# Package com.codename1.security

package com.codename1.security

Cryptographic primitives and conveniences: hashing, message authentication, symmetric/asymmetric encryption, digital signatures, JWTs, OTPs and random number generation.

##### What lives in this package

- `Hash` / `Hmac` -- pure-Java MD5, SHA-1, SHA-224, SHA-256, SHA-384, SHA-512 and HMAC variants. Available on every platform with identical output.
- `SecureRandom` -- wraps the platform CSPRNG.
- `Cipher` -- AES (CBC, GCM, ECB) and RSA (OAEP, PKCS#1) encryption. Backed by the platform's native crypto.
- `Signature` -- RSA and ECDSA digital signatures.
- `KeyGenerator` / `KeyPair` / `SecretKey` / `PublicKey` / `PrivateKey` -- key material containers and generators.
- `Jwt` -- JSON Web Token signing and verification (HS, RS and ES families).
- `Otp` -- RFC 4226/6238 HOTP and TOTP one-time passwords, compatible with standard authenticator apps.
- `Base32` -- 32-character encoding commonly used for OTP shared secrets. URL-safe Base64 (used by JWTs) lives on [com.codename1.util.Base64#encodeUrlSafe(byte[])] / `Base64.decodeUrlSafe(String)` so it can share the existing SIMD-optimized encoder.

For a segmented OTP input widget see `OtpField`.

##### Design notes

Hash and HMAC ship a built-in implementation written in portable Java so they work everywhere without depending on the platform's crypto stack -- they are also what JWT (HS family), HOTP and TOTP build on.

AES, RSA, digital signatures and the secure RNG go through the platform's native crypto provider via `CodenameOneImplementation`. The default implementation uses the JRE's `java.security` / `javax.crypto` via reflection, so JavaSE (simulator) and Android work out of the box. Other ports may override the bridge methods with direct native calls.

- Class
  Description
  AuthenticationOptions
  Configures a single call to `Biometrics.authenticate(AuthenticationOptions)`.
  Base32
  Base32 encoder/decoder per RFC 4648.
  BiometricError
  Typed error codes returned by `Biometrics` and `SecureStorage` when an asynchronous operation fails.
  BiometricException
  Thrown via the failure path of an `AsyncResource` returned by `Biometrics` or `SecureStorage` when the underlying biometric or keychain operation fails.
  Biometrics
  Entry point for biometric authentication (Touch ID, Face ID, fingerprint, Android `BiometricPrompt`).
  BiometricType
  Enumerates the biometric authentication modalities that may be available on a device.
  Cipher
  Convenience entry points for symmetric (AES) and asymmetric (RSA) encryption.
  CryptoException
  Thrown by classes in this package when a cryptographic operation fails.
  Hash
  Streaming and one-shot cryptographic hash (message digest) functions.
  Hmac
  Keyed-hash message authentication (HMAC, RFC 2104) on top of any hash algorithm supported by `Hash`.
  Jwt
  JSON Web Token (RFC 7519) signing and verification.
  Key
  Common base for every key type in the security package -- `SecretKey` for symmetric algorithms, `PublicKey` and `PrivateKey` for asymmetric ones.
  KeyGenerator
  Generates fresh cryptographic key material.
  KeyPair
  A matched pair of `PublicKey` / `PrivateKey`.
  Otp
  Counter-based (HOTP, RFC 4226) and time-based (TOTP, RFC 6238) one-time password generators.
  PrivateKey
  A private key -- paired with a `PublicKey` to form a key pair.
  PublicKey
  A public key -- paired with a `PrivateKey` to form a key pair.
  SecretKey
  A symmetric secret key.
  SecureRandom
  Cryptographically secure random number generator.
  SecureStorage
  Biometric-gated secure storage backed by the platform keychain.
  Signature
  Digital signature creation and verification.