Seal Secrets Management

A development guide for Seal, a service that encrypts data and controls who can decrypt it using rules recorded on the Sui blockchain. It can protect data stored on services such as Walrus, IPFS, or S3.

In plain words
What is it for?
Use it to encrypt and decrypt private data, define access policies, manage encrypted files, and add Seal protection to web applications.
Why use it?
It provides a way to combine encryption with blockchain-based access rules instead of relying only on storage permissions.

Skill for Claude CodeCodex

Part of the sui-stack-dev plugin — 6 skills, 3 commands, 2 agents shipped together

Install

Getting it into your agent

One page per mod, every tool's command on it. A separate URL per tool would split the same page into five that compete with each other.

agentmods
npx agentmods add skills/0x-j/sui-stack-claude-code-plugin/seal-encryption
Any agent
npx skills add 0x-j/sui-stack-claude-code-plugin --skill seal-encryption
Clone the repo
git clone --depth 1 https://github.com/0x-j/sui-stack-claude-code-plugin

Made for: Claude Code, Codex.

Or install sui-stack-dev, the plugin that ships this one along with the rest of its 6 skills, 3 commands, 2 agents.

Per session 83 Skills are progressive disclosure: only the name and description are preloaded; the body loads when the skill is used.
When invoked 5,575 The whole file, excluding the scripts and references it only reads on demand.
Security scan A 0 findings. Scan, not verified.
Origin original No closer match found in the catalogue.
Token cost

What it costs to keep this loaded

Counted locally with the o200k_base tokenizer, which is exact for GPT models; Claude uses its own tokenizer and its counts differ. Treat this as one consistent yardstick across the catalogue rather than a bill. Prices are per million input tokens.

ModelPer sessionOnce invoked
Fable 5 $0.00083 $0.05575
Opus 5 $0.00042 $0.02788
Sonnet 5 $0.00017 $0.01115
Haiku 4.5 $0.00008 $0.00558

Measured 3d ago against content hash b343fa511951, method: parsed. Prices are Anthropic first-party input rates as of 2026-08-30, from the pricing page.

Security

Grade A, and why

Seal Secrets Management scanned grade A with 0 findings against 26 rules in 11 categories — prompt injection, anti-refusal, data exfiltration, privilege escalation, supply chain, agent snooping, system-prompt leakage, SSRF and excessive agency — measured 3d ago.

A static scan of the body, not an audit. Every finding is printed with the line that produced it so you can judge whether it matters here. A mod is markdown that instructs an agent; that is exactly why what it instructs is worth reading.

Nothing flagged

None of the 26 patterns this scan looks for appear in this file: no shell pipes, no recursive deletes, no credential paths, no hidden text, no instruction-override or anti-refusal phrasing, no agent-config snooping. That is not a guarantee, it is the absence of the things that are checkable.

skills/seal-encryption/SKILL.md · 878 lines

How it starts

The opening of the file, as written. The whole thing — 878 lines — stays where its author put it; the contents beside it link to each section on GitHub.

Seal Secrets Management

Provides expert guidance for using Seal, a decentralized secrets management (DSM) service that relies on access control policies defined and validated on Sui. Application developers and users can use Seal to secure sensitive data at rest on decentralized storage like Walrus, or on any other onchain/offchain storage.

Overview

Seal is a decentralized secrets management service that combines Sui blockchain's access control capabilities with encryption to protect sensitive data across any storage medium. Unlike traditional encryption libraries, Seal provides policy-based access management enforced by smart contracts on Sui.

Key features:

  • Sui-based access control - Define and validate access policies on Sui blockchain
  • Storage agnostic - Works with Walrus, IPFS, S3, onchain, or any storage
  • Policy enforcement - Smart contract-enforced access rules
  • Multiple encryption modes - Symmetric and asymmetric encryption
  • Decentralized key management - Distributed key handling without central authority
  • Streaming support - Encrypt large files efficiently
  • Browser compatible - Works in web applications

Use cases:

  • Secure sensitive data on Walrus or other decentralized storage
  • Encrypted onchain data with offchain access control
  • Private NFT metadata and assets
  • Confidential document sharing with policy-based access
  • Multi-party data access with Sui smart contract governance

Official documentation: https://seal-docs.wal.app/ and https://sdk.mystenlabs.com/seal

Note: Seal is a DSM service, not just an encryption library. Access policies are defined on Sui, providing decentralized, trustless access management.

Installation

Install Seal SDK

# Using npm
npm install @mysten/seal

# Using yarn
yarn add @mysten/seal

# Using pnpm
pnpm add @mysten/seal

Required Dependencies

# Seal typically requires Walrus SDK as well
npm install @mysten/walrus @mysten/sui

Encryption Basics

Read the full file on GitHub · 878 lines

Changes

What this file has done since we first saw it

Hashed on every crawl. A supply-chain change to an agent config is a question of when, not whether, so the history is kept rather than the latest state alone.

  1. 3d ago First seen · 878 lines · 83 tokens per session scan A b343fa511951

Subscribe to this mod's changes

Seal Secrets Management is a skill published in the GitHub repository 0x-j/sui-stack-claude-code-plugin (10 stars, last pushed 6mo ago), licensed MIT. It adds 83 tokens to every session and 5,575 once invoked, about $0.0004 per session on Opus 5. A static security scan graded it A with 0 findings. No closer match exists in the catalogue, so it is treated as the original; first seen 2026-08-31.