diff --git a/.github/workflows/integration-test.yml b/.github/workflows/integration-test.yml
index 899b28d4..cceeb3aa 100644
--- a/.github/workflows/integration-test.yml
+++ b/.github/workflows/integration-test.yml
@@ -24,12 +24,12 @@ jobs:
         uses: actions/checkout@v4
 
       - name: Install nix
-        uses: cachix/install-nix-action@v27
+        uses: cachix/install-nix-action@v30
         with:
-          install_url: https://releases.nixos.org/nix/nix-2.22.0/install
+          install_url: https://releases.nixos.org/nix/nix-2.24.9/install
 
       - name: Set up cachix
-        uses: cachix/cachix-action@v14
+        uses: cachix/cachix-action@v15
         with:
           name: holochain-ci
 
diff --git a/CHANGELOG.md b/CHANGELOG.md
index a097dbd0..7af86c39 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -7,6 +7,7 @@ The format is based on [Keep a Changelog](https://keepachangelog.com/en/1.0.0/).
 ### Added
 ### Fixed
 ### Changed
+- Zome call signing has been changed in Holochain to remove the requirement of imitating Holochain serialization. Signing is now a simplified process of serializing zome call parameters using MessagePack, then computing a SHA2 512-bit hash of the serialized bytes and signing the hash. The zome call payload consists of the serialized bytes and the signature.
 ### Removed
 
 ## 2024-11-12: v0.19.0-dev.2
diff --git a/Cargo.lock b/Cargo.lock
index a87e4cfd..e721888f 100644
--- a/Cargo.lock
+++ b/Cargo.lock
@@ -143,9 +143,9 @@ dependencies = [
 
 [[package]]
 name = "cc"
-version = "1.2.0"
+version = "1.2.1"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "1aeb932158bd710538c73702db6945cb68a8fb08c519e6e12706b94263b36db8"
+checksum = "fd9de9f2205d5ef3fd67e685b0df337994ddd4495e2a28d185500d0e1edfea47"
 dependencies = [
  "shlex",
 ]
@@ -470,9 +470,9 @@ checksum = "3a9bfc1af68b1726ea47d3d5109de126281def866b33970e10fbab11b5dafab3"
 
 [[package]]
 name = "hdi"
-version = "0.6.0-dev.2"
+version = "0.6.0-dev.4"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "53159bb4f411ea083642d2fb48ccf0648c761ee292212fceb9fa7a013d298e29"
+checksum = "fd2b81d1ca8036deba19b4d55ece09def176eeb062a49391369ccb424223c917"
 dependencies = [
  "getrandom",
  "hdk_derive",
@@ -488,9 +488,9 @@ dependencies = [
 
 [[package]]
 name = "hdk"
-version = "0.5.0-dev.4"
+version = "0.5.0-dev.6"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "bd8c893bb6777a3fff50a47604e9051ff05abc2eba83bbf6c227084d8f3f5603"
+checksum = "9f2c97f85f43c82aa95488bed64f85aa2ac84cc209adf1bfc8f6e3a2f3a8110a"
 dependencies = [
  "getrandom",
  "hdi",
@@ -508,9 +508,9 @@ dependencies = [
 
 [[package]]
 name = "hdk_derive"
-version = "0.5.0-dev.2"
+version = "0.5.0-dev.4"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "ee069cd3ba1ae4d0677832b43b8307ae022cfd57235509a634114425f42522f5"
+checksum = "3477a3b1fa6e302d14144397a7cf669e7806e6b116e6f432411d232d8c3c243d"
 dependencies = [
  "darling 0.14.4",
  "heck",
@@ -536,9 +536,9 @@ checksum = "7f24254aa9a54b5c858eaee2f5bccdb46aaf0e486a595ed5fd8f86ba55232a70"
 
 [[package]]
 name = "holo_hash"
-version = "0.5.0-dev.2"
+version = "0.5.0-dev.3"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "52b1609ab3426ffbc6b96c0ae917d5281682f6bde22c1799fdc2d2f65d1c716d"
+checksum = "e9ef5f1b831a64ab1e1d2a2d6c76b8140c59660cd9b6c745eaf0c4b0d03b9257"
 dependencies = [
  "base64",
  "blake2b_simd",
@@ -549,14 +549,15 @@ dependencies = [
  "kitsune_p2p_dht_arc",
  "serde",
  "serde_bytes",
+ "sha2",
  "thiserror",
 ]
 
 [[package]]
 name = "holochain_integrity_types"
-version = "0.5.0-dev.2"
+version = "0.5.0-dev.3"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "1ad6856a52474f4d99818b3492260e1a53e8d7a766584bce1e8dfd2a3475dfc3"
+checksum = "8835be40ef1c0dffbfa111991611169a886506c48d45c91dce9523eae7639a14"
 dependencies = [
  "holo_hash",
  "holochain_secure_primitive",
@@ -658,9 +659,9 @@ dependencies = [
 
 [[package]]
 name = "holochain_zome_types"
-version = "0.5.0-dev.4"
+version = "0.5.0-dev.6"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "992e6f17a7bf5248d9739a92a64f067f3c5a0c47b71bc197c6d637223846212e"
+checksum = "0c9a6ecee3de89277f3711c4fa41d9627287b494a2e043b3dd43afd284b328bc"
 dependencies = [
  "derive_more",
  "holo_hash",
@@ -749,9 +750,9 @@ dependencies = [
 
 [[package]]
 name = "itoa"
-version = "1.0.11"
+version = "1.0.13"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "49f1f14873335454500d59611f1cf4a4b0f786f9ac11f4312a78e4cf2566695b"
+checksum = "540654e97a3f4470a492cd30ff187bc95d89557a903a2bbf112e2fae98104ef2"
 
 [[package]]
 name = "js-sys"
@@ -819,9 +820,9 @@ checksum = "bbd2bcb4c963f2ddae06a2efc7e9f3591312473c50c6685e1f298068316e66fe"
 
 [[package]]
 name = "libc"
-version = "0.2.162"
+version = "0.2.164"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "18d287de67fe55fd7e1581fe933d965a5a9477b38e949cfa9f8574ef01506398"
+checksum = "433bfe06b8c75da9b2e3fbea6e5329ff87748f0b144ef75306e674c3f6f7c13f"
 
 [[package]]
 name = "lock_api"
@@ -1063,9 +1064,9 @@ dependencies = [
 
 [[package]]
 name = "serde_json"
-version = "1.0.132"
+version = "1.0.133"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "d726bfaff4b320266d395898905d0eba0345aae23b54aee3a737e260fd46db03"
+checksum = "c7fceb2473b9166b2294ef05efcb65a3db80803f0b03ef86a5fc88a2b85ee377"
 dependencies = [
  "indexmap",
  "itoa",
@@ -1085,6 +1086,17 @@ dependencies = [
  "digest",
 ]
 
+[[package]]
+name = "sha2"
+version = "0.10.8"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "793db75ad2bcafc3ffa7c68b215fee268f537982cd901d132f89c6343f3a3dc8"
+dependencies = [
+ "cfg-if",
+ "cpufeatures",
+ "digest",
+]
+
 [[package]]
 name = "shlex"
 version = "1.3.0"
@@ -1285,9 +1297,9 @@ checksum = "42ff0bf0c66b8238c6f3b578df37d0b7848e55df8577b3f74f92a69acceeb825"
 
 [[package]]
 name = "unicode-ident"
-version = "1.0.13"
+version = "1.0.14"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "e91b56cd4cadaeb79bbf1a5645f6b4f8dc5bde8834ad5894a8db35fda9efa1fe"
+checksum = "adb9e6ca4f869e1180728b7950e35922a7fc6397f7b641499e8f3ef06e50dc83"
 
 [[package]]
 name = "valuable"
diff --git a/docs/client.appcallzomerequest.md b/docs/client.appcallzomerequest.md
index e34e930e..be64897d 100644
--- a/docs/client.appcallzomerequest.md
+++ b/docs/client.appcallzomerequest.md
@@ -8,7 +8,7 @@
 **Signature:**
 
 ```typescript
-export type AppCallZomeRequest = NonProvenanceCallZomeRequest | RoleNameCallZomeRequest | CallZomeRequestSigned | RoleNameCallZomeRequestSigned;
+export type AppCallZomeRequest = NonProvenanceCallZomeRequest | RoleNameCallZomeRequest | CallZomeRequest;
 ```
-**References:** [NonProvenanceCallZomeRequest](./client.nonprovenancecallzomerequest.md)<!-- -->, [RoleNameCallZomeRequest](./client.rolenamecallzomerequest.md)<!-- -->, [CallZomeRequestSigned](./client.callzomerequestsigned.md)<!-- -->, [RoleNameCallZomeRequestSigned](./client.rolenamecallzomerequestsigned.md)
+**References:** [NonProvenanceCallZomeRequest](./client.nonprovenancecallzomerequest.md)<!-- -->, [RoleNameCallZomeRequest](./client.rolenamecallzomerequest.md)<!-- -->, [CallZomeRequest](./client.callzomerequest.md)
 
diff --git a/docs/client.callzomerequest.md b/docs/client.callzomerequest.md
index 2e5bdd79..1e8b8ddc 100644
--- a/docs/client.callzomerequest.md
+++ b/docs/client.callzomerequest.md
@@ -8,7 +8,7 @@
 **Signature:**
 
 ```typescript
-export type CallZomeRequest = CallZomeRequestGeneric<any>;
+export type CallZomeRequest = CallZomeRequestGeneric<unknown>;
 ```
 **References:** [CallZomeRequestGeneric](./client.callzomerequestgeneric.md)
 
diff --git a/docs/client.callzomerequestunsigned.cap_secret.md b/docs/client.callzomerequestparams.cap_secret.md
similarity index 53%
rename from docs/client.callzomerequestunsigned.cap_secret.md
rename to docs/client.callzomerequestparams.cap_secret.md
index 63e8a67d..8bc8b6e0 100644
--- a/docs/client.callzomerequestunsigned.cap_secret.md
+++ b/docs/client.callzomerequestparams.cap_secret.md
@@ -1,8 +1,8 @@
 <!-- Do not edit this file. It is automatically generated by API Documenter. -->
 
-[Home](./index.md) &gt; [@holochain/client](./client.md) &gt; [CallZomeRequestUnsigned](./client.callzomerequestunsigned.md) &gt; [cap\_secret](./client.callzomerequestunsigned.cap_secret.md)
+[Home](./index.md) &gt; [@holochain/client](./client.md) &gt; [CallZomeRequestParams](./client.callzomerequestparams.md) &gt; [cap\_secret](./client.callzomerequestparams.cap_secret.md)
 
-## CallZomeRequestUnsigned.cap\_secret property
+## CallZomeRequestParams.cap\_secret property
 
 **Signature:**
 
diff --git a/docs/client.callzomerequestunsigned.expires_at.md b/docs/client.callzomerequestparams.expires_at.md
similarity index 51%
rename from docs/client.callzomerequestunsigned.expires_at.md
rename to docs/client.callzomerequestparams.expires_at.md
index 73d59cd7..8b469cf6 100644
--- a/docs/client.callzomerequestunsigned.expires_at.md
+++ b/docs/client.callzomerequestparams.expires_at.md
@@ -1,8 +1,8 @@
 <!-- Do not edit this file. It is automatically generated by API Documenter. -->
 
-[Home](./index.md) &gt; [@holochain/client](./client.md) &gt; [CallZomeRequestUnsigned](./client.callzomerequestunsigned.md) &gt; [expires\_at](./client.callzomerequestunsigned.expires_at.md)
+[Home](./index.md) &gt; [@holochain/client](./client.md) &gt; [CallZomeRequestParams](./client.callzomerequestparams.md) &gt; [expires\_at](./client.callzomerequestparams.expires_at.md)
 
-## CallZomeRequestUnsigned.expires\_at property
+## CallZomeRequestParams.expires\_at property
 
 **Signature:**
 
diff --git a/docs/client.callzomerequestunsigned.md b/docs/client.callzomerequestparams.md
similarity index 61%
rename from docs/client.callzomerequestunsigned.md
rename to docs/client.callzomerequestparams.md
index 23175fe4..4222eb87 100644
--- a/docs/client.callzomerequestunsigned.md
+++ b/docs/client.callzomerequestparams.md
@@ -1,14 +1,14 @@
 <!-- Do not edit this file. It is automatically generated by API Documenter. -->
 
-[Home](./index.md) &gt; [@holochain/client](./client.md) &gt; [CallZomeRequestUnsigned](./client.callzomerequestunsigned.md)
+[Home](./index.md) &gt; [@holochain/client](./client.md) &gt; [CallZomeRequestParams](./client.callzomerequestparams.md)
 
-## CallZomeRequestUnsigned interface
+## CallZomeRequestParams interface
 
 
 **Signature:**
 
 ```typescript
-export interface CallZomeRequestUnsigned extends CallZomeRequest 
+export interface CallZomeRequestParams extends CallZomeRequest 
 ```
 **Extends:** [CallZomeRequest](./client.callzomerequest.md)
 
@@ -37,7 +37,7 @@ Description
 </th></tr></thead>
 <tbody><tr><td>
 
-[cap\_secret](./client.callzomerequestunsigned.cap_secret.md)
+[cap\_secret](./client.callzomerequestparams.cap_secret.md)
 
 
 </td><td>
@@ -54,7 +54,7 @@ Description
 </td></tr>
 <tr><td>
 
-[expires\_at](./client.callzomerequestunsigned.expires_at.md)
+[expires\_at](./client.callzomerequestparams.expires_at.md)
 
 
 </td><td>
@@ -71,7 +71,7 @@ number
 </td></tr>
 <tr><td>
 
-[nonce](./client.callzomerequestunsigned.nonce.md)
+[nonce](./client.callzomerequestparams.nonce.md)
 
 
 </td><td>
diff --git a/docs/client.callzomerequestunsigned.nonce.md b/docs/client.callzomerequestparams.nonce.md
similarity index 54%
rename from docs/client.callzomerequestunsigned.nonce.md
rename to docs/client.callzomerequestparams.nonce.md
index ac1ff7f3..64617cd6 100644
--- a/docs/client.callzomerequestunsigned.nonce.md
+++ b/docs/client.callzomerequestparams.nonce.md
@@ -1,8 +1,8 @@
 <!-- Do not edit this file. It is automatically generated by API Documenter. -->
 
-[Home](./index.md) &gt; [@holochain/client](./client.md) &gt; [CallZomeRequestUnsigned](./client.callzomerequestunsigned.md) &gt; [nonce](./client.callzomerequestunsigned.nonce.md)
+[Home](./index.md) &gt; [@holochain/client](./client.md) &gt; [CallZomeRequestParams](./client.callzomerequestparams.md) &gt; [nonce](./client.callzomerequestparams.nonce.md)
 
-## CallZomeRequestUnsigned.nonce property
+## CallZomeRequestParams.nonce property
 
 **Signature:**
 
diff --git a/docs/client.callzomerequestsigned.bytes.md b/docs/client.callzomerequestsigned.bytes.md
new file mode 100644
index 00000000..4b25ba0e
--- /dev/null
+++ b/docs/client.callzomerequestsigned.bytes.md
@@ -0,0 +1,11 @@
+<!-- Do not edit this file. It is automatically generated by API Documenter. -->
+
+[Home](./index.md) &gt; [@holochain/client](./client.md) &gt; [CallZomeRequestSigned](./client.callzomerequestsigned.md) &gt; [bytes](./client.callzomerequestsigned.bytes.md)
+
+## CallZomeRequestSigned.bytes property
+
+**Signature:**
+
+```typescript
+bytes: Uint8Array;
+```
diff --git a/docs/client.callzomerequestsigned.md b/docs/client.callzomerequestsigned.md
index 05fbabe8..1c4e695c 100644
--- a/docs/client.callzomerequestsigned.md
+++ b/docs/client.callzomerequestsigned.md
@@ -8,9 +8,8 @@
 **Signature:**
 
 ```typescript
-export interface CallZomeRequestSigned extends CallZomeRequestUnsigned 
+export interface CallZomeRequestSigned 
 ```
-**Extends:** [CallZomeRequestUnsigned](./client.callzomerequestunsigned.md)
 
 ## Properties
 
@@ -37,6 +36,23 @@ Description
 </th></tr></thead>
 <tbody><tr><td>
 
+[bytes](./client.callzomerequestsigned.bytes.md)
+
+
+</td><td>
+
+
+</td><td>
+
+Uint8Array
+
+
+</td><td>
+
+
+</td></tr>
+<tr><td>
+
 [signature](./client.callzomerequestsigned.signature.md)
 
 
diff --git a/docs/client.md b/docs/client.md
index 90b7e3ce..272053aa 100644
--- a/docs/client.md
+++ b/docs/client.md
@@ -594,7 +594,7 @@ Description
 </td></tr>
 <tr><td>
 
-[CallZomeRequestSigned](./client.callzomerequestsigned.md)
+[CallZomeRequestParams](./client.callzomerequestparams.md)
 
 
 </td><td>
@@ -604,7 +604,7 @@ Description
 </td></tr>
 <tr><td>
 
-[CallZomeRequestUnsigned](./client.callzomerequestunsigned.md)
+[CallZomeRequestSigned](./client.callzomerequestsigned.md)
 
 
 </td><td>
diff --git a/flake.lock b/flake.lock
index 6e6d3a54..88869bfd 100644
--- a/flake.lock
+++ b/flake.lock
@@ -53,11 +53,11 @@
     "hc-scaffold": {
       "flake": false,
       "locked": {
-        "lastModified": 1730407032,
-        "narHash": "sha256-NNnow8Cne1KBJ4WvJ6eT1OzcqyJiii35Q2ElVdI0ozA=",
+        "lastModified": 1731921057,
+        "narHash": "sha256-8Qn6yXNVRTAiKCwlZpD9PDW6JQZh7lgOEa9kmnsbXnM=",
         "owner": "holochain",
         "repo": "scaffolding",
-        "rev": "f838294a3c4f45b3e8e41297ea36eb91cfedee80",
+        "rev": "2c5dc235c2e42b458bbc40cdd8c35bf588a2c40c",
         "type": "github"
       },
       "original": {
@@ -70,16 +70,16 @@
     "holochain": {
       "flake": false,
       "locked": {
-        "lastModified": 1730855012,
-        "narHash": "sha256-oW4d2DRHxktRkkGbilWL8ZufXfA3vGeMXLnLgi12Ewk=",
+        "lastModified": 1732065228,
+        "narHash": "sha256-4QBB/HAv6MoVaHVYsbhhvj2UnfIT0bCb0cgcoeNn07A=",
         "owner": "holochain",
         "repo": "holochain",
-        "rev": "525b63fb019eac866e096033ba194c2d8bb45b9a",
+        "rev": "0069772823ce6f761f793544ca7ec8877cd47a39",
         "type": "github"
       },
       "original": {
         "owner": "holochain",
-        "ref": "holochain-0.5.0-dev.4",
+        "ref": "holochain-0.5.0-dev.6",
         "repo": "holochain",
         "type": "github"
       }
@@ -96,11 +96,11 @@
         "rust-overlay": "rust-overlay"
       },
       "locked": {
-        "lastModified": 1730912125,
-        "narHash": "sha256-zKdkSsd5d6OtY9YgBh42Pkx0NqyquWy3uktB606FZ/g=",
+        "lastModified": 1732123243,
+        "narHash": "sha256-ugJEN44UgCQYPoxV1WN32ybPxij9M8uTnDLCfWi4Rb0=",
         "owner": "holochain",
         "repo": "holonix",
-        "rev": "3919d71452577ccfe094a5ec3ce9581b959bb099",
+        "rev": "f58fb5e1c490704d90daa1b461701de7c70d685a",
         "type": "github"
       },
       "original": {
diff --git a/package-lock.json b/package-lock.json
index 64f06998..c61ef000 100644
--- a/package-lock.json
+++ b/package-lock.json
@@ -10,11 +10,11 @@
       "license": "CAL-1.0",
       "dependencies": {
         "@bitgo/blake2b": "^3.2.4",
-        "@holochain/serialization": "^0.1.0-beta-rc.3",
         "@msgpack/msgpack": "^2.8.0",
         "emittery": "^1.0.1",
         "isomorphic-ws": "^5.0.0",
         "js-base64": "^3.7.5",
+        "js-sha512": "^0.9.0",
         "libsodium-wrappers": "^0.7.13",
         "lodash-es": "^4.17.21",
         "ws": "^8.14.2"
@@ -560,11 +560,6 @@
         "node": "^12.22.0 || ^14.17.0 || >=16.0.0"
       }
     },
-    "node_modules/@holochain/serialization": {
-      "version": "0.1.0-beta-rc.3",
-      "resolved": "https://registry.npmjs.org/@holochain/serialization/-/serialization-0.1.0-beta-rc.3.tgz",
-      "integrity": "sha512-DJx4V2KXHVLciyOGjOYKTM/JLBpBEZ3RsPIRCgf7qmwhQdxXvhi2p+oFFRD51yUT5uC1/MzIVeJCl/R60PwFbw=="
-    },
     "node_modules/@humanwhocodes/config-array": {
       "version": "0.13.0",
       "resolved": "https://registry.npmjs.org/@humanwhocodes/config-array/-/config-array-0.13.0.tgz",
@@ -879,9 +874,9 @@
       }
     },
     "node_modules/@types/node": {
-      "version": "22.9.0",
-      "resolved": "https://registry.npmjs.org/@types/node/-/node-22.9.0.tgz",
-      "integrity": "sha512-vuyHg81vvWA1Z1ELfvLko2c8f34gyA0zaic0+Rllc5lbCnbSyuvb2Oxpm6TAUAC/2xZN3QGqxBNggD1nNR2AfQ==",
+      "version": "22.9.1",
+      "resolved": "https://registry.npmjs.org/@types/node/-/node-22.9.1.tgz",
+      "integrity": "sha512-p8Yy/8sw1caA8CdRIQBG5tiLHmxtQKObCijiAa9Ez+d4+PRffM4054xbju0msf+cvhJpnFEeNjxmVT/0ipktrg==",
       "dev": true,
       "dependencies": {
         "undici-types": "~6.19.8"
@@ -1406,9 +1401,9 @@
       "dev": true
     },
     "node_modules/cross-spawn": {
-      "version": "7.0.5",
-      "resolved": "https://registry.npmjs.org/cross-spawn/-/cross-spawn-7.0.5.tgz",
-      "integrity": "sha512-ZVJrKKYunU38/76t0RMOulHOnUcbU9GbpWKAOZ0mhjr7CX6FVrH+4FrAapSOekrgFQ3f/8gwMEuIft0aKq6Hug==",
+      "version": "7.0.6",
+      "resolved": "https://registry.npmjs.org/cross-spawn/-/cross-spawn-7.0.6.tgz",
+      "integrity": "sha512-uV2QOWP2nWzsy2aMp8aRibhi9dlzF5Hgh5SHaB9OiTGEyDTiJJyx0uy51QXdyWbtAHNua4XJzUKca3OzKUd3vA==",
       "dev": true,
       "dependencies": {
         "path-key": "^3.1.0",
@@ -1616,9 +1611,9 @@
       }
     },
     "node_modules/es-abstract": {
-      "version": "1.23.3",
-      "resolved": "https://registry.npmjs.org/es-abstract/-/es-abstract-1.23.3.tgz",
-      "integrity": "sha512-e+HfNH61Bj1X9/jLc5v1owaLYuHdeHHSQlkhCBiTK8rBvKaULl/beGMxwrMXjpYrv4pz22BlY570vVePA2ho4A==",
+      "version": "1.23.5",
+      "resolved": "https://registry.npmjs.org/es-abstract/-/es-abstract-1.23.5.tgz",
+      "integrity": "sha512-vlmniQ0WNPwXqA0BnmwV3Ng7HxiGlh6r5U6JcTMNx8OilcAGqVJBHJcPjqOMaczU9fRuRK5Px2BdVyPRnKMMVQ==",
       "dev": true,
       "dependencies": {
         "array-buffer-byte-length": "^1.0.1",
@@ -1636,7 +1631,7 @@
         "function.prototype.name": "^1.1.6",
         "get-intrinsic": "^1.2.4",
         "get-symbol-description": "^1.0.2",
-        "globalthis": "^1.0.3",
+        "globalthis": "^1.0.4",
         "gopd": "^1.0.1",
         "has-property-descriptors": "^1.0.2",
         "has-proto": "^1.0.3",
@@ -1652,10 +1647,10 @@
         "is-string": "^1.0.7",
         "is-typed-array": "^1.1.13",
         "is-weakref": "^1.0.2",
-        "object-inspect": "^1.13.1",
+        "object-inspect": "^1.13.3",
         "object-keys": "^1.1.1",
         "object.assign": "^4.1.5",
-        "regexp.prototype.flags": "^1.5.2",
+        "regexp.prototype.flags": "^1.5.3",
         "safe-array-concat": "^1.1.2",
         "safe-regex-test": "^1.0.3",
         "string.prototype.trim": "^1.2.9",
@@ -2270,9 +2265,9 @@
       }
     },
     "node_modules/flatted": {
-      "version": "3.3.1",
-      "resolved": "https://registry.npmjs.org/flatted/-/flatted-3.3.1.tgz",
-      "integrity": "sha512-X8cqMLLie7KsNUDSdzeN8FYK9rEt4Dt67OsG/DNGnYTSDBG4uFAJFBnUeiV+zCVAvwFy56IjM9sH51jVaEhNxw==",
+      "version": "3.3.2",
+      "resolved": "https://registry.npmjs.org/flatted/-/flatted-3.3.2.tgz",
+      "integrity": "sha512-AiwGJM8YcNOaobumgtng+6NHuOqC3A7MixFeDafM3X9cIUM+xUXoS5Vfgf+OihAYe20fxqNM9yPBXJzRtZ/4eA==",
       "dev": true
     },
     "node_modules/for-each": {
@@ -3056,6 +3051,11 @@
       "resolved": "https://registry.npmjs.org/js-base64/-/js-base64-3.7.7.tgz",
       "integrity": "sha512-7rCnleh0z2CkXhH67J8K1Ytz0b2Y+yxTPL+/KOJoa20hfnVQ/3/T6W/KflYI4bRHRagNeXeU2bkNGI3v1oS/lw=="
     },
+    "node_modules/js-sha512": {
+      "version": "0.9.0",
+      "resolved": "https://registry.npmjs.org/js-sha512/-/js-sha512-0.9.0.tgz",
+      "integrity": "sha512-mirki9WS/SUahm+1TbAPkqvbCiCfOAAsyXeHxK1UkullnJVVqoJG2pL9ObvT05CN+tM7fxhfYm0NbXn+1hWoZg=="
+    },
     "node_modules/js-yaml": {
       "version": "3.14.1",
       "resolved": "https://registry.npmjs.org/js-yaml/-/js-yaml-3.14.1.tgz",
diff --git a/package.json b/package.json
index a928192e..0dc5857b 100644
--- a/package.json
+++ b/package.json
@@ -43,11 +43,11 @@
   },
   "dependencies": {
     "@bitgo/blake2b": "^3.2.4",
-    "@holochain/serialization": "^0.1.0-beta-rc.3",
     "@msgpack/msgpack": "^2.8.0",
     "emittery": "^1.0.1",
     "isomorphic-ws": "^5.0.0",
     "js-base64": "^3.7.5",
+    "js-sha512": "^0.9.0",
     "libsodium-wrappers": "^0.7.13",
     "lodash-es": "^4.17.21",
     "ws": "^8.14.2"
@@ -72,4 +72,4 @@
     "tsx": "^4.7.2",
     "typescript": "^4.9.5"
   }
-}
\ No newline at end of file
+}
diff --git a/src/api/app/types.ts b/src/api/app/types.ts
index 9ca96705..54706fc9 100644
--- a/src/api/app/types.ts
+++ b/src/api/app/types.ts
@@ -55,8 +55,7 @@ export type RoleNameCallZomeRequestSigned = Omit<
 export type AppCallZomeRequest =
   | NonProvenanceCallZomeRequest
   | RoleNameCallZomeRequest
-  | CallZomeRequestSigned
-  | RoleNameCallZomeRequestSigned;
+  | CallZomeRequest;
 
 /**
  * @public
@@ -91,7 +90,7 @@ export interface AppEvents {
 /**
  * @public
  */
-export interface CallZomeRequestUnsigned extends CallZomeRequest {
+export interface CallZomeRequestParams extends CallZomeRequest {
   cap_secret: CapSecret | null;
   nonce: Nonce256Bit;
   expires_at: number;
@@ -100,7 +99,8 @@ export interface CallZomeRequestUnsigned extends CallZomeRequest {
 /**
  * @public
  */
-export interface CallZomeRequestSigned extends CallZomeRequestUnsigned {
+export interface CallZomeRequestSigned {
+  bytes: Uint8Array;
   signature: Uint8Array;
 }
 
diff --git a/src/api/app/websocket.ts b/src/api/app/websocket.ts
index 27721e36..eca32319 100644
--- a/src/api/app/websocket.ts
+++ b/src/api/app/websocket.ts
@@ -30,7 +30,7 @@ import {
   SignalCb,
   CallZomeRequest,
   CallZomeRequestSigned,
-  CallZomeRequestUnsigned,
+  CallZomeRequestParams,
   CallZomeResponse,
   CallZomeResponseGeneric,
   CreateCloneCellRequest,
@@ -66,9 +66,9 @@ import {
   randomNonce,
 } from "../zome-call-signing.js";
 import { encodeHashToBase64 } from "../../utils/index.js";
-import { hashZomeCall } from "@holochain/serialization";
 import _sodium from "libsodium-wrappers";
 import { WsClient } from "../client.js";
+import { sha512 } from "js-sha512";
 
 /**
  * A class to establish a websocket connection to an App interface, for a
@@ -603,7 +603,7 @@ export const signZomeCall = async (request: CallZomeRequest) => {
       )}, ${encodeHashToBase64(request.cell_id[1])}]`
     );
   }
-  const unsignedZomeCallPayload: CallZomeRequestUnsigned = {
+  const unsignedZomeCallPayload: CallZomeRequestParams = {
     cap_secret: signingCredentialsForCell.capSecret,
     cell_id: request.cell_id,
     zome_name: request.zome_name,
@@ -613,15 +613,16 @@ export const signZomeCall = async (request: CallZomeRequest) => {
     nonce: await randomNonce(),
     expires_at: getNonceExpiration(),
   };
-  const hashedZomeCall = await hashZomeCall(unsignedZomeCallPayload);
+  const bytes = encode(unsignedZomeCallPayload);
+  const bytesHash = new Uint8Array(sha512.array(bytes));
   await _sodium.ready;
   const sodium = _sodium;
   const signature = sodium
-    .crypto_sign(hashedZomeCall, signingCredentialsForCell.keyPair.privateKey)
+    .crypto_sign(bytesHash, signingCredentialsForCell.keyPair.privateKey)
     .subarray(0, sodium.crypto_sign_BYTES);
 
   const signedZomeCall: CallZomeRequestSigned = {
-    ...unsignedZomeCallPayload,
+    bytes,
     signature,
   };
   return signedZomeCall;
diff --git a/src/api/index.ts b/src/api/index.ts
index 8cb359db..4de4bcf7 100644
--- a/src/api/index.ts
+++ b/src/api/index.ts
@@ -1,4 +1,3 @@
-export { hashZomeCall } from "@holochain/serialization";
 export * from "./admin/index.js";
 export * from "./app/index.js";
 export {
diff --git a/src/environments/launcher.ts b/src/environments/launcher.ts
index f5c4b44f..4a3d780c 100644
--- a/src/environments/launcher.ts
+++ b/src/environments/launcher.ts
@@ -1,8 +1,5 @@
 import { AppAuthenticationToken, CallZomeRequest } from "../api/index.js";
-import {
-  CallZomeRequestSigned,
-  CallZomeRequestUnsigned,
-} from "../api/index.js";
+import { CallZomeRequestSigned, CallZomeRequestParams } from "../api/index.js";
 import { InstalledAppId } from "../types.js";
 
 export interface LauncherEnvironment {
@@ -61,7 +58,7 @@ interface CallZomeRequestSignedElectron
 
 interface CallZomeRequestUnsignedElectron
   extends Omit<
-    CallZomeRequestUnsigned,
+    CallZomeRequestParams,
     | "cap_secret"
     | "cell_id"
     | "provenance"