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Encryption, authentication, Secure communication
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JavaScript
// SHA-256 (+ HMAC and PBKDF2) for JavaScript.
//
// Written in 2014-2016 by Dmitry Chestnykh.
// Public domain, no warranty.
//
// Functions (accept and return Uint8Arrays):
//
// sha256(message) -> hash
// sha256.hmac(key, message) -> mac
// sha256.pbkdf2(password, salt, rounds, dkLen) -> dk
//
// Classes:
//
// new sha256.Hash()
// new sha256.HMAC(key)
//
export var digestLength = 32
export var blockSize = 64
// SHA-256 constants
const K = new Uint32Array([
0x428a2f98, 0x71374491, 0xb5c0fbcf, 0xe9b5dba5, 0x3956c25b,
0x59f111f1, 0x923f82a4, 0xab1c5ed5, 0xd807aa98, 0x12835b01,
0x243185be, 0x550c7dc3, 0x72be5d74, 0x80deb1fe, 0x9bdc06a7,
0xc19bf174, 0xe49b69c1, 0xefbe4786, 0x0fc19dc6, 0x240ca1cc,
0x2de92c6f, 0x4a7484aa, 0x5cb0a9dc, 0x76f988da, 0x983e5152,
0xa831c66d, 0xb00327c8, 0xbf597fc7, 0xc6e00bf3, 0xd5a79147,
0x06ca6351, 0x14292967, 0x27b70a85, 0x2e1b2138, 0x4d2c6dfc,
0x53380d13, 0x650a7354, 0x766a0abb, 0x81c2c92e, 0x92722c85,
0xa2bfe8a1, 0xa81a664b, 0xc24b8b70, 0xc76c51a3, 0xd192e819,
0xd6990624, 0xf40e3585, 0x106aa070, 0x19a4c116, 0x1e376c08,
0x2748774c, 0x34b0bcb5, 0x391c0cb3, 0x4ed8aa4a, 0x5b9cca4f,
0x682e6ff3, 0x748f82ee, 0x78a5636f, 0x84c87814, 0x8cc70208,
0x90befffa, 0xa4506ceb, 0xbef9a3f7, 0xc67178f2
])
function hashBlocks (w, v, p, pos, len) {
let a, b, c, d, e, f, g, h, u, i, j, t1, t2
while (len >= 64) {
a = v[0]
b = v[1]
c = v[2]
d = v[3]
e = v[4]
f = v[5]
g = v[6]
h = v[7]
for (i = 0; i < 16; i++) {
j = pos + i * 4
w[i] = (((p[j] & 0xff) << 24) | ((p[j + 1] & 0xff) << 16) |
((p[j + 2] & 0xff) << 8) | (p[j + 3] & 0xff))
}
for (i = 16; i < 64; i++) {
u = w[i - 2]
t1 = (u >>> 17 | u << (32 - 17)) ^ (u >>> 19 | u << (32 - 19)) ^ (u >>> 10)
u = w[i - 15]
t2 = (u >>> 7 | u << (32 - 7)) ^ (u >>> 18 | u << (32 - 18)) ^ (u >>> 3)
w[i] = (t1 + w[i - 7] | 0) + (t2 + w[i - 16] | 0)
}
for (i = 0; i < 64; i++) {
t1 = (((((e >>> 6 | e << (32 - 6)) ^ (e >>> 11 | e << (32 - 11)) ^
(e >>> 25 | e << (32 - 25))) + ((e & f) ^ (~e & g))) | 0) +
((h + ((K[i] + w[i]) | 0)) | 0)) | 0
t2 = (((a >>> 2 | a << (32 - 2)) ^ (a >>> 13 | a << (32 - 13)) ^
(a >>> 22 | a << (32 - 22))) + ((a & b) ^ (a & c) ^ (b & c))) | 0
h = g
g = f
f = e
e = (d + t1) | 0
d = c
c = b
b = a
a = (t1 + t2) | 0
}
v[0] += a
v[1] += b
v[2] += c
v[3] += d
v[4] += e
v[5] += f
v[6] += g
v[7] += h
pos += 64
len -= 64
}
return pos
}
// Hash implements SHA256 hash algorithm.
const Hash = /** @class */ (function () {
function Hash () {
this.digestLength = digestLength
this.blockSize = blockSize
// Note: Int32Array is used instead of Uint32Array for performance reasons.
this.state = new Int32Array(8) // hash state
this.temp = new Int32Array(64) // temporary state
this.buffer = new Uint8Array(128) // buffer for data to hash
this.bufferLength = 0 // number of bytes in buffer
this.bytesHashed = 0 // number of total bytes hashed
this.finished = false // indicates whether the hash was finalized
this.reset()
}
// Resets hash state making it possible
// to re-use this instance to hash other data.
Hash.prototype.reset = function () {
this.state[0] = 0x6a09e667
this.state[1] = 0xbb67ae85
this.state[2] = 0x3c6ef372
this.state[3] = 0xa54ff53a
this.state[4] = 0x510e527f
this.state[5] = 0x9b05688c
this.state[6] = 0x1f83d9ab
this.state[7] = 0x5be0cd19
this.bufferLength = 0
this.bytesHashed = 0
this.finished = false
return this
}
// Cleans internal buffers and re-initializes hash state.
Hash.prototype.clean = function () {
for (var i = 0; i < this.buffer.length; i++) {
this.buffer[i] = 0
}
for (var i = 0; i < this.temp.length; i++) {
this.temp[i] = 0
}
this.reset()
}
// Updates hash state with the given data.
//
// Optionally, length of the data can be specified to hash
// fewer bytes than data.length.
//
// Throws error when trying to update already finalized hash:
// instance must be reset to use it again.
Hash.prototype.update = function (data, dataLength) {
if (dataLength === void 0) { dataLength = data.length }
if (this.finished) {
throw new Error("SHA256: can't update because hash was finished.")
}
let dataPos = 0
this.bytesHashed += dataLength
if (this.bufferLength > 0) {
while (this.bufferLength < 64 && dataLength > 0) {
this.buffer[this.bufferLength++] = data[dataPos++]
dataLength--
}
if (this.bufferLength === 64) {
hashBlocks(this.temp, this.state, this.buffer, 0, 64)
this.bufferLength = 0
}
}
if (dataLength >= 64) {
dataPos = hashBlocks(this.temp, this.state, data, dataPos, dataLength)
dataLength %= 64
}
while (dataLength > 0) {
this.buffer[this.bufferLength++] = data[dataPos++]
dataLength--
}
return this
}
// Finalizes hash state and puts hash into out.
//
// If hash was already finalized, puts the same value.
Hash.prototype.finish = function (out) {
if (!this.finished) {
const bytesHashed = this.bytesHashed
const left = this.bufferLength
const bitLenHi = (bytesHashed / 0x20000000) | 0
const bitLenLo = bytesHashed << 3
const padLength = (bytesHashed % 64 < 56) ? 64 : 128
this.buffer[left] = 0x80
for (var i = left + 1; i < padLength - 8; i++) {
this.buffer[i] = 0
}
this.buffer[padLength - 8] = (bitLenHi >>> 24) & 0xff
this.buffer[padLength - 7] = (bitLenHi >>> 16) & 0xff
this.buffer[padLength - 6] = (bitLenHi >>> 8) & 0xff
this.buffer[padLength - 5] = (bitLenHi >>> 0) & 0xff
this.buffer[padLength - 4] = (bitLenLo >>> 24) & 0xff
this.buffer[padLength - 3] = (bitLenLo >>> 16) & 0xff
this.buffer[padLength - 2] = (bitLenLo >>> 8) & 0xff
this.buffer[padLength - 1] = (bitLenLo >>> 0) & 0xff
hashBlocks(this.temp, this.state, this.buffer, 0, padLength)
this.finished = true
}
for (var i = 0; i < 8; i++) {
out[i * 4 + 0] = (this.state[i] >>> 24) & 0xff
out[i * 4 + 1] = (this.state[i] >>> 16) & 0xff
out[i * 4 + 2] = (this.state[i] >>> 8) & 0xff
out[i * 4 + 3] = (this.state[i] >>> 0) & 0xff
}
return this
}
// Returns the final hash digest.
Hash.prototype.digest = function () {
const out = new Uint8Array(this.digestLength)
this.finish(out)
return out
}
// Internal function for use in HMAC for optimization.
Hash.prototype._saveState = function (out) {
for (let i = 0; i < this.state.length; i++) {
out[i] = this.state[i]
}
}
// Internal function for use in HMAC for optimization.
Hash.prototype._restoreState = function (from, bytesHashed) {
for (let i = 0; i < this.state.length; i++) {
this.state[i] = from[i]
}
this.bytesHashed = bytesHashed
this.finished = false
this.bufferLength = 0
}
return Hash
}())
export { Hash }
// HMAC implements HMAC-SHA256 message authentication algorithm.
const HMAC = /** @class */ (function () {
function HMAC (key) {
this.inner = new Hash()
this.outer = new Hash()
this.blockSize = this.inner.blockSize
this.digestLength = this.inner.digestLength
const pad = new Uint8Array(this.blockSize)
if (key.length > this.blockSize) {
(new Hash()).update(key).finish(pad).clean()
} else {
for (var i = 0; i < key.length; i++) {
pad[i] = key[i]
}
}
for (var i = 0; i < pad.length; i++) {
pad[i] ^= 0x36
}
this.inner.update(pad)
for (var i = 0; i < pad.length; i++) {
pad[i] ^= 0x36 ^ 0x5c
}
this.outer.update(pad)
this.istate = new Uint32Array(8)
this.ostate = new Uint32Array(8)
this.inner._saveState(this.istate)
this.outer._saveState(this.ostate)
for (var i = 0; i < pad.length; i++) {
pad[i] = 0
}
}
// Returns HMAC state to the state initialized with key
// to make it possible to run HMAC over the other data with the same
// key without creating a new instance.
HMAC.prototype.reset = function () {
this.inner._restoreState(this.istate, this.inner.blockSize)
this.outer._restoreState(this.ostate, this.outer.blockSize)
return this
}
// Cleans HMAC state.
HMAC.prototype.clean = function () {
for (let i = 0; i < this.istate.length; i++) {
this.ostate[i] = this.istate[i] = 0
}
this.inner.clean()
this.outer.clean()
}
// Updates state with provided data.
HMAC.prototype.update = function (data) {
this.inner.update(data)
return this
}
// Finalizes HMAC and puts the result in out.
HMAC.prototype.finish = function (out) {
if (this.outer.finished) {
this.outer.finish(out)
} else {
this.inner.finish(out)
this.outer.update(out, this.digestLength).finish(out)
}
return this
}
// Returns message authentication code.
HMAC.prototype.digest = function () {
const out = new Uint8Array(this.digestLength)
this.finish(out)
return out
}
return HMAC
}())
export { HMAC }
// Returns SHA256 hash of data.
export function hash (data) {
const h = (new Hash()).update(data)
const digest = h.digest()
h.clean()
return digest
}
// Function hash is both available as module.hash and as default export.
// export default hash
// Returns HMAC-SHA256 of data under the key.
export function hmac (key, data) {
const h = (new HMAC(key)).update(data)
const digest = h.digest()
h.clean()
return digest
}
// Fills hkdf buffer like this:
// T(1) = HMAC-Hash(PRK, T(0) | info | 0x01)
function fillBuffer (buffer, hmac, info, counter) {
// Counter is a byte value: check if it overflowed.
const num = counter[0]
if (num === 0) {
throw new Error('hkdf: cannot expand more')
}
// Prepare HMAC instance for new data with old key.
hmac.reset()
// Hash in previous output if it was generated
// (i.e. counter is greater than 1).
if (num > 1) {
hmac.update(buffer)
}
// Hash in info if it exists.
if (info) {
hmac.update(info)
}
// Hash in the counter.
hmac.update(counter)
// Output result to buffer and clean HMAC instance.
hmac.finish(buffer)
// Increment counter inside typed array, this works properly.
counter[0]++
}
const hkdfSalt = new Uint8Array(digestLength) // Filled with zeroes.
export function hkdf (key, salt, info, length) {
if (salt === void 0) { salt = hkdfSalt }
if (length === void 0) { length = 32 }
const counter = new Uint8Array([1])
// HKDF-Extract uses salt as HMAC key, and key as data.
const okm = hmac(salt, key)
// Initialize HMAC for expanding with extracted key.
// Ensure no collisions with `hmac` function.
const hmac_ = new HMAC(okm)
// Allocate buffer.
const buffer = new Uint8Array(hmac_.digestLength)
let bufpos = buffer.length
const out = new Uint8Array(length)
for (let i = 0; i < length; i++) {
if (bufpos === buffer.length) {
fillBuffer(buffer, hmac_, info, counter)
bufpos = 0
}
out[i] = buffer[bufpos++]
}
hmac_.clean()
buffer.fill(0)
counter.fill(0)
return out
}
// Derives a key from password and salt using PBKDF2-HMAC-SHA256
// with the given number of iterations.
//
// The number of bytes returned is equal to dkLen.
//
// (For better security, avoid dkLen greater than hash length - 32 bytes).
export function pbkdf2 (password, salt, iterations, dkLen) {
const prf = new HMAC(password)
const len = prf.digestLength
const ctr = new Uint8Array(4)
const t = new Uint8Array(len)
const u = new Uint8Array(len)
const dk = new Uint8Array(dkLen)
for (var i = 0; i * len < dkLen; i++) {
const c = i + 1
ctr[0] = (c >>> 24) & 0xff
ctr[1] = (c >>> 16) & 0xff
ctr[2] = (c >>> 8) & 0xff
ctr[3] = (c >>> 0) & 0xff
prf.reset()
prf.update(salt)
prf.update(ctr)
prf.finish(u)
for (var j = 0; j < len; j++) {
t[j] = u[j]
}
for (var j = 2; j <= iterations; j++) {
prf.reset()
prf.update(u).finish(u)
for (let k = 0; k < len; k++) {
t[k] ^= u[k]
}
}
for (var j = 0; j < len && i * len + j < dkLen; j++) {
dk[i * len + j] = t[j]
}
}
for (var i = 0; i < len; i++) {
t[i] = u[i] = 0
}
for (var i = 0; i < 4; i++) {
ctr[i] = 0
}
prf.clean()
return dk
}