base64-ng-subtle

Optional subtle::ConstantTimeEq integration for base64-ng.

The core base64-ng crate stays zero-runtime-dependency. This companion crate is for applications that already admit the subtle crate and want explicit comparison helpers for decoded or encoded Base64 material.

[dependencies]
base64-ng = "1.2.0"
base64-ng-subtle = "1.2.0"

use base64_ng::ct;
use base64_ng_subtle::SubtleEqExt;

let decoded = ct::STANDARD.decode_secret(b"aGVsbG8=").unwrap();
assert!(decoded.subtle_verify(b"hello"));

Length is public: mismatched lengths return Choice::from(0) immediately. Use fixed-size protocol tokens when length must not vary.