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Multi-party Compute 用户指南

本指南介绍了如何使用 Multi-party Compute API 管理分布式密钥、参与者和政策。它适用于学习关键用户体验历程的预览版客户。

概览

MPC API 包含两个主要组件：

Core MPC 管理分布式密钥、提案和签名仪式的生命周期。
政策引擎负责强制执行治理，在操作执行前进行授权。

如需详细了解 API 访问权限和加密签名如何交互，请参阅安全和授权。

注意： 单人模拟与多用户模拟：在实际环境中，此系统依赖于多个角色（管理员、政策作者和签名者）之间严格的职责分离，每个角色都具有不同的加密密钥和 IAM 权限。不过，为了简化测试和学习，本指南的结构设计让单个开发者可以在单个工作站上扮演所有角色。如需详细了解这些角色在实际场景中如何交互，请参阅安全和授权。

前提条件

开始之前，请确保您满足以下方面的要求：

Google Cloud 项目。请参阅创建项目以创建一个项目。
如果未使用 Cloud Shell，则需要安装 gcloud CLI 并进行身份验证。
已启用所需的 API（如果尚未启用）。您需要两个 API：本指南中使用的新 MPC API，以及 Cloud Key Management Service（如果您使用它来生成/签署同意密钥）。
```
  gcloud services enable mpc.googleapis.com cloudkms.googleapis.com
```
如需查看已启用的 API，请执行以下操作：
```
  gcloud services list --enabled
```

已安装 Python 3.9+ 和教程辅助库：

  pip install embit eth-account eth-utils requests

（可选）如果您的组织使用外部身份提供方（例如 Okta 或 Microsoft Entra ID）进行身份验证，而不使用 Google 账号，请参阅配置员工身份联合 (BYOID)，以使用联合身份配置应用默认凭据 (ADC)。

设置

更新以下变量，以填充本指南中的命令。

必需设置

您必须自定义这些参数。如果使用占位值，本指南将无法正常运行。

参数	值	说明
项目 ID	`my-project`	您为加入预览版而向我们提供的消费者项目 ID。
网域 ID	`67317436-0f29-ba9e-9146-d11c0bd8df9b`	我们为您的实例分配的唯一网域 ID。
实例路径 ID	`mpc-unit-bob-123`	我们为您的实例分配的路径实例 ID。
位置	`us-central1`	部署位置。必须为 `us-central1`（预览版不支持其他区域）。

教程资源标签

这些是本教程中创建的资源的名称。默认值有效，可以保留，以尽量减少设置过程中的阻碍。

参数	值	说明
Cloud KMS 密钥环 ID	`mpc-assent-keys`	Cloud Key Management Service KeyRing，用于存储在 Cloud KMS 中的外部同意密钥。
Signer 1 ID	`signer-alice`	MPC 签名者 1。
签署者 2 ID	`signer-bob`	MPC 签名者 2。
签名者 3 ID	`signer-charlie`	MPC 签署者 3。
Policy Author 1 ID	`author-dave`	政策作者 1。
Policy Author 2 ID	`author-eve`	政策作者 2。
政策 ID	`ethereum-transfer-policy`	政策 ID（例如 `ethereum-transfer-policy` 或 `bitcoin-psbt-policy`）。
KeyRing ID	`my-key-ring`	KeyRing ID。
密钥 ID	`my-key`	密钥 ID。
提案 ID	`my-proposal`	提案 ID。

第 1 步：生成同意密钥

如需使用 MPC API，您必须为以下不同角色生成密钥对。请注意，这些是外部加密同意密钥，与设置期间在内部生成的分布式 MPC 阈值密钥分片不同。

政策作者：授权治理政策。
签名者：对提案表示赞同（投票/批准）。

A. 参与者密钥 (secp256k1)

为参与者生成必要的加密密钥。这些命令具有幂等性。

Cloud KMS

我们建议您在 Cloud Key Management Service 中管理同意密钥。确保您的身份有权创建密钥环、创建密钥、签名和查看公钥验证器（例如 roles/cloudkms.admin 和 roles/cloudkms.signerVerifier）。确保您已创建 KeyRing，然后为所有签名者生成 secp256k1 密钥。

provision_keyring() {
  if gcloud kms keyrings describe "mpc-assent-keys" --location="us-central1" > /dev/null 2>&1; then
    echo "KeyRing 'mpc-assent-keys' already exists."
  else
    echo "KeyRing 'mpc-assent-keys' not found. Creating it..."
    gcloud kms keyrings create "mpc-assent-keys" --location="us-central1"
  fi
}

provision_kms_key() {
  local id=$1
  if gcloud kms keys describe "${id}-key" --keyring="mpc-assent-keys" --location="us-central1" > /dev/null 2>&1; then
    echo "KMS key '${id}-key' already exists."
  else
    echo "KMS key '${id}-key' not found. Creating it..."
    gcloud kms keys create "${id}-key" \
      --keyring="mpc-assent-keys" \
      --location="us-central1" \
      --purpose=asymmetric-signing \
      --default-algorithm=ec-sign-secp256k1-sha256 \
      --protection-level=hsm
  fi

  gcloud kms keys versions get-public-key 1 \
    --key="${id}-key" \
    --keyring="mpc-assent-keys" \
    --location="us-central1" \
    --output-file="${id}_pub.pem"

  echo "Retrieved public key from KMS and saved to ${id}_pub.pem:"
  cat "${id}_pub.pem"
}

# Run Setup
provision_keyring

# Generate Keys
for ID in signer-alice signer-bob signer-charlie; do
  echo "Generating KMS key for $ID..."
  provision_kms_key "$ID"
done

OpenSSL

您可以使用标准 OpenSSL 为每个参与者生成 secp256k1 密钥。

provision_openssl_key() {
  local id=$1
  if [[ ! -f "${id}_priv.pem" ]]; then
    openssl ecparam -name secp256k1 -genkey -noout -out "${id}_priv.pem"
    openssl ec -in "${id}_priv.pem" -pubout -out "${id}_pub.pem"
    echo "Wrote private key to ${id}_priv.pem and public key to ${id}_pub.pem:"
    cat "${id}_pub.pem"
  else
    echo "Private key file '${id}_priv.pem' already exists. Skipping OpenSSL generation."
    echo "Using existing public key from '${id}_pub.pem':"
    cat "${id}_pub.pem"
  fi
}

for ID in signer-alice signer-bob signer-charlie; do
  echo "Generating OpenSSL key for $ID..."
  provision_openssl_key "$ID"
done

B. 政策作者密钥 (secp256k1)

Cloud KMS

同样，我们建议您在 Cloud Key Management Service 中管理这些同意密钥。确保您的身份有权创建密钥环、创建密钥、签名和查看公钥验证器（例如 roles/cloudkms.admin 和 roles/cloudkms.signerVerifier）。确保您已创建 KeyRing，然后为所有政策作者生成 secp256k1 密钥。

provision_keyring() {
  if gcloud kms keyrings describe "mpc-assent-keys" --location="us-central1" > /dev/null 2>&1; then
    echo "KeyRing 'mpc-assent-keys' already exists."
  else
    echo "KeyRing 'mpc-assent-keys' not found. Creating it..."
    gcloud kms keyrings create "mpc-assent-keys" --location="us-central1"
  fi
}

provision_kms_key() {
  local id=$1
  if gcloud kms keys describe "${id}-key" --keyring="mpc-assent-keys" --location="us-central1" > /dev/null 2>&1; then
    echo "KMS key '${id}-key' already exists."
  else
    echo "KMS key '${id}-key' not found. Creating it..."
    gcloud kms keys create "${id}-key" \
      --keyring="mpc-assent-keys" \
      --location="us-central1" \
      --purpose=asymmetric-signing \
      --default-algorithm=ec-sign-secp256k1-sha256 \
      --protection-level=hsm
  fi

  gcloud kms keys versions get-public-key 1 \
    --key="${id}-key" \
    --keyring="mpc-assent-keys" \
    --location="us-central1" \
    --output-file="${id}_pub.pem"

  echo "Retrieved public key from KMS and saved to ${id}_pub.pem:"
  cat "${id}_pub.pem"
}

provision_keyring

for ID in author-dave author-eve; do
  echo "Generating KMS key for $ID..."
  provision_kms_key "$ID"
done

OpenSSL

政策作者使用 secp256k1 曲线来签署治理政策和管理操作。您可以使用标准 OpenSSL 生成这些密钥。

provision_openssl_key() {
  local id=$1
  if [[ ! -f "${id}_priv.pem" ]]; then
    openssl ecparam -name secp256k1 -genkey -noout -out "${id}_priv.pem"
    openssl ec -in "${id}_priv.pem" -pubout -out "${id}_pub.pem"
    echo "Wrote private key to ${id}_priv.pem and public key to ${id}_pub.pem:"
    cat "${id}_pub.pem"
  else
    echo "Private key file '${id}_priv.pem' already exists. Skipping OpenSSL generation."
    echo "Using existing public key from '${id}_pub.pem':"
    cat "${id}_pub.pem"
  fi
}

for ID in author-dave author-eve; do
  echo "Generating OpenSSL key for $ID..."
  provision_openssl_key "$ID"
done

第 2 步：注册参与者

任何实体都必须先注册为参与者，然后才能参与 MPC 流程（作为签名者）或政策流程（作为政策作者）。

注册需要管理员和参与者之间进行带外协调：

实体（签名者或作者）在本地生成密钥对，并安全地将公钥传输给管理员。
管理员（拥有标准 Google Cloud IAM 权限）调用 API 来注册公钥。

curl

provision_participant() {
  local id=$1
  local name=$2
  local pubkey_b64

  # Read the public key from the file generated in Step 1
  echo "Reading public key from ${id}_pub.pem..."
  # Public key must be represented as Base64 encoded bytes of the PEM/DER format.
  pubkey_b64=$(openssl base64 -A -in "${id}_pub.pem")

  # Check existence
  if curl -s -f -o /dev/null -H "Authorization: Bearer $(gcloud auth application-default print-access-token)" \
    -H "X-Goog-User-Project: my-project" \
    "https://67317436-0f29-ba9e-9146-d11c0bd8df9b.us-central1.mpc.goog/v1alpha1/projects/my-project/locations/us-central1/instances/mpc-unit-bob-123/mpc/signers/$id"; then
    echo "Participant '$id' already exists. Skipping registration."
  else
    echo "Participant '$id' not found. Registering..."
    curl -X POST \
      -H "Authorization: Bearer $(gcloud auth application-default print-access-token)" \
      -H "X-Goog-User-Project: my-project" \
      -H "Content-Type: application/json" \
      -d "{
        \"displayName\": \"$name\",
        \"activePublicAssentKey\": {
          \"publicKey\": \"$pubkey_b64\",
          \"algorithm\": \"PUBLIC_KEY_SIGNATURE_ALGORITHM_ECDSA_SECP256K1\"
        }
      }" \
      "https://67317436-0f29-ba9e-9146-d11c0bd8df9b.us-central1.mpc.goog/v1alpha1/projects/my-project/locations/us-central1/instances/mpc-unit-bob-123/mpc/signers?participant_id=$id" | jq
  fi
}

echo "Registering Signers..."
for ID in signer-alice signer-bob signer-charlie; do
  provision_participant "$ID" "Signer $ID"
done

echo "Registering Policy Authors..."
for ID in author-dave author-eve; do
  provision_participant "$ID" "Author $ID"
done

第 3 步：配置政策引擎

通过设置信任包和创建政策来配置政策引擎。

A. 初始化政策作者信任包

确定授权的政策作者。这是实例的单例资源。

curl

# Get current sequence from the API. If null (initial state), fallback to 0.
NEXT_BUNDLE_SEQUENCE=$(curl -s -H "Authorization: Bearer $(gcloud auth application-default print-access-token)" \
  -H "X-Goog-User-Project: my-project" \
  "https://67317436-0f29-ba9e-9146-d11c0bd8df9b.us-central1.mpc.goog/v1alpha1/projects/my-project/locations/us-central1/instances/mpc-unit-bob-123/policyEngine/policyAuthorTrustBundle" \
  | jq -r '.sequenceNumber // 0')

# Calculate higher sequence number.
NEXT_BUNDLE_SEQUENCE=$((NEXT_BUNDLE_SEQUENCE + 1))

curl -X PATCH \
  -H "Authorization: Bearer $(gcloud auth application-default print-access-token)" \
  -H "X-Goog-User-Project: my-project" \
  -H "Content-Type: application/json" \
  -d '{
    "sequenceNumber": '"$NEXT_BUNDLE_SEQUENCE"',
    "authors": [
      {"authorId": "'"author-dave"'"},
      {"authorId": "'"author-eve"'"}
    ]
  }' \
https://67317436-0f29-ba9e-9146-d11c0bd8df9b.us-central1.mpc.goog/v1alpha1/projects/my-project/locations/us-central1/instances/mpc-unit-bob-123/policyEngine/policyAuthorTrustBundle | jq

B. 创建政策 (PENDING_ACTIVE)

定义政策 ID（ethereum-transfer-policy 或 bitcoin-psbt-policy），并创建一条规则来描述允许执行的操作。虽然您可以配置多项政策来管理不同的场景，但本指南仅演示如何为以太坊或比特币交易设置政策。默认情况下，政策引擎会快速失败（默认屏蔽）；如果没有任何政策明确允许某项交易，该交易就会被拒绝。

在创建或批准政策之前，作者必须对表示意图的载荷进行签名。您可以使用以下辅助函数来处理二进制序列化和签名。

以太坊

此规则允许向 Alice 的特定地址进行较小金额的以太坊转账（<= 2 ETH，表示为 2,000,000,000 Gwei）。

1. 生成 Quorum 签名

使用 Cloud KMS：

sign_policy() {
  local author_id=$1
  local sequence=$2
  local cedar_doc=$3
  local policy_id=$4
  export _HELPER_POLICY_ID="$policy_id"
  export _HELPER_SEQUENCE="$sequence"
  export _HELPER_CEDAR_DOC="$cedar_doc"
  python3 -c "import os; p='my-project'; l='us-central1'; i='mpc-unit-bob-123'; pol=os.environ.get('_HELPER_POLICY_ID'); s=int(os.environ.get('_HELPER_SEQUENCE')); d=os.environ.get('_HELPER_CEDAR_DOC'); n=f'projects/{p}/locations/{l}/instances/{i}/policyEngine/policies/{pol}'; payload=b'action:ACTIVE\n'+n.encode('utf-8')+b'sequence:'+s.to_bytes(8,'little')+b'cedar_document:'+d.encode('utf-8'); open('payload.bin', 'wb').write(payload)"
  gcloud kms asymmetric-sign \
    --version=1 \
    --key="${author_id}-key" \
    --keyring="mpc-assent-keys" \
    --location="us-central1" \
    --digest-algorithm=sha256 \
    --input-file=payload.bin \
    --signature-file=policy_sig.bin > /dev/null
  openssl base64 -A -in policy_sig.bin
}

# Sign as Author 1 (Sequence 0)
QUORUM_SIGNATURE=$(sign_policy "author-dave" 0 'permit(principal == User::"alice", action == Action::"Transfer", resource == Resource::"mpc_operation") when { context.transaction.to_address == "0x1111111111111111111111111111111111111111" && context.transaction.value_gwei <= 2000000000 };' "ethereum-transfer-policy")

使用 OpenSSL：

sign_policy() {
  local author_id=$1
  local sequence=$2
  local cedar_doc=$3
  local policy_id=$4
  export _HELPER_POLICY_ID="$policy_id"
  export _HELPER_SEQUENCE="$sequence"
  export _HELPER_CEDAR_DOC="$cedar_doc"
  python3 -c "import os; p='my-project'; l='us-central1'; i='mpc-unit-bob-123'; pol=os.environ.get('_HELPER_POLICY_ID'); s=int(os.environ.get('_HELPER_SEQUENCE')); d=os.environ.get('_HELPER_CEDAR_DOC'); n=f'projects/{p}/locations/{l}/instances/{i}/policyEngine/policies/{pol}'; payload=b'action:ACTIVE\n'+n.encode('utf-8')+b'sequence:'+s.to_bytes(8,'little')+b'cedar_document:'+d.encode('utf-8'); open('payload.bin', 'wb').write(payload)"
  openssl dgst -sha256 -sign "${author_id}_priv.pem" -out policy_sig.bin payload.bin
  openssl base64 -A -in policy_sig.bin
}

# Sign as Author 1 (Sequence 0)
QUORUM_SIGNATURE=$(sign_policy "author-dave" 0 'permit(principal == User::"alice", action == Action::"Transfer", resource == Resource::"mpc_operation") when { context.transaction.to_address == "0x1111111111111111111111111111111111111111" && context.transaction.value_gwei <= 2000000000 };' "ethereum-transfer-policy")

2. 调用 CreatePolicy API

# Check existence
if curl -s -f -o /dev/null -H "Authorization: Bearer $(gcloud auth application-default print-access-token)" \
  -H "X-Goog-User-Project: my-project" \
  "https://67317436-0f29-ba9e-9146-d11c0bd8df9b.us-central1.mpc.goog/v1alpha1/projects/my-project/locations/us-central1/instances/mpc-unit-bob-123/policyEngine/policies/ethereum-transfer-policy"; then
  echo "Policy 'ethereum-transfer-policy' already exists. Skipping creation."
else
  echo "Policy 'ethereum-transfer-policy' not found. Creating..."
  curl -X POST \
    -H "Authorization: Bearer $(gcloud auth application-default print-access-token)" \
    -H "X-Goog-User-Project: my-project" \
    -H "Content-Type: application/json" \
    -d '{
      "displayName": "Ethereum Transfer Permit Policy",
      "rule": {
        "cedarDocument": "permit(principal == User::\"alice\", action == Action::\"Transfer\", resource == Resource::\"mpc_operation\") when { context.transaction.to_address == \"0x1111111111111111111111111111111111111111\" && context.transaction.value_gwei <= 2000000000 };"
      },
      "createAuthorSignature": {
        "authorId": "'"author-dave"'",
        "signature": "'"$QUORUM_SIGNATURE"'",
        "approvalTime": "'"$(date -u +"%Y-%m-%dT%H:%M:%SZ")"'"
      }
    }' \
  "https://67317436-0f29-ba9e-9146-d11c0bd8df9b.us-central1.mpc.goog/v1alpha1/projects/my-project/locations/us-central1/instances/mpc-unit-bob-123/policyEngine/policies?policy_id=ethereum-transfer-policy" | jq
fi

比特币

此规则允许使用 bitcoin.transaction.v2 架构 (BIP 174 PSBT) 进行比特币转账，前提是净出站转账金额不超过 250,000 聪（context.transaction.spend_amount_scaled <= 2500000，或 0.0025 BTC，标准化为 10^-9 固定小数单位），且矿工费不超过 10,000 聪 (context.transaction.max_fee_atomic <= 100000)。

permit(
  principal == User::"alice",
  action == Action::"Transfer",
  resource == Resource::"mpc_operation"
)
when {
  context.transaction.schema == "bitcoin.transaction.v2" &&
  context.transaction.spend_amount_scaled <= 2500000 &&
  context.transaction.max_fee_atomic <= 100000
};

1. 生成 Quorum 签名

使用 Cloud KMS：

sign_policy() {
  local author_id=$1
  local sequence=$2
  local cedar_doc=$3
  local policy_id=$4
  export _HELPER_POLICY_ID="$policy_id"
  export _HELPER_SEQUENCE="$sequence"
  export _HELPER_CEDAR_DOC="$cedar_doc"
  python3 -c "import os; p='my-project'; l='us-central1'; i='mpc-unit-bob-123'; pol=os.environ.get('_HELPER_POLICY_ID'); s=int(os.environ.get('_HELPER_SEQUENCE')); d=os.environ.get('_HELPER_CEDAR_DOC'); n=f'projects/{p}/locations/{l}/instances/{i}/policyEngine/policies/{pol}'; payload=b'action:ACTIVE\n'+n.encode('utf-8')+b'sequence:'+s.to_bytes(8,'little')+b'cedar_document:'+d.encode('utf-8'); open('payload.bin', 'wb').write(payload)"
  gcloud kms asymmetric-sign \
    --version=1 \
    --key="${author_id}-key" \
    --keyring="mpc-assent-keys" \
    --location="us-central1" \
    --digest-algorithm=sha256 \
    --input-file=payload.bin \
    --signature-file=policy_sig.bin > /dev/null
  openssl base64 -A -in policy_sig.bin
}

# Sign as Author 1 (Sequence 0)
QUORUM_SIGNATURE=$(sign_policy "author-dave" 0 'permit(principal == User::"alice", action == Action::"Transfer", resource == Resource::"mpc_operation") when { context.transaction.schema == "bitcoin.transaction.v2" && context.transaction.spend_amount_scaled <= 2500000 && context.transaction.max_fee_atomic <= 100000 };' "bitcoin-psbt-policy")

使用 OpenSSL：

sign_policy() {
  local author_id=$1
  local sequence=$2
  local cedar_doc=$3
  local policy_id=$4
  export _HELPER_POLICY_ID="$policy_id"
  export _HELPER_SEQUENCE="$sequence"
  export _HELPER_CEDAR_DOC="$cedar_doc"
  python3 -c "import os; p='my-project'; l='us-central1'; i='mpc-unit-bob-123'; pol=os.environ.get('_HELPER_POLICY_ID'); s=int(os.environ.get('_HELPER_SEQUENCE')); d=os.environ.get('_HELPER_CEDAR_DOC'); n=f'projects/{p}/locations/{l}/instances/{i}/policyEngine/policies/{pol}'; payload=b'action:ACTIVE\n'+n.encode('utf-8')+b'sequence:'+s.to_bytes(8,'little')+b'cedar_document:'+d.encode('utf-8'); open('payload.bin', 'wb').write(payload)"
  openssl dgst -sha256 -sign "${author_id}_priv.pem" -out policy_sig.bin payload.bin
  openssl base64 -A -in policy_sig.bin
}

# Sign as Author 1 (Sequence 0)
QUORUM_SIGNATURE=$(sign_policy "author-dave" 0 'permit(principal == User::"alice", action == Action::"Transfer", resource == Resource::"mpc_operation") when { context.transaction.schema == "bitcoin.transaction.v2" && context.transaction.spend_amount_scaled <= 2500000 && context.transaction.max_fee_atomic <= 100000 };' "bitcoin-psbt-policy")

2. 调用 CreatePolicy API

# Check existence
if curl -s -f -o /dev/null -H "Authorization: Bearer $(gcloud auth application-default print-access-token)" \
  -H "X-Goog-User-Project: my-project" \
  "https://67317436-0f29-ba9e-9146-d11c0bd8df9b.us-central1.mpc.goog/v1alpha1/projects/my-project/locations/us-central1/instances/mpc-unit-bob-123/policyEngine/policies/bitcoin-psbt-policy"; then
  echo "Policy 'bitcoin-psbt-policy' already exists. Skipping creation."
else
  echo "Policy 'bitcoin-psbt-policy' not found. Creating..."
  curl -X POST \
    -H "Authorization: Bearer $(gcloud auth application-default print-access-token)" \
    -H "X-Goog-User-Project: my-project" \
    -H "Content-Type: application/json" \
    -d '{
      "displayName": "Bitcoin PSBT Permit Policy",
      "rule": {
        "cedarDocument": "permit(principal == User::\"alice\", action == Action::\"Transfer\", resource == Resource::\"mpc_operation\") when { context.transaction.schema == \"bitcoin.transaction.v2\" && context.transaction.spend_amount_scaled <= 2500000 && context.transaction.max_fee_atomic <= 100000 };"
      },
      "createAuthorSignature": {
        "authorId": "'"author-dave"'",
        "signature": "'"$QUORUM_SIGNATURE"'",
        "approvalTime": "'"$(date -u +"%Y-%m-%dT%H:%M:%SZ")"'"
      }
    }' \
  "https://67317436-0f29-ba9e-9146-d11c0bd8df9b.us-central1.mpc.goog/v1alpha1/projects/my-project/locations/us-central1/instances/mpc-unit-bob-123/policyEngine/policies?policy_id=bitcoin-psbt-policy" | jq
fi

C. 批准政策（转换为 ACTIVE）

如果您的政策设置需要 M-of-N 签名，则后续作者会调用 AddQuorumSignature。

如需生成签名，您必须先检索政策的当前序列。

以太坊

# 1. Get the policy state and sequence
POLICY_INFO=$(curl -s -H "Authorization: Bearer $(gcloud auth application-default print-access-token)" \
  -H "X-Goog-User-Project: my-project" \
  "https://67317436-0f29-ba9e-9146-d11c0bd8df9b.us-central1.mpc.goog/v1alpha1/projects/my-project/locations/us-central1/instances/mpc-unit-bob-123/policyEngine/policies/ethereum-transfer-policy")

POLICY_STATE=$(echo "$POLICY_INFO" | jq -r '.state // "UNKNOWN"')

if [ "$POLICY_STATE" == "PENDING_ACTIVE" ]; then
  POLICY_SEQUENCE=$(echo "$POLICY_INFO" | jq -r '.globalSequence // 0')
  echo "Policy Sequence: $POLICY_SEQUENCE"

  # 2. Sign as Author 2
  QUORUM_SIGNATURE_SEQ=$(sign_policy "author-eve" $POLICY_SEQUENCE 'permit(principal == User::"alice", action == Action::"Transfer", resource == Resource::"mpc_operation") when { context.transaction.to_address == "0x1111111111111111111111111111111111111111" && context.transaction.value_gwei <= 2000000000 };' "ethereum-transfer-policy")

  # 3. Call AddQuorumSignature
  curl -X POST \
    -H "Authorization: Bearer $(gcloud auth application-default print-access-token)" \
    -H "X-Goog-User-Project: my-project" \
    -H "Content-Type: application/json" \
    -d '{
      "name": "projects/my-project/locations/us-central1/instances/mpc-unit-bob-123/policyEngine/policies/ethereum-transfer-policy",
      "signature": {
        "authorId": "'"author-eve"'",
        "signature": "'"$QUORUM_SIGNATURE_SEQ"'",
        "approvalTime": "'"$(date -u +"%Y-%m-%dT%H:%M:%SZ")"'"
      }
    }' \
  "https://67317436-0f29-ba9e-9146-d11c0bd8df9b.us-central1.mpc.goog/v1alpha1/projects/my-project/locations/us-central1/instances/mpc-unit-bob-123/policyEngine/policies/ethereum-transfer-policy:addQuorumSignature" | jq
elif [ "$POLICY_STATE" == "ACTIVE" ]; then
  echo "Policy 'ethereum-transfer-policy' is already ACTIVE. Skipping signature."
else
  echo "Policy 'ethereum-transfer-policy' is in an unknown or unexpected state: $POLICY_STATE"
fi

比特币

# 1. Get the policy state and sequence
POLICY_INFO=$(curl -s -H "Authorization: Bearer $(gcloud auth application-default print-access-token)" \
  -H "X-Goog-User-Project: my-project" \
  "https://67317436-0f29-ba9e-9146-d11c0bd8df9b.us-central1.mpc.goog/v1alpha1/projects/my-project/locations/us-central1/instances/mpc-unit-bob-123/policyEngine/policies/bitcoin-psbt-policy")

POLICY_STATE=$(echo "$POLICY_INFO" | jq -r '.state // "UNKNOWN"')

if [ "$POLICY_STATE" == "PENDING_ACTIVE" ]; then
  POLICY_SEQUENCE=$(echo "$POLICY_INFO" | jq -r '.globalSequence // 0')
  echo "Policy Sequence: $POLICY_SEQUENCE"

  # 2. Sign as Author 2
  QUORUM_SIGNATURE_SEQ=$(sign_policy "author-eve" $POLICY_SEQUENCE 'permit(principal == User::"alice", action == Action::"Transfer", resource == Resource::"mpc_operation") when { context.transaction.schema == "bitcoin.transaction.v2" && context.transaction.spend_amount_scaled <= 2500000 && context.transaction.max_fee_atomic <= 100000 };' "bitcoin-psbt-policy")

  # 3. Call AddQuorumSignature
  curl -X POST \
    -H "Authorization: Bearer $(gcloud auth application-default print-access-token)" \
    -H "X-Goog-User-Project: my-project" \
    -H "Content-Type: application/json" \
    -d '{
      "name": "projects/my-project/locations/us-central1/instances/mpc-unit-bob-123/policyEngine/policies/bitcoin-psbt-policy",
      "signature": {
        "authorId": "'"author-eve"'",
        "signature": "'"$QUORUM_SIGNATURE_SEQ"'",
        "approvalTime": "'"$(date -u +"%Y-%m-%dT%H:%M:%SZ")"'"
      }
    }' \
  "https://67317436-0f29-ba9e-9146-d11c0bd8df9b.us-central1.mpc.goog/v1alpha1/projects/my-project/locations/us-central1/instances/mpc-unit-bob-123/policyEngine/policies/bitcoin-psbt-policy:addQuorumSignature" | jq
elif [ "$POLICY_STATE" == "ACTIVE" ]; then
  echo "Policy 'bitcoin-psbt-policy' is already ACTIVE. Skipping signature."
else
  echo "Policy 'bitcoin-psbt-policy' is in an unknown or unexpected state: $POLICY_STATE"
fi

第 4 步：创建密钥

现在，我们创建一个密钥环并生成一个分布式密钥。

A. 创建密钥环

MPC 密钥的逻辑分组。

curl

# Check existence
if curl -s -f -o /dev/null -H "Authorization: Bearer $(gcloud auth application-default print-access-token)" \
  -H "X-Goog-User-Project: my-project" \
  "https://67317436-0f29-ba9e-9146-d11c0bd8df9b.us-central1.mpc.goog/v1alpha1/projects/my-project/locations/us-central1/instances/mpc-unit-bob-123/mpc/keyRings/my-key-ring"; then
  echo "KeyRing 'my-key-ring' already exists. Skipping creation."
else
  echo "KeyRing 'my-key-ring' not found. Creating..."
  curl -X POST \
    -H "Authorization: Bearer $(gcloud auth application-default print-access-token)" \
    -H "X-Goog-User-Project: my-project" \
    -H "Content-Type: application/json" \
    -d '{}' \
  https://67317436-0f29-ba9e-9146-d11c0bd8df9b.us-central1.mpc.goog/v1alpha1/projects/my-project/locations/us-central1/instances/mpc-unit-bob-123/mpc/keyRings?key_ring_id=my-key-ring | jq
fi

B. 生成分布式密钥 (DKG)

发起异步仪式，在参与者之间生成分布式密钥。

curl

# Check existence
if curl -s -f -o /dev/null -H "Authorization: Bearer $(gcloud auth application-default print-access-token)" \
  -H "X-Goog-User-Project: my-project" \
  "https://67317436-0f29-ba9e-9146-d11c0bd8df9b.us-central1.mpc.goog/v1alpha1/projects/my-project/locations/us-central1/instances/mpc-unit-bob-123/mpc/keyRings/my-key-ring/keys/my-key"; then
  echo "Key 'my-key' already exists. Skipping generation."
else
  echo "Key 'my-key' not found. Generating..."
  curl -X POST \
    -H "Authorization: Bearer $(gcloud auth application-default print-access-token)" \
    -H "X-Goog-User-Project: my-project" \
    -H "Content-Type: application/json" \
    -d '{
      "threshold": 2,
      "algorithm": "ECDSA_SECP256K1",
      "participantShares": [
        {"participantId": "projects/my-project/locations/us-central1/instances/mpc-unit-bob-123/mpc/signers/signer-alice"},
        {"participantId": "projects/my-project/locations/us-central1/instances/mpc-unit-bob-123/mpc/signers/signer-bob"},
        {"participantId": "projects/my-project/locations/us-central1/instances/mpc-unit-bob-123/mpc/signers/signer-charlie"}
      ]
    }' \
  https://67317436-0f29-ba9e-9146-d11c0bd8df9b.us-central1.mpc.goog/v1alpha1/projects/my-project/locations/us-central1/instances/mpc-unit-bob-123/mpc/keyRings/my-key-ring/keys?key_id=my-key | jq
fi

此操作会返回一个长时间运行的操作 (LRO)。您必须等待密钥 state 变为 ACTIVE（这意味着 DKG 仪式已成功）。

🕵️‍♂️ 检查按键状态（轮询）

定期运行以下命令来轮询密钥状态，直到响应中的 state 字段变为 ACTIVE（表示 DKG 仪式已成功）。

curl

curl -X GET \
  -H "Authorization: Bearer $(gcloud auth application-default print-access-token)" \
  -H "X-Goog-User-Project: my-project" \
https://67317436-0f29-ba9e-9146-d11c0bd8df9b.us-central1.mpc.goog/v1alpha1/projects/my-project/locations/us-central1/instances/mpc-unit-bob-123/mpc/keyRings/my-key-ring/keys/my-key | jq

C. 派生区块链地址并定位 UTXO

当分布式密钥变为 ACTIVE 后，MPC 密钥即可使用。在此步骤中，您将从 MPC 密钥生成 (0x04 || X || Y) 返回的 65 字节未压缩公钥中派生出区块链专用地址，并找到交易所需的任何未花费资金。

以太坊

以太坊地址派生自 64 字节未压缩公钥点 (pub_bytes[1:]) 的 Keccak-256 哈希，取最后 20 个字节。

地址派生脚本 (`derive_address.py`)

执行以下代码块，以创建并运行 derive_address.py：

cat <<'EOF' > derive_address.py
import base64
from eth_utils import keccak, to_checksum_address

# Insert your base64 public_key from Step 4.B
PUBLIC_KEY_B64 = "your-public-key"

pub_bytes = base64.b64decode(PUBLIC_KEY_B64)
if len(pub_bytes) == 65 and pub_bytes[0] == 4:
    raw_addr = "0x" + keccak(pub_bytes[1:])[-20:].hex()
    checksummed_addr = to_checksum_address(raw_addr)
    print("Ethereum Address:", checksummed_addr)
else:
    print(f"Error: Expected 65-byte uncompressed key, got {len(pub_bytes)} bytes.")
EOF
python3 derive_address.py

为以太坊地址充值

在第 6 步中广播之前，请确保您的派生以太坊地址有足够的 Sepolia 测试网 ETH 来支付交易价值和 gas 费用。您可以将新派生的地址输入到 Ethereum Sepolia 水龙头中，申请免费的测试网 ETH。

比特币

比特币地址派生自未压缩的 65 字节 secp256k1 EC 公钥 (0x04 || X || Y)。同一公钥支持多种地址格式：

原生隔离见证 (P2WPKH / BIP 173)：Bech32 地址（主网上的 bc1q...，Testnet4 上的 tb1q...），具有 22 字节的见证 scriptPubKey (0014<hash160>)。这是推荐的现代格式，交易费用最低。
嵌套隔离见证 (P2SH-P2WPKH / BIP 49)：封装的隔离见证地址（主网上的 3...，Testnet4 上的 2...），具有 23 字节的 scriptPubKey (a914<hash160>87) 和 22 字节的 redeemScript (0014<hash160>)，与旧系统兼容。
Legacy (P2PKH / BIP 44)：原始 Pay-to-PubKey-Hash Base58 地址（主网上的 1...，Testnet4 上的 m/n...），具有 25 字节的 scriptPubKey (76a914<hash160>88ac)。

地址派生脚本 (`derive_btc_address.py`)

执行以下代码块，以创建并运行 derive_btc_address.py：

cat <<'EOF' > derive_btc_address.py
"""Derives Bitcoin addresses (Native SegWit, Nested SegWit, Legacy) from an MPC public key using embit."""

import base64
from embit import ec, script
from embit.networks import NETWORKS

# Insert the Base64-encoded public key from Step 4.B (publicKey field, decodes to 65 raw bytes)
PUBLIC_KEY_B64 = "your-public-key"

raw_bytes = base64.b64decode(PUBLIC_KEY_B64)
if len(raw_bytes) != 65 or raw_bytes[0] != 4:
  raise ValueError(f"Expected 65-byte uncompressed public key (0x04...), got {len(raw_bytes)} bytes")

# 1. Parse and compress public key to 33 bytes
pub = ec.PublicKey.parse(raw_bytes)
pub.compressed = True
compressed_pubkey_hex = pub.sec().hex()

print("================================================================")
print(f"Compressed Public Key (33 bytes): {compressed_pubkey_hex}")
print("================================================================")

# 2. Native SegWit (P2WPKH - BIP 173)
p2wpkh = script.p2wpkh(pub)
print("\n[1. Native SegWit (P2WPKH / Bech32 - BIP 173)]")
print(f"  ScriptPubKey:           {p2wpkh.data.hex()}")
print(f"  Testnet4 Address (tb):  {p2wpkh.address(NETWORKS['test'])}")
print(f"  Mainnet Address (bc):   {p2wpkh.address(NETWORKS['main'])}")

# 3. Nested SegWit (P2SH-P2WPKH - BIP 49)
p2sh_p2wpkh = script.p2sh(p2wpkh)
print("\n[2. Nested SegWit (P2SH-P2WPKH / Base58 - BIP 49)]")
print(f"  RedeemScript:           {p2wpkh.data.hex()}")
print(f"  ScriptPubKey:           {p2sh_p2wpkh.data.hex()}")
print(f"  Testnet4 Address (2):   {p2sh_p2wpkh.address(NETWORKS['test'])}")
print(f"  Mainnet Address (3):    {p2sh_p2wpkh.address(NETWORKS['main'])}")

# 4. Legacy (P2PKH - BIP 44)
p2pkh = script.p2pkh(pub)
print("\n[3. Legacy (P2PKH / Base58 - BIP 44)]")
print(f"  ScriptPubKey:           {p2pkh.data.hex()}")
print(f"  Testnet4 Address (m/n): {p2pkh.address(NETWORKS['test'])}")
print(f"  Mainnet Address (1):    {p2pkh.address(NETWORKS['main'])}")
EOF

python3 derive_btc_address.py

定位未花费的输出 (UTXO)

与基于账号的区块链不同，比特币交易会花费特定的未花费交易输出 (UTXO)。在第 5 步中构建事务之前：

为派生的原生隔离见证地址充值（例如，使用测试网水龙头）。
使用您的比特币节点 (bitcoin-cli listunspent 1 9999999 "[\"tb1q...\"]") 或区块浏览器 API 查询您地址的未花费 UTXO。
请注意第 5 步中的以下 4 个参数：
- txid：未花费输出的 32 字节交易哈希。
- vout：从零开始的输出索引（例如 0 或 1）。
- value：未花费的金额，以聪为单位（例如，200000 聪 = 0.002 BTC）。
- scriptPubKey：锁定脚本十六进制（例如 0014...）。

第 5 步：执行 MPC 操作

通过评估交易并创建提案来执行 MPC 操作。

A. 评估交易（获取授权令牌）

在对 MPC 操作进行签名之前，请根据您的政策对载荷进行授权，以接收 JWS 令牌和 32 字节的签名摘要。

以太坊

🛑 案例 A：拒绝（价值过高）

尝试授权一笔 3 ETH 的交易（超出 2 ETH 的限额）。

# Payload for 3 ETH (Hex equivalent contains value_gwei > 2B)
RAW_TX_BYTES_HEX="ef808504a817c8008252089411111111111111111111111111111111111111118829a2241af62c00008083aa36a78080"

curl -X POST \
  -H "Authorization: Bearer $(gcloud auth application-default print-access-token)" \
  -H "X-Goog-User-Project: my-project" \
  -H "Content-Type: application/json" \
  -d '{
    "principal": "User::\"alice\"",
    "action": "Action::\"Transfer\"",
    "resource": "Resource::\"mpc_operation\"",
    "schema": "ETHEREUM_TX_V1",
    "payload": "'"$RAW_TX_BYTES_HEX"'"
  }' \
https://67317436-0f29-ba9e-9146-d11c0bd8df9b.us-central1.mpc.goog/v1alpha1/projects/my-project/locations/us-central1/instances/mpc-unit-bob-123/policyEngine:authorizePayload | jq

预期响应：decision: DENY

✅ 情况 B：批准（允许的值）

尝试授权一笔 1 Gwei 的交易（在 2 ETH 限额内）。

# Payload for 1 Gwei
RAW_TX_BYTES_HEX="eb808504a817c800825208941111111111111111111111111111111111111111843b9aca008083aa36a78080"

RESPONSE=$(curl -s -X POST \
  -H "Authorization: Bearer $(gcloud auth application-default print-access-token)" \
  -H "X-Goog-User-Project: my-project" \
  -H "Content-Type: application/json" \
  -d '{
    "principal": "User::\"alice\"",
    "action": "Action::\"Transfer\"",
    "resource": "Resource::\"mpc_operation\"",
    "schema": "ETHEREUM_TX_V1",
    "payload": "'"$RAW_TX_BYTES_HEX"'"
  }' \
https://67317436-0f29-ba9e-9146-d11c0bd8df9b.us-central1.mpc.goog/v1alpha1/projects/my-project/locations/us-central1/instances/mpc-unit-bob-123/policyEngine:authorizePayload)

echo "$RESPONSE" | jq

# Automatically capture variables for next steps
DIGEST_HEX=$(echo "$RESPONSE" | jq -r .digest)
POLICY_ENGINE_TOKEN=$(echo "$RESPONSE" | jq -r .token)

# Convert to Base64 (which curl expects for bytes fields)
DIGEST_B64=$(python3 -c "import base64; print(base64.b64encode(bytes.fromhex('$DIGEST_HEX')).decode('utf-8'))")
POLICY_ENGINE_TOKEN_B64=$(python3 -c "import base64; print(base64.b64encode('$POLICY_ENGINE_TOKEN'.encode('utf-8')).decode('utf-8'))")

预期响应：decision: PERMIT以及 token。

比特币

在比特币 UTXO 模型中，交易会花费特定的未花费输出。在 SegWit (BIP 143) 中，计算签名哈希需要知道所花费输入的聪金额和锁定脚本。

政策引擎要求使用 BIP 174 PSBT v0 格式 (BITCOIN_TX_V2)，并为每个输入填充 PSBT_IN_WITNESS_UTXO。

PSBT 构建脚本 (`build_psbt.py`)

执行以下代码块，组装有效的 BIP 174 PSBT v0 载荷：

cat <<'EOF' > build_psbt.py
"""Constructs a BIP 174 PSBT v0 payload using embit for Bitcoin policy evaluation."""

from embit import script, transaction
from embit.psbt import PSBT

# 1. Inputs (From Step 4.C)
PREV_TXID_HEX = "8f594f33156993f1c980c2273dcae4a92cf2517fbc29264421395e63a63916d8"
PREV_VOUT = int("1")
INPUT_VALUE_SATS = int("200000")  # Total UTXO input value in satoshis
SENDER_SCRIPTPUBKEY_HEX = "0014eced05cd51d964102a20c856b09080ad620e9da2"

# 2. Output Allocations
RECIPIENT_SATS = int("50000")  # Recipient payment in satoshis
MINER_FEE_SATS = int("250")  # Miner fee in satoshis
RECIPIENT_SCRIPTPUBKEY_HEX = "0014751e76e8199196d454941c45d1b3a323f1433bd6"

# Change Output calculation: InputSats - RecipientSats - MinerFeeSats
CHANGE_SATS = INPUT_VALUE_SATS - RECIPIENT_SATS - MINER_FEE_SATS
if CHANGE_SATS <= 0:
  raise ValueError(f"Insufficient input satoshis ({INPUT_VALUE_SATS}) for payment and fee")

# 3. Construct Unsigned Transaction (Version 2, 1 input, 2 outputs, locktime 0)
tx = transaction.Transaction(
    version=2,
    vin=[transaction.TransactionInput(
        txid=bytes.fromhex(PREV_TXID_HEX),
        vout=PREV_VOUT,
        sequence=0xFFFFFFFF,
    )],
    vout=[
        transaction.TransactionOutput(
            value=RECIPIENT_SATS,
            script_pubkey=script.Script(bytes.fromhex(RECIPIENT_SCRIPTPUBKEY_HEX)),
        ),
        transaction.TransactionOutput(
            value=CHANGE_SATS,
            script_pubkey=script.Script(bytes.fromhex(SENDER_SCRIPTPUBKEY_HEX)),
        ),
    ],
    locktime=0,
)

# 4. Package into BIP 174 PSBT with Input Witness UTXO
psbt = PSBT(tx)
psbt.inputs[0].witness_utxo = transaction.TransactionOutput(
    value=INPUT_VALUE_SATS,
    script_pubkey=script.Script(bytes.fromhex(SENDER_SCRIPTPUBKEY_HEX)),
)

print(psbt.serialize().hex())
EOF

BTC_PSBT_HEX=$(python3 build_psbt.py)
echo "Generated PSBT Hex (${#BTC_PSBT_HEX} chars):"
echo "$BTC_PSBT_HEX"

🛑 Case A: Rejection (Fee Limit Exceeded)

尝试授权一笔矿工费超过 10,000 聪政策限额的交易。在此示例中，在 build_psbt.py 中设置 MINER_FEE_SATS = 15000（和 CHANGE_SATS = 135000）会扩缩到 max_fee_atomic = 150000（超出政策上限 100000），从而生成以下载荷，触发政策引擎做出 DENY 决策。

# Construct a PSBT payload with miner_fee_sats = 15000 -> max_fee_atomic = 150000 (exceeds 100000 limit)
REJECTED_PSBT_HEX="70736274ff0100710200000001d81639a6635e3921442629bc7f51f22ca9e4ca3d27c280c9f1936915334f598f0100000000ffffffff0250c3000000000000160014751e76e8199196d454941c45d1b3a323f1433bd6580f020000000000160014eced05cd51d964102a20c856b09080ad620e9da2000000000001011f400d030000000000160014eced05cd51d964102a20c856b09080ad620e9da2000000"

curl -X POST \
  -H "Authorization: Bearer $(gcloud auth application-default print-access-token)" \
  -H "X-Goog-User-Project: my-project" \
  -H "Content-Type: application/json" \
  -d '{
    "principal": "User::\"alice\"",
    "action": "Action::\"Transfer\"",
    "resource": "Resource::\"mpc_operation\"",
    "schema": "BITCOIN_TX_V2",
    "payload": "'"$REJECTED_PSBT_HEX"'"
  }' \
https://67317436-0f29-ba9e-9146-d11c0bd8df9b.us-central1.mpc.goog/v1alpha1/projects/my-project/locations/us-central1/instances/mpc-unit-bob-123/policyEngine:authorizePayload | jq

预期响应：decision: DENY

✅ 情况 B：批准（允许的比特币 PSBT）

尝试授权之前构建的有效 PSBT（RECIPIENT_SATS = 50000 映射到 spend_amount_scaled = 500000 <= 2500000，MINER_FEE_SATS = 250 映射到 max_fee_atomic = 2500 <= 100000）。

RESPONSE=$(curl -s -X POST \
  -H "Authorization: Bearer $(gcloud auth application-default print-access-token)" \
  -H "X-Goog-User-Project: my-project" \
  -H "Content-Type: application/json" \
  -d '{
    "principal": "User::\"alice\"",
    "action": "Action::\"Transfer\"",
    "resource": "Resource::\"mpc_operation\"",
    "schema": "BITCOIN_TX_V2",
    "payload": "'"$BTC_PSBT_HEX"'"
  }' \
https://67317436-0f29-ba9e-9146-d11c0bd8df9b.us-central1.mpc.goog/v1alpha1/projects/my-project/locations/us-central1/instances/mpc-unit-bob-123/policyEngine:authorizePayload)

echo "$RESPONSE" | jq

# Automatically capture variables for next steps
DIGEST_HEX=$(echo "$RESPONSE" | jq -r .digest)
POLICY_ENGINE_TOKEN=$(echo "$RESPONSE" | jq -r .token)

# Convert to Base64 (which curl expects for bytes fields)
DIGEST_B64=$(python3 -c "import base64; print(base64.b64encode(bytes.fromhex('$DIGEST_HEX')).decode('utf-8'))")
POLICY_ENGINE_TOKEN_B64=$(python3 -c "import base64; print(base64.b64encode('$POLICY_ENGINE_TOKEN'.encode('utf-8')).decode('utf-8'))")

预期响应：decision: PERMIT，以及 JWS token 和 32 字节 BIP 143 sighash digest。

此操作会返回：

decision：PERMIT 或 DENY
token：JWS 政策令牌（合规性证明）。
digest：采用十六进制编码的 32 字节签名摘要。
evaluatedPolicyIds：已评估且影响决策的政策。

B. 创建提案（发起签署）

提供摘要载荷以供签名，并附上在第 5A 步中收到的政策引擎令牌。

curl

# Check existence
if curl -s -f -o /dev/null -H "Authorization: Bearer $(gcloud auth application-default print-access-token)" \
  -H "X-Goog-User-Project: my-project" \
  "https://67317436-0f29-ba9e-9146-d11c0bd8df9b.us-central1.mpc.goog/v1alpha1/projects/my-project/locations/us-central1/instances/mpc-unit-bob-123/mpc/keyRings/my-key-ring/keys/my-key/proposals/my-proposal"; then
  echo "Proposal 'my-proposal' already exists. Skipping creation."
else
  echo "Proposal 'my-proposal' not found. Creating..."
  curl -X POST \
    -H "Authorization: Bearer $(gcloud auth application-default print-access-token)" \
    -H "X-Goog-User-Project: my-project" \
    -H "Content-Type: application/json" \
    -d '{
      "digest": "'"$DIGEST_B64"'",
      "keyVersion": "projects/my-project/locations/us-central1/instances/mpc-unit-bob-123/mpc/keyRings/my-key-ring/keys/my-key/versions/1",
      "initiator": "projects/my-project/locations/us-central1/instances/mpc-unit-bob-123/mpc/signers/signer-alice",
      "policyApproverSignature": "'"$POLICY_ENGINE_TOKEN_B64"'"
    }' \
  https://67317436-0f29-ba9e-9146-d11c0bd8df9b.us-central1.mpc.goog/v1alpha1/projects/my-project/locations/us-central1/instances/mpc-unit-bob-123/mpc/keyRings/my-key-ring/keys/my-key/proposals?proposal_id=my-proposal | jq
fi

此操作会返回一个长时间运行的操作 (LRO)。预期的 Proposal state 将为 PENDING_ASSENT（表示已准备好供参与者签署）。

🕵️‍♂️ 检查提案状态（轮询）

定期运行以下命令，轮询提案状态。

curl

curl -X GET \
  -H "Authorization: Bearer $(gcloud auth application-default print-access-token)" \
  -H "X-Goog-User-Project: my-project" \
https://67317436-0f29-ba9e-9146-d11c0bd8df9b.us-central1.mpc.goog/v1alpha1/projects/my-project/locations/us-central1/instances/mpc-unit-bob-123/mpc/keyRings/my-key-ring/keys/my-key/proposals/my-proposal | jq

C. 记录参与者的决定（同意）

参与者必须使用其本地私钥（密钥共享）对提案哈希进行签名，并转发同意。

1. 签署提案摘要

Cloud KMS

sign_digest() {
  local signer_id=$1
  local digest_hex=$2

  local digest_b64=$(python3 -c "import base64, sys; print(base64.b64encode(bytes.fromhex('$digest_hex')).decode('utf-8'))")

  # Direct API calls are used here because the input is already a pre-computed 32-byte digest from the MPC.
  # Tools like gcloud assume input is raw data and apply a redundant hashing layer, altering the payload.
  # Unlike Policy signings which hash raw administrative text, Proposal signatures must sign this exact 32-byte hash as-is.
  curl -s -X POST \
    -H "Authorization: Bearer $(gcloud auth application-default print-access-token)" \
    -H "Content-Type: application/json" \
    -d "{\"digest\": {\"sha256\": \"$digest_b64\"}}" \
  https://cloudkms.googleapis.com/v1/projects/my-project/locations/us-central1/keyRings/mpc-assent-keys/cryptoKeys/${signer_id}-key/cryptoKeyVersions/1:asymmetricSign | jq -r .signature
}

SIGNER_2_SIG_B64=$(sign_digest "signer-bob" "$DIGEST_HEX")
SIGNER_3_SIG_B64=$(sign_digest "signer-charlie" "$DIGEST_HEX")

OpenSSL

sign_digest() {
  local signer_id=$1
  local digest_hex=$2

  python3 -c "import sys; sys.stdout.buffer.write(bytes.fromhex('$digest_hex'))" > digest.bin

  openssl pkeyutl -sign -inkey "${signer_id}_priv.pem" -in digest.bin -out digest_sig.bin

  openssl base64 -A -in digest_sig.bin
}

SIGNER_2_SIG_B64=$(sign_digest "signer-bob" "$DIGEST_HEX")
SIGNER_3_SIG_B64=$(sign_digest "signer-charlie" "$DIGEST_HEX")

2. 记录决策

curl

# 1. Check state for Signer 2
PROPOSAL_INFO=$(curl -s -H "Authorization: Bearer $(gcloud auth application-default print-access-token)" \
  -H "X-Goog-User-Project: my-project" \
  "https://67317436-0f29-ba9e-9146-d11c0bd8df9b.us-central1.mpc.goog/v1alpha1/projects/my-project/locations/us-central1/instances/mpc-unit-bob-123/mpc/keyRings/my-key-ring/keys/my-key/proposals/my-proposal")

PROPOSAL_STATE=$(echo "$PROPOSAL_INFO" | jq -r '.state // "UNKNOWN"')

if [ "$PROPOSAL_STATE" == "PENDING_ASSENT" ]; then
  echo "Recording assent for Signer 2..."
  curl -X POST \
    -H "Authorization: Bearer $(gcloud auth application-default print-access-token)" \
    -H "X-Goog-User-Project: my-project" \
    -H "Content-Type: application/json" \
    -d '{
      "signature": "'"$SIGNER_2_SIG_B64"'",
      "decision": "ASSENT",
      "participant": "signer-bob"
    }' \
  https://67317436-0f29-ba9e-9146-d11c0bd8df9b.us-central1.mpc.goog/v1alpha1/projects/my-project/locations/us-central1/instances/mpc-unit-bob-123/mpc/keyRings/my-key-ring/keys/my-key/proposals/my-proposal:recordParticipantDecision | jq
elif [ "$PROPOSAL_STATE" == "READY" ] || [ "$PROPOSAL_STATE" == "SUCCEEDED" ]; then
  echo "Proposal is in state $PROPOSAL_STATE. Skipping Signer 2."
else
  echo "Proposal is in an unknown or unexpected state: $PROPOSAL_STATE"
fi

# 2. Re-check state for Signer 3 (Signer 2 might have triggered a state change)
PROPOSAL_INFO=$(curl -s -H "Authorization: Bearer $(gcloud auth application-default print-access-token)" \
  -H "X-Goog-User-Project: my-project" \
  "https://67317436-0f29-ba9e-9146-d11c0bd8df9b.us-central1.mpc.goog/v1alpha1/projects/my-project/locations/us-central1/instances/mpc-unit-bob-123/mpc/keyRings/my-key-ring/keys/my-key/proposals/my-proposal")

PROPOSAL_STATE=$(echo "$PROPOSAL_INFO" | jq -r '.state // "UNKNOWN"')

if [ "$PROPOSAL_STATE" == "PENDING_ASSENT" ]; then
  echo "Recording assent for Signer 3..."
  curl -X POST \
    -H "Authorization: Bearer $(gcloud auth application-default print-access-token)" \
    -H "X-Goog-User-Project: my-project" \
    -H "Content-Type: application/json" \
    -d '{
      "signature": "'"$SIGNER_3_SIG_B64"'",
      "decision": "ASSENT",
      "participant": "signer-charlie"
    }' \
  https://67317436-0f29-ba9e-9146-d11c0bd8df9b.us-central1.mpc.goog/v1alpha1/projects/my-project/locations/us-central1/instances/mpc-unit-bob-123/mpc/keyRings/my-key-ring/keys/my-key/proposals/my-proposal:recordParticipantDecision | jq
elif [ "$PROPOSAL_STATE" == "READY" ] || [ "$PROPOSAL_STATE" == "SUCCEEDED" ]; then
  echo "Proposal is in state $PROPOSAL_STATE. Skipping Signer 3."
else
  echo "Proposal is in an unknown or unexpected state: $PROPOSAL_STATE"
fi

D. 提取最终签名

达到同意阈值后，请检查提案状态或获取签名。

curl

curl -X GET \
  -H "Authorization: Bearer $(gcloud auth application-default print-access-token)" \
  -H "X-Goog-User-Project: my-project" \
https://67317436-0f29-ba9e-9146-d11c0bd8df9b.us-central1.mpc.goog/v1alpha1/projects/my-project/locations/us-central1/instances/mpc-unit-bob-123/mpc/keyRings/my-key-ring/keys/my-key/proposals/my-proposal | jq

如果提案处于 SUCCEEDED 状态，请查看返回的 JSON 中的 finalSignature 字段。

第 6 步：将交易广播到区块链

当您的提案达到 SUCCEEDED 状态并且您已提取 finalSignature 后，最后一步是构建已签名的网络交易并将其广播到网络。

以太坊

恢复标识符派生和广播

MPC API 会返回原始 64 字节 ECDSA 签名（包含 r 和 s 值）。服务器会确保签名采用规范的 low-s 形式 (EIP-2)。不过，以太坊需要恢复标识符 (v) 来派生发送者的地址并验证签名，而标准的 64 字节 MPC 签名不会直接返回该标识符。

以下 Python 脚本可处理这种复杂情况。它会通过匹配您预期的发件人地址来动态确定正确的恢复位，构建有效的交易，并将其广播到网络。

广播脚本：

在终端中执行以下可复制粘贴的代码块，以编写并运行 broadcast_eth.py：

cat <<'EOF' > broadcast_eth.py
"""Broadcasts an Ethereum transaction using a normalized MPC signature."""

import base64
import os
import requests
from eth_account import Account
try:
    from eth_account._utils.transactions import encode_transaction, serializable_unsigned_transaction_from_dict
except ImportError:
    from eth_account._utils.legacy_transactions import encode_transaction, serializable_unsigned_transaction_from_dict

# ==========================================
# 1. INPUTS
# ==========================================
FINAL_SIGNATURE_B64 = "your-final-signature"
RPC_URL = "https://ethereum-sepolia-rpc.publicnode.com"
EXPECTED_SENDER = "0xyour-mpc-key-address"

if not FINAL_SIGNATURE_B64 or FINAL_SIGNATURE_B64 == "your-final-signature":
    raise ValueError("FINAL_SIGNATURE_B64 is not set. Please provide a valid signature.")

# ==========================================
# 2. TRANSACTION PARAMETERS
# ==========================================
CHAIN_ID = 11155111  # Sepolia Testnet
tx_dict = {
    "nonce": int("0"),
    "gasPrice": int("20000000000"),  # 20 Gwei
    "gas": int("21000"),
    "to": "0x1111111111111111111111111111111111111111",
    "value": int("1000000000"),  # 1 Gwei
    "data": b"",
    "chainId": CHAIN_ID,
}

# ==========================================
# 3. DECODE & SPLIT SIGNATURE
# ==========================================
missing_padding = len(FINAL_SIGNATURE_B64) % 4
if missing_padding:
    FINAL_SIGNATURE_B64 += "=" * (4 - missing_padding)

sig_bytes = base64.b64decode(FINAL_SIGNATURE_B64)
r = int.from_bytes(sig_bytes[:32], byteorder="big")
s = int.from_bytes(sig_bytes[32:], byteorder="big")

# ==========================================
# 4. RECOVERY IDENTIFIER (V) DERIVATION
# ==========================================
chain_v_base = (CHAIN_ID * 2) + 35

# ==========================================
# 5. GENERATE UNSIGNED TX & RECOVER SENDER ADDRESS
# ==========================================
unsigned_tx = serializable_unsigned_transaction_from_dict(tx_dict)

derived_sender = None
encoded_tx = None
final_v = chain_v_base

EXPECTED_SENDER_PLACEHOLDER = "0xyour-mpc-key-address"
is_valid_expected = EXPECTED_SENDER and EXPECTED_SENDER != EXPECTED_SENDER_PLACEHOLDER

for parity in [0, 1]:
    try_v = chain_v_base + parity
    try:
        tx_candidate = encode_transaction(unsigned_tx, vrs=(try_v, r, s))
        addr = Account.recover_transaction("0x" + tx_candidate.hex())

        if is_valid_expected and EXPECTED_SENDER.lower() == addr.lower():
            derived_sender = addr
            final_v = try_v
            encoded_tx = tx_candidate
            break

        if not is_valid_expected and derived_sender is None:
            derived_sender = addr
            final_v = try_v
            encoded_tx = tx_candidate
            print(f"Warning: EXPECTED_SENDER not provided or is placeholder. Assuming first recovered address: {addr}")

    except Exception:
        continue

if encoded_tx is None:
    if is_valid_expected:
        raise ValueError(f"Could not recover address matching EXPECTED_SENDER: {EXPECTED_SENDER}")
    else:
        raise ValueError("Could not derive broadcastable transaction. Ensure signature matches payload.")

if derived_sender:
    print(f"Derived Sender Address: {derived_sender}")
else:
    print("Derived Sender Address: Could not recover (ensure signature matches current transaction payload)")

valid_tx_hex = "0x" + encoded_tx.hex()
print(f"Broadcastable Transaction Hex:\n{valid_tx_hex}\n")

# ==========================================
# 6. BROADCAST TO NETWORK
# ==========================================
payload = {
    "jsonrpc": "2.0",
    "method": "eth_sendRawTransaction",
    "params": [valid_tx_hex],
    "id": 1,
}

print(f"Broadcasting to {RPC_URL}...")
response = requests.post(RPC_URL, json=payload)
resp_json = response.json()
print("RPC Response:", resp_json)
if "result" in resp_json:
    tx_hash = resp_json["result"]
    print(f"View transaction on Sepolia Etherscan: https://sepolia.etherscan.io/tx/{tx_hash}")
EOF

python3 broadcast_eth.py

问题排查常见错误

invalid sender: recovery failed 或 invalid transaction v, r, s values：如果脚本中的交易参数与已签名的载荷不完全匹配，就会发生这种情况。确保 value、nonce 和 to 字段与第 5 步中处理的内容一致。
insufficient funds for gas * price + value：您的交易在加密方面有效，并且已被节点接受，但您的 MPC 密钥的以太坊地址没有足够的测试网 ETH 来支付操作费用。您需要先为地址充值，然后才能广播。

比特币

SegWit 线路交易组装和广播

对于比特币原生隔离见证交易 (BIP 141)，必须将原始 64 字节 (r, s) MPC 签名格式化为规范的低 S ASN.1 DER，附加 0x01 (SIGHASH_ALL)，并与 33 字节压缩公钥一起组装到 2 元素隔离见证堆栈中：[DER signature || 0x01, compressed public key]。

广播脚本：

执行以下代码块，以创建并运行 broadcast_btc.py：

cat <<'EOF' > broadcast_btc.py
"""Assembles a signed Bitcoin Native SegWit transaction from an MPC signature using embit and broadcasts it."""

import base64
import urllib.request
from embit import ec, script, transaction

# ==========================================
# 1. INPUTS
# ==========================================
FINAL_SIGNATURE_B64 = "your-final-signature"
COMPRESSED_PUBKEY_HEX = "03deb76948c14003446a8c1d79e88fb3607c9bbc1f5143b186aa7b61d6b1facc36"

PREV_TXID_HEX = "8f594f33156993f1c980c2273dcae4a92cf2517fbc29264421395e63a63916d8"
PREV_VOUT = int("1")

RECIPIENT_SATS = int("50000")
RECIPIENT_SCRIPTPUBKEY_HEX = "0014751e76e8199196d454941c45d1b3a323f1433bd6"

CHANGE_SATS = int("149750")
CHANGE_SCRIPTPUBKEY_HEX = "0014eced05cd51d964102a20c856b09080ad620e9da2"

BROADCAST_API_URL = "https://mempool.space/testnet4/api/tx"

# ==========================================
# 2. CONVERT RAW (r, s) SIGNATURE TO CANONICAL LOW-S ASN.1 DER + SIGHASH_ALL
# ==========================================
sig_bytes = base64.b64decode(FINAL_SIGNATURE_B64)
internal_sig = ec.secp256k1.ecdsa_signature_parse_compact(sig_bytes)
ec.secp256k1.ecdsa_signature_normalize(internal_sig, internal_sig)
der_sig = ec.secp256k1.ecdsa_signature_serialize_der(internal_sig) + b"\x01"  # 0x01 = SIGHASH_ALL

# ==========================================
# 3. BUILD TRANSACTION & ATTACH SEGWIT WITNESS STACK
# ==========================================
tx = transaction.Transaction(
    version=2,
    vin=[transaction.TransactionInput(
        txid=bytes.fromhex(PREV_TXID_HEX),
        vout=PREV_VOUT,
        sequence=0xFFFFFFFF,
    )],
    vout=[
        transaction.TransactionOutput(
            value=RECIPIENT_SATS,
            script_pubkey=script.Script(bytes.fromhex(RECIPIENT_SCRIPTPUBKEY_HEX)),
        ),
        transaction.TransactionOutput(
            value=CHANGE_SATS,
            script_pubkey=script.Script(bytes.fromhex(CHANGE_SCRIPTPUBKEY_HEX)),
        ),
    ],
    locktime=0,
)

pubkey_bytes = bytes.fromhex(COMPRESSED_PUBKEY_HEX)
tx.vin[0].witness = transaction.Witness([der_sig, pubkey_bytes])

signed_tx_hex = tx.serialize().hex()
print("--- Signed Bitcoin SegWit Wire Transaction Hex ---")
print(signed_tx_hex)

# ==========================================
# 4. BROADCAST TO NETWORK
# ==========================================
if BROADCAST_API_URL:
  print(f"\nBroadcasting to {BROADCAST_API_URL}...")
  try:
    req = urllib.request.Request(
        BROADCAST_API_URL,
        data=signed_tx_hex.encode("utf-8"),
        headers={"Content-Type": "text/plain"},
        method="POST",
    )
    with urllib.request.urlopen(req) as resp:
      txid_result = resp.read().decode("utf-8").strip()
      print(f"✅ Broadcast Successful! Transaction ID (txid): {txid_result}")
      print(f"Track in Mempool Explorer: https://mempool.space/testnet4/tx/{txid_result}")
  except Exception as e:
    print(f"Broadcast response: {e}")
EOF

python3 broadcast_btc.py

问题排查常见错误

mandatory-script-verify-flag-failed (Signature must be zero for failed CHECK(MULTI)SIG operation) / non-mandatory-script-verify-flag (Non-canonical DER signature)：确保签名的 s 组件采用规范的 low-s 形式 (s <= N/2)，并经过正确的 DER 编码。
bad-txns-in-belowout / bad-txns-fee-negative：总输出超过输入值。确保您的变化量计算结果 (InputSatoshis - PaymentSatoshis - MinerFee) 严格为正数。

📖 附录：运维实战宝典（查询和检查）

您可以使用这些只读命令随时检查资源的状态。

👥 1. 参与者和签名者

检查实例中的参与者和签名者。

A. 列出所有已注册的参与者

curl

curl -H "Authorization: Bearer $(gcloud auth application-default print-access-token)" \
  -H "X-Goog-User-Project: my-project" \
https://67317436-0f29-ba9e-9146-d11c0bd8df9b.us-central1.mpc.goog/v1alpha1/projects/my-project/locations/us-central1/instances/mpc-unit-bob-123/mpc/signers | jq

B. 获取特定参与者的详细信息

curl

curl -H "Authorization: Bearer $(gcloud auth application-default print-access-token)" \
  -H "X-Goog-User-Project: my-project" \
https://67317436-0f29-ba9e-9146-d11c0bd8df9b.us-central1.mpc.goog/v1alpha1/projects/my-project/locations/us-central1/instances/mpc-unit-bob-123/mpc/signers/signer-alice | jq

📜 2. 政策引擎

检查政策和信任包。

A. 获取政策作者信任包

curl

curl -H "Authorization: Bearer $(gcloud auth application-default print-access-token)" \
  -H "X-Goog-User-Project: my-project" \
https://67317436-0f29-ba9e-9146-d11c0bd8df9b.us-central1.mpc.goog/v1alpha1/projects/my-project/locations/us-central1/instances/mpc-unit-bob-123/policyEngine/policyAuthorTrustBundle | jq

B. 列出所有政策

curl

curl -H "Authorization: Bearer $(gcloud auth application-default print-access-token)" \
  -H "X-Goog-User-Project: my-project" \
https://67317436-0f29-ba9e-9146-d11c0bd8df9b.us-central1.mpc.goog/v1alpha1/projects/my-project/locations/us-central1/instances/mpc-unit-bob-123/policyEngine/policies | jq

C. 获取特定政策的详细信息

curl

curl -H "Authorization: Bearer $(gcloud auth application-default print-access-token)" \
  -H "X-Goog-User-Project: my-project" \
https://67317436-0f29-ba9e-9146-d11c0bd8df9b.us-central1.mpc.goog/v1alpha1/projects/my-project/locations/us-central1/instances/mpc-unit-bob-123/policyEngine/policies/ethereum-transfer-policy | jq

🔑 3. 密钥和密钥环

检查密钥环和密钥。

A. 列出所有 KeyRing

curl

curl -H "Authorization: Bearer $(gcloud auth application-default print-access-token)" \
  -H "X-Goog-User-Project: my-project" \
https://67317436-0f29-ba9e-9146-d11c0bd8df9b.us-central1.mpc.goog/v1alpha1/projects/my-project/locations/us-central1/instances/mpc-unit-bob-123/mpc/keyRings | jq

B. 列出密钥环中的所有密钥

curl

curl -H "Authorization: Bearer $(gcloud auth application-default print-access-token)" \
  -H "X-Goog-User-Project: my-project" \
https://67317436-0f29-ba9e-9146-d11c0bd8df9b.us-central1.mpc.goog/v1alpha1/projects/my-project/locations/us-central1/instances/mpc-unit-bob-123/mpc/keyRings/my-key-ring/keys | jq

C. 获取特定分布式密钥的状态（DKG 状态）

curl

curl -H "Authorization: Bearer $(gcloud auth application-default print-access-token)" \
  -H "X-Goog-User-Project: my-project" \
https://67317436-0f29-ba9e-9146-d11c0bd8df9b.us-central1.mpc.goog/v1alpha1/projects/my-project/locations/us-central1/instances/mpc-unit-bob-123/mpc/keyRings/my-key-ring/keys/my-key | jq

📝 4. 提案（签名操作）

检查提案和签署状态。

A. 列出密钥的所有提案

curl

curl -H "Authorization: Bearer $(gcloud auth application-default print-access-token)" \
  -H "X-Goog-User-Project: my-project" \
https://67317436-0f29-ba9e-9146-d11c0bd8df9b.us-central1.mpc.goog/v1alpha1/projects/my-project/locations/us-central1/instances/mpc-unit-bob-123/mpc/keyRings/my-key-ring/keys/my-key/proposals | jq

B. 获取特定提案的详细信息或状态

curl

curl -H "Authorization: Bearer $(gcloud auth application-default print-access-token)" \
  -H "X-Goog-User-Project: my-project" \
https://67317436-0f29-ba9e-9146-d11c0bd8df9b.us-central1.mpc.goog/v1alpha1/projects/my-project/locations/us-central1/instances/mpc-unit-bob-123/mpc/keyRings/my-key-ring/keys/my-key/proposals/my-proposal | jq

Multi-party Compute 用户指南 使用集合让一切井井有条 根据您的偏好保存内容并对其进行分类。

概览

前提条件

设置

必需设置

教程资源标签

第 1 步：生成同意密钥

A. 参与者密钥 (secp256k1)

Cloud KMS

OpenSSL

B. 政策作者密钥 (secp256k1)

Cloud KMS

OpenSSL

第 2 步：注册参与者

curl

第 3 步：配置政策引擎

A. 初始化政策作者信任包

curl

B. 创建政策 (PENDING_ACTIVE)

以太坊

比特币

C. 批准政策（转换为 ACTIVE）

以太坊

比特币

第 4 步：创建密钥

A. 创建密钥环

curl

B. 生成分布式密钥 (DKG)

curl

🕵️‍♂️ 检查按键状态（轮询）

curl

C. 派生区块链地址并定位 UTXO

以太坊

地址派生脚本 (derive_address.py)

为以太坊地址充值

比特币

地址派生脚本 (derive_btc_address.py)

定位未花费的输出 (UTXO)

第 5 步：执行 MPC 操作

A. 评估交易（获取授权令牌）

以太坊

🛑 案例 A：拒绝（价值过高）

✅ 情况 B：批准（允许的值）

比特币

PSBT 构建脚本 (build_psbt.py)

🛑 Case A: Rejection (Fee Limit Exceeded)

✅ 情况 B：批准（允许的比特币 PSBT）

B. 创建提案（发起签署）

curl

🕵️‍♂️ 检查提案状态（轮询）

curl

C. 记录参与者的决定（同意）

1. 签署提案摘要

Cloud KMS

OpenSSL

2. 记录决策

curl

D. 提取最终签名

curl

第 6 步：将交易广播到区块链

以太坊

恢复标识符派生和广播

问题排查常见错误

比特币

SegWit 线路交易组装和广播

问题排查常见错误

📖 附录：运维实战宝典（查询和检查）

👥 1. 参与者和签名者

A. 列出所有已注册的参与者

curl

B. 获取特定参与者的详细信息

curl

📜 2. 政策引擎

A. 获取政策作者信任包

curl

B. 列出所有政策

curl

C. 获取特定政策的详细信息

curl

🔑 3. 密钥和密钥环

Multi-party Compute 用户指南

地址派生脚本 (`derive_address.py`)

地址派生脚本 (`derive_btc_address.py`)

PSBT 构建脚本 (`build_psbt.py`)