reference/library/2e.md · urbit.org

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1+++

2title = "2e: Insecure Hashing"

3weight = 8

4template = "doc.html"

5aliases = ["/docs/reference/library/2e"]

6+++

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/library/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`

46FNV-1a scrambler

48Hashes `a` with the 31-bit nonzero FNV-1a non-cryptographic hash algorithm,

49producing an atom.

51#### Accepts

53`a` is a noun.

55#### Produces

57An atom.

59#### Source

61```hoon

62 ++ mug

63 ~/ %mug

64 |= a=*

65 ?^ a

66 =+ b=[p=$(a -.a) q=$(a +.a)]

67 |- ^- @

68 =+ c=(fnv (mix p.b (fnv q.b)))

69 =+ d=(mix (rsh 0 31 c) (end 0 31 c))

70 ?. =(0 d) d

71 $(q.b +(q.b))

72 =+ b=2.166.136.261

73 |- ^- @

74 =+ c=b

75 =+ [d=0 e=(met 3 a)]

76 |- ^- @

77 ?: =(d e)

78 =+ f=(mix (rsh 0 31 c) (end 0 31 c))

79 ?. =(0 f) f

80 ^$(b +(b))

81 $(c (fnv (mix c (cut 3 [d 1] a))), d +(d))

82```

84#### Examples

86```

87 > (mug 10.000)

88 178.152.889

90 > (mug 10.001)

91 714.838.017

93 > (mug 1)

94 67.918.732

96 > (mug (some 10))

97 1.872.403.737

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

100 1.067.931.605

101```

102

103

104---

105### `++muk`

106

107Standard MurmurHash3

108

109Implementation of the 32-bit

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

111non-cryptographic hash algorithm. Takes `a` as the seed, `b` as the key length

112in [blocks](@/docs/hoon/library/2c.md) of size 3, and `c` as the key, producing an atom.

114#### Accepts

116`a` is an atom.

118`b` is an atom.

120`c` is an atom.

122#### Produces

124An atom.

126#### Source

128```hoon

129 ++ muk

130 ~% %muk ..muk ~

131 =+ ~(. fe 5)

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

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

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

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

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

137 =/ h1 syd

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

139 =/ blocks (rip 5 key)

140 =/ i nblocks

141 =. h1 =/ hi h1 |-

142 ?: =(0 i) hi :: negative array index

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

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

145 =. k1 (rol 0 15 k1)

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

147 =. hi (mix hi k1)

148 =. hi (rol 0 13 hi)

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

150 $(i (dec i))

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

152 =/ k1 0

153 =/ tlen (dis len 3)

154 =. h1

155 ?+ tlen h1 :: fallthrough switch

156 $3 =. k1 (mix k1 (lsh 0 16 (snag 2 tail)))

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

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

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

160 =. k1 (rol 0 15 k1)

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

162 (mix h1 k1)

163 $2 =. k1 (mix k1 (lsh 0 8 (snag 1 tail)))

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

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

166 =. k1 (rol 0 15 k1)

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

168 (mix h1 k1)

169 $1 =. k1 (mix k1 (snag 0 tail))

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

171 =. k1 (rol 0 15 k1)

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

173 (mix h1 k1)

174 ==

175 =. h1 (mix h1 len)

176 |^ (fmix32 h1)

177 ++ fmix32

178 |= h=@

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

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

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

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

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

184 h

185 --

186```

187

188#### Examples

189

190```

191 > (muk 6 1 3)

192 3.427.677.118

193

194 > (muk 6 2 'jerry')

195 ! exit

196

197 > (muk 6 2 'je')

198 3.602.081.716

199

200 > (met 3 'jerry')

201 5

202

203 > (met 3 'je')

204 2

205

206 > (muk 6 5 'jerry')

207 1.276.447.489

208

209 > (muk 6 15 'jerry')

210 2.881.503.571

211

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

213 > e

214 44.228

215

216 > (muk e 11 10.000)

217 246.077.549

218```

219

220

221---

222### `++mum`

223

22431-bit MurmurHash3 scrambler

225

226Hashes `a` with the 31-bit MurmurHash3 non-cryptographic hash algorithm,

227producing an atom.

229#### Accepts

231`a` is a noun.

233#### Produces

235An atom.

237#### Source

239```hoon

240 ++ mum

241 ~/ %mum

242 |= a=*

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

244 ++ trim

245 |= key=@

246 =+ syd=0xcafe.babe

247 |- ^- @

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

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

250 ?.(=(0 ham) ham $(syd +(syd)))

251```

252

253#### Examples

254

255```

256 > (mum 10.000)

257 795.713.195

258

259 > (mum 10.001)

260 420.521.697

261

262 > (mum 'jerry')

263 1.540.161.753

264

265 > (mum 1)

266 1.901.865.568

267

268 > (mum (some 10))

269 2.099.076.946

270

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

272 1.719.833.228

273```

274

275

276---