diff --git a/src/core/lib/LS47.mjs b/src/core/lib/LS47.mjs new file mode 100644 index 00000000..a4ef10a5 --- /dev/null +++ b/src/core/lib/LS47.mjs @@ -0,0 +1,148 @@ +/** + * @author n1073645 [n1073645@gmail.com] + * @copyright Crown Copyright 2020 + * @license Apache-2.0 + */ + +import OperationError from "../errors/OperationError.mjs"; + +let letters = "_abcdefghijklmnopqrstuvwxyz.0123456789,-+*/:?!'()"; +let tiles = []; + +export function init_tiles() { + for (let i = 0; i < 49; i++) + tiles.push([letters.charAt(i), [Math.floor(i/7), i % 7]]); +} + +function rotate_down(key, col, n) { + let lines = []; + for (let i = 0; i < 7; i++) + lines.push(key.slice(i*7, (i + 1) * 7)); + let lefts = []; + let mids = []; + let rights = []; + lines.forEach((element) => { + lefts.push(element.slice(0, col)); + mids.push(element.charAt(col)); + rights.push(element.slice(col+1)); + }); + n = (7 - n % 7) % 7; + mids = mids.slice(n).concat(mids.slice(0, n)); + let result = ""; + for (let i = 0; i < 7; i++) + result += lefts[i] + mids[i] + rights[i]; + return result; +} + +function rotate_right(key, row, n) { + let mid = key.slice(row * 7, (row + 1) * 7); + n = (7 - n % 7) % 7; + return key.slice(0, 7 * row) + mid.slice(n) + mid.slice(0, n) + key.slice(7 * (row + 1)); +} + +function find_ix(letter) { + for (let i = 0; i < tiles.length; i++) + if (tiles[i][0] === letter) + return tiles[i][1]; + throw new OperationError("Letter " + letter + " is not included in LS47"); +} + +export function derive_key(password) { + let i = 0; + let k = letters; + for (const c of password) { + let [row, col] = find_ix(c); + k = rotate_down(rotate_right(k, i, col), i, row); + i = (i + 1) % 7; + } + return k; +} + +function check_key(key) { + if (key.length !== letters.length) + throw new OperationError("Wrong key size"); + let counts = new Array(); + for (let i = 0; i < letters.length; i++) + counts[letters.charAt(i)] = 0; + for (const elem of letters){ + if (letters.indexOf(elem) === -1) + throw new OperationError("Letter " + elem + " not in LS47!"); + counts[elem]++; + if (counts[elem] > 1) + throw new OperationError("Letter duplicated in the key!"); + } +} + +function find_pos (key, letter) { + let index = key.indexOf(letter); + if (index >= 0 && index < 49) + return [Math.floor(index/7), index%7]; + throw new OperationError("Letter " + letter + " is not in the key!"); +} + +function find_at_pos(key, coord) { + return key.charAt(coord[1] + (coord[0] * 7)); +} + +function add_pos(a, b) { + return [(a[0] + b[0]) % 7, (a[1] + b[1]) % 7]; +} + +function sub_pos(a, b) { + let asub = a[0] - b[0]; + let bsub = a[1] - b[1]; + return [asub - (Math.floor(asub/7) * 7), bsub - (Math.floor(bsub/7) * 7)]; +} + +function encrypt(key, plaintext) { + check_key(key); + let mp = [0, 0]; + let ciphertext = ''; + for (const p of plaintext) { + let pp = find_pos(key, p); + let mix = find_ix(find_at_pos(key, mp)); + let cp = add_pos(pp, mix); + let c = find_at_pos(key, cp); + ciphertext += c; + key = rotate_right(key, pp[0], 1); + cp = find_pos(key, c); + key = rotate_down(key, cp[1], 1); + mp = add_pos(mp, find_ix(c)); + } + return ciphertext; +} + +function decrypt(key, ciphertext) { + check_key(key); + let mp = [0,0]; + let plaintext = ''; + for (const c of ciphertext) { + let cp = find_pos(key, c); + let mix = find_ix(find_at_pos(key, mp)); + let pp = sub_pos(cp, mix); + let p = find_at_pos(key, pp); + + plaintext += p; + key = rotate_right(key, pp[0], 1); + cp = find_pos(key, c); + key = rotate_down(key, cp[1], 1); + mp = add_pos(mp, find_ix(c)); + } + return plaintext; +} + +export function encrypt_pad(key, plaintext, signature, padding_size) { + init_tiles(); + check_key(key); + let padding = ""; + for (let i = 0; i < padding_size; i++) { + padding += letters.charAt(Math.floor(Math.random() * letters.length)); + } + return encrypt(key, padding+plaintext+'---'+signature); +} + +export function decrypt_pad(key, ciphertext, padding_size) { + init_tiles(); + check_key(key); + return decrypt(key, ciphertext).slice(padding_size); +} \ No newline at end of file diff --git a/src/core/operations/LS47Decrypt.mjs b/src/core/operations/LS47Decrypt.mjs new file mode 100644 index 00000000..ffda8f93 --- /dev/null +++ b/src/core/operations/LS47Decrypt.mjs @@ -0,0 +1,58 @@ +/** + * @author n1073645 [n1073645@gmail.com] + * @copyright Crown Copyright 2020 + * @license Apache-2.0 + */ + +import Operation from "../Operation.mjs"; +import * as LS47 from "../lib/LS47.mjs" + +/** + * LS47 Decrypt operation + */ +class LS47Decrypt extends Operation { + + /** + * LS47Decrypt constructor + */ + constructor() { + super(); + + this.name = "LS47 Decrypt"; + this.module = "Crypto"; + this.description = ""; + this.infoURL = ""; + this.inputType = "string"; + this.outputType = "string"; + this.args = [ + { + name: "Password", + type: "string", + value: "" + }, + { + name: "Padding", + type: "number", + value: 10 + } + ]; + } + + /** + * @param {string} input + * @param {Object[]} args + * @returns {string} + */ + run(input, args) { + + this.padding_size = parseInt(args[1], 10); + + LS47.init_tiles(); + + let key = LS47.derive_key(args[0]); + return LS47.decrypt_pad(key, input, this.padding_size); + } + +} + +export default LS47Decrypt; diff --git a/src/core/operations/LS47Encrypt.mjs b/src/core/operations/LS47Encrypt.mjs new file mode 100644 index 00000000..bf3b0306 --- /dev/null +++ b/src/core/operations/LS47Encrypt.mjs @@ -0,0 +1,63 @@ +/** + * @author n1073645 [n1073645@gmail.com] + * @copyright Crown Copyright 2020 + * @license Apache-2.0 + */ + +import Operation from "../Operation.mjs"; +import * as LS47 from "../lib/LS47.mjs" + +/** + * LS47 Encrypt operation + */ +class LS47Encrypt extends Operation { + + /** + * LS47Encrypt constructor + */ + constructor() { + super(); + + this.name = "LS47 Encrypt"; + this.module = "Crypto"; + this.description = ""; + this.infoURL = ""; + this.inputType = "string"; + this.outputType = "string"; + this.args = [ + { + name: "Password", + type: "string", + value: "" + }, + { + name: "Padding", + type: "number", + value: 10 + }, + { + name: "Signature", + type: "string", + value: "" + } + ]; + } + + /** + * @param {string} input + * @param {Object[]} args + * @returns {string} + */ + run(input, args) { + + this.padding_size = parseInt(args[1], 10); + + LS47.init_tiles(); + + let key = LS47.derive_key(args[0]); + return LS47.encrypt_pad(key, input, args[2], this.padding_size); + } + +} + +export default LS47Encrypt;