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1+++

2title = "2e: Insecure Hashing"

3weight = 8

4template = "doc.html"

5+++

7### `++fnv`

9FNV scrambler

11Hashes an atom with the 32-bit FNV non-cryptographic hash algorithm. Multiplies

12`a` by the prime number 16,777,619 and then takes the [block](@/docs/hoon/reference/stdlib/2c.md) of size

135 off the product's end, producing an atom.

15#### Accepts

17`a` is an atom.

19#### Produces

21An atom.

23#### Source

25```hoon

26 ++ fnv |=(a=@ (end 5 1 (mul 16.777.619 a)))

27```

29#### Examples

31```

32 > (fnv 10.000)

33 272.465.456

35 > (fnv 10.001)

36 289.243.075

38 > (fnv 1)

39 16.777.619

40```

43---

44### `++mug` {#mug}

46murmur3 scrambler

48Hashes `a` with the 31-bit murmur3 non-cryptographic hash algorithm,

49producing an atom.

51#### Accepts

53`a` is a noun.

55#### Produces

57An atom.

59#### Source

61```hoon

62++ mug :: mug with murmur3

63 ~/ %mug

64 |= a/*

65 |^ (trim ?@(a a (mix $(a -.a) (mix 0x7fff.ffff $(a +.a)))))

66 ++ trim :: 31-bit nonzero

67 |= key/@

68 =+ syd=0xcafe.babe

69 |- ^- @

70 =+ haz=(muk syd (met 3 key) key)

71 =+ ham=(mix (rsh 0 31 haz) (end 0 31 haz))

72 ?.(=(0 ham) ham $(syd +(syd)))

73 --

74```

76#### Examples

78```

79 > (mug 10.000)

80 795.713.195

82 > (mug 10.001)

83 420.521.697

85 > (mug 1)

86 1.901.865.568

88 > (mug (some 10))

89 2.099.076.946

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

92 1.719.833.228

93```

96---

97### `++muk`

99Standard MurmurHash3

100

101Implementation of the 32-bit

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

103non-cryptographic hash algorithm. Takes `a` as the seed, `b` as the key length

104in [blocks](@/docs/hoon/reference/stdlib/2c.md) of size 3, and `c` as the key, producing an atom.

106#### Accepts

108`a` is an atom.

110`b` is an atom.

112`c` is an atom.

114#### Produces

116An atom.

118#### Source

120```hoon

121 ++ muk

122 ~% %muk ..muk ~

123 =+ ~(. fe 5)

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

125 ?> &((lte (met 5 syd) 1) (lte (met 0 len) 31))

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

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

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

129 =/ h1 syd

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

131 =/ blocks (rip 5 key)

132 =/ i nblocks

133 =. h1 =/ hi h1 |-

134 ?: =(0 i) hi :: negative array index

135 =/ k1 (snag (sub nblocks i) blocks)

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

137 =. k1 (rol 0 15 k1)

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

139 =. hi (mix hi k1)

140 =. hi (rol 0 13 hi)

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

142 $(i (dec i))

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

144 =/ k1 0

145 =/ tlen (dis len 3)

146 =. h1

147 ?+ tlen h1 :: fallthrough switch

148 $3 =. k1 (mix k1 (lsh 0 16 (snag 2 tail)))

149 =. k1 (mix k1 (lsh 0 8 (snag 1 tail)))

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

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

152 =. k1 (rol 0 15 k1)

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

154 (mix h1 k1)

155 $2 =. k1 (mix k1 (lsh 0 8 (snag 1 tail)))

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

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

158 =. k1 (rol 0 15 k1)

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

160 (mix h1 k1)

161 $1 =. k1 (mix k1 (snag 0 tail))

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

163 =. k1 (rol 0 15 k1)

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

165 (mix h1 k1)

166 ==

167 =. h1 (mix h1 len)

168 |^ (fmix32 h1)

169 ++ fmix32

170 |= h=@

171 =. h (mix h (rsh 0 16 h))

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

173 =. h (mix h (rsh 0 13 h))

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

175 =. h (mix h (rsh 0 16 h))

176 h

177 --

178```

179

180#### Examples

181

182```

183 > (muk 6 1 3)

184 3.427.677.118

185

186 > (muk 6 2 'jerry')

187 ! exit

188

189 > (muk 6 2 'je')

190 3.602.081.716

191

192 > (met 3 'jerry')

193 5

194

195 > (met 3 'je')

196 2

197

198 > (muk 6 5 'jerry')

199 1.276.447.489

200

201 > (muk 6 15 'jerry')

202 2.881.503.571

203

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

205 > e

206 44.228

207

208 > (muk e 11 10.000)

209 246.077.549

210```

211

212

213---

214### `++mum`

215

21631-bit MurmurHash3 scrambler

217

218Hashes `a` with the 31-bit MurmurHash3 non-cryptographic hash algorithm,

219producing an atom.

221#### Accepts

223`a` is a noun.

225#### Produces

227An atom.

229#### Source

231```hoon

232 ++ mum

233 ~/ %mum

234 |= a=*

235 |^ (trim ?@(a a (mix $(a -.a) (mix 0x7fff.ffff $(a +.a)))))

236 ++ trim

237 |= key=@

238 =+ syd=0xcafe.babe

239 |- ^- @

240 =+ haz=(muk syd (met 3 key) key)

241 =+ ham=(mix (rsh 0 31 haz) (end 0 31 haz))

242 ?.(=(0 ham) ham $(syd +(syd)))

243```

244

245#### Examples

246

247```

248 > (mum 10.000)

249 795.713.195

250

251 > (mum 10.001)

252 420.521.697

253

254 > (mum 'jerry')

255 1.540.161.753

256

257 > (mum 1)

258 1.901.865.568

259

260 > (mum (some 10))

261 2.099.076.946

262

263 > (mum [1 2 3 4 5 ~])

264 1.719.833.228

265```

266

267

268---