anchor.diff:    /// // on a trusted piece of paper, but receives the message and signature
     /// // from an untrusted source (thus, desires to verify the signature).
     /// final publicKey = await RsassaPkcs1V15PublicKey.importSpkiKey(
  -  ///   keyData: PemCodec(PemLabel.publicKey).decode(pemPublicKey),
  -  ///   hash: HashAlgorithm.sha256,
  -  ///   extractable: false,
  -  ///   usages: [KeyUsage.verify],
  +  ///   PemCodec(PemLabel.publicKey).decode(pemPublicKey),
  +  ///   sha256,
     /// );
     /// final isValid = await publicKey.verify(
  -  ///   signature: signature,
  -  ///   data: () async* {
  +  ///   signature,
  +  ///   () async* {
     ///     yield utf8.encode(message);
     ///   }(),
     /// );
  
positive.code: /// Key for signing/verifying with HMAC.
  ///
  /// An [HmacSecretKey] instance holds a symmetric secret key and a
  /// [HashAlgorithm], which can be used to create and verify HMAC signatures as
  /// specified in [FIPS PUB 180-4][1].
  ///
  /// Instances of [HmacSecretKey] can be imported using
  
negative.code:   ///
    /// // Generate a key-pair.
    /// final keyPair = await RsassaPkcs1V15PrivateKey.generateKey(
    ///   4096,
    ///   BigInt.from(65537),
    ///   sha256,
    /// );
    ///
    /// // Export public, so Alice can use it later.
  