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1+++

2title = "2e: Insecure Hashing"

3weight = 8

4template = "doc.html"

5+++

7## `++mug` {#mug}

9murmur3 scrambler

11Hashes `a` with the 31-bit murmur3 non-cryptographic hash algorithm,

12producing an atom.

14#### Accepts

16`a` is a noun.

18#### Produces

20An atom.

22#### Source

24```hoon

25++ mug

26 ~/ %mug

27 |= a=*

28 |^ ?@ a (mum 0xcafe.babe 0x7fff a)

29 =/ b (cat 5 $(a -.a) $(a +.a))

30 (mum 0xdead.beef 0xfffe b)

31 ::

32 ++ mum

33 |= [syd=@uxF fal=@F key=@]

34 =/ wyd (met 3 key)

35 =| i=@ud

36 |- ^- @F

37 ?: =(8 i) fal

38 =/ haz=@F (muk syd wyd key)

39 =/ ham=@F (mix (rsh [0 31] haz) (end [0 31] haz))

40 ?.(=(0 ham) ham $(i +(i), syd +(syd)))

41 --

42```

44#### Examples

46```

47> (mug 10.000)

48795.713.195

49```

51```

52> (mug 10.001)

53420.521.697

54```

56```

57> (mug 1)

581.901.865.568

59```

61```

62> (mug (some 10))

63750.200.080

64```

66```

67> (mug [1 2 3 4 5 ~])

681.565.443.491

69```

71---

73## `++muk`

75Standard MurmurHash3

77Implementation of the 32-bit

78[MurmurHash3](https://en.wikipedia.org/wiki/MurmurHash#Algorithm)

79non-cryptographic hash algorithm. Takes `syd` as the seed, `len` as the key length

80in [blocks](/docs/hoon/reference/stdlib/2c) of size 3, and `key` as the key, producing an atom.

82#### Accepts

84`syd` is an atom.

86`len` is an atom.

88`key` is an atom.

90#### Produces

92An atom.

94#### Source

96```hoon

97++ muk :: standard murmur3

98 ~% %muk ..muk ~

99 =+ ~(. fe 5)

100 |= [syd=@ len=@ key=@]

101 =. syd (end 5 syd)

102 =/ pad (sub len (met 3 key))

103 =/ data (weld (rip 3 key) (reap pad 0))

104 =/ nblocks (div len 4) :: intentionally off-by-one

105 =/ h1 syd

106 =+ [c1=0xcc9e.2d51 c2=0x1b87.3593]

107 =/ blocks (rip 5 key)

108 =/ i nblocks

109 =. h1 =/ hi h1 |-

110 ?: =(0 i) hi

111 =/ k1 (snag (sub nblocks i) blocks) :: negative array index

112 =. k1 (sit (mul k1 c1))

113 =. k1 (rol 0 15 k1)

114 =. k1 (sit (mul k1 c2))

115 =. hi (mix hi k1)

116 =. hi (rol 0 13 hi)

117 =. hi (sum (sit (mul hi 5)) 0xe654.6b64)

118 $(i (dec i))

119 =/ tail (slag (mul 4 nblocks) data)

120 =/ k1 0

121 =/ tlen (dis len 3)

122 =. h1

123 ?+ tlen h1 :: fallthrough switch

124 %3 =. k1 (mix k1 (lsh [0 16] (snag 2 tail)))

125 =. k1 (mix k1 (lsh [0 8] (snag 1 tail)))

126 =. k1 (mix k1 (snag 0 tail))

127 =. k1 (sit (mul k1 c1))

128 =. k1 (rol 0 15 k1)

129 =. k1 (sit (mul k1 c2))

130 (mix h1 k1)

131 %2 =. k1 (mix k1 (lsh [0 8] (snag 1 tail)))

132 =. k1 (mix k1 (snag 0 tail))

133 =. k1 (sit (mul k1 c1))

134 =. k1 (rol 0 15 k1)

135 =. k1 (sit (mul k1 c2))

136 (mix h1 k1)

137 %1 =. k1 (mix k1 (snag 0 tail))

138 =. k1 (sit (mul k1 c1))

139 =. k1 (rol 0 15 k1)

140 =. k1 (sit (mul k1 c2))

141 (mix h1 k1)

142 ==

143 =. h1 (mix h1 len)

144 |^ (fmix32 h1)

145 ++ fmix32

146 |= h=@

147 =. h (mix h (rsh [0 16] h))

148 =. h (sit (mul h 0x85eb.ca6b))

149 =. h (mix h (rsh [0 13] h))

150 =. h (sit (mul h 0xc2b2.ae35))

151 =. h (mix h (rsh [0 16] h))

152 h

153 --

154```

155

156#### Examples

157

158```

159 > (muk 6 1 3)

160 3.427.677.118

161

162 > (muk 6 2 'jerry')

163 ! exit

164

165 > (muk 6 2 'je')

166 3.602.081.716

167

168 > (met 3 'jerry')

169 5

170

171 > (met 3 'je')

172 2

173

174 > (muk 6 5 'jerry')

175 1.276.447.489

176

177 > (muk 6 15 'jerry')

178 2.881.503.571

179

180 > =e (cut 3 [0 2] eny) :: `eny` is 512 bits of entropy (a random number).

181 > e

182 44.228

183

184 > (muk e 11 10.000)

185 246.077.549

186```

187

188---