diff --git a/cgo/extern.go b/cgo/extern.go
index d0f53d0f..2db31537 100644
--- a/cgo/extern.go
+++ b/cgo/extern.go
@@ -11,13 +11,12 @@ import (
 	"github.com/filecoin-project/go-address"
 
 	"github.com/filecoin-project/go-state-types/abi"
-	"github.com/filecoin-project/go-state-types/crypto"
 )
 
 //export cgo_extern_get_chain_randomness
 func cgo_extern_get_chain_randomness(
-	handle C.uint64_t, pers C.int64_t, round C.int64_t,
-	entropy C.buf_t, entropyLen C.int32_t,
+	handle C.uint64_t,
+	round C.int64_t,
 	output C.buf_t,
 ) (res C.int32_t) {
 	defer func() {
@@ -33,11 +32,11 @@ func cgo_extern_get_chain_randomness(
 		return ErrInvalidHandle
 	}
 
-	rand, err := externs.GetChainRandomness(ctx, crypto.DomainSeparationTag(pers), abi.ChainEpoch(round), C.GoBytes(unsafe.Pointer(entropy), entropyLen))
+	rand, err := externs.GetChainRandomness(ctx, abi.ChainEpoch(round))
 
 	switch err {
 	case nil:
-		copy(out[:], rand)
+		copy(out[:], rand[:])
 		return 0
 	default:
 		return ErrIO
@@ -46,8 +45,8 @@ func cgo_extern_get_chain_randomness(
 
 //export cgo_extern_get_beacon_randomness
 func cgo_extern_get_beacon_randomness(
-	handle C.uint64_t, pers C.int64_t, round C.int64_t,
-	entropy C.buf_t, entropyLen C.int32_t,
+	handle C.uint64_t,
+	round C.int64_t,
 	output C.buf_t,
 ) (res C.int32_t) {
 	defer func() {
@@ -63,11 +62,11 @@ func cgo_extern_get_beacon_randomness(
 		return ErrInvalidHandle
 	}
 
-	rand, err := externs.GetBeaconRandomness(ctx, crypto.DomainSeparationTag(pers), abi.ChainEpoch(round), C.GoBytes(unsafe.Pointer(entropy), entropyLen))
+	rand, err := externs.GetBeaconRandomness(ctx, abi.ChainEpoch(round))
 
 	switch err {
 	case nil:
-		copy(out[:], rand)
+		copy(out[:], rand[:])
 		return 0
 	default:
 		return ErrIO
diff --git a/cgo/interface.go b/cgo/interface.go
index 750a8fc2..d1217fd6 100644
--- a/cgo/interface.go
+++ b/cgo/interface.go
@@ -5,7 +5,6 @@ import (
 
 	"github.com/filecoin-project/go-address"
 	"github.com/filecoin-project/go-state-types/abi"
-	"github.com/filecoin-project/go-state-types/crypto"
 	"github.com/ipfs/go-cid"
 	blockstore "github.com/ipfs/go-ipfs-blockstore"
 )
@@ -29,8 +28,8 @@ const (
 )
 
 type Externs interface {
-	GetChainRandomness(ctx context.Context, personalization crypto.DomainSeparationTag, epoch abi.ChainEpoch, entropy []byte) ([]byte, error)
-	GetBeaconRandomness(ctx context.Context, personalization crypto.DomainSeparationTag, epoch abi.ChainEpoch, entropy []byte) ([]byte, error)
+	GetChainRandomness(ctx context.Context, epoch abi.ChainEpoch) ([32]byte, error)
+	GetBeaconRandomness(ctx context.Context, epoch abi.ChainEpoch) ([32]byte, error)
 	VerifyConsensusFault(ctx context.Context, h1, h2, extra []byte) (*ConsensusFault, int64)
 	TipsetCid(ctx context.Context, epoch abi.ChainEpoch) (cid.Cid, error)
 
diff --git a/rust/Cargo.lock b/rust/Cargo.lock
index 16a4f045..be677dd2 100644
--- a/rust/Cargo.lock
+++ b/rust/Cargo.lock
@@ -66,20 +66,11 @@ dependencies = [
  "libc",
 ]
 
-[[package]]
-name = "ansi_term"
-version = "0.12.1"
-source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "d52a9bb7ec0cf484c551830a7ce27bd20d67eac647e1befb56b0be4ee39a55d2"
-dependencies = [
- "winapi 0.3.9",
-]
-
 [[package]]
 name = "anyhow"
-version = "1.0.66"
+version = "1.0.68"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "216261ddc8289130e551ddcd5ce8a064710c0d064a4d2895c67151c92b5443f6"
+checksum = "2cb2f989d18dd141ab8ae82f64d1a8cdd37e0840f73a406896cf5e99502fab61"
 dependencies = [
  "backtrace",
 ]
@@ -104,9 +95,9 @@ checksum = "8da52d66c7071e2e3fa2a1e5c6d088fec47b593032b254f5e980de8ea54454d6"
 
 [[package]]
 name = "async-trait"
-version = "0.1.59"
+version = "0.1.60"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "31e6e93155431f3931513b243d371981bb2770112b370c82745a1d19d2f99364"
+checksum = "677d1d8ab452a3936018a687b20e6f7cf5363d713b732b8884001317b0e48aa3"
 dependencies = [
  "proc-macro2",
  "quote",
@@ -407,9 +398,9 @@ dependencies = [
 
 [[package]]
 name = "cc"
-version = "1.0.77"
+version = "1.0.78"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "e9f73505338f7d905b19d18738976aae232eb46b8efc15554ffc56deb5d9ebe4"
+checksum = "a20104e2335ce8a659d6dd92a51a767a0c062599c73b343fd152cb401e828c3d"
 
 [[package]]
 name = "cfg-if"
@@ -802,9 +793,9 @@ dependencies = [
 
 [[package]]
 name = "cxx"
-version = "1.0.83"
+version = "1.0.85"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "bdf07d07d6531bfcdbe9b8b739b104610c6508dcc4d63b410585faf338241daf"
+checksum = "5add3fc1717409d029b20c5b6903fc0c0b02fa6741d820054f4a2efa5e5816fd"
 dependencies = [
  "cc",
  "cxxbridge-flags",
@@ -814,9 +805,9 @@ dependencies = [
 
 [[package]]
 name = "cxx-build"
-version = "1.0.83"
+version = "1.0.85"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "d2eb5b96ecdc99f72657332953d4d9c50135af1bac34277801cc3937906ebd39"
+checksum = "b4c87959ba14bc6fbc61df77c3fcfe180fc32b93538c4f1031dd802ccb5f2ff0"
 dependencies = [
  "cc",
  "codespan-reporting",
@@ -829,15 +820,15 @@ dependencies = [
 
 [[package]]
 name = "cxxbridge-flags"
-version = "1.0.83"
+version = "1.0.85"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "ac040a39517fd1674e0f32177648334b0f4074625b5588a64519804ba0553b12"
+checksum = "69a3e162fde4e594ed2b07d0f83c6c67b745e7f28ce58c6df5e6b6bef99dfb59"
 
 [[package]]
 name = "cxxbridge-macro"
-version = "1.0.83"
+version = "1.0.85"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "1362b0ddcfc4eb0a1f57b68bd77dd99f0e826958a96abd0ae9bd092e114ffed6"
+checksum = "3e7e2adeb6a0d4a282e581096b06e1791532b7d576dcde5ccd9382acf55db8e6"
 dependencies = [
  "proc-macro2",
  "quote",
@@ -1189,6 +1180,7 @@ name = "filcrypto"
 version = "0.7.5"
 dependencies = [
  "anyhow",
+ "blake2b_simd",
  "bls-signatures",
  "blstrs",
  "byteorder",
@@ -1198,10 +1190,10 @@ dependencies = [
  "filepath",
  "fr32",
  "fvm 2.1.0",
- "fvm 3.0.0-alpha.15",
+ "fvm 3.0.0-alpha.16",
  "fvm_ipld_blockstore",
  "fvm_ipld_encoding 0.2.3",
- "fvm_ipld_encoding 0.3.0",
+ "fvm_ipld_encoding 0.3.2",
  "fvm_shared 2.0.0",
  "fvm_shared 3.0.0-alpha.15",
  "group",
@@ -1304,18 +1296,17 @@ dependencies = [
 
 [[package]]
 name = "flexi_logger"
-version = "0.24.1"
+version = "0.24.2"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "99659bcfd52cfece972bd00acb9dba7028094d47e699ea8b193b9aaebd5c362b"
+checksum = "ade8e86c48285f138a4d6ca15a2912e39bd6c74d62db42da4f1985f651a0b057"
 dependencies = [
- "ansi_term",
  "atty",
  "chrono",
  "glob",
  "lazy_static",
  "log",
+ "nu-ansi-term",
  "regex",
- "rustversion",
  "thiserror",
 ]
 
@@ -1422,9 +1413,9 @@ dependencies = [
 
 [[package]]
 name = "fvm"
-version = "3.0.0-alpha.15"
+version = "3.0.0-alpha.16"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "c3bc434d9563f9a9c4555acc442fb2953ed51f301c216c9d357c8d6d52247a9c"
+checksum = "ac9f5169c14ce1d132c786390077825d065d04002aace0fdebdab931f6cf28ed"
 dependencies = [
  "anyhow",
  "blake2b_simd",
@@ -1437,7 +1428,7 @@ dependencies = [
  "fvm-wasm-instrument 0.4.0",
  "fvm_ipld_amt 0.5.0",
  "fvm_ipld_blockstore",
- "fvm_ipld_encoding 0.3.0",
+ "fvm_ipld_encoding 0.3.2",
  "fvm_ipld_hamt 0.6.1",
  "fvm_shared 3.0.0-alpha.15",
  "lazy_static",
@@ -1507,7 +1498,7 @@ dependencies = [
  "anyhow",
  "cid",
  "fvm_ipld_blockstore",
- "fvm_ipld_encoding 0.3.0",
+ "fvm_ipld_encoding 0.3.2",
  "itertools 0.10.5",
  "once_cell",
  "serde",
@@ -1545,9 +1536,9 @@ dependencies = [
 
 [[package]]
 name = "fvm_ipld_encoding"
-version = "0.3.0"
+version = "0.3.2"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "cf531c59e7c9a4c9044a34d1b44c9d544fab1eb0ba50aaa18121fe698d4fec35"
+checksum = "189214585b1dc3c2a92682aa175cce1991c1a09542e5338c400d00c15b706142"
 dependencies = [
  "anyhow",
  "cid",
@@ -1592,7 +1583,7 @@ dependencies = [
  "cid",
  "forest_hash_utils",
  "fvm_ipld_blockstore",
- "fvm_ipld_encoding 0.3.0",
+ "fvm_ipld_encoding 0.3.2",
  "libipld-core 0.14.0",
  "multihash",
  "once_cell",
@@ -1649,7 +1640,7 @@ dependencies = [
  "data-encoding-macro",
  "filecoin-proofs-api",
  "fvm_ipld_blockstore",
- "fvm_ipld_encoding 0.3.0",
+ "fvm_ipld_encoding 0.3.2",
  "lazy_static",
  "libsecp256k1",
  "log",
@@ -1706,9 +1697,9 @@ dependencies = [
 
 [[package]]
 name = "ghost"
-version = "0.1.6"
+version = "0.1.7"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "eb19fe8de3ea0920d282f7b77dd4227aea6b8b999b42cdf0ca41b2472b14443a"
+checksum = "41973d4c45f7a35af8753ba3457cc99d406d863941fd7f52663cff54a5ab99b3"
 dependencies = [
  "proc-macro2",
  "quote",
@@ -1939,9 +1930,9 @@ dependencies = [
 
 [[package]]
 name = "itoa"
-version = "1.0.4"
+version = "1.0.5"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "4217ad341ebadf8d8e724e264f13e593e0648f5b3e94b3896a5df283be015ecc"
+checksum = "fad582f4b9e86b6caa621cabeb0963332d92eea04729ab12892c2533951e6440"
 
 [[package]]
 name = "js-sys"
@@ -2069,9 +2060,9 @@ dependencies = [
 
 [[package]]
 name = "link-cplusplus"
-version = "1.0.7"
+version = "1.0.8"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "9272ab7b96c9046fbc5bc56c06c117cb639fe2d509df0c421cad82d2915cf369"
+checksum = "ecd207c9c713c34f95a097a5b029ac2ce6010530c7b49d7fea24d977dede04f5"
 dependencies = [
  "cc",
 ]
@@ -2315,6 +2306,16 @@ dependencies = [
  "minimal-lexical",
 ]
 
+[[package]]
+name = "nu-ansi-term"
+version = "0.46.0"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "77a8165726e8236064dbb45459242600304b42a5ea24ee2948e18e023bf7ba84"
+dependencies = [
+ "overload",
+ "winapi 0.3.9",
+]
+
 [[package]]
 name = "num"
 version = "0.1.42"
@@ -2456,6 +2457,12 @@ dependencies = [
  "winapi 0.3.9",
 ]
 
+[[package]]
+name = "overload"
+version = "0.1.1"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "b15813163c1d831bf4a13c3610c05c0d03b39feb07f7e09fa234dac9b15aaf39"
+
 [[package]]
 name = "pairing"
 version = "0.22.0"
@@ -2488,9 +2495,9 @@ dependencies = [
 
 [[package]]
 name = "paste"
-version = "1.0.10"
+version = "1.0.11"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "cf1c2c742266c2f1041c914ba65355a83ae8747b05f208319784083583494b4b"
+checksum = "d01a5bd0424d00070b0098dd17ebca6f961a959dead1dbcbbbc1d1cd8d3deeba"
 
 [[package]]
 name = "pathdiff"
@@ -2581,9 +2588,9 @@ checksum = "dbf0c48bc1d91375ae5c3cd81e3722dff1abcf81a30960240640d223f59fe0e5"
 
 [[package]]
 name = "proc-macro2"
-version = "1.0.47"
+version = "1.0.49"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "5ea3d908b0e36316caf9e9e2c4625cdde190a7e6f440d794667ed17a1855e725"
+checksum = "57a8eca9f9c4ffde41714334dee777596264c7825420f521abc92b5b5deb63a5"
 dependencies = [
  "unicode-ident",
 ]
@@ -2599,9 +2606,9 @@ dependencies = [
 
 [[package]]
 name = "quote"
-version = "1.0.21"
+version = "1.0.23"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "bbe448f377a7d6961e30f5955f9b8d106c3f5e449d493ee1b125c1d43c2b5179"
+checksum = "8856d8364d252a14d474036ea1358d63c9e6965c8e5c1885c18f73d70bff9c7b"
 dependencies = [
  "proc-macro2",
 ]
@@ -2853,15 +2860,15 @@ dependencies = [
 
 [[package]]
 name = "rustversion"
-version = "1.0.9"
+version = "1.0.11"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "97477e48b4cf8603ad5f7aaf897467cf42ab4218a38ef76fb14c2d6773a6d6a8"
+checksum = "5583e89e108996506031660fe09baa5011b9dd0341b89029313006d1fb508d70"
 
 [[package]]
 name = "ryu"
-version = "1.0.11"
+version = "1.0.12"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "4501abdff3ae82a1c1b477a17252eb69cee9e66eb915c1abaa4f44d873df9f09"
+checksum = "7b4b9743ed687d4b4bcedf9ff5eaa7398495ae14e61cba0a295704edbc7decde"
 
 [[package]]
 name = "safer-ffi"
@@ -2897,21 +2904,21 @@ checksum = "d29ab0c6d3fc0ee92fe66e2d99f700eab17a8d57d1c1d3b748380fb20baa78cd"
 
 [[package]]
 name = "scratch"
-version = "1.0.2"
+version = "1.0.3"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "9c8132065adcfd6e02db789d9285a0deb2f3fcb04002865ab67d5fb103533898"
+checksum = "ddccb15bcce173023b3fedd9436f882a0739b8dfb45e4f6b6002bee5929f61b2"
 
 [[package]]
 name = "semver"
-version = "1.0.14"
+version = "1.0.16"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "e25dfac463d778e353db5be2449d1cce89bd6fd23c9f1ea21310ce6e5a1b29c4"
+checksum = "58bc9567378fc7690d6b2addae4e60ac2eeea07becb2c64b9f218b53865cba2a"
 
 [[package]]
 name = "serde"
-version = "1.0.150"
+version = "1.0.151"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "e326c9ec8042f1b5da33252c8a37e9ffbd2c9bef0155215b6e6c80c790e05f91"
+checksum = "97fed41fc1a24994d044e6db6935e69511a1153b52c15eb42493b26fa87feba0"
 dependencies = [
  "serde_derive",
 ]
@@ -2927,18 +2934,18 @@ dependencies = [
 
 [[package]]
 name = "serde_bytes"
-version = "0.11.7"
+version = "0.11.8"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "cfc50e8183eeeb6178dcb167ae34a8051d63535023ae38b5d8d12beae193d37b"
+checksum = "718dc5fff5b36f99093fc49b280cfc96ce6fc824317783bff5a1fed0c7a64819"
 dependencies = [
  "serde",
 ]
 
 [[package]]
 name = "serde_derive"
-version = "1.0.150"
+version = "1.0.151"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "42a3df25b0713732468deadad63ab9da1f1fd75a48a15024b50363f128db627e"
+checksum = "255abe9a125a985c05190d687b320c12f9b1f0b99445e608c21ba0782c719ad8"
 dependencies = [
  "proc-macro2",
  "quote",
@@ -2959,9 +2966,9 @@ dependencies = [
 
 [[package]]
 name = "serde_json"
-version = "1.0.89"
+version = "1.0.91"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "020ff22c755c2ed3f8cf162dbb41a7268d934702f3ed3631656ea597e08fc3db"
+checksum = "877c235533714907a8c2464236f5c4b2a17262ef1bd71f38f35ea592c8da6883"
 dependencies = [
  "itoa",
  "ryu",
@@ -2970,9 +2977,9 @@ dependencies = [
 
 [[package]]
 name = "serde_repr"
-version = "0.1.9"
+version = "0.1.10"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "1fe39d9fbb0ebf5eb2c7cb7e2a47e4f462fad1379f1166b8ae49ad9eae89a7ca"
+checksum = "9a5ec9fa74a20ebbe5d9ac23dac1fc96ba0ecfe9f50f2843b52e537b10fbcb4e"
 dependencies = [
  "proc-macro2",
  "quote",
@@ -3239,9 +3246,9 @@ checksum = "6bdef32e8150c2a081110b42772ffe7d7c9032b606bc226c8260fd97e0976601"
 
 [[package]]
 name = "syn"
-version = "1.0.105"
+version = "1.0.107"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "60b9b43d45702de4c839cb9b51d9f529c5dd26a4aff255b42b1ebc03e88ee908"
+checksum = "1f4064b5b16e03ae50984a5a8ed5d4f8803e6bc1fd170a3cda91a1be4b18e3f5"
 dependencies = [
  "proc-macro2",
  "quote",
@@ -3306,18 +3313,18 @@ dependencies = [
 
 [[package]]
 name = "thiserror"
-version = "1.0.37"
+version = "1.0.38"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "10deb33631e3c9018b9baf9dcbbc4f737320d2b576bac10f6aefa048fa407e3e"
+checksum = "6a9cd18aa97d5c45c6603caea1da6628790b37f7a34b6ca89522331c5180fed0"
 dependencies = [
  "thiserror-impl",
 ]
 
 [[package]]
 name = "thiserror-impl"
-version = "1.0.37"
+version = "1.0.38"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "982d17546b47146b28f7c22e3d08465f6b8903d0ea13c1660d9d84a6e7adcdbb"
+checksum = "1fb327af4685e4d03fa8cbcf1716380da910eeb2bb8be417e7f9fd3fb164f36f"
 dependencies = [
  "proc-macro2",
  "quote",
@@ -3371,9 +3378,9 @@ checksum = "099b7128301d285f79ddd55b9a83d5e6b9e97c92e0ea0daebee7263e932de992"
 
 [[package]]
 name = "unicode-ident"
-version = "1.0.5"
+version = "1.0.6"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "6ceab39d59e4c9499d4e5a8ee0e2735b891bb7308ac83dfb4e80cad195c9f6f3"
+checksum = "84a22b9f218b40614adcb3f4ff08b703773ad44fa9423e4e0d346d5db86e4ebc"
 
 [[package]]
 name = "unicode-normalization"
diff --git a/rust/Cargo.toml b/rust/Cargo.toml
index 2d651462..ab45ba13 100644
--- a/rust/Cargo.toml
+++ b/rust/Cargo.toml
@@ -47,6 +47,7 @@ lazy_static = "1.4.0"
 serde = "1.0.117"
 serde_tuple = "0.5"
 safer-ffi = { version = "0.0.7", features = ["proc_macros"] }
+blake2b_simd = "1.0.0"
 
 [dependencies.filecoin-proofs-api]
 package = "filecoin-proofs-api"
diff --git a/rust/src/fvm/cgo/externs.rs b/rust/src/fvm/cgo/externs.rs
index a384dbd6..beecab7f 100644
--- a/rust/src/fvm/cgo/externs.rs
+++ b/rust/src/fvm/cgo/externs.rs
@@ -28,19 +28,13 @@ extern "C" {
 
     pub fn cgo_extern_get_chain_randomness(
         handle: u64,
-        pers: i64,
         round: i64,
-        entropy: *const u8,
-        entropy_len: i32,
         randomness: *mut [u8; 32],
     ) -> i32;
 
     pub fn cgo_extern_get_beacon_randomness(
         handle: u64,
-        pers: i64,
         round: i64,
-        entropy: *const u8,
-        entropy_len: i32,
         randomness: *mut [u8; 32],
     ) -> i32;
 
diff --git a/rust/src/fvm/externs.rs b/rust/src/fvm/externs.rs
index 78bd33a2..a116ee68 100644
--- a/rust/src/fvm/externs.rs
+++ b/rust/src/fvm/externs.rs
@@ -1,5 +1,8 @@
 use anyhow::{anyhow, Context};
+use byteorder::{BigEndian, WriteBytesExt};
+use std::io::Write;
 
+use blake2b_simd::Params;
 use fvm2::externs::{Consensus as Consensus2, Externs as Externs2, Rand as Rand2};
 use fvm3::externs::{Chain as Chain3, Consensus as Consensus3, Externs as Externs3, Rand as Rand3};
 
@@ -42,15 +45,8 @@ impl Rand3 for CgoExterns {
     ) -> anyhow::Result<[u8; 32]> {
         unsafe {
             let mut buf = [0u8; 32];
-            match cgo_extern_get_chain_randomness(
-                self.handle,
-                pers as i64,
-                round,
-                entropy.as_ptr(),
-                entropy.len() as i32,
-                &mut buf,
-            ) {
-                0 => Ok(buf),
+            match cgo_extern_get_chain_randomness(self.handle, round, &mut buf) {
+                0 => draw_randomness(&buf, pers, round, entropy),
                 r @ 1.. => panic!("invalid return value from has: {}", r),
                 x if x == FvmError::InvalidHandle as i32 => {
                     panic!("extern {} not registered", self.handle)
@@ -71,15 +67,8 @@ impl Rand3 for CgoExterns {
     ) -> anyhow::Result<[u8; 32]> {
         unsafe {
             let mut buf = [0u8; 32];
-            match cgo_extern_get_beacon_randomness(
-                self.handle,
-                pers as i64,
-                round,
-                entropy.as_ptr(),
-                entropy.len() as i32,
-                &mut buf,
-            ) {
-                0 => Ok(buf),
+            match cgo_extern_get_beacon_randomness(self.handle, round, &mut buf) {
+                0 => draw_randomness(&buf, pers, round, entropy),
                 r @ 1.. => panic!("invalid return value from has: {}", r),
                 x if x == FvmError::InvalidHandle as i32 => {
                     panic!("extern {} not registered", self.handle)
@@ -113,6 +102,22 @@ impl Rand2 for CgoExterns {
     }
 }
 
+fn draw_randomness(
+    rbase: &[u8; 32],
+    pers: i64,
+    round: ChainEpoch,
+    entropy: &[u8],
+) -> anyhow::Result<[u8; 32]> {
+    let mut state = Params::new().hash_length(32).to_state();
+    state.write_i64::<BigEndian>(pers)?;
+    state.write_all(rbase)?;
+    state.write_i64::<BigEndian>(round)?;
+    state.write_all(entropy)?;
+    let mut ret = [0u8; 32];
+    ret.clone_from_slice(state.finalize().as_bytes());
+    Ok(ret)
+}
+
 impl Consensus3 for CgoExterns {
     fn verify_consensus_fault(
         &self,