gocryptfs is a production-grade, FUSE-based encrypted overlay filesystem written in Go. It transparently encrypts file contents and filenames on the fly, supporting both forward mode (encrypting a plaintext directory) and reverse mode (presenting an encrypted view of a plaintext directory). The system uses multiple cryptographic backends (AES-GCM, AES-SIV, XChaCha20-Poly1305) with optional OpenSSL hardware acceleration, HKDF key derivation, and scrypt-based password hashing. It provides a rich CLI with subcommands for mounting, initializing filesystems, changing passwords, filesystem checking, and benchmarking. The architecture is a monolithic CLI tool that mounts a FUSE filesystem, with internal packages for content encryption, filename encryption (EME), safe syscall wrappers, and a control socket for path encryption/decryption. The codebase demonstrates strong security practices (O_NOFOLLOW, *at syscalls, memory wiping) and includes an extensive test suite with backward compatibility testing against multiple filesystem versions.