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author | 2020-11-16 00:10:28 +0100 | |
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committer | 2020-11-16 00:10:28 +0100 | |
commit | e06ec920f7a5d784e674c4c4b4e6d1da3dc7391d (patch) | |
tree | 55713f725f77b44ebfec86e4eec3ce33e71458ca /node_modules/browserify-aes/ghash.js | |
download | website_creator-e06ec920f7a5d784e674c4c4b4e6d1da3dc7391d.tar.gz website_creator-e06ec920f7a5d784e674c4c4b4e6d1da3dc7391d.tar.bz2 website_creator-e06ec920f7a5d784e674c4c4b4e6d1da3dc7391d.zip |
api, login, auth
Diffstat (limited to 'node_modules/browserify-aes/ghash.js')
-rw-r--r-- | node_modules/browserify-aes/ghash.js | 89 |
1 files changed, 89 insertions, 0 deletions
diff --git a/node_modules/browserify-aes/ghash.js b/node_modules/browserify-aes/ghash.js new file mode 100644 index 0000000..26bfedd --- /dev/null +++ b/node_modules/browserify-aes/ghash.js @@ -0,0 +1,89 @@ +var Buffer = require('safe-buffer').Buffer +var ZEROES = Buffer.alloc(16, 0) + +function toArray (buf) { + return [ + buf.readUInt32BE(0), + buf.readUInt32BE(4), + buf.readUInt32BE(8), + buf.readUInt32BE(12) + ] +} + +function fromArray (out) { + var buf = Buffer.allocUnsafe(16) + buf.writeUInt32BE(out[0] >>> 0, 0) + buf.writeUInt32BE(out[1] >>> 0, 4) + buf.writeUInt32BE(out[2] >>> 0, 8) + buf.writeUInt32BE(out[3] >>> 0, 12) + return buf +} + +function GHASH (key) { + this.h = key + this.state = Buffer.alloc(16, 0) + this.cache = Buffer.allocUnsafe(0) +} + +// from http://bitwiseshiftleft.github.io/sjcl/doc/symbols/src/core_gcm.js.html +// by Juho Vähä-Herttua +GHASH.prototype.ghash = function (block) { + var i = -1 + while (++i < block.length) { + this.state[i] ^= block[i] + } + this._multiply() +} + +GHASH.prototype._multiply = function () { + var Vi = toArray(this.h) + var Zi = [0, 0, 0, 0] + var j, xi, lsbVi + var i = -1 + while (++i < 128) { + xi = (this.state[~~(i / 8)] & (1 << (7 - (i % 8)))) !== 0 + if (xi) { + // Z_i+1 = Z_i ^ V_i + Zi[0] ^= Vi[0] + Zi[1] ^= Vi[1] + Zi[2] ^= Vi[2] + Zi[3] ^= Vi[3] + } + + // Store the value of LSB(V_i) + lsbVi = (Vi[3] & 1) !== 0 + + // V_i+1 = V_i >> 1 + for (j = 3; j > 0; j--) { + Vi[j] = (Vi[j] >>> 1) | ((Vi[j - 1] & 1) << 31) + } + Vi[0] = Vi[0] >>> 1 + + // If LSB(V_i) is 1, V_i+1 = (V_i >> 1) ^ R + if (lsbVi) { + Vi[0] = Vi[0] ^ (0xe1 << 24) + } + } + this.state = fromArray(Zi) +} + +GHASH.prototype.update = function (buf) { + this.cache = Buffer.concat([this.cache, buf]) + var chunk + while (this.cache.length >= 16) { + chunk = this.cache.slice(0, 16) + this.cache = this.cache.slice(16) + this.ghash(chunk) + } +} + +GHASH.prototype.final = function (abl, bl) { + if (this.cache.length) { + this.ghash(Buffer.concat([this.cache, ZEROES], 16)) + } + + this.ghash(fromArray([0, abl, 0, bl])) + return this.state +} + +module.exports = GHASH |