mirror of https://github.com/status-im/nim-eth.git
45 lines
1.2 KiB
Nim
45 lines
1.2 KiB
Nim
# nim-eth
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# Copyright (c) 2020-2023 Status Research & Development GmbH
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# Licensed and distributed under either of
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# * MIT license (license terms in the root directory or at https://opensource.org/licenses/MIT).
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# * Apache v2 license (license terms in the root directory or at https://www.apache.org/licenses/LICENSE-2.0).
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# at your option. This file may not be copied, modified, or distributed except according to those terms.
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#
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{.push raises: [].}
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import
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nimcrypto/[hmac, hash]
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export hmac, hash
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proc hkdf*(
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HashType: typedesc, ikm, salt, info: openArray[byte],
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output: var openArray[byte]) =
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var ctx: HMAC[HashType]
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ctx.init(salt)
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ctx.update(ikm)
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let prk = ctx.finish().data
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const hashLen = HashType.bits div 8
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var t: MDigest[HashType.bits]
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var numIters = output.len div hashLen
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if output.len mod hashLen != 0:
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inc numIters
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for i in 0 ..< numIters:
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ctx.init(prk)
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if i != 0:
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ctx.update(t.data)
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ctx.update(info)
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ctx.update([uint8(i + 1)])
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t = ctx.finish()
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let iStart = i * hashLen
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var sz = hashLen
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if iStart + sz >= output.len:
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sz = output.len - iStart
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copyMem(addr output[iStart], addr t.data, sz)
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ctx.clear()
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