# Implementing Digital Signatures With Ed25519

> Ed25519 is a high-performance digital signature algorithm using the Edwards curve Curve25519. It provides 128-bit security with 64-byte signatures and 32-byte keys, offering significant advantages ove

- **Type:** Skill
- **Install:** `agentstack add skill-pinkpixel-dev-skills-collection-2-implementing-digital-signatures-with-ed25519`
- **Verified:** Yes — security-reviewed for prompt injection and unsafe behavior
- **Seller:** [pinkpixel-dev](https://agentstack.voostack.com/s/pinkpixel-dev)
- **Installs:** 0
- **Category:** [Agent Skills](https://agentstack.voostack.com/c/agent-skills)
- **Latest version:** 0.1.0
- **License:** MIT
- **Upstream author:** [pinkpixel-dev](https://github.com/pinkpixel-dev)
- **Source:** https://github.com/pinkpixel-dev/skills-collection-2/tree/main/SKILLS/implementing-digital-signatures-with-ed25519

## Install

```sh
agentstack add skill-pinkpixel-dev-skills-collection-2-implementing-digital-signatures-with-ed25519
```

Requires the [AgentStack CLI](https://agentstack.voostack.com/docs/cli). Works with Claude Code, Cursor, and any MCP-compatible agent.

## About

# Implementing Digital Signatures with Ed25519

## Overview

Ed25519 is a high-performance digital signature algorithm using the Edwards curve Curve25519. It provides 128-bit security with 64-byte signatures and 32-byte keys, offering significant advantages over RSA and ECDSA including deterministic signatures (no random nonce needed), resistance to side-channel attacks, and fast verification. This skill covers implementing Ed25519 for document signing, code signing, and API authentication.

## When to Use

- When deploying or configuring implementing digital signatures with ed25519 capabilities in your environment
- When establishing security controls aligned to compliance requirements
- When building or improving security architecture for this domain
- When conducting security assessments that require this implementation

## Prerequisites

- Familiarity with cryptography concepts and tools
- Access to a test or lab environment for safe execution
- Python 3.8+ with required dependencies installed
- Appropriate authorization for any testing activities

## Objectives

- Generate Ed25519 key pairs for signing
- Sign messages and files with Ed25519
- Verify signatures against public keys
- Implement multi-signature verification
- Build a simple code signing system
- Compare Ed25519 performance with RSA and ECDSA

## Key Concepts

### Ed25519 vs RSA vs ECDSA

| Property | Ed25519 | RSA-3072 | ECDSA P-256 |
|----------|---------|----------|-------------|
| Security | 128-bit | 128-bit | 128-bit |
| Public key size | 32 bytes | 384 bytes | 64 bytes |
| Signature size | 64 bytes | 384 bytes | 64 bytes |
| Key generation | ~50 us | ~100 ms | ~1 ms |
| Sign | ~70 us | ~5 ms | ~200 us |
| Verify | ~200 us | ~200 us | ~500 us |
| Deterministic | Yes | No (PSS) | No (unless RFC 6979) |

### Key Properties

- **Deterministic**: Same message + key always produces same signature
- **Collision-resistant**: No separate hash function needed
- **Side-channel resistant**: Constant-time implementation
- **Small keys**: 32 bytes each (public and private)

## Security Considerations

- Ed25519 does not support key recovery from signatures
- Verify the full message, not a hash (Ed25519 hashes internally)
- Public keys must be validated before use (check for low-order points)
- Private keys should be stored encrypted at rest
- Ed25519 is not yet approved for all NIST use cases (Ed448 is preferred for federal)

## Validation Criteria

- [ ] Key pair generation produces valid Ed25519 keys
- [ ] Signature verification succeeds for valid message
- [ ] Signature verification fails for tampered message
- [ ] Signature verification fails for wrong public key
- [ ] Deterministic: same input produces same signature
- [ ] File signing and verification works correctly
- [ ] Performance meets or exceeds RSA-3072

## Source & license

This open-source skill is cataloged on AgentStack and links to its original source — we do not rehost the code.

- **Author:** [pinkpixel-dev](https://github.com/pinkpixel-dev)
- **Source:** [pinkpixel-dev/skills-collection-2](https://github.com/pinkpixel-dev/skills-collection-2)
- **License:** MIT

Install and usage instructions live in the source repository linked above.

## Pricing

- **Free** — Free

## Security capabilities

Automated source analysis of v0.1.0 — what this tool can access:

- **Network access:** no
- **Filesystem access:** no
- **Shell / process execution:** no
- **Environment & secrets:** no
- **Dynamic code execution:** no

*"Yes" means the capability is present in the source — more access means more to trust, not that it is unsafe.*


## Versions

- **0.1.0** — security scan: passed — Imported from the upstream source.

## Links

- Listing page: https://agentstack.voostack.com/l/skill-pinkpixel-dev-skills-collection-2-implementing-digital-signatures-with-ed25519
- Seller: https://agentstack.voostack.com/s/pinkpixel-dev
- Browse the marketplace: https://agentstack.voostack.com/browse

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