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ECC Key Pair Generator & ECDSA Tool

A developer-friendly Elliptic Curve Cryptography (ECC) playground for generating keys, signing and verifying messages (ECDSA), and securely deriving shared secrets (ECDH) — all executed locally in your browser with no data sent to any server.

100% Client-Side Execution. No Data Sent to Server Secure

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We do not store, log any key you enter. This tool is intended for personal and educational use. We suggest not to use online tools to protect real production secrets.

How This ECC Tool Works

This tool provides a practical, browser-based implementation of Elliptic Curve Cryptography (ECC) using modern, audited JavaScript cryptographic libraries. All cryptographic operations are executed entirely on the client side — your keys and messages never leave your device.

Supported curves include secp256k1 (widely used in blockchain systems) and NIST P-256 (commonly used in TLS, certificates, and enterprise security).

ECDSA vs RSA – Cryptographic Comparison

ECDSA and RSA are both widely used public-key cryptographic algorithms, but they differ significantly in performance, key size, and security characteristics. The table below highlights the key differences to help you choose the right algorithm for your use case.

Aspect ECDSA (Elliptic Curve Digital Signature Algorithm) RSA (Rivest–Shamir–Adleman)
Cryptographic Basis Elliptic Curve Discrete Logarithm Problem (ECDLP) Integer Factorization Problem
Key Size (≈128-bit security) 256-bit 3072-bit
Signature Size ~64 bytes 256–384 bytes
Performance Fast signing, fast verification Slow signing, fast verification
Bandwidth Usage Low (small keys & signatures) High (large keys & signatures)
CPU & Memory Efficiency Highly efficient on mobile & embedded devices Resource-intensive for constrained devices
Security per Bit High Lower compared to ECC
Common Use Cases Blockchain, TLS, WebAuthn, IoT, Secure APIs Legacy systems, older TLS implementations, enterprise PKI
Key Generation Speed Fast Slow (large prime generation)
Forward Secrecy Support Yes (when used with ECDH) No (without additional protocols)
Modern Recommendation ✅ Strongly recommended for modern systems ⚠️ Acceptable for legacy compatibility

In modern cryptographic systems, ECDSA is generally preferred due to its smaller key sizes, better performance, and stronger security guarantees.

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Key Pair Generation

A key pair consists of a private key and a corresponding public key. The private key must be kept secret, while the public key can be shared freely.

  • Private Key: A randomly generated 256-bit value
  • Public Key: Derived mathematically from the private key

In this tool, keys are generated using a cryptographically secure random number generator and displayed in hexadecimal format.

Example (JavaScript)

// Generate a private key
const privateKey = curve.utils.randomPrivateKey();

// Derive the public key (uncompressed)
const publicKey = curve.getPublicKey(privateKey, false);

ECDSA – Digital Signatures

ECDSA (Elliptic Curve Digital Signature Algorithm) is used to prove the authenticity and integrity of a message. A signature is created using a private key and can be verified by anyone holding the corresponding public key.

Typical Use Cases
  • Authenticating API requests
  • Blockchain transactions
  • Software integrity verification
Signing a Message

const message = new TextEncoder().encode("Hello, ECC");
const signature = curve.sign(message, privateKey);

// Compact hex representation
const signatureHex = signature.toCompactHex();
Verifying a Signature

const isValid = curve.verify(
  signatureHex,
  message,
  publicKey
);

If the verification succeeds, it confirms that the message has not been altered and was signed by the holder of the private key.

ECDH – Secure Key Exchange

ECDH (Elliptic Curve Diffie–Hellman) allows two parties to derive the same shared secret over an insecure channel without ever transmitting the secret itself.

Each party combines their own private key with the other party’s public key to compute an identical shared secret.

Common Applications
  • Secure session key negotiation
  • End-to-end encrypted messaging
  • TLS and secure transport protocols
Example (JavaScript)

// Alice's private key + Bob's public key
const sharedSecret = curve.getSharedSecret(
  alicePrivateKey,
  bobPublicKey
);

// Derive a symmetric key (SHA-256)
const derivedKey = sha256(sharedSecret);

The derived key is typically used as input for symmetric encryption algorithms such as AES.

Security Notes & Best Practices

  • Never share or reuse private keys across environments
  • Use ECDSA for authentication, not encryption
  • Use ECDH only to derive keys, not as a direct encryption mechanism
  • Always hash shared secrets before using them as encryption keys
  • Prefer modern curves such as secp256k1 or P-256

This tool is intended for educational, testing, and development purposes. For production systems, always rely on well-audited cryptographic libraries and follow established security standards.

References

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