AI agents call aes_decrypt to retrieve information from Crypto_MCP without modifying anything — typically the context-gathering step in research, monitoring, and reporting workflows, before the agent takes action elsewhere.
Decryption is a read operation that transforms encrypted data into plaintext form without side effects on the data itself. While decryption enables access to sensitive information, the tool itself performs no creation, modification, deletion, or execution of external operations. The severity is low because misuse primarily risks information disclosure rather than system compromise, data loss, or financial harm.
From the tool's definition Tool name 'aes_decrypt' and description 'decrypt text with aes' indicate a decryption operation that retrieves/queries data without modifying or deleting it.
Documented attack patterns abuse exactly the kind of access aes_decrypt gives an agent:
PolicyLayer is an MCP gateway — it sits between your AI agents and Crypto_MCP, and nothing reaches the server without passing your rules. This is the rule we recommend for aes_decrypt:
{
"version": "1",
"default": "deny",
"tools": {
"aes_decrypt": {}
}
}aes_decrypt is read-only, so it stays allowed — but everything else on the server is denied unless you say otherwise.
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decrypt text with aes. It is categorised as a Read tool in the Crypto_MCP MCP Server, which means it retrieves data without modifying state.
Register the Crypto_ MCP server in PolicyLayer and add a rule for aes_decrypt: allow, deny, rate-limit, or require approval. Point your MCP client at the PolicyLayer proxy URL and the rule is enforced on every call, before it reaches Crypto_MCP. Nothing to install.
aes_decrypt is a Read tool with low risk. Read-only tools are generally safe to allow by default.
Yes. Add a rate_limit block to the aes_decrypt rule in your PolicyLayer policy. For example, setting max: 10 and window: 60 limits the tool to 10 calls per minute. Rate limits are tracked per agent session and reset automatically.
Set action: deny in the PolicyLayer policy for aes_decrypt. The AI agent will receive a policy violation error and cannot call the tool. You can also include a reason field to explain why the tool is blocked.
aes_decrypt is provided by the Crypto_ MCP server (1595901624/crypto-mcp). PolicyLayer sits as a proxy in front of this server to enforce policies before tool calls reach the server.
Start from Crypto_MCP, add the rest of your stack, and see everything your agents can call. Then put policy on all of it.
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14 Crypto_MCP tools catalogued and risk-classified — across an index of 43,000+ MCP servers.