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Preliminary kx api

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Missing dependent apis and tests
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Emil Bay 2018-02-15 22:31:13 +01:00
parent b883b2a8df
commit 002969f78d
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1 changed files with 79 additions and 0 deletions
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crypto_kx.js Normal file
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var assert = require('nanoassert')
var randombytes_buf = require('./randombytes').randombytes_buf
var generichash = require('./crypto_generichash')
var crypto_scalarmult_base = require('./crypto_scalarmult').crypto_scalarmult_base
exports.crypto_kx_PUBLICKEYBYTES = 32
exports.crypto_kx_SECRETKEYBYTES = 32
exports.crypto_kx_SEEDBYTES = 32
exports.crypto_kx_SESSIONKEYBYTES = 32
exports.crypto_kx_PRIMITIVE = ''
exports.crypto_kx_keypair = function (pk, sk) {
assert(sk.byteLength >= exports.crypto_kx_SECRETKEYBYTES, 'sk must be at least crypto_kx_SECRETKEYBYTES')
assert(pk.byteLength >= exports.crypto_kx_PUBLICKEYBYTES, 'pk must be at least crypto_kx_PUBLICKEYBYTES')
randombytes_buf(sk.subarray(0, exports.crypto_kx_SECRETKEYBYTES))
crypto_scalarmult_base(
pk.subarray(0, exports.crypto_kx_PUBLICKEYBYTES),
sk.subarray(0, exports.crypto_kx_SECRETKEYBYTES)
)
}
exports.crypto_kx_seed_keypair = function (pk, sk, seed) {
assert(sk.byteLength >= exports.crypto_kx_SECRETKEYBYTES, 'sk must be at least crypto_kx_SECRETKEYBYTES')
assert(pk.byteLength >= exports.crypto_kx_PUBLICKEYBYTES, 'pk must be at least crypto_kx_PUBLICKEYBYTES')
assert(seed.byteLength >= exports.crypto_kx_SEEDBYTES, 'seed must be at least crypto_kx_SEEDBYTES')
generichash.crypto_generichash(
sk.subarray(0, exports.crypto_kx_SECRETKEYBYTES),
seed.subarray(0, exports.crypto_kx_SEEDBYTES)
)
crypto_scalarmult_base(
pk.subarray(0, exports.crypto_kx_PUBLICKEYBYTES),
sk.subarray(0, exports.crypto_kx_SECRETKEYBYTES)
)
}
exports.crypto_kx_client_session_keys = calc.bind(null, false)
exports.crypto_kx_server_session_keys = calc.bind(null, true)
function calc (server, rx, tx, pk, sk, remote_pk) {
if (rx == null) rx = tx
if (tx == null) tx = rx
assert(rx >= exports.crypto_kx_SESSIONKEYBYTES, 'rx must be at least crypto_kx_SESSIONKEYBYTES')
assert(tx >= exports.crypto_kx_SESSIONKEYBYTES, 'tx should be at least crypto_kx_SESSIONKEYBYTES')
assert(sk.byteLength >= exports.crypto_kx_SECRETKEYBYTES, 'sk must be at least crypto_kx_SECRETKEYBYTES')
assert(pk.byteLength >= exports.crypto_kx_PUBLICKEYBYTES, 'pk must be at least crypto_kx_PUBLICKEYBYTES')
assert(remote_pk.byteLength >= exports.crypto_kx_PUBLICKEYBYTES, 'remote_pk must be at least crypto_kx_PUBLICKEYBYTES')
rx = rx.subarray(0, exports.crypto_kx_SESSIONKEYBYTES)
tx = tx.subarray(0, exports.crypto_kx_SESSIONKEYBYTES)
sk = sk.subarray(0, exports.crypto_kx_SECRETKEYBYTES)
pk = pk.subarray(0, exports.crypto_kx_PUBLICKEYBYTES)
remote_pk = remote_pk.subarray(0, exports.crypto_kx_PUBLICKEYBYTES)
var keys = new Uint8Array(2 * exports.crypto_kx_SESSIONKEYBYTES)
var hash = generichash.crypto_generichash_instance(null, keys.byteLength)
var q = new Uint8Array(scalarmult.crypto_scalarmult_BYTES)
scalarmult.crypto_scalamult(q, sk, remote_pk)
hash.update(q)
q.fill(0)
// if server, then remote_pk == client_pk
hash.update(server ? remote_pk : pk)
hash.update(server ? pk : remote_pk)
hash.final(keys)
// TODO clear out hash
rx.set(keys.subarray(0, exports.crypto_kx_SESSIONKEYBYTES))
tx.set(keys.subarray(exports.crypto_kx_SESSIONKEYBYTES))
}