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Merge 31e6ce5aa8 into c57556f49f

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Barry Brown 2025-05-26 06:07:43 +01:00 • committed by GitHub
commit 81111f1b9e
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6 changed files with 374 additions and 61 deletions
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44
src/core/operations/AffineCipherDecode.mjs
View file

@ -5,8 +5,7 @@
*/
import Operation from "../Operation.mjs";
import Utils from "../Utils.mjs";
import OperationError from "../errors/OperationError.mjs";
import { affineDecrypt, affineDecryptInverse, AFFINE_ALPHABETS } from "../lib/Ciphers.mjs";
/**
* Affine Cipher Decode operation
@ -21,7 +20,7 @@ class AffineCipherDecode extends Operation {
this.name = "Affine Cipher Decode";
this.module = "Ciphers";
this.description = "The Affine cipher is a type of monoalphabetic substitution cipher. To decrypt, each letter in an alphabet is mapped to its numeric equivalent, decrypted by a mathematical function, and converted back to a letter.";
this.description = "The Affine cipher is a type of monoalphabetic substitution cipher. To decrypt, each letter in an alphabet is mapped to its numeric equivalent, decrypted by a mathematical function (the inverse of ax+b % m), and converted back to a letter.";
this.infoURL = "https://wikipedia.org/wiki/Affine_cipher";
this.inputType = "string";
this.outputType = "string";
@ -35,6 +34,16 @@ class AffineCipherDecode extends Operation {
"name": "b",
"type": "number",
"value": 0
},
{
"name": "Alphabet",
"type": "editableOption",
"value": AFFINE_ALPHABETS
},
{
"name": "Use modular inverse values",
"type": "boolean",
"value": false
}
];
}
@ -47,32 +56,9 @@ class AffineCipherDecode extends Operation {
* @throws {OperationError} if a or b values are invalid
*/
run(input, args) {
const alphabet = "abcdefghijklmnopqrstuvwxyz",
[a, b] = args,
aModInv = Utils.modInv(a, 26); // Calculates modular inverse of a
let output = "";
if (!/^\+?(0|[1-9]\d*)$/.test(a) || !/^\+?(0|[1-9]\d*)$/.test(b)) {
throw new OperationError("The values of a and b can only be integers.");
}
if (Utils.gcd(a, 26) !== 1) {
throw new OperationError("The value of `a` must be coprime to 26.");
}
for (let i = 0; i < input.length; i++) {
if (alphabet.indexOf(input[i]) >= 0) {
// Uses the affine decode function (y-b * A') % m = x (where m is length of the alphabet and A' is modular inverse)
output += alphabet[Utils.mod((alphabet.indexOf(input[i]) - b) * aModInv, 26)];
} else if (alphabet.indexOf(input[i].toLowerCase()) >= 0) {
// Same as above, accounting for uppercase
output += alphabet[Utils.mod((alphabet.indexOf(input[i].toLowerCase()) - b) * aModInv, 26)].toUpperCase();
} else {
// Non-alphabetic characters
output += input[i];
}
}
return output;
const a = args[0], b = args[1], alphabet = args[2], useInverse = args[3];
if (useInverse) return affineDecryptInverse(input, a, b, alphabet);
else return affineDecrypt(input, a, b, alphabet);
}
/**

12
src/core/operations/AffineCipherEncode.mjs
View file

@ -5,7 +5,7 @@
*/
import Operation from "../Operation.mjs";
import { affineEncode } from "../lib/Ciphers.mjs";
import { affineEncrypt, AFFINE_ALPHABETS } from "../lib/Ciphers.mjs";
/**
* Affine Cipher Encode operation
@ -20,7 +20,7 @@ class AffineCipherEncode extends Operation {
this.name = "Affine Cipher Encode";
this.module = "Ciphers";
this.description = "The Affine cipher is a type of monoalphabetic substitution cipher, wherein each letter in an alphabet is mapped to its numeric equivalent, encrypted using simple mathematical function, <code>(ax + b) % 26</code>, and converted back to a letter.";
this.description = "The Affine cipher is a type of monoalphabetic substitution cipher, wherein each letter in an alphabet is mapped to its numeric equivalent, encrypted using simple mathematical function, <code>(ax + b) % m</code>, and converted back to a letter.";
this.infoURL = "https://wikipedia.org/wiki/Affine_cipher";
this.inputType = "string";
this.outputType = "string";
@ -34,6 +34,11 @@ class AffineCipherEncode extends Operation {
"name": "b",
"type": "number",
"value": 0
},
{
"name": "Alphabet",
"type": "editableOption",
"value": AFFINE_ALPHABETS
}
];
}
@ -44,7 +49,8 @@ class AffineCipherEncode extends Operation {
* @returns {string}
*/
run(input, args) {
return affineEncode(input, args);
const a = args[0], b = args[1], alphabet = args[2];
return affineEncrypt(input, a, b, alphabet);
}
/**