feat: add a patched keccak dependency via a fork

Cargo.lock

@@ -4389,11 +4389,11 @@ dependencies = [
 [[package]]
 name = "keccak"
 version = "0.2.0"
-source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "9e24a010dd405bd7ed803e5253182815b41bf2e6a80cc3bfc066658e03a198aa"
+source = "git+https://github.com/logos-blockchain/sponges?rev=16ac194828f8e25e5eaf38d33970b4515e13b676#16ac194828f8e25e5eaf38d33970b4515e13b676"
 dependencies = [
  "cfg-if",
  "cpufeatures 0.3.0",
+ "risc0-zkvm",
 ]
 
 [[package]]

Cargo.toml

@@ -92,8 +92,9 @@ tokio = { version = "1.50", features = [
   "fs",
 ] }
 tokio-util = "0.7.18"
-risc0-zkvm = { version = "3.0.5", default-features = false, features = ['std'] }
-risc0-build = "3.0.5"
+# Unstable fearture needed for keccak optimization
+risc0-zkvm = { version = "3.0.5", default-features = false, features = ['std', 'unstable'] }
+risc0-build = { version = "3.0.5", features = ['unstable'] }
 anyhow = "1.0.98"
 derive_more = "2.1.1"
 num_cpus = "1.13.1"
@@ -178,6 +179,10 @@ opt-level = 'z'
 lto = true
 codegen-units = 1
 
+# Keccak speedup for in-guest ML KEM
+[patch.crates-io]
+keccak = { git = "https://github.com/logos-blockchain/sponges", rev = "16ac194828f8e25e5eaf38d33970b4515e13b676" }
+
 # Keep backtraces but drop full DWARF type info to avoid LLD OOM/SIGBUS when
 # linking large integration-test binaries on resource-constrained CI runners.
 [profile.dev]
@@ -323,4 +328,4 @@ clippy.cargo = { level = "deny", priority = -1 }
 clippy.cargo-common-metadata = "allow"
 # Reason: hard to address right now and mostly comes from dependencies
 # so the fix would be just a long list of exceptions.
-clippy.multiple-crate-versions = "allow"
+clippy.multiple-crate-versions = "allow"