Macros

Macros

Configuration lives in user_settings.h, which selects WOLFNANO_HAVE_* features and includes wolfnano_target.h (asm/SP bundle) and wolfnano_config.h (which maps the selections to real wolfSSL macros and applies the standing size cuts).

Feature selection (WOLFNANO_HAVE_*)

Flag	Enables	wolfSSL macro(s)
WOLFNANO_HAVE_SHA256	SHA-256 (default on)	default; NO_SHA256 drops it
WOLFNANO_HAVE_SHA384	SHA-384/512	WOLFSSL_SHA384, WOLFSSL_SHA512
WOLFNANO_HAVE_HKDF	HKDF (TLS 1.3 key schedule)	HAVE_HKDF
WOLFNANO_HAVE_AESGCM	AES-GCM	HAVE_AESGCM
WOLFNANO_HAVE_CHACHA	ChaCha20-Poly1305	HAVE_CHACHA, HAVE_POLY1305
WOLFNANO_HAVE_ECC	ECDHE + ECDSA (P-256)	HAVE_ECC, ECC_USER_CURVES
WOLFNANO_HAVE_ECC384	adds P-384	HAVE_ECC384
WOLFNANO_HAVE_CURVE25519	X25519	HAVE_CURVE25519
WOLFNANO_HAVE_ED25519	Ed25519	HAVE_ED25519 (pulls SHA-512)
WOLFNANO_HAVE_RSA_VERIFY	RSA verify (cert chains, RSA-PSS)	WOLFSSL_RSA_VERIFY_ONLY, WC_RSA_PSS
WOLFNANO_RSA_FULL	adds RSA keygen/sign (tooling, not the no-alloc product)	WOLFSSL_KEY_GEN
WOLFNANO_X509	X.509 cert path (needs heap)	cert path + WOLFSSL_SMALL_CERT_VERIFY
WOLFNANO_X509_HOSTNAME	leaf hostname (SAN/CN, RFC 6125) matching; default on with WOLFNANO_X509. Set 0 for a key-pin-only cert build (~0.5 KB smaller)	gates wn_CheckServerName
WOLFNANO_MLKEM	ML-KEM-768 + X25519MLKEM768 hybrid	WOLFSSL_HAVE_MLKEM
WOLFNANO_MLDSA	ML-DSA-65 verify (no-malloc)	WOLFSSL_HAVE_MLDSA, verify-only
WOLFNANO_MLDSA_SIGN	adds ML-DSA keygen/sign (needs memory)	drops verify-only
WOLFNANO_FIPS	approved-mode suites (ECDHE P-256 + AES-GCM only)	drops X25519/ChaCha/Ed25519 from offers
WOLFNANO_SEND_ALERTS	emit a fatal TLS alert on handshake failure (off by default)	RFC 8446 6.2 alert codes

When a feature is off, the build has no undefined references for it.

Handshake curve selection (offer both, pick one per build)

The (EC)DHE key-exchange curve is chosen at build time; the key share is single-curve per build to keep the footprint minimal.

Build flags	Negotiated group	PSK client .text	Use when
(default)	X25519 (0x001d)	17.2 KB	smallest build; X25519 is cryptographically strong (Curve25519)
WOLFNANO_HAVE_ECDHE_P256	secp256r1 (0x0017)	24.8 KB	FIPS / CNSA, or maximum enterprise interop
WOLFNANO_FIPS	secp256r1 only	24.8 KB	approved-mode (also drops X25519/ChaCha/Ed25519 from offers)

Both are interop-verified live against OpenSSL and wolfSSL. Note on FIPS: X25519 is not weaker than P-256 - it was simply standardized later (NIST SP 800-186, 2023), so FIPS 140-3 boundaries historically covered only the NIST prime curves. Default to X25519 for size; select P-256 when a validated module or broad interop requires it.

Asm / speedup selection (WOLFNANO_ASM=<arch>)

One Makefile switch bundles a target's asm macros (wolfnano_target.h) + asm source files + toolchain/-march, mirroring wolfSSL --enable-intelasm / --enable-armasm / --enable-sp=yes,asm but with no ./configure. Default is the lightweight generic-math build; the fast specialized SP + symmetric asm is opt-in (larger code, the speed/size trade is the customer's, as in wolfSSL).

WOLFNANO_ASM	target	speedups	status
none (default)	PORTABLE_C	none (generic WOLFSSL_SP_MATH_ALL)	run + tested
intel	x86_64	AES-NI, AVX1/2, SP x86_64 asm, AVX2 ML-KEM/ML-DSA	run + tested
thumb2	Cortex-M33	Thumb2 AES/SHA asm + SP Cortex-M asm	cross-builds
aarch64	ARMv8-A	NEON + crypto-ext AES/SHA + SP arm64 asm	scaffolded
armv7	ARMv8-32	32-bit ARM asm + SP arm32 asm	cross-builds
riscv64	RISC-V 64	scalar AES/SHA/ChaCha asm (SP stays C)	scaffolded

make bench runs the all-algo benchmark for none then intel. make targets cross-compiles the floor for every non-host arch (skips cleanly without a toolchain). See Benchmarks.

Backend selection

• WOLFNANO_CRYPTO=src (default): submodule crypto, GPLv3.
• WOLFNANO_CRYPTO=fips: customer-supplied FIPS bundle (see FIPS).

Build toggles

• MALLOC=1: relax the true-no-allocator bar during bring-up (-DWOLFNANO_ALLOW_MALLOC).
• WOLFNANO_ASM=<arch>: select the asm/speedup bundle (see above); default none. The target macro it sets (WOLFNANO_TARGET_*) drives wolfnano_target.h.

Standing size cuts

Always applied in wolfnano_config.h: no old TLS, no MD5/SHA-1/DES3/RC4/DSA, no RSA/DH, no PWDBASED/PKCS12, single-threaded, no filesystem, no error strings. Cert-time validation (NO_ASN_TIME) stays off until the X.509 adder, which brings a time hook.