sodium-javascript/crypto_sign.js
2020-06-24 14:08:55 +02:00

320 lines
6.7 KiB
JavaScript

/* eslint-disable camelcase, one-var */
const { crypto_verify_32 } = require('./crypto_verify')
const { crypto_hash } = require('./crypto_hash')
const {
gf, gf0, gf1, D, D2,
X, Y, I, A, Z, M, S,
sel25519, pack25519,
inv25519, unpack25519
} = require('./internal/ed25519')
const { randombytes } = require('./randombytes')
const crypto_sign_BYTES = 64
const crypto_sign_PUBLICKEYBYTES = 32
const crypto_sign_SECRETKEYBYTES = 64
const crypto_sign_SEEDBYTES = 32
module.exports = {
crypto_sign_keypair,
crypto_sign_seed_keypair,
crypto_sign,
crypto_sign_detached,
crypto_sign_open,
crypto_sign_verify_detached,
crypto_sign_BYTES,
crypto_sign_PUBLICKEYBYTES,
crypto_sign_SECRETKEYBYTES,
crypto_sign_SEEDBYTES
}
function set25519 (r, a) {
for (let i = 0; i < 16; i++) r[i] = a[i] | 0
}
function pow2523 (o, i) {
var c = gf()
var a
for (a = 0; a < 16; a++) c[a] = i[a]
for (a = 250; a >= 0; a--) {
S(c, c)
if (a !== 1) M(c, c, i)
}
for (a = 0; a < 16; a++) o[a] = c[a]
}
function add (p, q) {
var a = gf(), b = gf(), c = gf(),
d = gf(), e = gf(), f = gf(),
g = gf(), h = gf(), t = gf()
Z(a, p[1], p[0])
Z(t, q[1], q[0])
M(a, a, t)
A(b, p[0], p[1])
A(t, q[0], q[1])
M(b, b, t)
M(c, p[3], q[3])
M(c, c, D2)
M(d, p[2], q[2])
A(d, d, d)
Z(e, b, a)
Z(f, d, c)
A(g, d, c)
A(h, b, a)
M(p[0], e, f)
M(p[1], h, g)
M(p[2], g, f)
M(p[3], e, h)
}
function cswap (p, q, b) {
var i
for (i = 0; i < 4; i++) {
sel25519(p[i], q[i], b)
}
}
function pack (r, p) {
var tx = gf(), ty = gf(), zi = gf()
inv25519(zi, p[2])
M(tx, p[0], zi)
M(ty, p[1], zi)
pack25519(r, ty)
r[31] ^= par25519(tx) << 7
}
function scalarmult (p, q, s) {
var b, i
set25519(p[0], gf0)
set25519(p[1], gf1)
set25519(p[2], gf1)
set25519(p[3], gf0)
for (i = 255; i >= 0; --i) {
b = (s[(i / 8) | 0] >> (i & 7)) & 1
cswap(p, q, b)
add(q, p)
add(p, p)
cswap(p, q, b)
}
}
function scalarbase (p, s) {
var q = [gf(), gf(), gf(), gf()]
set25519(q[0], X)
set25519(q[1], Y)
set25519(q[2], gf1)
M(q[3], X, Y)
scalarmult(p, q, s)
}
function crypto_sign_keypair (pk, sk, seeded) {
check(pk, crypto_sign_PUBLICKEYBYTES)
check(sk, crypto_sign_SECRETKEYBYTES)
var d = new Uint8Array(64)
var p = [gf(), gf(), gf(), gf()]
var i
if (!seeded) randombytes(sk, 32)
crypto_hash(d, sk, 32)
d[0] &= 248
d[31] &= 127
d[31] |= 64
scalarbase(p, d)
pack(pk, p)
for (i = 0; i < 32; i++) sk[i + 32] = pk[i]
return 0
}
function crypto_sign_seed_keypair (pk, sk, seed) {
check(seed, crypto_sign_SEEDBYTES)
sk.set(seed)
return crypto_sign_keypair(pk, sk, true)
}
var L = new Float64Array([0xed, 0xd3, 0xf5, 0x5c, 0x1a, 0x63, 0x12, 0x58, 0xd6, 0x9c, 0xf7, 0xa2, 0xde, 0xf9, 0xde, 0x14, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0x10])
function modL (r, x) {
var carry, i, j, k
for (i = 63; i >= 32; --i) {
carry = 0
for (j = i - 32, k = i - 12; j < k; ++j) {
x[j] += carry - 16 * x[i] * L[j - (i - 32)]
carry = (x[j] + 128) >> 8
x[j] -= carry * 256
}
x[j] += carry
x[i] = 0
}
carry = 0
for (j = 0; j < 32; j++) {
x[j] += carry - (x[31] >> 4) * L[j]
carry = x[j] >> 8
x[j] &= 255
}
for (j = 0; j < 32; j++) x[j] -= carry * L[j]
for (i = 0; i < 32; i++) {
x[i + 1] += x[i] >> 8
r[i] = x[i] & 255
}
}
function reduce (r) {
var x = new Float64Array(64)
for (let i = 0; i < 64; i++) x[i] = r[i]
for (let i = 0; i < 64; i++) r[i] = 0
modL(r, x)
}
// Note: difference from C - smlen returned, not passed as argument.
function crypto_sign (sm, m, sk) {
check(sm, crypto_sign_BYTES + m.length)
check(m, 0)
check(sk, crypto_sign_SECRETKEYBYTES)
var n = m.length
var d = new Uint8Array(64), h = new Uint8Array(64), r = new Uint8Array(64)
var i, j, x = new Float64Array(64)
var p = [gf(), gf(), gf(), gf()]
crypto_hash(d, sk, 32)
d[0] &= 248
d[31] &= 127
d[31] |= 64
var smlen = n + 64
for (i = 0; i < n; i++) sm[64 + i] = m[i]
for (i = 0; i < 32; i++) sm[32 + i] = d[32 + i]
crypto_hash(r, sm.subarray(32), n + 32)
reduce(r)
scalarbase(p, r)
pack(sm, p)
for (i = 32; i < 64; i++) sm[i] = sk[i]
crypto_hash(h, sm, n + 64)
reduce(h)
for (i = 0; i < 64; i++) x[i] = 0
for (i = 0; i < 32; i++) x[i] = r[i]
for (i = 0; i < 32; i++) {
for (j = 0; j < 32; j++) {
x[i + j] += h[i] * d[j]
}
}
modL(sm.subarray(32), x)
return smlen
}
function crypto_sign_detached (sig, m, sk) {
var sm = new Uint8Array(m.length + crypto_sign_BYTES)
crypto_sign(sm, m, sk)
for (let i = 0; i < crypto_sign_BYTES; i++) sig[i] = sm[i]
}
function unpackneg (r, p) {
var t = gf(), chk = gf(), num = gf(),
den = gf(), den2 = gf(), den4 = gf(),
den6 = gf()
set25519(r[2], gf1)
unpack25519(r[1], p)
S(num, r[1])
M(den, num, D)
Z(num, num, r[2])
A(den, r[2], den)
S(den2, den)
S(den4, den2)
M(den6, den4, den2)
M(t, den6, num)
M(t, t, den)
pow2523(t, t)
M(t, t, num)
M(t, t, den)
M(t, t, den)
M(r[0], t, den)
S(chk, r[0])
M(chk, chk, den)
if (neq25519(chk, num)) M(r[0], r[0], I)
S(chk, r[0])
M(chk, chk, den)
if (neq25519(chk, num)) return -1
if (par25519(r[0]) === (p[31] >> 7)) Z(r[0], gf0, r[0])
M(r[3], r[0], r[1])
return 0
}
function crypto_sign_open (msg, sm, pk) {
check(msg, sm.length - crypto_sign_BYTES)
check(sm, crypto_sign_BYTES)
check(pk, crypto_sign_PUBLICKEYBYTES)
var n = sm.length
var m = new Uint8Array(sm.length)
var i, mlen
var t = new Uint8Array(32), h = new Uint8Array(64)
var p = [gf(), gf(), gf(), gf()],
q = [gf(), gf(), gf(), gf()]
mlen = -1
if (n < 64) return false
if (unpackneg(q, pk)) return false
for (i = 0; i < n; i++) m[i] = sm[i]
for (i = 0; i < 32; i++) m[i + 32] = pk[i]
crypto_hash(h, m, n)
reduce(h)
scalarmult(p, q, h)
scalarbase(q, sm.subarray(32))
add(p, q)
pack(t, p)
n -= 64
if (crypto_verify_32(sm, 0, t, 0)) {
for (i = 0; i < n; i++) m[i] = 0
throw new Error('crypto_sign_open failed')
}
for (i = 0; i < n; i++) msg[i] = sm[i + 64]
mlen = n
return mlen
}
function crypto_sign_verify_detached (sig, m, pk) {
check(sig, crypto_sign_BYTES)
var sm = new Uint8Array(m.length + crypto_sign_BYTES)
var i = 0
for (i = 0; i < crypto_sign_BYTES; i++) sm[i] = sig[i]
for (i = 0; i < m.length; i++) sm[i + crypto_sign_BYTES] = m[i]
return crypto_sign_open(m, sm, pk)
}
function par25519 (a) {
var d = new Uint8Array(32)
pack25519(d, a)
return d[0] & 1
}
function neq25519 (a, b) {
var c = new Uint8Array(32), d = new Uint8Array(32)
pack25519(c, a)
pack25519(d, b)
return crypto_verify_32(c, 0, d, 0)
}
function check (buf, len) {
if (!buf || (len && buf.length < len)) throw new Error('Argument must be a buffer' + (len ? ' of length ' + len : ''))
}