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tessl/npm-peculiar--webcrypto

A WebCrypto polyfill for Node.js that provides comprehensive cryptographic operations using standard Web Crypto API

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asymmetric-cryptography.mddocs/

Asymmetric Cryptography

Asymmetric cryptographic algorithms using key pairs (public and private keys) for encryption, decryption, digital signatures, and key agreement.

Capabilities

RSA Algorithms

RSA public-key cryptography for signatures and encryption with various padding schemes.

/**
 * RSA key generation parameters
 */
interface RsaKeyGenParams extends Algorithm {
  name: "RSASSA-PKCS1-v1_5" | "RSA-PSS" | "RSA-OAEP" | "RSAES-PKCS1-v1_5";
  modulusLength: 1024 | 2048 | 3072 | 4096;
  publicExponent: Uint8Array; // Usually [1, 0, 1] for 65537
}

interface RsaHashedKeyGenParams extends RsaKeyGenParams {
  hash: "SHA-1" | "SHA-256" | "SHA-384" | "SHA-512";
}

RSASSA-PKCS1-v1_5

RSA signatures with PKCS#1 v1.5 padding.

interface RsaPkcs1Params extends Algorithm {
  name: "RSASSA-PKCS1-v1_5";
}

RSA-PSS

RSA signatures with Probabilistic Signature Scheme padding.

interface RsaPssParams extends Algorithm {
  name: "RSA-PSS";
  saltLength: number; // Salt length in bytes
}

RSA-OAEP

RSA encryption with Optimal Asymmetric Encryption Padding.

interface RsaOaepParams extends Algorithm {
  name: "RSA-OAEP";
  label?: BufferSource; // Optional label
}

RSAES-PKCS1-v1_5

RSA encryption with PKCS#1 v1.5 padding (legacy compatibility).

interface RsaEsParams extends Algorithm {
  name: "RSAES-PKCS1-v1_5";
}

Usage Example:

// Generate RSA key pair
const keyPair = await crypto.subtle.generateKey(
  {
    name: "RSA-PSS",
    modulusLength: 2048,
    publicExponent: new Uint8Array([1, 0, 1]),
    hash: "SHA-256",
  },
  true,
  ["sign", "verify"]
);

// Sign data
const data = new TextEncoder().encode("Data to sign");
const signature = await crypto.subtle.sign(
  { name: "RSA-PSS", saltLength: 32 },
  keyPair.privateKey,
  data
);

// Verify signature
const isValid = await crypto.subtle.verify(
  { name: "RSA-PSS", saltLength: 32 },
  keyPair.publicKey,
  signature,
  data
);

Elliptic Curve Algorithms

Elliptic Curve cryptography for efficient signatures and key agreement.

/**
 * EC key generation parameters
 */
interface EcKeyGenParams extends Algorithm {
  name: "ECDSA" | "ECDH";
  namedCurve: "P-256" | "P-384" | "P-521" | "K-256" | string; // Includes Brainpool curves
}

ECDSA (Elliptic Curve Digital Signature Algorithm)

Digital signatures using elliptic curve cryptography.

interface EcdsaParams extends Algorithm {
  name: "ECDSA";
  hash: "SHA-1" | "SHA-256" | "SHA-384" | "SHA-512";
}

Usage Example:

// Generate ECDSA key pair
const keyPair = await crypto.subtle.generateKey(
  { name: "ECDSA", namedCurve: "P-256" },
  true,
  ["sign", "verify"]
);

// Sign with ECDSA
const data = new TextEncoder().encode("Message to sign");
const signature = await crypto.subtle.sign(
  { name: "ECDSA", hash: "SHA-256" },
  keyPair.privateKey,
  data
);

// Verify ECDSA signature
const isValid = await crypto.subtle.verify(
  { name: "ECDSA", hash: "SHA-256" },
  keyPair.publicKey,
  signature,
  data
);

ECDH (Elliptic Curve Diffie-Hellman)

Key agreement protocol for deriving shared secrets.

interface EcdhKeyDeriveParams extends Algorithm {
  name: "ECDH";
  public: CryptoKey; // Other party's public key
}

Usage Example:

// Generate key pairs for both parties
const aliceKeys = await crypto.subtle.generateKey(
  { name: "ECDH", namedCurve: "P-256" },
  false,
  ["deriveKey", "deriveBits"]
);

const bobKeys = await crypto.subtle.generateKey(
  { name: "ECDH", namedCurve: "P-256" },
  false,
  ["deriveKey", "deriveBits"]
);

// Derive shared key
const sharedKey = await crypto.subtle.deriveKey(
  { name: "ECDH", public: bobKeys.publicKey },
  aliceKeys.privateKey,
  { name: "AES-GCM", length: 256 },
  false,
  ["encrypt", "decrypt"]
);

Supported Curves

Standard Curves

  • P-256: NIST P-256 (secp256r1)
  • P-384: NIST P-384 (secp384r1)
  • P-521: NIST P-521 (secp521r1)
  • K-256: secp256k1 (Bitcoin curve)

Brainpool Curves

  • brainpoolP160r1, brainpoolP160t1
  • brainpoolP192r1, brainpoolP192t1
  • brainpoolP224r1, brainpoolP224t1
  • brainpoolP256r1, brainpoolP256t1
  • brainpoolP320r1, brainpoolP320t1
  • brainpoolP384r1, brainpoolP384t1
  • brainpoolP512r1, brainpoolP512t1

Key Classes

RSA Key Classes

class RsaPrivateKey extends AsymmetricKey {
  public algorithm: RsaHashedKeyAlgorithm;
  public type: "private";
  public usages: KeyUsage[];
  public extractable: boolean;
}

class RsaPublicKey extends AsymmetricKey {
  public algorithm: RsaHashedKeyAlgorithm;
  public type: "public"; 
  public usages: KeyUsage[];
  public extractable: boolean;
}

interface RsaHashedKeyAlgorithm extends KeyAlgorithm {
  name: "RSASSA-PKCS1-v1_5" | "RSA-PSS" | "RSA-OAEP" | "RSAES-PKCS1-v1_5";
  modulusLength: number;
  publicExponent: Uint8Array;
  hash: KeyAlgorithm;
}

EC Key Classes

class EcPrivateKey extends AsymmetricKey {
  public algorithm: EcKeyAlgorithm;
  public type: "private";
  public usages: KeyUsage[];
  public extractable: boolean;
}

class EcPublicKey extends AsymmetricKey {
  public algorithm: EcKeyAlgorithm;
  public type: "public";
  public usages: KeyUsage[];
  public extractable: boolean;
}

interface EcKeyAlgorithm extends KeyAlgorithm {
  name: "ECDSA" | "ECDH";
  namedCurve: string;
}

Install with Tessl CLI

npx tessl i tessl/npm-peculiar--webcrypto

docs

asymmetric-cryptography.md

crypto-interface.md

hash-functions.md

index.md

key-derivation.md

modern-cryptography.md

symmetric-encryption.md

tile.json