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import { createHash, createCipheriv, createDecipheriv } from "crypto";
interface EncryptionData {
ct: string;
iv: string;
s: string;
}
function encrypt(data: string, key: string): string {
let salt = "";
let salted = "";
let dx = Buffer.alloc(0);
// Generate salt, as 8 random lowercase letters
salt = String.fromCharCode(...Array(8).fill(0).map(_ => Math.floor(Math.random() * 26) + 97))
// Our final key and iv come from the key and salt being repeatedly hashed
// dx = md5(md5(md5(key + salt) + key + salt) + key + salt)
// For each round of hashing, we append the result to salted, resulting in a 96 character string
// The first 64 characters are the key, and the last 32 are the iv
for (let x = 0; x < 3; x++) {
dx = createHash("md5")
.update(
Buffer.concat([
Buffer.from(dx),
Buffer.from(key),
Buffer.from(salt),
])
)
.digest();
salted += dx.toString("hex");
}
let aes = createCipheriv(
"aes-256-cbc",
Buffer.from(salted.substring(0, 64), "hex"), // Key
Buffer.from(salted.substring(64, 64 + 32), "hex") // IV
);
return JSON.stringify({
ct: aes.update(data, null, "base64") + aes.final("base64"),
iv: salted.substring(64, 64 + 32),
s: Buffer.from(salt).toString("hex"),
});
}
function decrypt(rawData: string, key: string): string {
let data: EncryptionData = JSON.parse(rawData);
// We get our decryption key by doing the inverse of the encryption process
let dk = Buffer.concat([Buffer.from(key), Buffer.from(data.s, "hex")]);
let arr = [Buffer.from(createHash("md5").update(dk).digest()).toString("hex")];
let result = arr[0];
for (let x = 1; x < 3; x++) {
arr.push(
Buffer.from(
createHash("md5")
.update(Buffer.concat([Buffer.from(arr[x - 1], "hex"), dk]))
.digest()
).toString("hex")
);
result += arr[x];
}
let aes = createDecipheriv(
"aes-256-cbc",
Buffer.from(result.substring(0, 64), "hex"),
Buffer.from(data.iv, "hex")
);
return aes.update(data.ct, "base64", "utf8") + aes.final("utf8");
}
export default {
encrypt,
decrypt,
};
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