std:crypto

Cryptographic functions for hashing, encryption, and JWT handling.

Import

import { Crypto } from "std:crypto";

Run

The functions can also be imported one by one, e.g. import { hash, hmac } from "std:crypto".

Hashing

hash(algorithm: String, data: String): String

Computes a cryptographic hash of the data and returns it as lowercase hex.

Algorithm	Output
"sha256"	64 hex chars
"sha512"	128 hex chars

import { Crypto } from "std:crypto";

let hash = Crypto.hash("sha256", "hello");
print(hash);  // 2cf24dba5fb0a30e26e83b2ac5b9e29e1b161e5c1fa7425e73043362938b9824

Run

hmac(algorithm: String, key: String, data: String): String

Computes an HMAC (Hash-based Message Authentication Code) and returns it as hex. Only "sha256" is supported.

import { Crypto } from "std:crypto";

let signature = Crypto.hmac("sha256", "secret-key", "message");
print(signature.length);  // 64

Run

---

Encryption

encrypt(algo: String, key: String, iv: String, data: String): String

Encrypts data using the specified algorithm. The key and IV are hex strings. Returns Base64-encoded ciphertext.

Algorithm	Key Length	IV Length
"aes-256-cbc"	32 bytes (64 hex)	16 bytes (32 hex)

import { Crypto } from "std:crypto";

let key = "0123456789abcdef0123456789abcdef0123456789abcdef0123456789abcdef";
let iv = "0123456789abcdef0123456789abcdef";
let encrypted = Crypto.encrypt("aes-256-cbc", key, iv, "secret message");
print(encrypted);  // IFL3l4O5UHCPSKn2OAPp2g==

Run

Use a random key and a new random IV for real data. The fixed values here are only for the example.

decrypt(algo: String, key: String, iv: String, ciphertext: String): String

Decrypts Base64-encoded ciphertext. Throws if the key, IV, or data is wrong.

import { Crypto } from "std:crypto";

let key = "0123456789abcdef0123456789abcdef0123456789abcdef0123456789abcdef";
let iv = "0123456789abcdef0123456789abcdef";
let encrypted = Crypto.encrypt("aes-256-cbc", key, iv, "secret message");
let decrypted = Crypto.decrypt("aes-256-cbc", key, iv, encrypted);
print(decrypted);  // secret message

Run

---

JWT (JSON Web Tokens)

jwtSign(payload: Map, secret: String): String

Creates a JWT signed with HS256.

import { Crypto } from "std:crypto";

let token = Crypto.jwtSign({
    "sub": "user123",
    "exp": 1735689600
}, "my-secret");
print(token);  // eyJhbGciOiJIUzI1NiIsInR5cCI6IkpXVCJ9...

Run

jwtVerify(token: String, secret: String): Map

Verifies the signature of a JWT and returns its payload. Throws on an invalid signature or format. It does not check claims such as exp; check them yourself.

import { Crypto } from "std:crypto";

let token = Crypto.jwtSign({ "sub": "user123" }, "my-secret");
let payload = Crypto.jwtVerify(token, "my-secret");
print(payload.sub);  // user123

try {
    Crypto.jwtVerify(token, "wrong-secret");
} catch (e) {
    print("invalid token");
}

Run