sdk: integrate libvuptsdk (renamed libzuptsdk); decouple --pq-box

libvuptsdk (git.securityops.co/cristiancmoises/libvuptsdk) is the renamed
libzuptsdk: only the .so filename/SONAME changed (libzuptsdk.so.2 ->
libvuptsdk.so.2); the C API (zuptsdk_* symbols, zuptsdk.h) is unchanged.

- Rename vendor/zuptsdk -> vendor/vuptsdk with libvuptsdk's headers.
- Makefile WITH_SDK=1 now links -lvuptsdk (+ its transitive libcrypto/libargon2
  deps via SDK_DEPLIBS) instead of -lzuptsdk, and installs libvuptsdk.so.*.
- DECOUPLE --pq-box: it needs the SEPARATE libpqvaptvupt, which libvuptsdk does
  NOT provide, so gate it behind a new WITH_PQBOX=1 (was folded into WITH_SDK).
  zupt_crypto_pqbox.c now keys on ZUPT_WITH_PQBOX; WITH_SDK=1 alone builds and
  links cleanly with just libvuptsdk and enables --pq-sdk + Argon2id.
- Banner/help renamed libzuptsdk -> libvuptsdk; the machine-readable 'Build:'
  line lists --pq-box only under WITH_PQBOX. GUI _get_caps matches on 'vuptsdk'.

Validated on Guix: WITH_SDK=1 links libvuptsdk + libcrypto + libargon2, runs,
banner 'Build: full (libvuptsdk: Argon2id, --pq-sdk available)', keygen --sdk +
--pq-sdk encrypt/decrypt byte-exact roundtrip. Default source-only build
unchanged (make check 16/16).

Makefile

@@ -63,7 +63,7 @@ ZUPT_SOURCES = src/zupt_main.c src/zupt_format.c src/zupt_lz.c src/zupt_lzh.c \
                src/zupt_x25519.c src/zupt_mlkem.c src/zupt_cpuid.c src/zupt_mlock.c \
                src/zupt_filetype.c src/zupt_disk.c src/zupt_dedup.c
 
-# --- Optional vendored libraries (libzuptsdk + libpqvaptvupt) ---
+# --- Optional vendored libraries (libvuptsdk + libpqvaptvupt) ---
 #
 # These are PREBUILT shared libraries shipped only as binaries (no source), so
 # they are NOT part of the source tree and a distro/source build must not need
@@ -72,21 +72,38 @@ ZUPT_SOURCES = src/zupt_main.c src/zupt_format.c src/zupt_lz.c src/zupt_lzh.c \
 # ML-KEM-768 + X25519 via --pq). The SDK-backed modes (--pq-sdk, --pq-box, and
 # the Argon2id password KDF) compile to "unsupported" stubs in that case.
 #
-# Set WITH_SDK=1 (with the vendored libs present under vendor/) to enable them.
+# libvuptsdk is the renamed libzuptsdk (git.securityops.co/cristiancmoises/
+# libvuptsdk); only the .so filename/SONAME changed (libzuptsdk.so.2 ->
+# libvuptsdk.so.2), the C API (zuptsdk_* symbols, zuptsdk.h) is unchanged.
+#
+# WITH_SDK=1 links libvuptsdk (--pq-sdk + Argon2id password KDF). WITH_PQBOX=1
+# links the SEPARATE libpqvaptvupt (--pq-box sealed box); it is independent of
+# WITH_SDK because the two are different upstream libraries. Enable either or
+# both, given the corresponding vendored .so is present.
 WITH_SDK ?= 0
 ifeq ($(WITH_SDK),1)
-ZUPTSDK_DIR ?= vendor/zuptsdk
+ZUPTSDK_DIR ?= vendor/vuptsdk
 ZUPTSDK_ABS := $(abspath $(ZUPTSDK_DIR))
 CFLAGS  += -DZUPT_WITH_SDK -I$(ZUPTSDK_DIR)/include
-PQVV_DIR ?= vendor/pqvaptvupt
-CFLAGS  += -I$(PQVV_DIR)/include
 LDFLAGS += -L$(ZUPTSDK_DIR) -Wl,-rpath,$(ZUPTSDK_ABS) -Wl,-rpath,'$$ORIGIN/$(ZUPTSDK_DIR)'
-LDLIBS  += -lzuptsdk
+# libvuptsdk pulls in OpenSSL 3 (libcrypto) and Argon2; the final link must be
-PQVV_ABS := $(abspath $(PQVV_DIR))
+# able to resolve those transitive symbols. On a distro they are on the default
-LDFLAGS += -L$(PQVV_DIR) -Wl,-rpath,$(PQVV_ABS) -Wl,-rpath,'$$ORIGIN/$(PQVV_DIR)'
+# library path; on Guix pass their -L via `guix shell openssl argon2`. Override
+# SDK_DEPLIBS= if your SDK build has different runtime deps.
+SDK_DEPLIBS ?= -lcrypto -largon2
+LDLIBS  += -lvuptsdk $(SDK_DEPLIBS)
 # Installed layout: vendored libs live in $(PREFIX)/lib/$(TARGET)/ — give the
 # binary a matching relative rpath so `make install` is self-contained.
 LDFLAGS += -Wl,-rpath,'$$ORIGIN/../lib/vaptvupt'
+endif
+
+WITH_PQBOX ?= 0
+ifeq ($(WITH_PQBOX),1)
+PQVV_DIR ?= vendor/pqvaptvupt
+PQVV_ABS := $(abspath $(PQVV_DIR))
+CFLAGS  += -DZUPT_WITH_PQBOX -I$(PQVV_DIR)/include
+LDFLAGS += -L$(PQVV_DIR) -Wl,-rpath,$(PQVV_ABS) -Wl,-rpath,'$$ORIGIN/$(PQVV_DIR)'
+LDFLAGS += -Wl,-rpath,'$$ORIGIN/../lib/vaptvupt'
 LDLIBS  += -lpqvaptvupt
 endif
 
@@ -218,7 +235,7 @@ audit-licenses:
 	             -not -path './build/*' \
 	             -not -path './build_obj/*' \
 	             -not -path './sdk/build/*' \
-	             -not -path './vendor/zuptsdk/include/*'); do \
+	             -not -path './vendor/vuptsdk/include/*'); do \
 	    BASE=$$(basename "$$f"); \
 	    case "$$BASE" in \
 	        vv_*|vaptvupt*) \
@@ -331,9 +348,12 @@ install: $(TARGET)
 	# the source tree).
 ifeq ($(WITH_SDK),1)
 	$(Q)mkdir -p $(DESTDIR)$(PREFIX)/lib/vaptvupt
-	$(Q)install -m 755 vendor/zuptsdk/libzuptsdk.so.2.0.0 $(DESTDIR)$(PREFIX)/lib/vaptvupt/libzuptsdk.so.2.0.0
+	$(Q)install -m 755 vendor/vuptsdk/libvuptsdk.so.2.0.0 $(DESTDIR)$(PREFIX)/lib/vaptvupt/libvuptsdk.so.2.0.0
-	$(Q)ln -sf libzuptsdk.so.2.0.0 $(DESTDIR)$(PREFIX)/lib/vaptvupt/libzuptsdk.so.2
+	$(Q)ln -sf libvuptsdk.so.2.0.0 $(DESTDIR)$(PREFIX)/lib/vaptvupt/libvuptsdk.so.2
-	$(Q)ln -sf libzuptsdk.so.2.0.0 $(DESTDIR)$(PREFIX)/lib/vaptvupt/libzuptsdk.so
+	$(Q)ln -sf libvuptsdk.so.2.0.0 $(DESTDIR)$(PREFIX)/lib/vaptvupt/libvuptsdk.so
+endif
+ifeq ($(WITH_PQBOX),1)
+	$(Q)mkdir -p $(DESTDIR)$(PREFIX)/lib/vaptvupt
 	$(Q)install -m 755 vendor/pqvaptvupt/libpqvaptvupt.so.0.6.0 $(DESTDIR)$(PREFIX)/lib/vaptvupt/libpqvaptvupt.so.0.6.0
 	$(Q)ln -sf libpqvaptvupt.so.0.6.0 $(DESTDIR)$(PREFIX)/lib/vaptvupt/libpqvaptvupt.so.0
 	$(Q)ln -sf libpqvaptvupt.so.0.6.0 $(DESTDIR)$(PREFIX)/lib/vaptvupt/libpqvaptvupt.so

gui/src/zupt_gui.py

@@ -194,7 +194,7 @@ ZUPT_VER_SHORT, ZUPT_VER_NUMBER, ZUPT_VER_FULL = _get_version()
 
 # ── Detect build capabilities from `version` (and `help` as fallback) ──
 #
-# The default build is SOURCE-ONLY: the libzuptsdk-backed modes (Argon2id
+# The default build is SOURCE-ONLY: the libvuptsdk-backed modes (Argon2id
 # KDF, --pq-sdk, --pq-box) are absent and fail with exit 1. Offering them in
 # the UI is the #1 reason "functions don't work". We detect what THIS binary
 # actually supports and build the encryption UI around it:
@@ -212,7 +212,7 @@ def _get_caps():
     for line in blob.splitlines():
         low = line.lower()
         if low.startswith("build:"):
-            sdk = ("full" in low) and ("libzuptsdk" in low)
+            sdk = ("full" in low) and ("vuptsdk" in low)
         elif low.startswith("kdf:"):
             default_kdf = "Argon2id" if "argon2id (default)" in low else "PBKDF2-SHA256"
         if "--pq-only" in line:

src/zupt_crypto_pqbox.c

@@ -33,7 +33,7 @@
  */
 #include "zupt.h"
 
-#ifdef ZUPT_WITH_SDK
+#ifdef ZUPT_WITH_PQBOX
 #include "zupt_keccak.h"
 #include "pqvaptvupt.h"
 #include <stdio.h>
@@ -182,7 +182,7 @@ int zupt_pqbox_decrypt_init(zupt_keyring_t *kr, const char *privkeyfile,
     return 0;
 }
 
-#else  /* !ZUPT_WITH_SDK */
+#else  /* !ZUPT_WITH_PQBOX */
 
 /* Source-only build (no vendored libpqvaptvupt binary). The --pq-box sealed-box
  * mode is unavailable; use native --pq (ML-KEM-768 + X25519) instead, or rebuild
@@ -212,4 +212,4 @@ int zupt_pqbox_decrypt_init(zupt_keyring_t *kr, const char *privkeyfile,
     return pqbox_unavailable("--pq-box decryption (this archive needs it)");
 }
 
-#endif /* ZUPT_WITH_SDK */
+#endif /* ZUPT_WITH_PQBOX */

src/zupt_main.c

@@ -92,8 +92,8 @@ static void usage(void) {
         "  --comment-file <FILE>     Read comment from file (max 4096 bytes).\n"
         "  --pq <pubkey>         Post-quantum HYBRID encryption (ML-KEM-768 + X25519) [recommended]\n"
         "  --pq-only <pubkey>    FULL post-quantum encryption (ML-KEM-768 only, no classical layer)\n"
-        "  --pq-sdk <pubkey>     Post-quantum encryption via libzuptsdk (WITH_SDK=1 builds only)\n"
+        "  --pq-sdk <pubkey>     Post-quantum encryption via libvuptsdk (WITH_SDK=1 builds only)\n"
-        "  --pq-box <pubkey>     Post-quantum sealed box via libpqvaptvupt (WITH_SDK=1 builds only)\n"
+        "  --pq-box <pubkey>     Post-quantum sealed box via libpqvaptvupt (WITH_PQBOX=1 builds only)\n"
         "  --dedup, -D           Block-level deduplication\n"
         "  --solid               Solid mode (single stream)\n"
         "  -y, --force           Overwrite an existing non-.zupt file as the output archive\n"
@@ -108,7 +108,7 @@ static void usage(void) {
         "  -p, --password <PW>   Decryption password\n"
         "  --pq <privkey>        Post-quantum HYBRID decryption (ML-KEM-768 + X25519)\n"
         "  --pq-only <privkey>   FULL post-quantum decryption (ML-KEM-768 only)\n"
-        "  --pq-sdk <privkey>    Post-quantum decryption via libzuptsdk (WITH_SDK=1 builds only)\n"
+        "  --pq-sdk <privkey>    Post-quantum decryption via libvuptsdk (WITH_SDK=1 builds only)\n"
         "  --pq-box <privkey>    Post-quantum sealed-box decryption (libpqvaptvupt)\n"
         "  -v, --verbose         Verbose output\n"
         "  -t, --threads <N>     Thread count for decompression\n"
@@ -119,8 +119,8 @@ static void usage(void) {
         "  -k <privkey>          Source private keyfile (with --pub)\n"
         "  (default)             Generate HYBRID keypair (ML-KEM-768 + X25519) for --pq\n"
         "  --pq-only             Generate FULL post-quantum keypair (ML-KEM-768 only) for --pq-only\n"
-        "  --sdk, --pq-sdk       Generate SDK v2 keypair (libzuptsdk; WITH_SDK=1 builds only)\n"
+        "  --sdk, --pq-sdk       Generate SDK v2 keypair (libvuptsdk; WITH_SDK=1 builds only)\n"
-        "  --box, --pq-box       Generate pq-box keypair (libpqvaptvupt; WITH_SDK=1 builds only)\n"
+        "  --box, --pq-box       Generate pq-box keypair (libpqvaptvupt; WITH_PQBOX=1 builds only)\n"
         "                          Use each key with its matching mode.\n"
         "\n"
         "Directories are traversed recursively.\n"
@@ -219,8 +219,16 @@ int main(int argc, char **argv) {
                "Encryption: AES-256-CTR + HMAC-SHA256\n"
 #ifdef ZUPT_WITH_SDK
                "KDF: Argon2id (default) / PBKDF2-SHA256 %d iter (--kdf pbkdf2)\n"
-               "Post-quantum: --pq hybrid (ML-KEM-768 + X25519), --pq-only (ML-KEM-768), --pq-sdk/--pq-box (libzuptsdk)\n"
+               "Post-quantum: --pq hybrid (ML-KEM-768 + X25519), --pq-only (ML-KEM-768), --pq-sdk (libvuptsdk)"
-               "Build: full (libzuptsdk: Argon2id, --pq-sdk, --pq-box available)\n"
+#ifdef ZUPT_WITH_PQBOX
+               ", --pq-box (libpqvaptvupt)"
+#endif
+               "\n"
+               "Build: full (libvuptsdk: Argon2id, --pq-sdk"
+#ifdef ZUPT_WITH_PQBOX
+               ", --pq-box"
+#endif
+               " available)\n"
 #else
                "KDF: PBKDF2-SHA256 %d iter (default; Argon2id needs WITH_SDK=1)\n"
                "Post-quantum: --pq hybrid (ML-KEM-768 + X25519), --pq-only (ML-KEM-768 only) — FIPS 203 + RFC 7748\n"
@@ -976,7 +984,7 @@ int main(int argc, char **argv) {
             if (zupt_sdk_hybrid_keygen(outfile, pubfile) != 0) {
                 fprintf(stderr,
                     "Error: SDK-v2 key generation is unavailable in this build.\n"
-                    "       --pq-sdk needs libzuptsdk, which is not part of the source-only\n"
+                    "       --pq-sdk needs libvuptsdk, which is not part of the source-only\n"
                     "       build. For post-quantum keys use one of the native modes:\n"
                     "         vaptvupt keygen -o key            # hybrid ML-KEM-768 + X25519 (--pq)\n"
                     "         vaptvupt keygen --pq-only -o key  # full PQ, ML-KEM-768 only (--pq-only)\n"

vendor/vuptsdk/include/vaptvupt.h

@@ -2,7 +2,7 @@
  * VaptVupt Codec — Next-generation lossless compression
  * Public API and data structures
  *
- * SPDX-License-Identifier: GPL-3.0-or-later
+ * SPDX-License-Identifier: AGPL-3.0-or-later
  * Copyright 2026 Cristian.
  * Zero dependencies. Pure C11.
  */

vendor/vuptsdk/include/vaptvupt_api.h

@@ -1,6 +1,6 @@
 /*
  * VaptVupt — Zupt Integration API
- * SPDX-License-Identifier: GPL-3.0-or-later
+ * SPDX-License-Identifier: AGPL-3.0-or-later
  * Copyright 2026 Cristian.
  *
  * ZUPT-COMPAT: This is the API that Zupt calls. It wraps the internal

vendor/vuptsdk/include/vv_ans.h

@@ -1,5 +1,5 @@
 /*
- * SPDX-License-Identifier: GPL-3.0-or-later
+ * SPDX-License-Identifier: AGPL-3.0-or-later
  *
  * VaptVupt — tANS Entropy Codec (v2: sparse header + 4-way interleaved)
  *

vendor/vuptsdk/include/vv_huffman.h

@@ -1,5 +1,5 @@
 /*
- * SPDX-License-Identifier: GPL-3.0-or-later
+ * SPDX-License-Identifier: AGPL-3.0-or-later
  *
  * VaptVupt — Canonical Huffman Codec
  *

vendor/vuptsdk/include/vv_platform.h

@@ -4,7 +4,7 @@
  * Provides unified abstractions for compiler intrinsics used throughout
  * the codebase. Supports GCC, Clang, MSVC, and Intel compilers.
  *
- * SPDX-License-Identifier: GPL-3.0-or-later
+ * SPDX-License-Identifier: AGPL-3.0-or-later
  */
 
 #ifndef VV_PLATFORM_H

vendor/vuptsdk/include/zupt.h

@@ -30,7 +30,7 @@
   #define zupt_mkdir(p) mkdir(p, 0755)
 #endif
 
-#define ZUPT_VERSION_STRING "2.2.3"
+#define ZUPT_VERSION_STRING "2.2.2"
 #define ZUPT_FORMAT_MAJOR   1
 #define ZUPT_FORMAT_MINOR   4
 
@@ -62,8 +62,8 @@
 /* Encryption types (stored in encryption header block) */
 #define ZUPT_ENC_PBKDF2     0x01  /* Password-based: PBKDF2 → AES-256-CTR + HMAC */
 #define ZUPT_ENC_PQ_HYBRID  0x02  /* ML-KEM-768 + X25519 hybrid KEM (legacy XOR+SHA3) */
-#define ZUPT_ENC_PQ_SDK_V2  0x03  /* libzuptsdk v2 header: HKDF combiner + commitment + HPKE binding */
+#define ZUPT_ENC_PQ_SDK_V2  0x03  /* libvuptsdk v2 header: HKDF combiner + commitment + HPKE binding */
-#define ZUPT_ENC_PW_ARGON2  0x04  /* Password-based via libzuptsdk: Argon2id + XChaCha20-Poly1305 */
+#define ZUPT_ENC_PW_ARGON2  0x04  /* Password-based via libvuptsdk: Argon2id + XChaCha20-Poly1305 */
 
 /* Block types */
 #define ZUPT_BLOCK_DATA       0x00
@@ -173,7 +173,7 @@ typedef struct {
     int level; uint32_t block_size; uint16_t codec_id;
     int verbose, encrypt, quiet, solid, threads;
     int pq_mode;           /* 1 = post-quantum hybrid KEM mode */
-    int sdk_mode;          /* 1 = use libzuptsdk-backed v3 crypto (HKDF combiner + commitment + HPKE) */
+    int sdk_mode;          /* 1 = use libvuptsdk-backed v3 crypto (HKDF combiner + commitment + HPKE) */
     int dedup;             /* 1 = block-level deduplication enabled */
     char password[256];
     char keyfile[ZUPT_MAX_PATH]; /* Path to .zupt-key file */
@@ -329,7 +329,7 @@ int zupt_hybrid_encrypt_init(zupt_keyring_t *kr, const char *pubkeyfile,
 int zupt_hybrid_decrypt_init(zupt_keyring_t *kr, const char *privkeyfile,
                               const uint8_t *enc_hdr, size_t enc_hdr_len);
 
-/* ─── SDK-backed crypto (zupt v2.2+, libzuptsdk under the hood) ─── */
+/* ─── SDK-backed crypto (zupt v2.2+, libvuptsdk under the hood) ─── */
 int zupt_sdk_hybrid_keygen(const char *privkeyfile, const char *pubkeyfile);
 int zupt_sdk_hybrid_encrypt_init(zupt_keyring_t *kr, const char *pubkeyfile,
                                   uint8_t *enc_hdr, size_t *enc_hdr_len);

vendor/vuptsdk/include/zupt_mlkem.h

@@ -21,6 +21,7 @@
 #define ZUPT_MLKEM_H
 
 #include <stdint.h>
+#include <stddef.h>
 
 #define MLKEM_K     3
 #define MLKEM_N     256
@@ -46,7 +47,8 @@ int zupt_mlkem768_keygen(uint8_t pk[MLKEM_PUBLICKEYBYTES],
  * ct: output ciphertext (1088 bytes)
  * ss: output shared secret (32 bytes)
  * pk: input public key (1184 bytes)
- * Returns 0 on success. */
+ * Returns 0 on success, non-zero if pk fails the FIPS 203 §7.2
+ * encapsulation-key modulus check (malformed key). */
 int zupt_mlkem768_encaps(uint8_t ct[MLKEM_CIPHERTEXTBYTES],
                           uint8_t ss[MLKEM_SSBYTES],
                           const uint8_t pk[MLKEM_PUBLICKEYBYTES]);
@@ -62,4 +64,14 @@ int zupt_mlkem768_decaps(uint8_t ss[MLKEM_SSBYTES],
                           const uint8_t ct[MLKEM_CIPHERTEXTBYTES],
                           const uint8_t sk[MLKEM_SECRETKEYBYTES]);
 
+/* FIPS 203 §7.2 encapsulation-key check (modulus check).
+ * Returns 0 iff `ek` is `len`==1184 bytes and every 12-bit coefficient is
+ * reduced mod q. Non-zero => malformed key; do not encapsulate against it. */
+int zupt_mlkem768_check_ek(const uint8_t *ek, size_t len);
+
+/* FIPS 203 §7.3 decapsulation-key check (hash check).
+ * Returns 0 iff `dk` is `len`==2400 bytes and the embedded H(ek) matches the
+ * SHA3-256 of the embedded encapsulation key. Non-zero => corrupt/forged key. */
+int zupt_mlkem768_check_dk(const uint8_t *dk, size_t len);
+
 #endif

vendor/vuptsdk/include/zuptsdk.h

@@ -1,10 +1,10 @@
 /*
- * libzuptsdk — Public C ABI for the Zupt backup compression library
+ * libvuptsdk — Public C ABI for the Zupt backup compression library
  *
  * Copyright (c) 2026 Cristian Cezar Moisés
  * SPDX-License-Identifier: AGPL-3.0-or-later
  *
- * Repository: https://git.securityops.co/cristiancmoises/zupt
+ * Repository: https://github.com/cristiancmoises/zupt
  * Website:    https://zupt.securityops.co
  * Contact:    zupt@riseup.net
  *
@@ -15,7 +15,7 @@
  * is gated behind the linker version tag ZUPTSDK_1.0. New symbols may be
  * added in minor versions (1.1, 1.2, ...) under new tags (ZUPTSDK_1.1, ...).
  * Existing symbols will never change signature within v1.x. Breaking
- * changes require a major version bump (libzuptsdk.so.2).
+ * changes require a major version bump (libvuptsdk.so.2).
  *
  * No symbol prefixed with anything other than `zuptsdk_` or `ZUPTSDK_` is
  * part of this ABI. Do not link against internal `zupt_*` symbols even if

vendor/vuptsdk/include/zuptsdk_easy.h

@@ -1,5 +1,5 @@
 /*
- * zuptsdk easy.h — high-level API for drop-in encryption.
+ * vuptsdk easy.h — high-level API for drop-in encryption.
  * SPDX-License-Identifier: AGPL-3.0-or-later
  *
  * Goal: 3 lines of code to encrypt/decrypt anything in any language.

vendor/vuptsdk/include/zuptsdk_metrics.h

@@ -1,4 +1,4 @@
-/* zuptsdk observability — metrics & structured logging hooks
+/* vuptsdk observability — metrics & structured logging hooks
  * SPDX-License-Identifier: AGPL-3.0-or-later
  */
 #ifndef ZUPTSDK_METRICS_H