Make BLAKE3 stateful
This commit is contained in:
Miguel Oliveira
parent
db4c272aea
commit
b9457e9dd5
181
blake3.lua
181
blake3.lua
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@ -118,90 +118,164 @@ local function merge(cvl, cvr)
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return cvl
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end
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local function blake3(iv, flags, msg, len)
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-- Set up the state.
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local stateCvs = {}
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local stateCv = iv
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local stateT = 0
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local stateN = 0
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local stateStart = CHUNK_START
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local stateEnd = 0
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local function update(state, message)
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expect(1, state, "table")
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expect(1, message, "string")
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-- Append to buffer.
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state.m = state.m .. message
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-- Split off complete blocks.
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local blockslen = #state.m - (#state.m - 1) % 64 - 1
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local blocks = state.m:sub(1, blockslen)
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state.m = state.m:sub(1 + blockslen)
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-- Digest complete blocks.
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for i = 1, #msg - 64, 64 do
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for i = 1, #blocks, 64 do
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-- Compress the block.
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local block = {("<I4I4I4I4I4I4I4I4I4I4I4I4I4I4I4I4"):unpack(msg, i)}
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local stateFlags = flags + stateStart + stateEnd
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stateCv = compress(stateCv, block, stateT, 64, stateFlags)
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stateStart = 0
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stateN = stateN + 1
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local block = {("<I4I4I4I4I4I4I4I4I4I4I4I4I4I4I4I4"):unpack(blocks, i)}
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local stateFlags = state.f + state.s + state.e
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state.cv = compress(state.cv, block, state.t, 64, stateFlags)
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state.s = 0
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state.n = state.n + 1
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if stateN == 15 then
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if state.n == 15 then
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-- Last block in chunk.
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stateEnd = CHUNK_END
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elseif stateN == 16 then
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state.e = CHUNK_END
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elseif state.n == 16 then
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-- Chunk complete, merge.
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local mergeCv = stateCv
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local mergeAmt = stateT + 1
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local mergeCv = state.cv
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local mergeAmt = state.t + 1
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while mergeAmt % 2 == 0 do
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local block = merge(table.remove(stateCvs), mergeCv)
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mergeCv = compress(iv, block, 0, 64, flags + PARENT)
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local block = merge(table.remove(state.cvs), mergeCv)
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mergeCv = compress(state.iv, block, 0, 64, state.f + PARENT)
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mergeAmt = mergeAmt / 2
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end
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-- Push back.
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table.insert(stateCvs, mergeCv)
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table.insert(state.cvs, mergeCv)
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-- Update state back to next chunk.
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stateCv = iv
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stateT = stateT + 1
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stateN = 0
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stateStart = CHUNK_START
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stateEnd = 0
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state.cv = state.iv
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state.t = state.t + 1
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state.n = 0
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state.s = CHUNK_START
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state.e = 0
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end
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end
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return state
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end
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local function finalize(state)
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-- Pad the last message block.
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local lastLen = #msg == 0 and 0 or (#msg - 1) % 64 + 1
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local padded = msg:sub(-lastLen) .. ("\0"):rep(64)
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local lastLen = #state.m
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local padded = state.m .. ("\0"):rep(64)
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local last = {("<I4I4I4I4I4I4I4I4I4I4I4I4I4I4I4I4"):unpack(padded)}
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-- Prepare output expansion state.
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local outCv, outBlock, outLen, outFlags
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if stateT > 0 then
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if state.t > 0 then
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-- Root is a parent, digest last block now and merge parents.
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local stateFlags = flags + stateStart + CHUNK_END
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local mergeCv = compress(stateCv, last, stateT, lastLen, stateFlags)
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for i = #stateCvs, 2, -1 do
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local block = merge(stateCvs[i], mergeCv)
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mergeCv = compress(iv, block, 0, 64, flags + PARENT)
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local stateFlags = state.f + state.s + CHUNK_END
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local mergeCv = compress(state.cv, last, state.t, lastLen, stateFlags)
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for i = #state.cvs, 2, -1 do
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local block = merge({unpack(state.cvs[i])}, mergeCv)
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mergeCv = compress(state.iv, block, 0, 64, state.f + PARENT)
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end
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-- Set output state.
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outCv = iv
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outBlock = merge(stateCvs[1], mergeCv)
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outLen = 64
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outFlags = flags + ROOT + PARENT
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return {
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expand = expand,
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cv = {unpack(state.iv)},
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m = merge({unpack(state.cvs[1])}, mergeCv),
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n = 64,
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f = state.f + ROOT + PARENT,
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}
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else
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-- Root block is in the first chunk, set output state.
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outCv = stateCv
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outBlock = last
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outLen = lastLen
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outFlags = flags + stateStart + CHUNK_END + ROOT
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-- Root is in the first chunk, set output state.
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return {
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expand = expand,
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cv = {unpack(state.cv)},
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m = last,
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n = lastLen,
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f = state.f + state.s + CHUNK_END + ROOT,
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}
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end
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end
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local function expand(out, len, offset)
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expect(1, out, "table")
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expect(1, len, "number")
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expect(2, offset, "nil", "number")
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offset = offset or 0
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-- Expand output.
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local out = {}
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for i = 0, len / 64 do
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local md = compress(outCv, outBlock, i, outLen, outFlags, true)
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local n = offset + i
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local md = compress(out.cv, out.m, n, out.n, out.f, true)
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out[i + 1] = ("<I4I4I4I4I4I4I4I4I4I4I4I4I4I4I4I4"):pack(unpack(md))
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end
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return table.concat(out):sub(1, len)
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end
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local function copy(state)
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-- Copy CV stack.
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local cvs = {}
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for i = 1, #state.cvs do cvs[i] = {unpack(state.cvs[i])} end
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return {
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update = update,
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finalize = finalize,
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copy = copy,
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iv = {unpack(state.iv)},
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cv = {unpack(state.cv)},
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cvs = cvs,
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m = state.m,
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t = state.t,
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n = state.n,
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s = state.s,
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e = state.e,
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f = state.f,
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}
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end
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local function new(iv, f)
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return {
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update = update,
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finalize = finalize,
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copy = copy,
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iv = iv,
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cv = iv,
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cvs = {},
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m = "",
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t = 0,
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n = 0,
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s = CHUNK_START,
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e = 0,
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f = f,
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}
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end
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local mod = {}
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function mod.new()
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return new({unpack(IV)}, 0)
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end
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function mod.newKeyed(key)
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expect(1, key, "string")
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assert(#key == 32, "key length must be 32")
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return new({("<I4I4I4I4I4I4I4I4"):unpack(key)}, KEYED_HASH)
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end
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function mod.newDk(context)
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expect(1, context, "string")
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local iv = new(IV, DERIVE_KEY_CONTEXT):update(context):finalize():expand(32)
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return new({("<I4I4I4I4I4I4I4I4"):unpack(iv)}, DERIVE_KEY_MATERIAL)
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end
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--- Hashes data using BLAKE3.
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--
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-- @tparam string message The input message.
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@ -213,8 +287,7 @@ function mod.digest(message, len)
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expect(2, len, "number", "nil")
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len = len or 32
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assert(len % 1 == 0 and len >= 1, "length must be a positive integer")
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return blake3(IV, 0, message, len)
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return new(IV, 0):update(message):finalize():expand(len)
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end
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--- Performs a keyed hash.
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@ -231,8 +304,8 @@ function mod.digestKeyed(key, message, len)
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expect(3, len, "number", "nil")
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len = len or 32
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assert(len % 1 == 0 and len >= 1, "length must be a positive integer")
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return blake3({("<I4I4I4I4I4I4I4I4"):unpack(key)}, KEYED_HASH, message, len)
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local h = new({("<I4I4I4I4I4I4I4I4"):unpack(key)}, KEYED_HASH)
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return h:update(message):finalize():expand(len)
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end
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--- Makes a context-based key derivation function (KDF).
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@ -242,17 +315,15 @@ end
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--
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function mod.deriveKey(context)
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expect(1, context, "string")
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local hash = blake3(IV, DERIVE_KEY_CONTEXT, context, 32)
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local iv = {("<I4I4I4I4I4I4I4I4"):unpack(hash)}
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local iv = new(IV, DERIVE_KEY_CONTEXT):update(context):finalize():expand(32)
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return function(material, len)
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expect(1, material, "string")
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expect(2, len, "number", "nil")
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len = len or 32
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assert(len % 1 == 0 and len >= 1, "length must be a positive integer")
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return blake3(iv, DERIVE_KEY_MATERIAL, material, len)
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local h = new({("<I4I4I4I4I4I4I4I4"):unpack(iv)}, DERIVE_KEY_MATERIAL)
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return h:update(material):finalize():expand(len)
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end
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end
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