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Signature

Unified cryptographic signature primitive supporting multiple algorithms (secp256k1, P-256, Ed25519).

New to ECDSA signatures? Start with Fundamentals to learn about secp256k1, signature components (r, s, v), signing/verification, malleability prevention, and common use cases.

Overview

Signature provides algorithm-agnostic signature handling with automatic metadata tracking. Supports ECDSA (secp256k1, P-256) and EdDSA (Ed25519) with format conversions (compact, DER). Key Features:

Multi-algorithm support (secp256k1, P-256, Ed25519)
Format conversions (compact, DER, RSV)
Signature validation and canonicalization
Public key recovery (secp256k1 only)
Zero-copy operations where possible
WASM acceleration available

Documentation

Core Operations

constructors - Create signatures from components, DER, compact formats, or algorithm-specific constructors
conversions - Convert between signature formats: compact, DER, RSV, and raw bytes
validation - Validate signatures, check canonicality, and prevent malleability attacks
recovery - Recover public keys and addresses from secp256k1 signatures using recovery ID
utilities - Extract components, compare signatures, and type guards

Formats

formats - Compare signature formats: compact (64B), DER (variable), RSV, and EIP-2098
eip-2098 - Compact 64-byte format with embedded recovery ID for gas savings

Advanced

usage-patterns - Real-world examples: Ethereum transactions, EIP-712, personal_sign
wasm - WASM-accelerated signature operations for improved performance
branded-signature - Type definition and metadata structure

Signature Format Comparison

Format	Size	Recovery	Use Case
Compact	64 bytes	❌ No	Standard ECDSA storage
Compact+V	65 bytes	✅ Yes	Ethereum transactions
DER	~70-72 bytes	❌ No	Bitcoin, X.509 certificates
EIP-2098	64 bytes	✅ Yes (embedded)	Gas-optimized Ethereum

See Signature Formats for detailed comparison.

Quick Reference

Quick Start

import { Signature, Hex } from 'tevm';

// Create from transaction components
const sig = Signature.fromSecp256k1(
  Hex.toBytes('0x1234...'), // r (32 bytes)
  Hex.toBytes('0x5678...'), // s (32 bytes)
  27                         // v (recovery ID)
);

// Or use universal constructor
const sig2 = Signature({
  r: rBytes,
  s: sBytes,
  v: 27,
  algorithm: 'secp256k1'
});

// Ensure canonical form (prevent malleability)
const canonical = Signature.normalize(sig);
console.log(Signature.isCanonical(canonical)); // true

// Convert between formats
const compact = Signature.toCompact(sig);    // 65 bytes (r + s + v)
const der = Signature.toDER(sig);            // ~70 bytes (ASN.1 encoded)

// Extract components
const r = Signature.getR(sig);  // 32 bytes
const s = Signature.getS(sig);  // 32 bytes
const v = Signature.getV(sig);  // 27 or 28

Effect Schema

import { SignatureSchema } from '@tevm/voltaire/Signature/effect'

// From compact bytes (64)
const bytes = new Uint8Array(64)
const sig = SignatureSchema.fromBytes(bytes)
sig.toHex()

Security Considerations

Signature Malleability

ECDSA signatures are malleable: both (r, s) and (r, -s mod n) are valid. Always normalize to prevent attacks:

// Wrong: Accept any signature
const address = Secp256k1.recoverAddress(sig, messageHash);

// Right: Normalize first
const canonical = Signature.normalize(sig);
const address = Secp256k1.recoverAddress(canonical, messageHash);

Standards:

Bitcoin BIP-62: Requires canonical low-s signatures
Ethereum: Enforces low-s in consensus rules
Best Practice: Always normalize before verification or storage

Recovery ID Validation

const v = Signature.getV(sig);

// Validate recovery ID range
if (v !== undefined && v !== 27 && v !== 28) {
  // Handle EIP-155 chain-specific v values
  const chainId = Math.floor((v - 35) / 2);
  const yParity = (v - 35) % 2;
  const standardV = 27 + yParity;
  // Create new signature with standard v...
}

Replay Attack Prevention

Ethereum uses EIP-155 to prevent cross-chain replay attacks:

// EIP-155 v encoding: v = chainId * 2 + 35 + yParity
const chainId = 1; // Mainnet
const yParity = v === 27 ? 0 : 1;
const eip155V = chainId * 2 + 35 + yParity; // 37 or 38

API Reference

Constructors

See Constructors for detailed documentation.

Signature.from(value) - Universal constructor
Signature.fromSecp256k1(r, s, v?) - secp256k1 ECDSA
Signature.fromP256(r, s) - P-256 ECDSA
Signature.fromEd25519(signature) - Ed25519
Signature.fromCompact(bytes, algorithm) - Compact format
Signature.fromDER(der, algorithm, v?) - DER encoding

Conversions

See Conversions for detailed documentation.

Signature.toBytes(signature) - Raw bytes (strips metadata)
Signature.toCompact(signature) - Compact format (64 or 65 bytes)
Signature.toDER(signature) - DER encoding (~70 bytes)

Validation

See Validation for detailed documentation.

Signature.isCanonical(signature) - Check if s ≤ n/2
Signature.normalize(signature) - Convert to canonical form

Component Extraction

See Utilities for detailed documentation.

Signature.getAlgorithm(signature) - Get algorithm
Signature.getR(signature) - Extract r component (32 bytes)
Signature.getS(signature) - Extract s component (32 bytes)
Signature.getV(signature) - Get recovery ID

Comparison

Signature.equals(a, b) - Compare signatures
Signature.is(value) - Type guard

Types

type SignatureAlgorithm = "secp256k1" | "p256" | "ed25519";

type BrandedSignature = Uint8Array & {
  readonly __tag: "Signature";
  readonly algorithm: SignatureAlgorithm;
  readonly v?: number; // Recovery ID for secp256k1 (27 or 28)
};

Constants

ECDSA_SIZE = 64;           // r + s
ECDSA_WITH_V_SIZE = 65;    // r + s + v
ED25519_SIZE = 64;         // Ed25519 signature
COMPONENT_SIZE = 32;       // r or s component
RECOVERY_ID_MIN = 27;      // Ethereum v value
RECOVERY_ID_MAX = 28;      // Ethereum v value

Errors

SignatureError - Base error class
InvalidSignatureLengthError - Invalid byte length
InvalidSignatureFormatError - Unsupported format
InvalidAlgorithmError - Invalid or unsupported algorithm
NonCanonicalSignatureError - Signature not canonical
InvalidDERError - DER encoding/decoding error

Structure

ECDSA (secp256k1, P-256)

Bytes: [r (32 bytes)][s (32 bytes)]
Metadata: algorithm, v (optional for secp256k1)

Ed25519

Bytes: [signature (64 bytes)]
Metadata: algorithm = 'ed25519'

Recovery ID (v)

27: First recovery attempt (Ethereum standard)
28: Second recovery attempt
Only applies to secp256k1
Not stored in signature bytes (metadata only)

Quick Start

import { Signature, Hex } from 'tevm';

// Create secp256k1 signature
const sig = Signature.fromSecp256k1(rBytes, sBytes, 27);

// Universal constructor
const sig2 = Signature({ r: rBytes, s: sBytes, v: 27 });

// Check algorithm
console.log(Signature.getAlgorithm(sig)); // "secp256k1"

// Normalize to canonical form
const canonical = Signature.normalize(sig);
console.log(Signature.isCanonical(canonical)); // true

// Convert to DER
const der = Signature.toDER(sig);

// Parse from DER
const parsed = Signature.fromDER(der, 'secp256k1', 27);

// Compare signatures
console.log(Signature.equals(sig, parsed)); // true

Complete Example

import { Signature, Address, Hash, Hex } from 'tevm';
import { Secp256k1, keccak256 } from 'tevm/crypto';

// 1. Parse Ethereum transaction signature
const tx = {
  r: '0x1234...',
  s: '0x5678...',
  v: 27
};

const sig = Signature.fromSecp256k1(
  Hex.toBytes(tx.r),
  Hex.toBytes(tx.s),
  tx.v
);

// 2. Validate and normalize (prevent malleability)
if (!Signature.isCanonical(sig)) {
  console.log('Non-canonical signature detected, normalizing...');
  sig = Signature.normalize(sig);
}

// 3. Verify signature structure
console.log('Algorithm:', Signature.getAlgorithm(sig)); // "secp256k1"
console.log('Recovery ID:', Signature.getV(sig));        // 27 or 28
console.log('Canonical:', Signature.isCanonical(sig));   // true

// 4. Recover signer address
const txHash = Hash(keccak256(encodedTxData));
const signer = Secp256k1.recoverAddress(sig, txHash);
console.log('Signer:', Address.toString(signer)); // "0x..."

// 5. Convert to different formats
const compact = Signature.toCompact(sig);  // 65 bytes (r + s + v)
const der = Signature.toDER(sig);          // ~70 bytes (DER encoded)

// 6. Round-trip verification
const parsed = Signature.fromDER(der, 'secp256k1', tx.v);
console.log('Equal:', Signature.equals(sig, parsed)); // true

External References

Signature (Effect) - Effect.ts integration with Schema validation
Secp256k1 Crypto - Signing and verification
Keccak256Hash - Message hashing
Address Primitive - Address types
Transaction Primitive - Transaction signing

Try it Live

​Signature

​Overview

​Documentation

​Core Operations

​Formats

​Advanced

​Signature Format Comparison

​Quick Reference

​Quick Start

​Effect Schema

​Security Considerations

​Signature Malleability

​Recovery ID Validation

​Replay Attack Prevention

​API Reference

​Constructors

​Conversions

​Validation

​Component Extraction

​Comparison

​Types

​Constants

​Errors

​Structure

​ECDSA (secp256k1, P-256)

​Ed25519

​Recovery ID (v)

​Quick Start

​Complete Example

​External References

​Related Documentation

Signature

Overview

Documentation

Core Operations

Formats

Advanced

Signature Format Comparison

Quick Reference

Quick Start

Effect Schema

Security Considerations

Signature Malleability

Recovery ID Validation

Replay Attack Prevention

API Reference

Constructors

Conversions

Validation

Component Extraction

Comparison

Types

Constants

Errors

Structure

ECDSA (secp256k1, P-256)

Ed25519

Recovery ID (v)

Quick Start

Complete Example

External References

Related Documentation