nestjs-scrypt

A NestJS module providing a wrapper around NodeJS crypto.scrypt function.

How to use

Install it using your favorite packet manager:

pnpm i @coniface/nestjs-scrypt

yarn add @coniface/nestjs-scrypt

npm i @coniface/nestjs-scrypt

Declare the module in your NestJS App declaration:

import { ScryptModule } from '@coniface/nestjs-scrypt';

@Module({
  imports: [
    ScryptModule.forRoot({}),
  ],
  controllers: [],
  providers: [],
})
export class AppModule {}

You can also pass specific Scrypt params on module creation.

Then use the ScryptService to hash and verify passphrases:

import { ScryptService } from '@coniface/nestjs-scrypt';

@Injectable()
export class UsersService {
  constructor(
    private readonly scryptService: ScryptService,
  ) {}

  private async derivePassphrase(passphrase: string): Promise<Buffer> {
    const key = await this.scryptService.kdf(passphrase);
    return key;
  }

  private async verifyPassphrase(key: Buffer, passphrase: string): Promise<boolean> {
    const result = await this.scryptService.verify(key, passphrase);
    return result;
  }
}

How it works

Based on scrypt utility developed for Tarsnap.

Parameters

Scrypt computation parameters are:

• cost CPU/memory cost parameter. Must be a power of two greater than one.
• blockSize Block size parameter.
• parallelization Parallelization parameter.
• maxMemory Memory upper bound.

This module also accepts:

• maxMemoryFrac Maximum fraction of available RAM scrypt should use for computing.
• maxTime Maximum time in seconds scrypt should spend computing the derived key.

By default, the module will be called with:

import { ScryptModule } from '@coniface/nestjs-scrypt';

@Module({
  imports: [
    // Will compute cost, blockSize and parallelization for a scrypt computation of 100ms
    ScryptModule.forRoot({
      maxTime: 0.1,
      maxMemory: os.totalmem(),
      maxMemoryFrac: 0.5,
    }),
  ],
  controllers: [],
  providers: [],
})
export class AppModule {}

If you want to increase computation complexity to 1s, you could create the module like so:

import { ScryptModule } from '@coniface/nestjs-scrypt';

@Module({
  imports: [
    // Will compute cost, blockSize and parallelization for a scrypt computation of 1s
    ScryptModule.forRoot({
      maxTime: 1,
    }),
  ],
  controllers: [],
  providers: [],
})
export class AppModule {}

You could also manually specify parameters that fit your system and avoid the initial parameters computation:

import { ScryptModule } from '@coniface/nestjs-scrypt';

@Module({
  imports: [
    // Manually define scrypt parameters, no initial computation
    ScryptModule.forRoot({
      cost: 14,
      blockSize: 8,
      parallelization: 1,
      maxMemory: 32 * 1024 * 1024,
    }),
  ],
  controllers: [],
  providers: [],
})
export class AppModule {}

Module creation

If no scrypt params are explicitly defined, the module will compute the best params for a computation time of 0.1 seconds. If a maxTime is defined, the module will compute the best params for a computation time matching this maxTime.