Audit and repair readers for fixed-length binary credentials and their text encodings without mutating raw bytes. Use when code loads Ed25519/X25519 keys, nonces, digests, MAC keys, signatures, tokens, or other opaque bytes from files or environment values; when `.strip()`, decoding, newline handling, or format auto-detection occurs before length/type validation; or when cryptographic tests fail intermittently for otherwise valid generated material.
