Update secp256k1 subtree to latest master #35781

1. 
   fanquake commented at 9:06 AM on July 23, 2026: member

   Includes:

   • https://github.com/bitcoin-core/secp256k1/pull/1765
   • https://github.com/bitcoin-core/secp256k1/pull/1845
   • https://github.com/bitcoin-core/secp256k1/pull/1877
   • https://github.com/bitcoin-core/secp256k1/pull/1879
   • https://github.com/bitcoin-core/secp256k1/pull/1881
   • https://github.com/bitcoin-core/secp256k1/pull/1882
   • https://github.com/bitcoin-core/secp256k1/pull/1884
   • https://github.com/bitcoin-core/secp256k1/pull/1887
   • https://github.com/bitcoin-core/secp256k1/pull/1889
   • https://github.com/bitcoin-core/secp256k1/pull/1890
   • https://github.com/bitcoin-core/secp256k1/pull/1894
2. Squashed 'src/secp256k1/' changes from bd0287d650..d2d04864ef

   d2d04864ef Merge bitcoin-core/secp256k1#1765: Add "silentpayments" module implementing BIP352 (take 4, limited to full-node scanning)
   9e4ec507e9 Merge bitcoin-core/secp256k1#1890: nonce: terminate RFC6979 loop at UINT_MAX
   afff8cba00 Merge bitcoin-core/secp256k1#1894: extrakeys: check invariant that x-only pubkeys have even Y
   b1bc6f3e0c nonce: terminate RFC6979 loop at UINT_MAX
   89a54b5aaf extrakeys: check invariant that x-only pubkeys have even Y
   cea6d11410 silentpayments: drop "shuffle outputs" recommendation from API docs
   1ae90bde8b silentpayments: flush labels before direct match
   84a02fa989 silentpayments: extract label batch checker
   8c3e6e6d99 Merge bitcoin-core/secp256k1#1889: field: serialize elements by word
   11dad6d06c Merge bitcoin-core/secp256k1#1887: Make theStack a maintainer and a security contact
   4aa16704ce silentpayments: skip slow benchmarks for low iters count (<= 2)
   7e4b313cd5 docs: update README
   f27a29687d ci: enable silentpayments module
   4f7a578d4b tests: add sha256 tag test
   936907b03f tests: add constant time tests
   b608a9d91b tests: add BIP-352 test vectors
   ca0136dcd5 silentpayments: optimize scanning by using batch inversion
   7ae555c524 silentpayments: add benchmarks for scanning
   f0fdd99d31 silentpayments: add examples/silentpayments.c
   1c1b2753f4 silentpayments: respect per-group recipients protocol limit (K_max=2323)
   d72a743273 silentpayments: receiving
   c83b6783b8 silentpayments: recipient label support
   b30ea3ebe4 silentpayments: sending
   a93e696a17 build: add skeleton for new silentpayments (BIP352) module
   e217ead5c4 field: serialize elements by word
   d5c64bafc7 SECURITY.md: Align the table
   9bd50f0cef SECURITY.md: Add theStack's key
   ebf594320d Merge bitcoin-core/secp256k1#1884: SECURITY.md: remove Jonas Nick from trusted keys
   21645c03a2 SECURITY.md: remove Jonas Nick from trusted keys
   b90075a074 Merge bitcoin-core/secp256k1#1882: scalar: correct `_scalar_get_bits_{limb32,var}` input condition docs
   5a8a411425 Merge bitcoin-core/secp256k1#1877: field: correct `fe_equal` magnitude bound for `b`
   6a599a4428 scalar: correct `_scalar_get_bits_{limb32,var}` input condition docs
   994b35010d field: correct fe_equal's b magnitude bound
   2ce4f71dc5 Merge bitcoin-core/secp256k1#1845: Improve checks for scalar _get_bits methods
   68b45fd4e2 Merge bitcoin-core/secp256k1#1881: tests: Fix GCC 17 snapshot warning
   9d75769dec tests: Fix GCC 17 snapshot warning
   9e3a165ad0 Merge bitcoin-core/secp256k1#1879: ci: add 'brew trust' invocation to macOS CI
   66260b78a2 ci: add 'brew trust' invocation to macOS CI
   0cad3df503 Improve checks for scalar _get_bits methods
   
   git-subtree-dir: src/secp256k1
   git-subtree-split: d2d04864ef9b056151603a3ced7980958b058028

   a33f240524
3. Update secp256k1 subtree to latest master c26d4e2d6f
4. 
   DrahtBot commented at 9:09 AM on July 23, 2026: contributor

   <!--e57a25ab6845829454e8d69fc972939a-->

   The following sections might be updated with supplementary metadata relevant to reviewers and maintainers.

   <!--006a51241073e994b41acfe9ec718e94-->

   Code Coverage & Benchmarks

   For details see: https://corecheck.dev/bitcoin/bitcoin/pulls/35781.

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   Reviews

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   Type	Reviewers
   ACK	sedited, theStack
   Concept ACK	real-or-random

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   Conflicts

   Reviewers, this pull request conflicts with the following ones:

   • #35301 (Silent Payments: Implement bip352 (take 2) by Eunovo)

   If you consider this pull request important, please also help to review the conflicting pull requests. Ideally, start with the one that should be merged first.

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5. 
   fanquake commented at 9:12 AM on July 23, 2026: member

   cc @real-or-random @theStack @josibake

6. sedited approved
7. 
   sedited commented at 9:33 AM on July 23, 2026: contributor

   ACK c26d4e2d6f03e26c6c20a4cc854f26d150f38b14

8. 
   real-or-random commented at 10:05 AM on July 23, 2026: contributor

   Concept ACK on updating to master, I have not verified that the subtree matches.

9. sedited requested review from Eunovo on Jul 23, 2026
10. theStack approved
11. 
    theStack commented at 7:21 PM on July 23, 2026: contributor

    ACK c26d4e2d6f03e26c6c20a4cc854f26d150f38b14 🤫

12. DrahtBot requested review from real-or-random on Jul 23, 2026
13. sedited merged this on Jul 23, 2026
14. sedited closed this on Jul 23, 2026

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15. fanquake deleted the branch on Jul 24, 2026

Review Requested
real-or-randomEunovo