Add "silentpayments" module implementing BIP352 (take 4, limited to full-node scanning)

.github/workflows/ci.yml

@@ -35,6 +35,7 @@ env:
   SCHNORRSIG: 'no'
   MUSIG: 'no'
   ELLSWIFT: 'no'
+  SILENTPAYMENTS: 'no'
   ### test options
   SECP256K1_TEST_ITERS: 64
   BENCH: 'yes'
@@ -83,18 +84,18 @@ jobs:
       matrix:
         configuration:
           - env_vars: { WIDEMUL: 'int64',  RECOVERY: 'yes' }
-          - env_vars: { WIDEMUL: 'int64',                   ECDH: 'yes', EXTRAKEYS: 'yes', SCHNORRSIG: 'yes', MUSIG: 'yes', ELLSWIFT: 'yes' }
+          - env_vars: { WIDEMUL: 'int64',                   ECDH: 'yes', EXTRAKEYS: 'yes', SCHNORRSIG: 'yes', MUSIG: 'yes', ELLSWIFT: 'yes', SILENTPAYMENTS: 'yes' }
           - env_vars: { WIDEMUL: 'int128' }
           - env_vars: { WIDEMUL: 'int128_struct',                                                             ELLSWIFT: 'yes' }
           - env_vars: { WIDEMUL: 'int128', RECOVERY: 'yes',              EXTRAKEYS: 'yes', SCHNORRSIG: 'yes', MUSIG: 'yes', ELLSWIFT: 'yes' }
-          - env_vars: { WIDEMUL: 'int128',                  ECDH: 'yes', EXTRAKEYS: 'yes', SCHNORRSIG: 'yes', MUSIG: 'yes' }
+          - env_vars: { WIDEMUL: 'int128',                  ECDH: 'yes', EXTRAKEYS: 'yes', SCHNORRSIG: 'yes', MUSIG: 'yes', SILENTPAYMENTS: 'yes' }
           - env_vars: { WIDEMUL: 'int128', ASM: 'x86_64',                                                     ELLSWIFT: 'yes' }
           - env_vars: {                    RECOVERY: 'yes',              EXTRAKEYS: 'yes', SCHNORRSIG: 'yes', MUSIG: 'yes' }
-          - env_vars: { CTIMETESTS: 'no',  RECOVERY: 'yes', ECDH: 'yes', EXTRAKEYS: 'yes', SCHNORRSIG: 'yes', MUSIG: 'yes', CPPFLAGS: '-DVERIFY' }
+          - env_vars: { CTIMETESTS: 'no',  RECOVERY: 'yes', ECDH: 'yes', EXTRAKEYS: 'yes', SCHNORRSIG: 'yes', MUSIG: 'yes', SILENTPAYMENTS: 'yes', CPPFLAGS: '-DVERIFY' }
           - env_vars: { BUILD: 'distcheck', WITH_VALGRIND: 'no', CTIMETESTS: 'no', BENCH: 'no' }
           - env_vars: { CPPFLAGS: '-DDETERMINISTIC' }
           - env_vars: { CFLAGS: '-O0', CTIMETESTS: 'no' }
-          - env_vars: { CFLAGS: '-O1',     RECOVERY: 'yes', ECDH: 'yes', EXTRAKEYS: 'yes', SCHNORRSIG: 'yes', MUSIG: 'yes', ELLSWIFT: 'yes' }
+          - env_vars: { CFLAGS: '-O1',     RECOVERY: 'yes', ECDH: 'yes', EXTRAKEYS: 'yes', SCHNORRSIG: 'yes', MUSIG: 'yes', ELLSWIFT: 'yes', SILENTPAYMENTS: 'yes' }
           - env_vars: { ECMULTGENKB: 2, ECMULTWINDOW: 2 }
           - env_vars: { ECMULTGENKB: 86, ECMULTWINDOW: 4 }
         cc:
@@ -146,6 +147,7 @@ jobs:
       SCHNORRSIG: 'yes'
       MUSIG: 'yes'
       ELLSWIFT: 'yes'
+      SILENTPAYMENTS: 'yes'
       CC: ${{ matrix.cc }}
 
     steps:
@@ -174,6 +176,7 @@ jobs:
       SCHNORRSIG: 'yes'
       MUSIG: 'yes'
       ELLSWIFT: 'yes'
+      SILENTPAYMENTS: 'yes'
       CTIMETESTS: 'no'
 
     steps:
@@ -204,6 +207,7 @@ jobs:
       SCHNORRSIG: 'yes'
       MUSIG: 'yes'
       ELLSWIFT: 'yes'
+      SILENTPAYMENTS: 'yes'
       CTIMETESTS: 'no'
 
     steps:
@@ -225,6 +229,7 @@ jobs:
       SCHNORRSIG: 'yes'
       MUSIG: 'yes'
       ELLSWIFT: 'yes'
+      SILENTPAYMENTS: 'yes'
       CTIMETESTS: 'no'
       CC: ${{ matrix.cc }}
 
@@ -265,6 +270,7 @@ jobs:
       SCHNORRSIG: 'yes'
       MUSIG: 'yes'
       ELLSWIFT: 'yes'
+      SILENTPAYMENTS: 'yes'
       CTIMETESTS: 'no'
 
     steps:
@@ -310,6 +316,7 @@ jobs:
       SCHNORRSIG: 'yes'
       MUSIG: 'yes'
       ELLSWIFT: 'yes'
+      SILENTPAYMENTS: 'yes'
       CTIMETESTS: 'no'
       SECP256K1_TEST_ITERS: 2
 
@@ -339,6 +346,7 @@ jobs:
       SCHNORRSIG: 'yes'
       MUSIG: 'yes'
       ELLSWIFT: 'yes'
+      SILENTPAYMENTS: 'yes'
       CTIMETESTS: 'no'
       CFLAGS: '-fsanitize=undefined,address -g'
       UBSAN_OPTIONS: 'print_stacktrace=1:halt_on_error=1'
@@ -385,6 +393,7 @@ jobs:
       SCHNORRSIG: 'yes'
       MUSIG: 'yes'
       ELLSWIFT: 'yes'
+      SILENTPAYMENTS: 'yes'
       CC: ${{ matrix.cc }}
       SECP256K1_TEST_ITERS: 32
       ASM: 'no'
@@ -410,6 +419,7 @@ jobs:
       SCHNORRSIG: 'yes'
       MUSIG: 'yes'
       ELLSWIFT: 'yes'
+      SILENTPAYMENTS: 'yes'
       CTIMETESTS: 'no'
 
     strategy:
@@ -442,14 +452,14 @@ jobs:
       fail-fast: false
       matrix:
         env_vars:
-          - { WIDEMUL: 'int64',  RECOVERY: 'yes', ECDH: 'yes', EXTRAKEYS: 'yes', SCHNORRSIG: 'yes', MUSIG: 'yes', ELLSWIFT: 'yes' }
+          - { WIDEMUL: 'int64',  RECOVERY: 'yes', ECDH: 'yes', EXTRAKEYS: 'yes', SCHNORRSIG: 'yes', MUSIG: 'yes', ELLSWIFT: 'yes', SILENTPAYMENTS: 'yes' }
           - { WIDEMUL: 'int128_struct', ECMULTGENKB: 2, ECMULTWINDOW: 4 }
-          - { WIDEMUL: 'int128',                  ECDH: 'yes', EXTRAKEYS: 'yes', SCHNORRSIG: 'yes', MUSIG: 'yes', ELLSWIFT: 'yes' }
+          - { WIDEMUL: 'int128',                  ECDH: 'yes', EXTRAKEYS: 'yes', SCHNORRSIG: 'yes', MUSIG: 'yes', ELLSWIFT: 'yes', SILENTPAYMENTS: 'yes' }
           - { WIDEMUL: 'int128', RECOVERY: 'yes' }
-          - { WIDEMUL: 'int128', RECOVERY: 'yes', ECDH: 'yes', EXTRAKEYS: 'yes', SCHNORRSIG: 'yes', MUSIG: 'yes', ELLSWIFT: 'yes' }
-          - { WIDEMUL: 'int128', RECOVERY: 'yes', ECDH: 'yes', EXTRAKEYS: 'yes', SCHNORRSIG: 'yes', MUSIG: 'yes', ELLSWIFT: 'yes', CC: 'gcc' }
-          - { WIDEMUL: 'int128', RECOVERY: 'yes', ECDH: 'yes', EXTRAKEYS: 'yes', SCHNORRSIG: 'yes', MUSIG: 'yes', ELLSWIFT: 'yes',            WRAPPER_CMD: 'valgrind --error-exitcode=42', SECP256K1_TEST_ITERS: 2 }
-          - { WIDEMUL: 'int128', RECOVERY: 'yes', ECDH: 'yes', EXTRAKEYS: 'yes', SCHNORRSIG: 'yes', MUSIG: 'yes', ELLSWIFT: 'yes', CC: 'gcc', WRAPPER_CMD: 'valgrind --error-exitcode=42', SECP256K1_TEST_ITERS: 2 }
+          - { WIDEMUL: 'int128', RECOVERY: 'yes', ECDH: 'yes', EXTRAKEYS: 'yes', SCHNORRSIG: 'yes', MUSIG: 'yes', ELLSWIFT: 'yes', SILENTPAYMENTS: 'yes' }
+          - { WIDEMUL: 'int128', RECOVERY: 'yes', ECDH: 'yes', EXTRAKEYS: 'yes', SCHNORRSIG: 'yes', MUSIG: 'yes', ELLSWIFT: 'yes', SILENTPAYMENTS: 'yes', CC: 'gcc' }
+          - { WIDEMUL: 'int128', RECOVERY: 'yes', ECDH: 'yes', EXTRAKEYS: 'yes', SCHNORRSIG: 'yes', MUSIG: 'yes', ELLSWIFT: 'yes', SILENTPAYMENTS: 'yes',            WRAPPER_CMD: 'valgrind --error-exitcode=42', SECP256K1_TEST_ITERS: 2 }
+          - { WIDEMUL: 'int128', RECOVERY: 'yes', ECDH: 'yes', EXTRAKEYS: 'yes', SCHNORRSIG: 'yes', MUSIG: 'yes', ELLSWIFT: 'yes', SILENTPAYMENTS: 'yes', CC: 'gcc', WRAPPER_CMD: 'valgrind --error-exitcode=42', SECP256K1_TEST_ITERS: 2 }
           - { WIDEMUL: 'int128', RECOVERY: 'yes', ECDH: 'yes', EXTRAKEYS: 'yes', SCHNORRSIG: 'yes', MUSIG: 'yes', ELLSWIFT: 'yes', CPPFLAGS: '-DVERIFY', CTIMETESTS: 'no' }
           - BUILD: 'distcheck'
 
@@ -494,13 +504,13 @@ jobs:
       fail-fast: false
       matrix:
         env_vars:
-          - { WIDEMUL: 'int64',  RECOVERY: 'yes', ECDH: 'yes', EXTRAKEYS: 'yes', SCHNORRSIG: 'yes', MUSIG: 'yes', ELLSWIFT: 'yes' }
+          - { WIDEMUL: 'int64',  RECOVERY: 'yes', ECDH: 'yes', EXTRAKEYS: 'yes', SCHNORRSIG: 'yes', MUSIG: 'yes', ELLSWIFT: 'yes', SILENTPAYMENTS: 'yes' }
           - { WIDEMUL: 'int128_struct', ECMULTGENPRECISION: 2, ECMULTWINDOW: 4 }
-          - { WIDEMUL: 'int128',                  ECDH: 'yes', EXTRAKEYS: 'yes', SCHNORRSIG: 'yes', MUSIG: 'yes', ELLSWIFT: 'yes' }
+          - { WIDEMUL: 'int128',                  ECDH: 'yes', EXTRAKEYS: 'yes', SCHNORRSIG: 'yes', MUSIG: 'yes', ELLSWIFT: 'yes', SILENTPAYMENTS: 'yes' }
           - { WIDEMUL: 'int128', RECOVERY: 'yes' }
-          - { WIDEMUL: 'int128', RECOVERY: 'yes', ECDH: 'yes', EXTRAKEYS: 'yes', SCHNORRSIG: 'yes', MUSIG: 'yes', ELLSWIFT: 'yes' }
-          - { WIDEMUL: 'int128', RECOVERY: 'yes', ECDH: 'yes', EXTRAKEYS: 'yes', SCHNORRSIG: 'yes', MUSIG: 'yes', ELLSWIFT: 'yes', CC: 'gcc' }
-          - { WIDEMUL: 'int128', RECOVERY: 'yes', ECDH: 'yes', EXTRAKEYS: 'yes', SCHNORRSIG: 'yes', MUSIG: 'yes', ELLSWIFT: 'yes', CPPFLAGS: '-DVERIFY' }
+          - { WIDEMUL: 'int128', RECOVERY: 'yes', ECDH: 'yes', EXTRAKEYS: 'yes', SCHNORRSIG: 'yes', MUSIG: 'yes', ELLSWIFT: 'yes', SILENTPAYMENTS: 'yes' }
+          - { WIDEMUL: 'int128', RECOVERY: 'yes', ECDH: 'yes', EXTRAKEYS: 'yes', SCHNORRSIG: 'yes', MUSIG: 'yes', ELLSWIFT: 'yes', SILENTPAYMENTS: 'yes', CC: 'gcc' }
+          - { WIDEMUL: 'int128', RECOVERY: 'yes', ECDH: 'yes', EXTRAKEYS: 'yes', SCHNORRSIG: 'yes', MUSIG: 'yes', ELLSWIFT: 'yes', SILENTPAYMENTS: 'yes', CPPFLAGS: '-DVERIFY' }
           - BUILD: 'distcheck'
 
     steps:
@@ -623,6 +633,7 @@ jobs:
       SCHNORRSIG: 'yes'
       MUSIG: 'yes'
       ELLSWIFT: 'yes'
+      SILENTPAYMENTS: 'yes'
 
     steps:
       - *CHECKOUT

.gitignore

@@ -12,6 +12,7 @@ ecdsa_example
 schnorr_example
 ellswift_example
 musig_example
+silentpayments_example
 *.exe
 *.so
 *.a

CMakeLists.txt

@@ -52,6 +52,7 @@ option(SECP256K1_ENABLE_MODULE_EXTRAKEYS "Enable extrakeys module." ON)
 option(SECP256K1_ENABLE_MODULE_SCHNORRSIG "Enable schnorrsig module." ON)
 option(SECP256K1_ENABLE_MODULE_MUSIG "Enable musig module." ON)
 option(SECP256K1_ENABLE_MODULE_ELLSWIFT "Enable ElligatorSwift module." ON)
+option(SECP256K1_ENABLE_MODULE_SILENTPAYMENTS "Enable Silent Payments module." ON)
 
 option(SECP256K1_USE_EXTERNAL_DEFAULT_CALLBACKS "Enable external default callback functions." OFF)
 if(SECP256K1_USE_EXTERNAL_DEFAULT_CALLBACKS)
@@ -285,6 +286,7 @@ message("  extrakeys ........................... ${SECP256K1_ENABLE_MODULE_EXTRA
 message("  schnorrsig .......................... ${SECP256K1_ENABLE_MODULE_SCHNORRSIG}")
 message("  musig ............................... ${SECP256K1_ENABLE_MODULE_MUSIG}")
 message("  ElligatorSwift ...................... ${SECP256K1_ENABLE_MODULE_ELLSWIFT}")
+message("  Silent Payments ..................... ${SECP256K1_ENABLE_MODULE_SILENTPAYMENTS}")
 message("Parameters:")
 message("  ecmult window size .................. ${SECP256K1_ECMULT_WINDOW_SIZE}")
 message("  ecmult gen table size ............... ${SECP256K1_ECMULT_GEN_KB} KiB")

Makefile.am

@@ -210,6 +210,17 @@ musig_example_LDFLAGS += -lbcrypt
 endif
 TESTS += musig_example
 endif
+if ENABLE_MODULE_SILENTPAYMENTS
+noinst_PROGRAMS += silentpayments_example
+silentpayments_example_SOURCES = examples/silentpayments.c
+silentpayments_example_CPPFLAGS = -I$(top_srcdir)/include -DSECP256K1_STATIC
+silentpayments_example_LDADD = libsecp256k1.la
+silentpayments_example_LDFLAGS = -static
+if BUILD_WINDOWS
+silentpayments_example_LDFLAGS += -lbcrypt
+endif
+TESTS += silentpayments_example
+endif
 endif
 
 ### Precomputed tables
@@ -252,6 +263,11 @@ maintainer-clean-local: clean-precomp
 ### Pregenerated test vectors
 ### (see the comments in the previous section for detailed rationale)
 TESTVECTORS = src/wycheproof/ecdsa_secp256k1_sha256_bitcoin_test.h
+TESTVECTORS += src/modules/silentpayments/vectors.h
+
+if ENABLE_MODULE_SILENTPAYMENTS
+TESTVECTORS += src/modules/silentpayments/vectors.h
+endif
 
 if ENABLE_MODULE_ECDH
 TESTVECTORS += src/wycheproof/ecdh_secp256k1_test.h
@@ -265,6 +281,10 @@ src/wycheproof/ecdh_secp256k1_test.h:
 	mkdir -p $(@D)
 	python3 $(top_srcdir)/tools/tests_wycheproof_generate_ecdh.py $(top_srcdir)/src/wycheproof/ecdh_secp256k1_test.json > $@
 
+src/modules/silentpayments/vectors.h:
+	mkdir -p $(@D)
+	python3 $(top_srcdir)/tools/tests_silentpayments_generate.py $(top_srcdir)/src/modules/silentpayments/bip352_send_and_receive_test_vectors.json > $@
+
 testvectors: $(TESTVECTORS)
 
 BUILT_SOURCES += $(TESTVECTORS)
@@ -314,3 +334,7 @@ endif
 if ENABLE_MODULE_ELLSWIFT
 include src/modules/ellswift/Makefile.am.include
 endif
+
+if ENABLE_MODULE_SILENTPAYMENTS
+include src/modules/silentpayments/Makefile.am.include
+endif

README.md

@@ -22,6 +22,7 @@ Features:
 * Optional module for Schnorr signatures according to [BIP-340](https://github.com/bitcoin/bips/blob/master/bip-0340.mediawiki).
 * Optional module for ElligatorSwift key exchange according to [BIP-324](https://github.com/bitcoin/bips/blob/master/bip-0324.mediawiki).
 * Optional module for MuSig2 Schnorr multi-signatures according to [BIP-327](https://github.com/bitcoin/bips/blob/master/bip-0327.mediawiki).
+* Optional module for Silent Payments sending and receiving according to [BIP-352](https://github.com/bitcoin/bips/blob/master/bip-0352.mediawiki).
 
 Implementation details
 ----------------------
@@ -150,6 +151,7 @@ Usage examples can be found in the [examples](examples) directory. To compile th
   * [Deriving a shared secret (ECDH) example](examples/ecdh.c)
   * [ElligatorSwift key exchange example](examples/ellswift.c)
   * [MuSig2 Schnorr multi-signatures example](examples/musig.c)
+  * [Silent Payments send and receive example](examples/silentpayments.c)
 
 To compile the examples, make sure the corresponding modules are enabled.
 

ci/ci.sh

@@ -13,7 +13,7 @@ print_environment() {
     # does not rely on bash.
     for var in WERROR_CFLAGS MAKEFLAGS BUILD \
             ECMULTWINDOW ECMULTGENKB ASM WIDEMUL WITH_VALGRIND EXTRAFLAGS \
-            EXPERIMENTAL ECDH RECOVERY EXTRAKEYS MUSIG SCHNORRSIG ELLSWIFT \
+            EXPERIMENTAL ECDH RECOVERY EXTRAKEYS MUSIG SCHNORRSIG ELLSWIFT SILENTPAYMENTS \
             SECP256K1_TEST_ITERS BENCH SECP256K1_BENCH_ITERS CTIMETESTS SYMBOL_CHECK \
             EXAMPLES \
             HOST WRAPPER_CMD \
@@ -64,6 +64,7 @@ fi
     --enable-module-extrakeys="$EXTRAKEYS" \
     --enable-module-schnorrsig="$SCHNORRSIG" \
     --enable-module-musig="$MUSIG" \
+    --enable-module-silentpayments="$SILENTPAYMENTS" \
     --enable-examples="$EXAMPLES" \
     --enable-ctime-tests="$CTIMETESTS" \
     --with-valgrind="$WITH_VALGRIND" \

configure.ac

@@ -191,6 +191,10 @@ AC_ARG_ENABLE(module_ellswift,
     AS_HELP_STRING([--enable-module-ellswift],[enable ElligatorSwift module [default=yes]]), [],
     [SECP_SET_DEFAULT([enable_module_ellswift], [yes], [yes])])
 
+AC_ARG_ENABLE(module_silentpayments,
+    AS_HELP_STRING([--enable-module-silentpayments],[enable Silent Payments module [default=yes]]), [],
+    [SECP_SET_DEFAULT([enable_module_silentpayments], [yes], [yes])])
+
 AC_ARG_ENABLE(external_default_callbacks,
     AS_HELP_STRING([--enable-external-default-callbacks],[enable external default callback functions [default=no]]), [],
     [SECP_SET_DEFAULT([enable_external_default_callbacks], [no], [no])])
@@ -397,6 +401,14 @@ SECP_CFLAGS="$SECP_CFLAGS $WERROR_CFLAGS"
 
 # Processing must be done in a reverse topological sorting of the dependency graph
 # (dependent module first).
+if test x"$enable_module_silentpayments" = x"yes"; then
+  if test x"$enable_module_schnorrsig" = x"no"; then
+    AC_MSG_ERROR([Module dependency error: You have disabled the schnorrsig module explicitly, but it is required by the silentpayments module.])
+  fi
+  enable_module_schnorrsig=yes
+  SECP_CONFIG_DEFINES="$SECP_CONFIG_DEFINES -DENABLE_MODULE_SILENTPAYMENTS=1"
+fi
+
 if test x"$enable_module_ellswift" = x"yes"; then
   SECP_CONFIG_DEFINES="$SECP_CONFIG_DEFINES -DENABLE_MODULE_ELLSWIFT=1"
 fi
@@ -470,6 +482,7 @@ AM_CONDITIONAL([ENABLE_MODULE_EXTRAKEYS], [test x"$enable_module_extrakeys" = x"
 AM_CONDITIONAL([ENABLE_MODULE_SCHNORRSIG], [test x"$enable_module_schnorrsig" = x"yes"])
 AM_CONDITIONAL([ENABLE_MODULE_MUSIG], [test x"$enable_module_musig" = x"yes"])
 AM_CONDITIONAL([ENABLE_MODULE_ELLSWIFT], [test x"$enable_module_ellswift" = x"yes"])
+AM_CONDITIONAL([ENABLE_MODULE_SILENTPAYMENTS], [test x"$enable_module_silentpayments" = x"yes"])
 AM_CONDITIONAL([USE_EXTERNAL_ASM], [test x"$enable_external_asm" = x"yes"])
 AM_CONDITIONAL([USE_ASM_ARM], [test x"$set_asm" = x"arm32"])
 AM_CONDITIONAL([BUILD_WINDOWS], [test "$build_windows" = "yes"])
@@ -494,6 +507,7 @@ echo "  module extrakeys        = $enable_module_extrakeys"
 echo "  module schnorrsig       = $enable_module_schnorrsig"
 echo "  module musig            = $enable_module_musig"
 echo "  module ellswift         = $enable_module_ellswift"
+echo "  module silentpayments   = $enable_module_silentpayments"
 echo
 echo "  asm                     = $set_asm"
 echo "  ecmult window size      = $set_ecmult_window"

examples/CMakeLists.txt

@@ -29,3 +29,7 @@ endif()
 if(SECP256K1_ENABLE_MODULE_MUSIG)
   add_example(musig)
 endif()
+
+if(SECP256K1_ENABLE_MODULE_SILENTPAYMENTS)
+  add_example(silentpayments)
+endif()