fix(deps): replace unmaintained rust-crypto with bitcoin::hashes::sha256, bump vulnerable deps by EddieHouston · Pull Request #208 · Blockstream/electrs

EddieHouston · 2026-04-16T13:08:38Z

Summary

Replace rust-crypto with bitcoin::hashes::sha256 for hardware-accelerated SHA-256 (SHA-NI on x86_64, ARMv8 crypto on aarch64)
Bump tokio 1.49→1.52 and tar 0.4.44→0.4.45 to resolve known vulnerabilities
Add unit tests for SHA-256 correctness (NIST test vectors + P2PKH script hash)
Resolves 11 of 18 cargo audit findings; remaining 7 are pinned by upstream crates (electrum-client, electrumd, minreq)

Motivation

cargo audit flagged 18 vulnerabilities and 15 warnings. The most actionable was rust-crypto, a direct dependency used only for SHA-256 hashing in three places:

compute_script_hash in src/new_index/schema.rs and src/new_index/precache.rs
get_status_hash and hash_ip_with_salt in src/electrum/server.rs

rust-crypto is unmaintained (last release 2016) and has a known AES miscomputation advisory (RUSTSEC-2022-0011). Its transitive dependency rustc-serialize has a stack overflow advisory (RUSTSEC-2022-0004) and is also unmaintained.

Migrated to bitcoin::hashes::sha256 (re-exported from the bitcoin crate, already a direct dependency) per reviewer feedback. This avoids adding a new top-level dependency and keeps hashing consistent with the rest of the codebase, which already uses bitcoin::hashes for sha256d, Midstate, etc.

Benchmark

Independent micro-benchmark (GitHub Actions ubuntu-latest, CPU with SHA-NI) comparing the pre-PR implementation against two modern alternatives. Workload: N strings of the form <txid>:<height>: fed into a single SHA-256 hasher, matching
the get_status_hash shape.

N	`rust-crypto` (pre-PR)	`sha2`	`bitcoin_hashes`
10	2.81 µs	559 ns	570 ns
100	27.3 µs	5.46 µs	5.41 µs
1000	273.8 µs	54.2 µs	53.9 µs

Both modern implementations are ~5× faster than rust-crypto and within noise of each other on SHA-NI hardware. Benchmark source is on branch bench/sha256-comparison for reproducibility.

Changes

File	Change
`Cargo.toml`	Remove `rust-crypto = "0.2"`; no new direct SHA-256 dep (uses `bitcoin::hashes::sha256` already in-tree)
`src/new_index/schema.rs`	Use `bitcoin::hashes::sha256` API
`src/new_index/precache.rs`	Use `bitcoin::hashes::sha256` API
`src/electrum/server.rs`	Use `bitcoin::hashes::sha256` API
`Cargo.lock`	Remove `rust-crypto`/`rustc-serialize` tree, bump `tokio` and `tar`

Advisories resolved

Crate	Advisory	Fix
`rust-crypto`	RUSTSEC-2022-0011 (AES miscomputation)	Replaced with `bitcoin::hashes::sha256`
`rustc-serialize`	RUSTSEC-2022-0004 (stack overflow)	Removed (transitive of `rust-crypto`)
`bytes`	RUSTSEC-2026-0007 (integer overflow)	Resolved in lockfile
`crossbeam-channel`	RUSTSEC-2025-0024 (double free)	Resolved in lockfile
`h2`	RUSTSEC-2024-0332 (CONTINUATION flood)	Resolved in lockfile
`hyper-util`	RUSTSEC-2025-0002 (incomplete requests)	Resolved in lockfile
`protobuf`	RUSTSEC-2024-0437 (uncontrolled recursion)	Resolved in lockfile
`rocksdb`	RUSTSEC-2024-0433 (miscompilation)	Resolved in lockfile
`url`	RUSTSEC-2024-0438 (hostname confusion)	Resolved in lockfile
`tokio`	RUSTSEC-2025-0023 (broadcast unsoundness)	Bumped 1.49→1.52
`tar`	RUSTSEC-2026-0068 (PAX header bypass)	Bumped 0.4.44→0.4.45

Remaining (upstream-blocked)

The 7 remaining advisories cannot be resolved without upstream releases. Most are in dev-only dependencies that do not ship in the production binary; electrum-client is the exception — it ships when the electrum-discovery feature is
enabled.

Crate	Advisory	Dep chain	Production?
`ring` 0.16.20	RUSTSEC-2025-0009	`electrum-client`, `electrumd`	Yes (via `electrum-discovery`)
`rustls` 0.16.0	RUSTSEC-2024-0336	`electrum-client`	Yes (via `electrum-discovery`)
`webpki` 0.21.4	RUSTSEC-2023-0052	`electrum-client`	Yes (via `electrum-discovery`)
`rustls` 0.19.1	RUSTSEC-2024-0336	`electrumd` → `ureq`	No (dev-dep)
`idna` 0.2.3	RUSTSEC-2024-0421	`electrumd` → `ureq`	No (dev-dep)
`rustls-webpki` 0.101.7	RUSTSEC-2026-0098, 0099	`minreq` → `corepc-node`	No (dev-dep)

Test plan

cargo check passes (default features)
cargo check --features liquid passes
cargo test new_index::schema::tests — 3 unit tests pass:
- test_sha256_empty_input — NIST test vector for SHA-256("")
- test_sha256_abc — NIST test vector for SHA-256("abc")
- test_p2pkh_script_hash — real P2PKH scriptPubKey verified against independent SHA-256 computation
rest of tests also pass: cargo test -p electrs

shesek · 2026-04-17T13:57:56Z

Have you considered using bitcoin_hashes::sha256 instead of the sha2 crate? (already available through the bitcoin::hashes re-export)

EddieHouston · 2026-04-20T07:19:33Z

Have you considered using bitcoin_hashes::sha256 instead of the sha2 crate? (already available through the bitcoin::hashes re-export)

Looking into it to see if we get the same hardware acceleration 👍 , looks like it may depend on the version.

EddieHouston · 2026-04-20T08:34:23Z

Have you considered using bitcoin_hashes::sha256 instead of the sha2 crate? (already available through the bitcoin::hashes re-export)

Looking into it to see if we get the same hardware acceleration 👍 , looks like it may depend on the version.

Running some benches on a branch on my fork: https://github.com/EddieHouston/electrs/actions/runs/24655997795

Looks like the version of bitcoin_hashes::sha256 is equivalent to sha2 (and both are 5x faster than what we havd in rust-crypto).

Will update to use bitcoin_hashes::sha256. Thanks!

Per reviewer feedback on PR Blockstream#208: bitcoin_hashes::sha256 is already available via the bitcoin crate re-export and provides equivalent SHA-NI hardware acceleration. Drops the direct sha2 dependency. Bench (ubuntu-latest w/ SHA-NI, 1000 tx status hashes): rust-crypto 273.8 µs sha2 54.2 µs bitcoin_hashes 53.9 µs

RCasatta

utACK 8559ab3 code review

would have been great to introduce unit tests with hardcoded values of hash_ip_with_salt and compute_script_hash in a separate commit before any other change, so that it's confirmed the following commit with the dep change doesn't change behaviour

EddieHouston · 2026-04-21T15:23:13Z

utACK 8559ab3 code review

would have been great to introduce unit tests with hardcoded values of hash_ip_with_salt and compute_script_hash in a separate commit before any other change, so that it's confirmed the following commit with the dep change doesn't change behaviour

Yep, good call for extra safety. Will redo the commits to incorporate this.

EddieHouston · 2026-04-21T15:45:06Z

utACK 8559ab3 code review
would have been great to introduce unit tests with hardcoded values of hash_ip_with_salt and compute_script_hash in a separate commit before any other change, so that it's confirmed the following commit with the dep change doesn't change behaviour

Yep, good call for extra safety. Will redo the commits to incorporate this.

Completed commit changes.

RCasatta

ACK b095dfc code review, tested new tests pass with and without the last commit

…ded expected values Add test_compute_script_hash_p2pkh (calls compute_script_hash directly, asserts hardcoded FullHash bytes for a P2PKH scriptPubKey) and test_hash_ip_with_salt (extracts hash_ip_with_salt to a free function, tests known salt+ip → hex). These tests establish the behavioral contract before the rust-crypto dep swap, so the following commit can prove the new implementation is bit-for-bit identical.

…256, bump vulnerable deps rust-crypto 0.2 is unmaintained (last release 2016) and has a known AES miscomputation advisory (RUSTSEC-2022-0011). Its transitive dependency rustc-serialize has a stack overflow advisory (RUSTSEC-2022-0004) and is also unmaintained. Replace the three SHA-256 call sites (compute_script_hash in schema.rs and precache.rs, get_status_hash and hash_ip_with_salt in server.rs) with bitcoin::hashes::sha256, already re-exported from the bitcoin crate — avoids adding a new top-level dependency and keeps hashing consistent with the rest of the codebase. Also bumps tokio (1.49->1.52, RUSTSEC-2025-0023) and tar (0.4.44->0.4.45, RUSTSEC-2026-0068). Resolves 11 of 18 cargo-audit findings; the remaining 7 are pinned by upstream deps (electrum-client, electrumd, minreq) and require upstream releases. Adds NIST SHA-256 test vectors (empty, 'abc') verifying the new implementation against known-good values.

EddieHouston force-pushed the fix/cargo-audit-vulnerabilities branch from 566076b to 45e3daa Compare April 16, 2026 13:48

EddieHouston requested review from RCasatta, philippem and shesek April 17, 2026 05:44

EddieHouston changed the title ~~fix(deps): replace unmaintained rust-crypto with sha2, bump vulnerabl…~~ fix(deps): replace unmaintained rust-crypto with bitcoin::hashes::sha256, bump vulnerable deps Apr 20, 2026

EddieHouston force-pushed the fix/cargo-audit-vulnerabilities branch from 6f607e9 to 8559ab3 Compare April 20, 2026 09:13

philippem previously approved these changes Apr 20, 2026

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Randy808 previously approved these changes Apr 20, 2026

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shesek previously approved these changes Apr 21, 2026

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RCasatta previously approved these changes Apr 21, 2026

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EddieHouston dismissed stale reviews from RCasatta, shesek, Randy808, and philippem via b095dfc April 21, 2026 15:44

EddieHouston force-pushed the fix/cargo-audit-vulnerabilities branch from 8559ab3 to b095dfc Compare April 21, 2026 15:44

EddieHouston requested review from RCasatta and shesek April 21, 2026 15:45

RCasatta previously approved these changes Apr 22, 2026

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shesek reviewed Apr 23, 2026

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Comment thread src/new_index/schema.rs Outdated

EddieHouston dismissed RCasatta’s stale review via 36e0954 April 23, 2026 06:07

EddieHouston force-pushed the fix/cargo-audit-vulnerabilities branch from b095dfc to 36e0954 Compare April 23, 2026 06:07

EddieHouston requested a review from shesek April 23, 2026 06:36

EddieHouston added 2 commits April 23, 2026 14:12

EddieHouston force-pushed the fix/cargo-audit-vulnerabilities branch from 36e0954 to c234cbf Compare April 23, 2026 12:12

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fix(deps): replace unmaintained rust-crypto with bitcoin::hashes::sha256, bump vulnerable deps#208

fix(deps): replace unmaintained rust-crypto with bitcoin::hashes::sha256, bump vulnerable deps#208
EddieHouston wants to merge 2 commits intoBlockstream:new-indexfrom
EddieHouston:fix/cargo-audit-vulnerabilities

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Summary

Motivation

Benchmark

Changes

Advisories resolved

Remaining (upstream-blocked)

Test plan

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