diff --git a/Cargo.lock b/Cargo.lock
index 621547fbd..e44ea2b77 100644
--- a/Cargo.lock
+++ b/Cargo.lock
@@ -146,21 +146,6 @@ dependencies = [
  "hybrid-array",
 ]
 
-[[package]]
-name = "curve25519-dalek"
-version = "4.1.3"
-source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "97fb8b7c4503de7d6ae7b42ab72a5a59857b4c937ec27a3d4539dba95b5ab2be"
-dependencies = [
- "cfg-if",
- "cpufeatures 0.2.17",
- "curve25519-dalek-derive",
- "fiat-crypto 0.2.9",
- "rustc_version",
- "subtle",
- "zeroize",
-]
-
 [[package]]
 name = "curve25519-dalek"
 version = "5.0.0"
@@ -171,7 +156,7 @@ dependencies = [
  "cpufeatures 0.3.0",
  "curve25519-dalek-derive",
  "digest 0.11.3",
- "fiat-crypto 0.3.0",
+ "fiat-crypto",
  "rustc_version",
  "subtle",
  "zeroize",
@@ -275,7 +260,7 @@ version = "3.0.0"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "6ebaa1a2bf1290ab3bfe5a7b771d050ebffab2711c19a81691c683a5144a25de"
 dependencies = [
- "curve25519-dalek 5.0.0",
+ "curve25519-dalek",
  "ed25519",
  "serde",
  "sha2 0.11.0",
@@ -284,12 +269,6 @@ dependencies = [
  "zeroize",
 ]
 
-[[package]]
-name = "fiat-crypto"
-version = "0.2.9"
-source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "28dea519a9695b9977216879a3ebfddf92f1c08c05d984f8996aecd6ecdc811d"
-
 [[package]]
 name = "fiat-crypto"
 version = "0.3.0"
@@ -458,7 +437,7 @@ dependencies = [
  "bitvec",
  "blake3",
  "cc",
- "curve25519-dalek 4.1.3",
+ "curve25519-dalek",
  "ed25519-dalek",
  "glob",
  "heapless 0.9.3",
@@ -789,7 +768,7 @@ version = "3.0.0"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "e7e8131a03190127fb2263afc72b322ecadae46b6ff8c6f399ff5d02f5559af6"
 dependencies = [
- "curve25519-dalek 5.0.0",
+ "curve25519-dalek",
  "rand_core",
 ]
 
diff --git a/Cargo.toml b/Cargo.toml
index c46902328..1c5efabe0 100644
--- a/Cargo.toml
+++ b/Cargo.toml
@@ -934,7 +934,7 @@ heapless = { version = "0.9",  default-features = false }
 
 # External crypto (optional; in-tree implementations are the default).
 ed25519-dalek    = { version = "3.0.0", default-features = false, features = ["alloc", "zeroize"], optional = true }
-curve25519-dalek = { version = "4.1.3", default-features = false, features = ["alloc", "zeroize"], optional = true }
+curve25519-dalek = { version = "5.0.0", default-features = false, features = ["alloc", "zeroize"], optional = true }
 x25519-dalek     = { version = "3",     default-features = false, features = ["static_secrets"], optional = true }
 sha3             = { version = "0.10",  default-features = false, optional = true }