diff --git a/Cargo.lock b/Cargo.lock
index f7ad7f7d..9aad4764 100644
--- a/Cargo.lock
+++ b/Cargo.lock
@@ -42,6 +42,15 @@ dependencies = [
  "generic-array",
 ]
 
+[[package]]
+name = "block-buffer"
+version = "0.12.0"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "cdd35008169921d80bc60d3d0ab416eecb028c4cd653352907921d95084790be"
+dependencies = [
+ "hybrid-array",
+]
+
 [[package]]
 name = "bumpalo"
 version = "3.19.1"
@@ -77,6 +86,12 @@ version = "1.0.4"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "9330f8b2ff13f34540b44e946ef35111825727b38d33286ef986142615121801"
 
+[[package]]
+name = "cmov"
+version = "0.5.3"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "3f88a43d011fc4a6876cb7344703e297c71dda42494fee094d5f7c76bf13f746"
+
 [[package]]
 name = "const-oid"
 version = "0.9.6"
@@ -130,6 +145,15 @@ dependencies = [
  "typenum",
 ]
 
+[[package]]
+name = "crypto-common"
+version = "0.2.1"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "77727bb15fa921304124b128af125e7e3b968275d1b108b379190264f4423710"
+dependencies = [
+ "hybrid-array",
+]
+
 [[package]]
 name = "ct-logs"
 version = "0.8.0"
@@ -139,6 +163,15 @@ dependencies = [
  "sct",
 ]
 
+[[package]]
+name = "ctutils"
+version = "0.4.2"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "7d5515a3834141de9eafb9717ad39eea8247b5674e6066c404e8c4b365d2a29e"
+dependencies = [
+ "cmov",
+]
+
 [[package]]
 name = "curve25519-dalek"
 version = "4.1.3"
@@ -148,7 +181,7 @@ dependencies = [
  "cfg-if",
  "cpufeatures",
  "curve25519-dalek-derive",
- "digest",
+ "digest 0.10.7",
  "fiat-crypto",
  "rustc_version",
  "subtle",
@@ -182,12 +215,23 @@ version = "0.10.7"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "9ed9a281f7bc9b7576e61468ba615a66a5c8cfdff42420a70aa82701a3b1e292"
 dependencies = [
- "block-buffer",
+ "block-buffer 0.10.4",
  "const-oid",
- "crypto-common",
+ "crypto-common 0.1.7",
  "subtle",
 ]
 
+[[package]]
+name = "digest"
+version = "0.11.2"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "4850db49bf08e663084f7fb5c87d202ef91a3907271aff24a94eb97ff039153c"
+dependencies = [
+ "block-buffer 0.12.0",
+ "crypto-common 0.2.1",
+ "ctutils",
+]
+
 [[package]]
 name = "ecdsa"
 version = "0.16.9"
@@ -195,7 +239,7 @@ source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "ee27f32b5c5292967d2d4a9d7f1e0b0aed2c15daded5a60300e4abb9d8020bca"
 dependencies = [
  "der",
- "digest",
+ "digest 0.10.7",
  "elliptic-curve",
  "rfc6979",
  "signature",
@@ -231,7 +275,7 @@ checksum = "b5e6043086bf7973472e0c7dff2142ea0b680d30e18d9cc40f267efbf222bd47"
 dependencies = [
  "base16ct",
  "crypto-bigint",
- "digest",
+ "digest 0.10.7",
  "ff",
  "generic-array",
  "group",
@@ -472,7 +516,7 @@ name = "hkd32"
 version = "0.8.0-pre"
 dependencies = [
  "hex-literal",
- "hmac",
+ "hmac 0.12.1",
  "once_cell",
  "pbkdf2",
  "rand_core",
@@ -487,7 +531,7 @@ version = "0.12.4"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "7b5f8eb2ad728638ea2c7d47a21db23b7b58a72ed6a38256b8a1849f15fbbdf7"
 dependencies = [
- "hmac",
+ "hmac 0.12.1",
 ]
 
 [[package]]
@@ -496,7 +540,16 @@ version = "0.12.1"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "6c49c37c09c17a53d937dfbb742eb3a961d65a994e6bcdcf37e7399d0cc8ab5e"
 dependencies = [
- "digest",
+ "digest 0.10.7",
+]
+
+[[package]]
+name = "hmac"
+version = "0.13.0"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "6303bc9732ae41b04cb554b844a762b4115a61bfaa81e3e83050991eeb56863f"
+dependencies = [
+ "digest 0.11.2",
 ]
 
 [[package]]
@@ -533,6 +586,15 @@ version = "1.0.3"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "df3b46402a9d5adb4c86a0cf463f42e19994e3ee891101b1841f30a545cb49a9"
 
+[[package]]
+name = "hybrid-array"
+version = "0.4.10"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "3944cf8cf766b40e2a1a333ee5e9b563f854d5fa49d6a8ca2764e97c6eddb214"
+dependencies = [
+ "typenum",
+]
+
 [[package]]
 name = "hyper"
 version = "0.14.32"
@@ -779,12 +841,12 @@ dependencies = [
 
 [[package]]
 name = "pbkdf2"
-version = "0.12.2"
+version = "0.13.0"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "f8ed6a7761f76e3b9f92dfb0a60a6a6477c61024b775147ff0973a02653abaf2"
+checksum = "112d82ceb8c5bf524d9af484d4e4970c9fd5a0cc15ba14ad93dccd28873b0629"
 dependencies = [
- "digest",
- "hmac",
+ "digest 0.11.2",
+ "hmac 0.13.0",
 ]
 
 [[package]]
@@ -872,7 +934,7 @@ version = "0.4.0"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "f8dd2a808d456c4a54e300a23e9f5a67e122c3024119acbfd73e3bf664491cb2"
 dependencies = [
- "hmac",
+ "hmac 0.12.1",
  "subtle",
 ]
 
@@ -1064,7 +1126,7 @@ checksum = "e3bf829a2d51ab4a5ddf1352d8470c140cadc8301b2ae1789db023f01cedd6ba"
 dependencies = [
  "cfg-if",
  "cpufeatures",
- "digest",
+ "digest 0.10.7",
 ]
 
 [[package]]
@@ -1075,7 +1137,7 @@ checksum = "a7507d819769d01a365ab707794a4084392c824f54a7a6a7862f8c3d0892b283"
 dependencies = [
  "cfg-if",
  "cpufeatures",
- "digest",
+ "digest 0.10.7",
 ]
 
 [[package]]
@@ -1106,7 +1168,7 @@ version = "2.2.0"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "77549399552de45a898a580c1b41d445bf730df867cc44e6c0233bbc4b8329de"
 dependencies = [
- "digest",
+ "digest 0.10.7",
  "rand_core",
 ]
 
diff --git a/hkd32/Cargo.toml b/hkd32/Cargo.toml
index 575cbdd3..83a63113 100644
--- a/hkd32/Cargo.toml
+++ b/hkd32/Cargo.toml
@@ -26,7 +26,7 @@ zeroize = { version = "1", default-features = false }
 
 # optional dependencies
 once_cell = { version = "1", optional = true }
-pbkdf2 = { version = "0.12", optional = true, default-features = false, features = ["hmac"] }
+pbkdf2 = { version = "0.13", optional = true, default-features = false, features = ["hmac"] }
 subtle-encoding = { version = "=0.6.0-pre", optional = true, default-features = false, path = "../subtle-encoding" }
 
 [dev-dependencies]