65 lines
1.4 KiB
Nim
65 lines
1.4 KiB
Nim
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import spec/digest
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type Randao* = object
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seed: Eth2Digest
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const MaxRandaoLevels = 10000
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proc initRandao*(seed: Eth2Digest): Randao =
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result.seed = seed
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proc initRandao*(bytes: openarray[byte]): Randao =
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if bytes.len != sizeof(Eth2Digest):
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raise newException(Exception, "Wrong randao size")
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var s: Eth2Digest
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s.data[0 .. ^1] = bytes
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initRandao(bytes)
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func repeatHash*(h: Eth2Digest, n: int): Eth2Digest =
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if n == 0: h
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else: repeatHash(eth2Hash(h.data), n - 1)
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iterator items(r: Randao): Eth2Digest =
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var h = r.seed
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for i in 0 .. MaxRandaoLevels:
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yield h
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h = eth2hash(h.data)
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proc initialCommitment*(r: Randao): Eth2Digest =
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var i = 0
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for h in r:
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if i == MaxRandaoLevels:
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return h
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inc i
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assert(false, "Unreachable")
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proc reveal*(r: Randao, commitment: Eth2Digest): Eth2Digest =
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if commitment == r.seed:
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raise newException(Exception, "Randao: cannot reveal for seed")
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result = r.seed
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for h in r:
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if h == commitment:
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return
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result = h
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raise newException(Exception, "Randao: commitment not found")
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when isMainModule:
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import times, nimcrypto
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var seed: Eth2Digest
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let r = initRandao(seed)
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var s = epochTime()
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var ic = r.initialCommitment()
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var e = epochTime()
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echo "initialCommitment: ", ic
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echo "Took time: ", e - s
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s = epochTime()
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let rev = r.reveal(ic)
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e = epochTime()
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echo "reveal: ", rev
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echo "Took time: ", e - s
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echo r.reveal(eth2hash([1.byte, 2, 3]))
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