Prohibit char codes that would overflow the BASE_MAP

[steveluscher]

Problem

Consider the char code of a character. Codes >255 are prohibited when constructing an alphabet (throws new TypeError(x + ' is ambiguous')) but they are accepted when decoding a string.

const bs58 = base('123456789ABCDEFGHJKLMNPQRSTUVWXYZabcdefghijkmnopqrstuvwxyz');
const str = 'ABC' + /* char code 256 */ '\u0100' + 'DEF';
const bytes = bs58.decode(str);  // WORKS

That code should absolutely fatal with ‘non-base58 character’.

Sandbox link

Bench

Before

$ SEED=1c80dc20398124b795fe1bc8f37bd586 npm start

> [email protected] start
> node index.js

Seed: 1c80dc20398124b795fe1bc8f37bd586
--------------------------------------------------
encode x 371,690 ops/sec ±0.06% (9 runs sampled)
decode x 420,041 ops/sec ±0.12% (9 runs sampled)
==================================================

After

$ SEED=1c80dc20398124b795fe1bc8f37bd586 npm start

> [email protected] start
> node index.js

Seed: 1c80dc20398124b795fe1bc8f37bd586
--------------------------------------------------
encode x 378,646 ops/sec ±0.04% (9 runs sampled)
decode x 432,351 ops/sec ±0.14% (9 runs sampled)
==================================================

Backports

• 3.x [backport 3.x] Prohibit char codes that would overflow the BASE_MAP #87
• 4.x [backport 4.x] Prohibit char codes that would overflow the BASE_MAP #89
• 5.x [backport 5.x] Prohibit char codes that would overflow the BASE_MAP #88

[steveluscher]

I guess the 5.x backport is not needed, if you decide to release this as 5.0.1.

[fanatid]

Thanks! Published

• v5.0.1
• v4.0.1
• v3.0.11

[melissamforbs]

reviewed