Squashed 'src/secp256k1/' changes from 4af241b320..00b0cb19a9

00b0cb19a9 docs: update README 54b8bc8ec6 ci: enable silentpayments module 96bd71fb8a tests: add BIP-352 test vectors c30bc013fe silentpayments: add benchmark for `scan_outputs` 91b1b3365b silentpayments: add examples/silentpayments.c b4475ea80c silentpayments: receiving 23c7aead63 silentpayments: recipient label support 79562d0cd1 silentpayments: sending 35f91359b8 build: add skeleton for new silentpayments (BIP352) module 0055b86780 Merge bitcoin-core/secp256k1#1551: Add ellswift usage example ea2d5f0f17 Merge bitcoin-core/secp256k1#1563: doc: Add convention for defaults ca06e58b2c Merge bitcoin-core/secp256k1#1564: build, ci: Adjust the default size of the precomputed table for signing e2af491263 ci: Switch to the new default value of the precomputed table for signing d94a9273f8 build: Adjust the default size of the precomputed table for signing fcc5d7381b Merge bitcoin-core/secp256k1#1565: cmake: Bump CMake minimum required version up to 3.16 9420eece24 cmake: Bump CMake minimum required version up to 3.16 16685649d2 doc: Add convention for defaults a5269373fa Merge bitcoin-core/secp256k1#1555: Fixed O3 replacement b8fe33332b cmake: Fixed O3 replacement 31f84595c4 Add ellswift usage example fe4fbaa7f3 examples: fix case typos in secret clearing paragraphs (s/, Or/, or/) git-subtree-dir: src/secp256k1 git-subtree-split: 00b0cb19a97718dfaab70aa7505ff157f22a31bd
josibake · Jul 15, 2024 · 5a0b27c · 5a0b27c
1 parent 1408944
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diff --git a/.cirrus.yml b/.cirrus.yml
@@ -22,6 +22,7 @@ env:
   RECOVERY: no
   SCHNORRSIG: no
   ELLSWIFT: no
+  SILENTPAYMENTS: no
   ### test options
   SECP256K1_TEST_ITERS:
   BENCH: yes
@@ -68,6 +69,7 @@ task:
     RECOVERY: yes
     SCHNORRSIG: yes
     ELLSWIFT: yes
+    SILENTPAYMENTS: yes
   matrix:
      # Currently only gcc-snapshot, the other compilers are tested on GHA with QEMU
      - env: { CC: 'gcc-snapshot' }
@@ -84,6 +86,7 @@ task:
     RECOVERY: yes
     SCHNORRSIG: yes
     ELLSWIFT: yes
+    SILENTPAYMENTS: yes
     WRAPPER_CMD: 'valgrind --error-exitcode=42'
     SECP256K1_TEST_ITERS: 2
   matrix:

diff --git a/.github/workflows/ci.yml b/.github/workflows/ci.yml
@@ -22,7 +22,7 @@ env:
   BUILD: 'check'
   ### secp256k1 config
   ECMULTWINDOW: 15
-  ECMULTGENKB: 22
+  ECMULTGENKB: 86
   ASM: 'no'
   WIDEMUL: 'auto'
   WITH_VALGRIND: 'yes'
@@ -33,6 +33,7 @@ env:
   RECOVERY: 'no'
   SCHNORRSIG: 'no'
   ELLSWIFT: 'no'
+  SILENTPAYMENTS: 'no'
   ### test options
   SECP256K1_TEST_ITERS:
   BENCH: 'yes'
@@ -71,18 +72,18 @@ jobs:
       matrix:
         configuration:
           - env_vars: { WIDEMUL: 'int64',  RECOVERY: 'yes' }
-          - env_vars: { WIDEMUL: 'int64',                   ECDH: 'yes', SCHNORRSIG: 'yes', ELLSWIFT: 'yes' }
+          - env_vars: { WIDEMUL: 'int64',                   ECDH: 'yes', SCHNORRSIG: 'yes', ELLSWIFT: 'yes', SILENTPAYMENTS: 'yes' }
           - env_vars: { WIDEMUL: 'int128' }
           - env_vars: { WIDEMUL: 'int128_struct',                                           ELLSWIFT: 'yes' }
           - env_vars: { WIDEMUL: 'int128', RECOVERY: 'yes',              SCHNORRSIG: 'yes', ELLSWIFT: 'yes' }
-          - env_vars: { WIDEMUL: 'int128',                  ECDH: 'yes', SCHNORRSIG: 'yes' }
+          - env_vars: { WIDEMUL: 'int128',                  ECDH: 'yes', SCHNORRSIG: 'yes',                  SILENTPAYMENTS: 'yes' }
           - env_vars: { WIDEMUL: 'int128', ASM: 'x86_64',                                   ELLSWIFT: 'yes' }
           - env_vars: {                    RECOVERY: 'yes',              SCHNORRSIG: 'yes' }
-          - env_vars: { CTIMETESTS: 'no',  RECOVERY: 'yes', ECDH: 'yes', SCHNORRSIG: 'yes', CPPFLAGS: '-DVERIFY' }
+          - env_vars: { CTIMETESTS: 'no',  RECOVERY: 'yes', ECDH: 'yes', SCHNORRSIG: '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', SCHNORRSIG: 'yes', ELLSWIFT: 'yes' }
+          - env_vars: { CFLAGS: '-O1',     RECOVERY: 'yes', ECDH: 'yes', SCHNORRSIG: 'yes', ELLSWIFT: 'yes', SILENTPAYMENTS: 'yes' }
           - env_vars: { ECMULTGENKB: 2, ECMULTWINDOW: 2 }
           - env_vars: { ECMULTGENKB: 86, ECMULTWINDOW: 4 }
         cc:
@@ -141,6 +142,7 @@ jobs:
       RECOVERY: 'yes'
       SCHNORRSIG: 'yes'
       ELLSWIFT: 'yes'
+      SILENTPAYMENTS: 'yes'
       CC: ${{ matrix.cc }}
 
     steps:
@@ -185,6 +187,7 @@ jobs:
       RECOVERY: 'yes'
       SCHNORRSIG: 'yes'
       ELLSWIFT: 'yes'
+      SILENTPAYMENTS: 'yes'
       CTIMETESTS: 'no'
 
     steps:
@@ -236,6 +239,7 @@ jobs:
       RECOVERY: 'yes'
       SCHNORRSIG: 'yes'
       ELLSWIFT: 'yes'
+      SILENTPAYMENTS: 'yes'
       CTIMETESTS: 'no'
 
     steps:
@@ -281,6 +285,7 @@ jobs:
       RECOVERY: 'yes'
       SCHNORRSIG: 'yes'
       ELLSWIFT: 'yes'
+      SILENTPAYMENTS: 'yes'
       CTIMETESTS: 'no'
 
     strategy:
@@ -336,6 +341,7 @@ jobs:
       RECOVERY: 'yes'
       SCHNORRSIG: 'yes'
       ELLSWIFT: 'yes'
+      SILENTPAYMENTS: 'yes'
       CTIMETESTS: 'no'
 
     steps:
@@ -388,6 +394,7 @@ jobs:
       RECOVERY: 'yes'
       SCHNORRSIG: 'yes'
       ELLSWIFT: 'yes'
+      SILENTPAYMENTS: 'yes'
       CTIMETESTS: 'no'
       SECP256K1_TEST_ITERS: 2
 
@@ -439,6 +446,7 @@ jobs:
       RECOVERY: 'yes'
       SCHNORRSIG: 'yes'
       ELLSWIFT: 'yes'
+      SILENTPAYMENTS: 'yes'
       CTIMETESTS: 'no'
       CFLAGS: '-fsanitize=undefined,address -g'
       UBSAN_OPTIONS: 'print_stacktrace=1:halt_on_error=1'
@@ -503,6 +511,7 @@ jobs:
       RECOVERY: 'yes'
       SCHNORRSIG: 'yes'
       ELLSWIFT: 'yes'
+      SILENTPAYMENTS: 'yes'
       CC: 'clang'
       SECP256K1_TEST_ITERS: 32
       ASM: 'no'
@@ -549,6 +558,7 @@ jobs:
       RECOVERY: 'yes'
       SCHNORRSIG: 'yes'
       ELLSWIFT: 'yes'
+      SILENTPAYMENTS: 'yes'
       CTIMETESTS: 'no'
 
     strategy:
@@ -605,14 +615,14 @@ jobs:
       fail-fast: false
       matrix:
         env_vars:
-          - { WIDEMUL: 'int64',  RECOVERY: 'yes', ECDH: 'yes', SCHNORRSIG: 'yes', ELLSWIFT: 'yes' }
+          - { WIDEMUL: 'int64',  RECOVERY: 'yes', ECDH: 'yes', SCHNORRSIG: 'yes', ELLSWIFT: 'yes', SILENTPAYMENTS: 'yes' }
           - { WIDEMUL: 'int128_struct', ECMULTGENKB: 2, ECMULTWINDOW: 4 }
-          - { WIDEMUL: 'int128',                  ECDH: 'yes', SCHNORRSIG: 'yes', ELLSWIFT: 'yes' }
+          - { WIDEMUL: 'int128',                  ECDH: 'yes', SCHNORRSIG: 'yes', ELLSWIFT: 'yes', SILENTPAYMENTS: 'yes' }
           - { WIDEMUL: 'int128', RECOVERY: 'yes' }
-          - { WIDEMUL: 'int128', RECOVERY: 'yes', ECDH: 'yes', SCHNORRSIG: 'yes', ELLSWIFT: 'yes' }
-          - { WIDEMUL: 'int128', RECOVERY: 'yes', ECDH: 'yes', SCHNORRSIG: 'yes', ELLSWIFT: 'yes', CC: 'gcc' }
-          - { WIDEMUL: 'int128', RECOVERY: 'yes', ECDH: 'yes', SCHNORRSIG: 'yes', ELLSWIFT: 'yes',            WRAPPER_CMD: 'valgrind --error-exitcode=42', SECP256K1_TEST_ITERS: 2 }
-          - { WIDEMUL: 'int128', RECOVERY: 'yes', ECDH: 'yes', SCHNORRSIG: 'yes', ELLSWIFT: 'yes', CC: 'gcc', WRAPPER_CMD: 'valgrind --error-exitcode=42', SECP256K1_TEST_ITERS: 2 }
+          - { WIDEMUL: 'int128', RECOVERY: 'yes', ECDH: 'yes', SCHNORRSIG: 'yes', ELLSWIFT: 'yes', SILENTPAYMENTS: 'yes' }
+          - { WIDEMUL: 'int128', RECOVERY: 'yes', ECDH: 'yes', SCHNORRSIG: 'yes', ELLSWIFT: 'yes', SILENTPAYMENTS: 'yes', CC: 'gcc' }
+          - { WIDEMUL: 'int128', RECOVERY: 'yes', ECDH: 'yes', SCHNORRSIG: 'yes', ELLSWIFT: 'yes', SILENTPAYMENTS: 'yes',            WRAPPER_CMD: 'valgrind --error-exitcode=42', SECP256K1_TEST_ITERS: 2 }
+          - { WIDEMUL: 'int128', RECOVERY: 'yes', ECDH: 'yes', SCHNORRSIG: 'yes', ELLSWIFT: 'yes', SILENTPAYMENTS: 'yes', CC: 'gcc', WRAPPER_CMD: 'valgrind --error-exitcode=42', SECP256K1_TEST_ITERS: 2 }
           - { WIDEMUL: 'int128', RECOVERY: 'yes', ECDH: 'yes', SCHNORRSIG: 'yes', ELLSWIFT: 'yes', CPPFLAGS: '-DVERIFY', CTIMETESTS: 'no' }
           - BUILD: 'distcheck'
 
@@ -780,6 +790,7 @@ jobs:
       RECOVERY: 'yes'
       SCHNORRSIG: 'yes'
       ELLSWIFT: 'yes'
+      SILENTPAYMENTS: 'yes'
 
     steps:
       - name: Checkout
@@ -864,5 +875,5 @@ jobs:
           CI_BUILD: ${{ runner.temp }}/${{ github.run_id }}${{ github.action }}/build
           CI_INSTALL: ${{ runner.temp }}/${{ github.run_id }}${{ github.action }}/install
         run: |
-          cmake -B ${{ env.CI_BUILD }} -DCMAKE_INSTALL_PREFIX=${{ env.CI_INSTALL }} && cmake --build ${{ env.CI_BUILD }} --target install && ls -RlAh ${{ env.CI_INSTALL }}
+          cmake -B ${{ env.CI_BUILD }} -DCMAKE_INSTALL_PREFIX=${{ env.CI_INSTALL }} && cmake --build ${{ env.CI_BUILD }} && cmake --install ${{ env.CI_BUILD }} && ls -RlAh ${{ env.CI_INSTALL }}
           gcc -o ecdsa examples/ecdsa.c -I ${{ env.CI_INSTALL }}/include -L ${{ env.CI_INSTALL }}/lib*/ -l secp256k1 -Wl,-rpath,"${{ env.CI_INSTALL }}/lib",-rpath,"${{ env.CI_INSTALL }}/lib64" && ./ecdsa
diff --git a/.gitignore b/.gitignore
@@ -10,6 +10,8 @@ ctime_tests
 ecdh_example
 ecdsa_example
 schnorr_example
+ellswift_example
+silentpayments_example
 *.exe
 *.so
 *.a

diff --git a/CHANGELOG.md b/CHANGELOG.md
@@ -7,6 +7,9 @@ and this project adheres to [Semantic Versioning](https://semver.org/spec/v2.0.0
 
 ## [Unreleased]
 
+#### Added
+ - Added usage example for an ElligatorSwift key exchange.
+
 ## [0.5.0] - 2024-05-06
 
 #### Added

diff --git a/CMakeLists.txt b/CMakeLists.txt
@@ -1,11 +1,4 @@
-cmake_minimum_required(VERSION 3.13)
-
-if(CMAKE_VERSION VERSION_GREATER_EQUAL 3.15)
-  # MSVC runtime library flags are selected by the CMAKE_MSVC_RUNTIME_LIBRARY abstraction.
-  cmake_policy(SET CMP0091 NEW)
-  # MSVC warning flags are not in CMAKE_<LANG>_FLAGS by default.
-  cmake_policy(SET CMP0092 NEW)
-endif()
+cmake_minimum_required(VERSION 3.16)
 
 project(libsecp256k1
   # The package (a.k.a. release) version is based on semantic versioning 2.0.0 of
@@ -59,9 +52,14 @@ option(SECP256K1_ENABLE_MODULE_RECOVERY "Enable ECDSA pubkey recovery module." O
 option(SECP256K1_ENABLE_MODULE_EXTRAKEYS "Enable extrakeys module." ON)
 option(SECP256K1_ENABLE_MODULE_SCHNORRSIG "Enable schnorrsig module." ON)
 option(SECP256K1_ENABLE_MODULE_ELLSWIFT "Enable ElligatorSwift module." ON)
+option(SECP256K1_ENABLE_MODULE_SILENTPAYMENTS "Enable Silent Payments module." OFF)
 
 # Processing must be done in a topological sorting of the dependency graph
 # (dependent module first).
+if(SECP256K1_ENABLE_MODULE_SILENTPAYMENTS)
+  add_compile_definitions(ENABLE_MODULE_SILENTPAYMENTS=1)
+endif()
+
 if(SECP256K1_ENABLE_MODULE_ELLSWIFT)
   add_compile_definitions(ENABLE_MODULE_ELLSWIFT=1)
 endif()
@@ -97,7 +95,7 @@ include(CheckStringOptionValue)
 check_string_option_value(SECP256K1_ECMULT_WINDOW_SIZE)
 add_compile_definitions(ECMULT_WINDOW_SIZE=${SECP256K1_ECMULT_WINDOW_SIZE})
 
-set(SECP256K1_ECMULT_GEN_KB 22 CACHE STRING "The size of the precomputed table for signing in multiples of 1024 bytes (on typical platforms). Larger values result in possibly better signing or key generation performance at the cost of a larger table. Valid choices are 2, 22, 86. The default value is a reasonable setting for desktop machines (currently 22). [default=22]")
+set(SECP256K1_ECMULT_GEN_KB 86 CACHE STRING "The size of the precomputed table for signing in multiples of 1024 bytes (on typical platforms). Larger values result in possibly better signing or key generation performance at the cost of a larger table. Valid choices are 2, 22, 86. The default value is a reasonable setting for desktop machines (currently 86). [default=86]")
 set_property(CACHE SECP256K1_ECMULT_GEN_KB PROPERTY STRINGS 2 22 86)
 check_string_option_value(SECP256K1_ECMULT_GEN_KB)
 if(SECP256K1_ECMULT_GEN_KB EQUAL 2)
@@ -185,7 +183,7 @@ else()
   string(REGEX REPLACE "-DNDEBUG[ \t\r\n]*" "" CMAKE_C_FLAGS_RELEASE "${CMAKE_C_FLAGS_RELEASE}")
   string(REGEX REPLACE "-DNDEBUG[ \t\r\n]*" "" CMAKE_C_FLAGS_MINSIZEREL "${CMAKE_C_FLAGS_MINSIZEREL}")
   # Prefer -O2 optimization level. (-O3 is CMake's default for Release for many compilers.)
-  string(REGEX REPLACE "-O3[ \t\r\n]*" "-O2" CMAKE_C_FLAGS_RELEASE "${CMAKE_C_FLAGS_RELEASE}")
+  string(REGEX REPLACE "-O3( |$)" "-O2\\1" CMAKE_C_FLAGS_RELEASE "${CMAKE_C_FLAGS_RELEASE}")
 endif()
 
 # Define custom "Coverage" build type.
@@ -305,6 +303,7 @@ message("  ECDSA pubkey recovery ............... ${SECP256K1_ENABLE_MODULE_RECOV
 message("  extrakeys ........................... ${SECP256K1_ENABLE_MODULE_EXTRAKEYS}")
 message("  schnorrsig .......................... ${SECP256K1_ENABLE_MODULE_SCHNORRSIG}")
 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")

diff --git a/CONTRIBUTING.md b/CONTRIBUTING.md
@@ -49,6 +49,7 @@ In addition, libsecp256k1 tries to maintain the following coding conventions:
 * Operations involving secret data should be tested for being constant time with respect to the secrets (see [src/ctime_tests.c](src/ctime_tests.c)).
 * Local variables containing secret data should be cleared explicitly to try to delete secrets from memory.
 * Use `secp256k1_memcmp_var` instead of `memcmp` (see [#823](https://github.com/bitcoin-core/secp256k1/issues/823)).
+* As a rule of thumb, the default values for configuration options should target standard desktop machines and align with Bitcoin Core's defaults, and the tests should mostly exercise the default configuration (see [#1549](https://github.com/bitcoin-core/secp256k1/issues/1549#issuecomment-2200559257)).
 
 #### Style conventions
 

diff --git a/Makefile.am b/Makefile.am
@@ -184,6 +184,28 @@ schnorr_example_LDFLAGS += -lbcrypt
 endif
 TESTS += schnorr_example
 endif
+if ENABLE_MODULE_ELLSWIFT
+noinst_PROGRAMS += ellswift_example
+ellswift_example_SOURCES = examples/ellswift.c
+ellswift_example_CPPFLAGS = -I$(top_srcdir)/include -DSECP256K1_STATIC
+ellswift_example_LDADD = libsecp256k1.la
+ellswift_example_LDFLAGS = -static
+if BUILD_WINDOWS
+ellswift_example_LDFLAGS += -lbcrypt
+endif
+TESTS += ellswift_example
+endif
+if ENABLE_MODULE_SILENTPAYMENTS
+noinst_PROGRAMS += silentpayments_example
+silentpayments_example_SOURCES = examples/silentpayments.c
+silentpayments_example_CPPFLAGS = -I$(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
@@ -226,11 +248,16 @@ 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
 
 src/wycheproof/ecdsa_secp256k1_sha256_bitcoin_test.h:
 	mkdir -p $(@D)
 	python3 $(top_srcdir)/tools/tests_wycheproof_generate.py $(top_srcdir)/src/wycheproof/ecdsa_secp256k1_sha256_bitcoin_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)
@@ -273,3 +300,7 @@ 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
diff --git a/README.md b/README.md
@@ -21,6 +21,7 @@ Features:
 * Optional module for ECDH key exchange.
 * 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 Silent Payments send and receive according to [BIP-352](https://github.com/bitcoin/bips/blob/master/bip-0352.mediawiki).
 
 Implementation details
 ----------------------
@@ -82,7 +83,7 @@ To maintain a pristine source tree, CMake encourages to perform an out-of-source
     $ cmake ..
     $ cmake --build .
     $ ctest  # run the test suite
-    $ sudo cmake --build . --target install  # optional
+    $ sudo cmake --install .  # optional
 
 To compile optional modules (such as Schnorr signatures), you need to run `cmake` with additional flags (such as `-DSECP256K1_ENABLE_MODULE_SCHNORRSIG=ON`). Run `cmake .. -LH` to see the full list of available flags.
 
@@ -114,6 +115,8 @@ Usage examples can be found in the [examples](examples) directory. To compile th
   * [ECDSA example](examples/ecdsa.c)
   * [Schnorr signatures example](examples/schnorr.c)
   * [Deriving a shared secret (ECDH) example](examples/ecdh.c)
+  * [ElligatorSwift key exchange example](examples/ellswift.c)
+  * [Silent Payments send and receive example](examples/silentpayments.c)
 
 To compile the Schnorr signature and ECDH examples, you also need to configure with `--enable-module-schnorrsig` and `--enable-module-ecdh`.
 

diff --git a/ci/ci.sh b/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 SCHNORRSIG ELLSWIFT \
+            EXPERIMENTAL ECDH RECOVERY SCHNORRSIG ELLSWIFT SILENTPAYMENTS \
             SECP256K1_TEST_ITERS BENCH SECP256K1_BENCH_ITERS CTIMETESTS\
             EXAMPLES \
             HOST WRAPPER_CMD \
@@ -77,6 +77,7 @@ esac
     --with-ecmult-gen-kb="$ECMULTGENKB" \
     --enable-module-ecdh="$ECDH" --enable-module-recovery="$RECOVERY" \
     --enable-module-ellswift="$ELLSWIFT" \
+    --enable-module-silentpayments="$SILENTPAYMENTS" \
     --enable-module-schnorrsig="$SCHNORRSIG" \
     --enable-examples="$EXAMPLES" \
     --enable-ctime-tests="$CTIMETESTS" \

diff --git a/configure.ac b/configure.ac
@@ -188,6 +188,10 @@ 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=no]]), [],
+    [SECP_SET_DEFAULT([enable_module_silentpayments], [no], [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])])
@@ -216,9 +220,9 @@ AC_ARG_WITH([ecmult-window], [AS_HELP_STRING([--with-ecmult-window=SIZE],
 AC_ARG_WITH([ecmult-gen-kb], [AS_HELP_STRING([--with-ecmult-gen-kb=2|22|86],
 [The size of the precomputed table for signing in multiples of 1024 bytes (on typical platforms).]
 [Larger values result in possibly better signing/keygeneration performance at the cost of a larger table.]
-[The default value is a reasonable setting for desktop machines (currently 22). [default=22]]
+[The default value is a reasonable setting for desktop machines (currently 86). [default=86]]
 )],
-[set_ecmult_gen_kb=$withval], [set_ecmult_gen_kb=22])
+[set_ecmult_gen_kb=$withval], [set_ecmult_gen_kb=86])
 
 AC_ARG_WITH([valgrind], [AS_HELP_STRING([--with-valgrind=yes|no|auto],
 [Build with extra checks for running inside Valgrind [default=auto]]
@@ -394,6 +398,10 @@ 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"$enable_module_silentpayments" = x"yes"; then
+  SECP_CONFIG_DEFINES="$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
@@ -450,6 +458,7 @@ AM_CONDITIONAL([ENABLE_MODULE_RECOVERY], [test x"$enable_module_recovery" = x"ye
 AM_CONDITIONAL([ENABLE_MODULE_EXTRAKEYS], [test x"$enable_module_extrakeys" = x"yes"])
 AM_CONDITIONAL([ENABLE_MODULE_SCHNORRSIG], [test x"$enable_module_schnorrsig" = x"yes"])
 AM_CONDITIONAL([ENABLE_MODULE_ELLSWIFT], [test x"$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"])
@@ -472,6 +481,7 @@ echo "  module recovery         = $enable_module_recovery"
 echo "  module extrakeys        = $enable_module_extrakeys"
 echo "  module schnorrsig       = $enable_module_schnorrsig"
 echo "  module ellswift         = $enable_module_ellswift"
+echo "  module silentpayments   = $enable_module_silentpayments"
 echo
 echo "  asm                     = $set_asm"
 echo "  ecmult window size      = $set_ecmult_window"