 + w42
    306   w59 = ssig1 w57 + w52 + ssig0 w44 + w43
    307   w60 = ssig1 w58 + w53 + ssig0 w45 + w44
    308   w61 = ssig1 w59 + w54 + ssig0 w46 + w45
    309   w62 = ssig1 w60 + w55 + ssig0 w47 + w46
    310   w63 = ssig1 w61 + w56 + ssig0 w48 + w47
    311   w64 = ssig1 w62 + w57 + ssig0 w49 + w48
    312   w65 = ssig1 w63 + w58 + ssig0 w50 + w49
    313   w66 = ssig1 w64 + w59 + ssig0 w51 + w50
    314   w67 = ssig1 w65 + w60 + ssig0 w52 + w51
    315   w68 = ssig1 w66 + w61 + ssig0 w53 + w52
    316   w69 = ssig1 w67 + w62 + ssig0 w54 + w53
    317   w70 = ssig1 w68 + w63 + ssig0 w55 + w54
    318   w71 = ssig1 w69 + w64 + ssig0 w56 + w55
    319   w72 = ssig1 w70 + w65 + ssig0 w57 + w56
    320   w73 = ssig1 w71 + w66 + ssig0 w58 + w57
    321   w74 = ssig1 w72 + w67 + ssig0 w59 + w58
    322   w75 = ssig1 w73 + w68 + ssig0 w60 + w59
    323   w76 = ssig1 w74 + w69 + ssig0 w61 + w60
    324   w77 = ssig1 w75 + w70 + ssig0 w62 + w61
    325   w78 = ssig1 w76 + w71 + ssig0 w63 + w62
    326   w79 = ssig1 w77 + w72 + ssig0 w64 + w63
    327 
    328 -- RFC 6234 6.2 steps 2, 3, 4
    329 block_hash :: Registers -> Schedule -> Registers
    330 block_hash r00@Registers {..} Schedule {..} =
    331   -- constants are the first 64 bits of the fractional parts of the
    332   -- cube roots of the first eighty prime numbers
    333   let r01 = step r00 0x428a2f98d728ae22 w00
    334       r02 = step r01 0x7137449123ef65cd w01
    335       r03 = step r02 0xb5c0fbcfec4d3b2f w02
    336       r04 = step r03 0xe9b5dba58189dbbc w03
    337       r05 = step r04 0x3956c25bf348b538 w04
    338       r06 = step r05 0x59f111f1b605d019 w05
    339       r07 = step r06 0x923f82a4af194f9b w06
    340       r08 = step r07 0xab1c5ed5da6d8118 w07
    341       r09 = step r08 0xd807aa98a3030242 w08
    342       r10 = step r09 0x12835b0145706fbe w09
    343       r11 = step r10 0x243185be4ee4b28c w10
    344       r12 = step r11 0x550c7dc3d5ffb4e2 w11
    345       r13 = step r12 0x72be5d74f27b896f w12
    346       r14 = step r13 0x80deb1fe3b1696b1 w13
    347       r15 = step r14 0x9bdc06a725c71235 w14
    348       r16 = step r15 0xc19bf174cf692694 w15
    349       r17 = step r16 0xe49b69c19ef14ad2 w16
    350       r18 = step r17 0xefbe4786384f25e3 w17
    351       r19 = step r18 0x0fc19dc68b8cd5b5 w18
    352       r20 = step r19 0x240ca1cc77ac9c65 w19
    353       r21 = step r20 0x2de92c6f592b0275 w20
    354       r22 = step r21 0x4a7484aa6ea6e483 w21
    355       r23 = step r22 0x5cb0a9dcbd41fbd4 w22
    356       r24 = step r23 0x76f988da831153b5 w23
    357       r25 = step r24 0x983e5152ee66dfab w24
    358       r26 = step r25 0xa831c66d2db43210 w25
    359       r27 = step r26 0xb00327c898fb213f w26
    360       r28 = step r27 0xbf597fc7beef0ee4 w27
    361       r29 = step r28 0xc6e00bf33da88fc2 w28
    362       r30 = step r29 0xd5a79147930aa725 w29
    363       r31 = step r30 0x06ca6351e003826f w30
    364       r32 = step r31 0x142929670a0e6e70 w31
    365       r33 = step r32 0x27b70a8546d22ffc w32
    366       r34 = step r33 0x2e1b21385c26c926 w33
    367       r35 = step r34 0x4d2c6dfc5ac42aed w34
    368       r36 = step r35 0x53380d139d95b3df w35
    369       r37 = step r36 0x650a73548baf63de w36
    370       r38 = step r37 0x766a0abb3c77b2a8 w37
    371       r39 = step r38 0x81c2c92e47edaee6 w38
    372       r40 = step r39 0x92722c851482353b w39
    373       r41 = step r40 0xa2bfe8a14cf10364 w40
    374       r42 = step r41 0xa81a664bbc423001 w41
    375       r43 = step r42 0xc24b8b70d0f89791 w42
    376       r44 = step r43 0xc76c51a30654be30 w43
    377       r45 = step r44 0xd192e819d6ef5218 w44
    378       r46 = step r45 0xd69906245565a910 w45
    379       r47 = step r46 0xf40e35855771202a w46
    380       r48 = step r47 0x106aa07032bbd1b8 w47
    381       r49 = step r48 0x19a4c116b8d2d0c8 w48
    382       r50 = step r49 0x1e376c085141ab53 w49
    383       r51 = step r50 0x2748774cdf8eeb99 w50
    384       r52 = step r51 0x34b0bcb5e19b48a8 w51
    385       r53 = step r52 0x391c0cb3c5c95a63 w52
    386       r54 = step r53 0x4ed8aa4ae3418acb w53
    387       r55 = step r54 0x5b9cca4f7763e373 w54
    388       r56 = step r55 0x682e6ff3d6b2b8a3 w55
    389       r57 = step r56 0x748f82ee5defb2fc w56
    390       r58 = step r57 0x78a5636f43172f60 w57
    391       r59 = step r58 0x84c87814a1f0ab72 w58
    392       r60 = step r59 0x8cc702081a6439ec w59
    393       r61 = step r60 0x90befffa23631e28 w60
    394       r62 = step r61 0xa4506cebde82bde9 w61
    395       r63 = step r62 0xbef9a3f7b2c67915 w62
    396       r64 = step r63 0xc67178f2e372532b w63
    397       r65 = step r64 0xca273eceea26619c w64
    398       r66 = step r65 0xd186b8c721c0c207 w65
    399       r67 = step r66 0xeada7dd6cde0eb1e w66
    400       r68 = step r67 0xf57d4f7fee6ed178 w67
    401       r69 = step r68 0x06f067aa72176fba w68
    402       r70 = step r69 0x0a637dc5a2c898a6 w69
    403       r71 = step r70 0x113f9804bef90dae w70
    404       r72 = step r71 0x1b710b35131c471b w71
    405       r73 = step r72 0x28db77f523047d84 w72
    406       r74 = step r73 0x32caab7b40c72493 w73
    407       r75 = step r74 0x3c9ebe0a15c9bebc w74
    408       r76 = step r75 0x431d67c49c100d4c w75
    409       r77 = step r76 0x4cc5d4becb3e42b6 w76
    410       r78 = step r77 0x597f299cfc657e2a w77
    411       r79 = step r78 0x5fcb6fab3ad6faec w78
    412       r80 = step r79 0x6c44198c4a475817 w79
    413       !(Registers a b c d e f g h) = r80
    414   in  Registers
    415         (a + h0) (b + h1) (c + h2) (d + h3)
    416         (e + h4) (f + h5) (g + h6) (h + h7)
    417 
    418 step :: Registers -> Word64 -> Word64 -> Registers
    419 step (Registers a b c d e f g h) k w =
    420   let t1 = h + bsig1 e + ch e f g + k + w
    421       t2 = bsig0 a + maj a b c
    422   in  Registers (t1 + t2) a b c (d + t1) e f g
    423 {-# INLINE step #-}
    424 
    425 -- RFC 6234 6.2 block pipeline
    426 --
    427 -- invariant:
    428 --   the input bytestring is exactly 1024 bits in length
    429 unsafe_hash_alg :: Registers -> BS.ByteString -> Registers
    430 unsafe_hash_alg rs bs = block_hash rs (prepare_schedule (unsafe_parse bs))
    431 
    432 -- register concatenation
    433 cat :: Registers -> BS.ByteString
    434 cat Registers {..} =
    435     BL.toStrict
    436     -- more efficient for small builder
    437   . BE.toLazyByteStringWith (BE.safeStrategy 128 BE.smallChunkSize) mempty
    438   $ mconcat [
    439         BSB.word64BE h0, BSB.word64BE h1, BSB.word64BE h2, BSB.word64BE h3
    440       , BSB.word64BE h4, BSB.word64BE h5, BSB.word64BE h6, BSB.word64BE h7
    441       ]
    442 
    443 -- | Compute a condensed representation of a strict bytestring via
    444 --   SHA-512.
    445 --
    446 --   The 512-bit output digest is returned as a strict bytestring.
    447 --
    448 --   >>> hash "strict bytestring input"
    449 --   "<strict 512-bit message digest>"
    450 hash :: BS.ByteString -> BS.ByteString
    451 hash bs = cat (go iv (pad bs)) where
    452   -- proof that 'go' always terminates safely:
    453   --
    454   -- let b = pad bs
    455   -- then length(b) = n * 1024 bits for some n >= 0                 (1)
    456   go :: Registers -> BS.ByteString -> Registers
    457   go !acc b
    458     -- if n == 0, then 'go' terminates safely                       (2)
    459     | BS.null b = acc
    460     -- if n > 0, then
    461     --
    462     -- let (c, r) = unsafe_splitAt 128 b
    463     -- then length(c) == 1024 bits                                  by (1)
    464     --      length(r) == m * 1024 bits for some m >= 0              by (1)
    465     --
    466     -- note 'unsafe_hash_alg' terminates safely for bytestring      (3)
    467     -- input of exactly 1024 bits in length
    468     --
    469     -- length(c) == 1024
    470     --   => 'unsafe_hash_alg' terminates safely                     by (3)
    471     --   => 'go' terminates safely                                  (4)
    472     -- length(r) == m * 1024 bits for m >= 0
    473     --   => next invocation of 'go' terminates safely               by (2), (4)
    474     --
    475     -- then by induction, 'go' always terminates safely (QED)
    476     | otherwise = case unsafe_splitAt 128 b of
    477         SSPair c r -> go (unsafe_hash_alg acc c) r
    478 
    479 -- | Compute a condensed representation of a lazy bytestring via
    480 --   SHA-512.
    481 --
    482 --   The 512-bit output digest is returned as a strict bytestring.
    483 --
    484 --   >>> hash_lazy "lazy bytestring input"
    485 --   "<strict 512-bit message digest>"
    486 hash_lazy :: BL.ByteString -> BS.ByteString
    487 hash_lazy bl = cat (go iv (pad_lazy bl)) where
    488   -- proof of safety proceeds analogously
    489   go :: Registers -> BL.ByteString -> Registers
    490   go !acc bs
    491     | BL.null bs = acc
    492     | otherwise = case splitAt128 bs of
    493         SLPair c r -> go (unsafe_hash_alg acc c) r
    494 
    495 -- HMAC -----------------------------------------------------------------------
    496 -- https://datatracker.ietf.org/doc/html/rfc2104#section-2
    497 
    498 data KeyAndLen = KeyAndLen
    499   {-# UNPACK #-} !BS.ByteString
    500   {-# UNPACK #-} !Int
    501 
    502 -- | Produce a message authentication code for a strict bytestring,
    503 --   based on the provided (strict, bytestring) key, via SHA-512.
    504 --
    505 --   The 512-bit MAC is returned as a strict bytestring.
    506 --
    507 --   Per RFC 2104, the key /should/ be a minimum of 64 bytes long. Keys
    508 --   exceeding 1024 bytes in length will first be hashed (via SHA-512).
    509 --
    510 --   >>> hmac "strict bytestring key" "strict bytestring input"
    511 --   "<strict 512-bit MAC>"
    512 hmac
    513   :: BS.ByteString -- ^ key
    514   -> BS.ByteString -- ^ text
    515   -> BS.ByteString
    516 hmac mk text =
    517     let step1 = k <> BS.replicate (128 - lk) 0x00
    518         step2 = BS.map (B.xor 0x36) step1
    519         step3 = step2 <> text
    520         step4 = hash step3
    521         step5 = BS.map (B.xor 0x5C) step1
    522         step6 = step5 <> step4
    523     in  hash step6
    524   where
    525     !(KeyAndLen k lk) =
    526       let l = BS.length mk
    527       in  if   l > 128
    528           then KeyAndLen (hash mk) 64
    529           else KeyAndLen mk l
    530 
    531 -- | Produce a message authentication code for a lazy bytestring, based
    532 --   on the provided (strict, bytestring) key, via SHA-512.
    533 --
    534 --   The 512-bit MAC is returned as a strict bytestring.
    535 --
    536 --   Per RFC 2104, the key /should/ be a minimum of 64 bytes long. Keys
    537 --   exceeding 1024 bytes in length will first be hashed (via SHA-512).
    538 --
    539 --   >>> hmac_lazy "strict bytestring key" "lazy bytestring input"
    540 --   "<strict 512-bit MAC>"
    541 hmac_lazy
    542   :: BS.ByteString -- ^ key
    543   -> BL.ByteString -- ^ text
    544   -> BS.ByteString
    545 hmac_lazy mk text =
    546     let step1 = k <> BS.replicate (128 - lk) 0x00
    547         step2 = BS.map (B.xor 0x36) step1
    548         step3 = BL.fromStrict step2 <> text
    549         step4 = hash_lazy step3
    550         step5 = BS.map (B.xor 0x5C) step1
    551         step6 = step5 <> step4
    552     in  hash step6
    553   where
    554     !(KeyAndLen k lk) =
    555       let l = BS.length mk
    556       in  if   l > 128
    557           then KeyAndLen (hash mk) 64
    558           else KeyAndLen mk l
    559