Macros

Macros

Configuration lives in user_settings.h. Crypto capabilities are selected with wolfSSL's own macros; wolfnano_config.h fills in prerequisites and applies the standing size cuts, and wolfnano_target.h selects the asm/SP bundle. wolfNano-owned WOLFNANO_* macros are reserved for policy that wolfSSL has no macro for: the TLS group offer, X.509 sub-options, PQC level, and memory model.

Crypto capabilities (wolfSSL macros)

Set these directly in user_settings.h; wolfnano_config.h completes the prerequisites and cuts. SHA-256 is on by default.

wolfSSL macro	Enables
WOLFSSL_SHA384	SHA-384 (pulls SHA-512)
HAVE_HKDF	HKDF (TLS 1.3 key schedule)
HAVE_AESGCM	AES-GCM
HAVE_CHACHA	ChaCha20-Poly1305 (pulls HAVE_POLY1305)
HAVE_ECC	ECDHE + ECDSA P-256 (pulls ECC_USER_CURVES)
HAVE_ECC384	adds P-384
HAVE_CURVE25519	X25519
HAVE_ED25519	Ed25519 (pulls SHA-512)

wolfNanoTLS policy macros (WOLFNANO_*)

Owned by wolfNanoTLS; no wolfSSL equivalent.

Flag	Enables	Effect
WOLFNANO_HAVE_ECDHE_P256	offer secp256r1 as the (EC)DHE group	single-group-per-build selector
WOLFNANO_HAVE_MLKEM_HYBRID	offer X25519MLKEM768 as the group	pulls ML-KEM-768 + X25519
WOLFNANO_HAVE_RSA_VERIFY	RSA verify (cert chains, RSA-PSS)	WOLFSSL_RSA_VERIFY_ONLY, WC_RSA_PSS, 4096 ceiling
WOLFNANO_RSA_FULL	adds RSA keygen/sign (tooling, not the no-alloc product)	WOLFSSL_KEY_GEN
WOLFNANO_X509	X.509 cert path; parses/verifies with wolfSSL's full asn.c/DecodedCert by default (complete, proven)	cert path + WOLFSSL_SMALL_CERT_VERIFY
WOLFNANO_X509_LITE	opt into the smaller native wn_x509 parser instead of asn.c (~15% / ~10 KB less .text). A stricter-but-narrower size tier: no name constraints/policies/CRL/OCSP, capped SAN pool; the handshake enforces the same wn_VerifyChain checks on both backends. Default off = asn.c. make ... X509_LITE=1	swaps the cert parse + CertificateVerify key-import backend
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_NO_X509_TIME	opt out of leaf/intermediate validity (notBefore/notAfter) checking; for clockless devices only. Default: cert builds enforce dates via the XTIME clock seam	drops wn_CertTimeValid
WOLFNANO_MLKEM	ML-KEM-768 + X25519MLKEM768 hybrid	WOLFSSL_HAVE_MLKEM
WOLFNANO_MLDSA	ML-DSA verify (no-malloc)	WOLFSSL_HAVE_MLDSA, verify-only
WOLFNANO_MLDSA_LEVEL	ML-DSA security level 2/3/5 (default 2)	selects ML-DSA-44/65/87
WOLFNANO_MLDSA_SIGN	adds ML-DSA keygen/sign (needs memory)	drops verify-only
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	CNSA, or maximum enterprise interop

Both are interop-verified live against OpenSSL and wolfSSL. X25519 is not weaker than P-256 - it was simply standardized later (NIST SP 800-186, 2023). Default to X25519 for size; select P-256 when 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.

Build toggles

• Memory model: default is plain wolfSSL (heap). Set wolfSSL's own macro to change it - WOLFSSL_SMALL_STACK (embedded) or WOLFSSL_NO_MALLOC (zero dynamic allocation). The MEM build convenience emits the -D: MEM=smallstack / MEM=nomalloc. (WOLFSSL_STATIC_MEMORY pool support is a planned follow-up - it needs a heap hint threaded through the shell, so it is not yet a selectable model.)
• 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) is off in PSK-only builds; the X.509 adder turns ASN time on and enforces leaf/intermediate validity via the XTIME clock seam (opt out with WOLFNANO_NO_X509_TIME).