webcrypto/src/mechs/aes/aes_gcm.ts

import * as core from "webcrypto-core";
import { AesCrypto } from "./crypto";
import { AesCryptoKey } from "./key";
import { setCryptoKey, getCryptoKey } from "../storage";

export class AesGcmProvider extends core.AesGcmProvider {
  public async onGenerateKey(
    algorithm: AesKeyGenParams,
    extractable: boolean,
    keyUsages: KeyUsage[]
  ): Promise<CryptoKey> {
    const key = await AesCrypto.generateKey(
      {
        name: this.name,
        length: algorithm.length,
      },
      extractable,
      keyUsages
    );

    return setCryptoKey(key);
  }

  public async onEncrypt(
    algorithm: AesGcmParams,
    key: AesCryptoKey,
    data: ArrayBuffer
  ): Promise<ArrayBuffer> {
    return AesCrypto.encrypt(
      algorithm,
      getCryptoKey(key) as AesCryptoKey,
      new Uint8Array(data)
    );
  }

  public async onDecrypt(
    algorithm: AesGcmParams,
    key: AesCryptoKey,
    data: ArrayBuffer
  ): Promise<ArrayBuffer> {
    return AesCrypto.decrypt(
      algorithm,
      getCryptoKey(key) as AesCryptoKey,
      new Uint8Array(data)
    );
  }

  public async onExportKey(
    format: KeyFormat,
    key: AesCryptoKey
  ): Promise<JsonWebKey | ArrayBuffer> {
    return AesCrypto.exportKey(format, getCryptoKey(key) as AesCryptoKey);
  }

  public async onImportKey(
    format: KeyFormat,
    keyData: JsonWebKey | ArrayBuffer,
    algorithm: Algorithm,
    extractable: boolean,
    keyUsages: KeyUsage[]
  ): Promise<CryptoKey> {
    const res = await AesCrypto.importKey(
      format,
      keyData,
      { name: algorithm.name },
      extractable,
      keyUsages
    );
    return setCryptoKey(res);
  }

  public override checkCryptoKey(key: CryptoKey, keyUsage?: KeyUsage) {
    super.checkCryptoKey(key, keyUsage);
    if (!(getCryptoKey(key) instanceof AesCryptoKey)) {
      throw new TypeError("key: Is not a AesCryptoKey");
    }
  }
}