Implement OCB mode
This commit is contained in:
Daniel Huigens
parent
cc4cc38fe7
commit
ba2b761da4
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@ -14,6 +14,7 @@ import hash from './hash';
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import cfb from './cfb';
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import gcm from './gcm';
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import eax from './eax';
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import ocb from './ocb';
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import publicKey from './public_key';
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import signature from './signature';
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import random from './random';
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@ -34,6 +35,8 @@ const mod = {
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gcm: gcm,
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/** @see module:crypto/eax */
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eax: eax,
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/** @see module:crypto/ocb */
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ocb: ocb,
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/** @see module:crypto/public_key */
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publicKey: publicKey,
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/** @see module:crypto/signature */
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312
src/crypto/ocb.js
Normal file
312
src/crypto/ocb.js
Normal file
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@ -0,0 +1,312 @@
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// OpenPGP.js - An OpenPGP implementation in javascript
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// Copyright (C) 2018 ProtonTech AG
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//
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// This library is free software; you can redistribute it and/or
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// modify it under the terms of the GNU Lesser General Public
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// License as published by the Free Software Foundation; either
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// version 3.0 of the License, or (at your option) any later version.
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//
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// This library is distributed in the hope that it will be useful,
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// but WITHOUT ANY WARRANTY; without even the implied warranty of
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// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
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// Lesser General Public License for more details.
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//
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// You should have received a copy of the GNU Lesser General Public
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// License along with this library; if not, write to the Free Software
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// Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
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/**
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* @fileoverview This module implements AES-OCB en/decryption.
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* @requires crypto/cipher
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* @requires util
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* @module crypto/ocb
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*/
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import ciphers from './cipher';
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import util from '../util';
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const blockLength = 16;
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const ivLength = 15;
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// https://tools.ietf.org/html/draft-ietf-openpgp-rfc4880bis-04#section-5.16.2:
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// While OCB [RFC7253] allows the authentication tag length to be of any
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// number up to 128 bits long, this document requires a fixed
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// authentication tag length of 128 bits (16 octets) for simplicity.
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const tagLength = 16;
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const { shiftLeft, shiftRight } = util;
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function zeros(bytes) {
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return new Uint8Array(bytes);
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}
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function ntz(n) {
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let ntz = 0;
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for(let i = 1; (n & i) === 0; i <<= 1) {
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ntz++;
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}
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return ntz;
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}
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function set_xor(S, T) {
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for (let i = 0; i < S.length; i++) {
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S[i] ^= T[i];
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}
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return S;
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}
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function xor(S, T) {
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return set_xor(S.slice(), T);
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}
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function concat(...arrays) {
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return util.concatUint8Array(arrays);
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}
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function double(S) {
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const double = S.slice();
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shiftLeft(double, 1);
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if (S[0] & 0b10000000) {
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double[15] ^= 0b10000111;
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}
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return double;
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}
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function constructKeyVariables(cipher, key, text, adata) {
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const aes = new ciphers[cipher](key);
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const encipher = aes.encrypt.bind(aes);
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const decipher = aes.decrypt.bind(aes);
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const L_x = encipher(zeros(16));
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const L_$ = double(L_x);
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const L = [];
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L[0] = double(L_$);
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const max_ntz = util.nbits(Math.max(text.length, adata.length) >> 4) - 1;
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for (let i = 1; i <= max_ntz; i++) {
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L[i] = double(L[i - 1]);
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}
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L.x = L_x;
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L.$ = L_$;
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return { encipher, decipher, L };
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}
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function hash(kv, key, adata) {
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if (!adata.length) {
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// Fast path
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return zeros(16);
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}
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const { encipher, L } = kv;
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//
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// Consider A as a sequence of 128-bit blocks
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//
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const m = adata.length >> 4;
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const offset = zeros(16);
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const sum = zeros(16);
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for (let i = 0; i < m; i++) {
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set_xor(offset, L[ntz(i + 1)]);
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set_xor(sum, encipher(xor(offset, adata)));
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adata = adata.subarray(16);
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}
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//
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// Process any final partial block; compute final hash value
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//
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if (adata.length) {
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set_xor(offset, L.x);
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const cipherInput = zeros(16);
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cipherInput.set(adata, 0);
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cipherInput[adata.length] = 0b10000000;
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set_xor(cipherInput, offset);
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set_xor(sum, encipher(cipherInput));
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}
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return sum;
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}
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/**
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* Encrypt plaintext input.
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* @param {String} cipher The symmetric cipher algorithm to use e.g. 'aes128'
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* @param {Uint8Array} plaintext The cleartext input to be encrypted
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* @param {Uint8Array} key The encryption key
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* @param {Uint8Array} nonce The nonce (15 bytes)
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* @param {Uint8Array} adata Associated data to sign
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* @returns {Promise<Uint8Array>} The ciphertext output
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*/
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async function encrypt(cipher, plaintext, key, nonce, adata) {
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//
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// Consider P as a sequence of 128-bit blocks
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//
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const m = plaintext.length >> 4;
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//
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// Key-dependent variables
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//
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const kv = constructKeyVariables(cipher, key, plaintext, adata);
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const { encipher, L } = kv;
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//
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// Nonce-dependent and per-encryption variables
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//
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// We assume here that TAGLEN mod 128 == 0 (tagLength === 16).
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const Nonce = concat(zeros(15 - nonce.length), new Uint8Array([1]), nonce);
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const bottom = Nonce[15] & 0b111111;
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Nonce[15] &= 0b11000000;
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const Ktop = encipher(Nonce);
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const Stretch = concat(Ktop, xor(Ktop.subarray(0, 8), Ktop.subarray(1, 9)));
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// Offset_0 = Stretch[1+bottom..128+bottom]
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const offset = shiftRight(Stretch.subarray(0 + (bottom >> 3), 17 + (bottom >> 3)), 8 - (bottom & 7)).subarray(1);
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const checksum = zeros(16);
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const C = new Uint8Array(plaintext.length + tagLength);
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//
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// Process any whole blocks
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//
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let i;
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let pos = 0;
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for (i = 0; i < m; i++) {
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set_xor(offset, L[ntz(i + 1)]);
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C.set(xor(offset, encipher(xor(offset, plaintext))), pos);
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set_xor(checksum, plaintext);
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plaintext = plaintext.subarray(16);
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pos += 16;
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}
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//
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// Process any final partial block and compute raw tag
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//
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if (plaintext.length) {
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set_xor(offset, L.x);
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const Pad = encipher(offset);
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C.set(xor(plaintext, Pad), pos);
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// Checksum_* = Checksum_m xor (P_* || 1 || zeros(127-bitlen(P_*)))
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const xorInput = zeros(16);
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xorInput.set(plaintext, 0);
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xorInput[plaintext.length] = 0b10000000;
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set_xor(checksum, xorInput);
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pos += plaintext.length;
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}
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const Tag = xor(encipher(xor(xor(checksum, offset), L.$)), hash(kv, key, adata));
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//
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// Assemble ciphertext
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//
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C.set(Tag, pos);
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return C;
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}
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/**
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* Decrypt ciphertext input.
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* @param {String} cipher The symmetric cipher algorithm to use e.g. 'aes128'
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* @param {Uint8Array} ciphertext The ciphertext input to be decrypted
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* @param {Uint8Array} key The encryption key
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* @param {Uint8Array} nonce The nonce (15 bytes)
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* @param {Uint8Array} adata Associated data to verify
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* @returns {Promise<Uint8Array>} The plaintext output
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*/
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async function decrypt(cipher, ciphertext, key, nonce, adata) {
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//
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// Consider C as a sequence of 128-bit blocks
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//
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const T = ciphertext.subarray(ciphertext.length - tagLength);
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ciphertext = ciphertext.subarray(0, ciphertext.length - tagLength);
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const m = ciphertext.length >> 4;
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//
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// Key-dependent variables
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//
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const kv = constructKeyVariables(cipher, key, ciphertext, adata);
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const { encipher, decipher, L } = kv;
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//
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// Nonce-dependent and per-encryption variables
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//
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// We assume here that TAGLEN mod 128 == 0 (tagLength === 16).
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const Nonce = concat(zeros(15 - nonce.length), new Uint8Array([1]), nonce);
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const bottom = Nonce[15] & 0b111111;
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Nonce[15] &= 0b11000000;
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const Ktop = encipher(Nonce);
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const Stretch = concat(Ktop, xor(Ktop.subarray(0, 8), Ktop.subarray(1, 9)));
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// Offset_0 = Stretch[1+bottom..128+bottom]
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const offset = shiftRight(Stretch.subarray(0 + (bottom >> 3), 17 + (bottom >> 3)), 8 - (bottom & 7)).subarray(1);
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const checksum = zeros(16);
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const P = new Uint8Array(ciphertext.length);
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//
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// Process any whole blocks
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//
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let i;
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let pos = 0;
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for (i = 0; i < m; i++) {
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set_xor(offset, L[ntz(i + 1)]);
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P.set(xor(offset, decipher(xor(offset, ciphertext))), pos);
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set_xor(checksum, P.subarray(pos));
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ciphertext = ciphertext.subarray(16);
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pos += 16;
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}
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//
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// Process any final partial block and compute raw tag
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//
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if (ciphertext.length) {
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set_xor(offset, L.x);
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const Pad = encipher(offset);
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P.set(xor(ciphertext, Pad), pos);
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// Checksum_* = Checksum_m xor (P_* || 1 || zeros(127-bitlen(P_*)))
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const xorInput = zeros(16);
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xorInput.set(P.subarray(pos), 0);
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xorInput[ciphertext.length] = 0b10000000;
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set_xor(checksum, xorInput);
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pos += ciphertext.length;
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}
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const Tag = xor(encipher(xor(xor(checksum, offset), L.$)), hash(kv, key, adata));
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//
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// Check for validity and assemble plaintext
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//
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if (!util.equalsUint8Array(Tag, T)) {
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throw new Error('Authentication tag mismatch in OCB ciphertext');
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}
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return P;
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}
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/**
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* Get OCB nonce as defined by {@link https://tools.ietf.org/html/draft-ietf-openpgp-rfc4880bis-04#section-5.16.2|RFC4880bis-04, section 5.16.2}.
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* @param {Uint8Array} iv The initialization vector (15 bytes)
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* @param {Uint8Array} chunkIndex The chunk index (8 bytes)
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*/
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function getNonce(iv, chunkIndex) {
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const nonce = iv.slice();
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for (let i = 0; i < chunkIndex.length; i++) {
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nonce[7 + i] ^= chunkIndex[i];
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}
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return nonce;
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}
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export default {
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blockLength,
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ivLength,
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encrypt,
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decrypt,
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getNonce
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};
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@ -7,4 +7,5 @@ describe('Crypto', function () {
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require('./pkcs5.js');
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require('./aes_kw.js');
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require('./eax.js');
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require('./ocb.js');
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});
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152
test/crypto/ocb.js
Normal file
152
test/crypto/ocb.js
Normal file
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@ -0,0 +1,152 @@
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// Modified by ProtonTech AG
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// Adapted from https://github.com/artjomb/cryptojs-extension/blob/8c61d159/test/eax.js
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const openpgp = typeof window !== 'undefined' && window.openpgp ? window.openpgp : require('../../dist/openpgp');
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const chai = require('chai');
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chai.use(require('chai-as-promised'));
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const expect = chai.expect;
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const ocb = openpgp.crypto.ocb;
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describe('Symmetric AES-OCB', function() {
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it('Passes all test vectors', async function() {
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const K = '000102030405060708090A0B0C0D0E0F';
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const keyBytes = openpgp.util.hex_to_Uint8Array(K);
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var vectors = [
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// From https://tools.ietf.org/html/rfc7253#appendix-A
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{
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N: 'BBAA99887766554433221100',
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A: '',
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P: '',
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C: '785407BFFFC8AD9EDCC5520AC9111EE6'
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},
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{
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N: 'BBAA99887766554433221101',
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A: '0001020304050607',
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P: '0001020304050607',
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C: '6820B3657B6F615A5725BDA0D3B4EB3A257C9AF1F8F03009'
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},
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{
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N: 'BBAA99887766554433221102',
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A: '0001020304050607',
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P: '',
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C: '81017F8203F081277152FADE694A0A00'
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},
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{
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N: 'BBAA99887766554433221103',
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A: '',
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P: '0001020304050607',
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C: '45DD69F8F5AAE72414054CD1F35D82760B2CD00D2F99BFA9'
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},
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{
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N: 'BBAA99887766554433221104',
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A: '000102030405060708090A0B0C0D0E0F',
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P: '000102030405060708090A0B0C0D0E0F',
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C: '571D535B60B277188BE5147170A9A22C3AD7A4FF3835B8C5701C1CCEC8FC3358'
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},
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{
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N: 'BBAA99887766554433221105',
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A: '000102030405060708090A0B0C0D0E0F',
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P: '',
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C: '8CF761B6902EF764462AD86498CA6B97'
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},
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{
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N: 'BBAA99887766554433221106',
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A: '',
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P: '000102030405060708090A0B0C0D0E0F',
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C: '5CE88EC2E0692706A915C00AEB8B2396F40E1C743F52436BDF06D8FA1ECA343D'
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},
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{
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N: 'BBAA99887766554433221107',
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A: '000102030405060708090A0B0C0D0E0F1011121314151617',
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P: '000102030405060708090A0B0C0D0E0F1011121314151617',
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C: '1CA2207308C87C010756104D8840CE1952F09673A448A122C92C62241051F57356D7F3C90BB0E07F'
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},
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{
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N: 'BBAA99887766554433221108',
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A: '000102030405060708090A0B0C0D0E0F1011121314151617',
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P: '',
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C: '6DC225A071FC1B9F7C69F93B0F1E10DE'
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},
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{
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N: 'BBAA99887766554433221109',
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A: '',
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P: '000102030405060708090A0B0C0D0E0F1011121314151617',
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C: '221BD0DE7FA6FE993ECCD769460A0AF2D6CDED0C395B1C3CE725F32494B9F914D85C0B1EB38357FF'
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},
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{
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N: 'BBAA9988776655443322110A',
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A: '000102030405060708090A0B0C0D0E0F101112131415161718191A1B1C1D1E1F',
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P: '000102030405060708090A0B0C0D0E0F101112131415161718191A1B1C1D1E1F',
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C: 'BD6F6C496201C69296C11EFD138A467ABD3C707924B964DEAFFC40319AF5A48540FBBA186C5553C68AD9F592A79A4240'
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},
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{
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N: 'BBAA9988776655443322110B',
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A: '000102030405060708090A0B0C0D0E0F101112131415161718191A1B1C1D1E1F',
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P: '',
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C: 'FE80690BEE8A485D11F32965BC9D2A32'
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},
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{
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N: 'BBAA9988776655443322110C',
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A: '',
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P: '000102030405060708090A0B0C0D0E0F101112131415161718191A1B1C1D1E1F',
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C: '2942BFC773BDA23CABC6ACFD9BFD5835BD300F0973792EF46040C53F1432BCDFB5E1DDE3BC18A5F840B52E653444D5DF'
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},
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{
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N: 'BBAA9988776655443322110D',
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A: '000102030405060708090A0B0C0D0E0F101112131415161718191A1B1C1D1E1F2021222324252627',
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P: '000102030405060708090A0B0C0D0E0F101112131415161718191A1B1C1D1E1F2021222324252627',
|
||||
C: 'D5CA91748410C1751FF8A2F618255B68A0A12E093FF454606E59F9C1D0DDC54B65E8628E568BAD7AED07BA06A4A69483A7035490C5769E60'
|
||||
},
|
||||
{
|
||||
N: 'BBAA9988776655443322110E',
|
||||
A: '000102030405060708090A0B0C0D0E0F101112131415161718191A1B1C1D1E1F2021222324252627',
|
||||
P: '',
|
||||
C: 'C5CD9D1850C141E358649994EE701B68'
|
||||
},
|
||||
{
|
||||
N: 'BBAA9988776655443322110F',
|
||||
A: '',
|
||||
P: '000102030405060708090A0B0C0D0E0F101112131415161718191A1B1C1D1E1F2021222324252627',
|
||||
C: '4412923493C57D5DE0D700F753CCE0D1D2D95060122E9F15A5DDBFC5787E50B5CC55EE507BCB084E479AD363AC366B95A98CA5F3000B1479'
|
||||
}
|
||||
];
|
||||
|
||||
const cipher = 'aes128';
|
||||
|
||||
for(const [i, vec] of vectors.entries()) {
|
||||
const msgBytes = openpgp.util.hex_to_Uint8Array(vec.P),
|
||||
nonceBytes = openpgp.util.hex_to_Uint8Array(vec.N),
|
||||
headerBytes = openpgp.util.hex_to_Uint8Array(vec.A),
|
||||
ctBytes = openpgp.util.hex_to_Uint8Array(vec.C);
|
||||
|
||||
// encryption test
|
||||
let ct = await ocb.encrypt(cipher, msgBytes, keyBytes, nonceBytes, headerBytes);
|
||||
expect(openpgp.util.Uint8Array_to_hex(ct)).to.equal(vec.C.toLowerCase());
|
||||
|
||||
// decryption test with verification
|
||||
let pt = await ocb.decrypt(cipher, ctBytes, keyBytes, nonceBytes, headerBytes);
|
||||
expect(openpgp.util.Uint8Array_to_hex(pt)).to.equal(vec.P.toLowerCase());
|
||||
|
||||
// tampering detection test
|
||||
ct = await ocb.encrypt(cipher, msgBytes, keyBytes, nonceBytes, headerBytes);
|
||||
ct[2] ^= 8;
|
||||
pt = ocb.decrypt(cipher, ct, keyBytes, nonceBytes, headerBytes);
|
||||
await expect(pt).to.eventually.be.rejectedWith('Authentication tag mismatch in OCB ciphertext')
|
||||
|
||||
// testing without additional data
|
||||
ct = await ocb.encrypt(cipher, msgBytes, keyBytes, nonceBytes, new Uint8Array());
|
||||
pt = await ocb.decrypt(cipher, ct, keyBytes, nonceBytes, new Uint8Array());
|
||||
expect(openpgp.util.Uint8Array_to_hex(pt)).to.equal(vec.P.toLowerCase());
|
||||
|
||||
// testing with multiple additional data
|
||||
ct = await ocb.encrypt(cipher, msgBytes, keyBytes, nonceBytes, openpgp.util.concatUint8Array([headerBytes, headerBytes, headerBytes]));
|
||||
pt = await ocb.decrypt(cipher, ct, keyBytes, nonceBytes, openpgp.util.concatUint8Array([headerBytes, headerBytes, headerBytes]));
|
||||
expect(openpgp.util.Uint8Array_to_hex(pt)).to.equal(vec.P.toLowerCase());
|
||||
}
|
||||
});
|
||||
});
|
||||
Loading…
Reference in New Issue
Block a user