sodium-javascript/crypto_scalarmult.js
2021-11-19 21:43:58 -08:00

106 lines
2.8 KiB
JavaScript

/* eslint-disable camelcase, one-var */
const ristretto255 = require('ristretto255')
const { crypto_core_ristretto255_BYTES, crypto_core_ristretto255_SCALARBYTES } = require('./crypto_core_ristretto255')
const { _9, _121665, gf, inv25519, pack25519, unpack25519, sel25519, A, M, Z, S } = require('./internal/ed25519')
const crypto_scalarmult_BYTES = 32
const crypto_scalarmult_SCALARBYTES = 32
module.exports = {
crypto_scalarmult,
crypto_scalarmult_base,
crypto_scalarmult_BYTES,
crypto_scalarmult_SCALARBYTES,
crypto_scalarmult_ristretto255,
crypto_scalarmult_ristretto255_base,
crypto_scalarmult_ristretto255_bytes,
crypto_scalarmult_ristretto255_scalarbytes,
crypto_scalarmult_ristretto255_BYTES: crypto_core_ristretto255_BYTES,
crypto_scalarmult_ristretto255_SCALARBYTES: crypto_core_ristretto255_SCALARBYTES
}
function crypto_scalarmult_ristretto255 (q, n, p) {
check(q, crypto_core_ristretto255_BYTES)
check(n, crypto_core_ristretto255_SCALARBYTES)
check(p, crypto_core_ristretto255_BYTES)
return q.set(ristretto255.scalarMult(n, p))
}
function crypto_scalarmult_ristretto255_base (q, n) {
check(q, crypto_core_ristretto255_BYTES)
check(n, crypto_core_ristretto255_SCALARBYTES)
return q.set(ristretto255.scalarMultBase(n))
}
function crypto_scalarmult_ristretto255_bytes () {
return crypto_scalarmult_ristretto255_BYTES
}
function crypto_scalarmult_ristretto255_scalarbytes () {
return crypto_scalarmult_ristretto255_SCALARBYTES
}
function crypto_scalarmult (q, n, p) {
check(q, crypto_scalarmult_BYTES)
check(n, crypto_scalarmult_SCALARBYTES)
check(p, crypto_scalarmult_BYTES)
var z = new Uint8Array(32)
var x = new Float64Array(80), r, i
var a = gf(), b = gf(), c = gf(),
d = gf(), e = gf(), f = gf()
for (i = 0; i < 31; i++) z[i] = n[i]
z[31] = (n[31] & 127) | 64
z[0] &= 248
unpack25519(x, p)
for (i = 0; i < 16; i++) {
b[i] = x[i]
d[i] = a[i] = c[i] = 0
}
a[0] = d[0] = 1
for (i = 254; i >= 0; --i) {
r = (z[i >>> 3] >>> (i & 7)) & 1
sel25519(a, b, r)
sel25519(c, d, r)
A(e, a, c)
Z(a, a, c)
A(c, b, d)
Z(b, b, d)
S(d, e)
S(f, a)
M(a, c, a)
M(c, b, e)
A(e, a, c)
Z(a, a, c)
S(b, a)
Z(c, d, f)
M(a, c, _121665)
A(a, a, d)
M(c, c, a)
M(a, d, f)
M(d, b, x)
S(b, e)
sel25519(a, b, r)
sel25519(c, d, r)
}
for (i = 0; i < 16; i++) {
x[i + 16] = a[i]
x[i + 32] = c[i]
x[i + 48] = b[i]
x[i + 64] = d[i]
}
var x32 = x.subarray(32)
var x16 = x.subarray(16)
inv25519(x32, x32)
M(x16, x16, x32)
pack25519(q, x16)
return 0
}
function crypto_scalarmult_base (q, n) {
return crypto_scalarmult(q, n, _9)
}
function check (buf, len) {
if (!buf || (len && buf.length < len)) throw new Error('Argument must be a buffer' + (len ? ' of length ' + len : ''))
}