harmony 鸿蒙Key Derivation Using Scrypt

2025-06-12
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Key Derivation Using Scrypt

For details about the corresponding algorithm specifications, see Scrypt.

How to Develop

Create an ScryptSpec object and use it as a parameter for key derivation.

SCRYPTSpec is a child class of KdfSpec. You need to specify the following:

algName: algorithm to use, which is SCRYPT.
passphrase: original password used to generate the derived key. If the string type is used, pass in the data used for key derivation instead of the string type such as HexString or base64. In addition, ensure that the string is encoded in UTF-8 format. Otherwise, the derived key may be different from what you expected.
salt: salt value.
n: number of iterations. The value must be a positive integer.
p: parallelization parameter. The value must be a positive integer.
r: block size. The value must be a positive integer.
maxMemory: maximum memory size. The value must be a positive integer.
keySize: length of the key to derive, in bytes. The value must be a positive integer.
Call cryptoFramework.createKdf with the string parameter set to SCRYPT to create a key derivation function object (Kdf) with the scrypt algorithm.
Call Kdf.generateSecret with the SCRYPT object to generate a derived key.

The following table lists how Kdf.generateSecret delivers the return value.

Return the result using await:

  import { cryptoFramework } from '@kit.CryptoArchitectureKit';
  import { BusinessError } from '@kit.BasicServicesKit';
  
  async function ScryptAwait() {
    try {
      let spec: cryptoFramework.ScryptSpec = {
        algName: 'SCRYPT',
        salt: new Uint8Array(16),
        passphrase: "password",
        n:1024,
        p:16,
        r:8,
        maxMemory:1024 * 16 * 8 * 10, //n * p * r * 10
        keySize: 64
      };
      let kdf = cryptoFramework.createKdf('SCRYPT');
      let secret = await kdf.generateSecret(spec);
      console.info("key derivation output is " + secret.data);
    } catch(error) {
      let e: BusinessError = error as BusinessError;
      console.error('key derivation failed, errCode: ' + e.code + ', errMsg: ' + e.message);
    }
  }

Return the result using a promise:

  import { cryptoFramework } from '@kit.CryptoArchitectureKit';
  import { BusinessError } from '@kit.BasicServicesKit';
  
  function ScryptPromise() {
    let spec: cryptoFramework.ScryptSpec = {
      algName: 'SCRYPT',
      passphrase: '123456',
      salt: new Uint8Array(16),
      n:1024,
      p:16,
      r:8,
      maxMemory:1024 * 16 * 8 * 10, //n * p * r * 10
      keySize: 64
    };
    let kdf = cryptoFramework.createKdf('SCRYPT');
    let kdfPromise = kdf.generateSecret(spec);
    kdfPromise.then((secret) => {
      console.info("key derivation output is " + secret.data);
    }).catch((error: BusinessError) => {
      console.error("key derivation error.");
    });
  }

Return the result synchronously:

  import { cryptoFramework } from '@kit.CryptoArchitectureKit';
  import { BusinessError } from '@kit.BasicServicesKit';

  function kdfSync() {
    try {
      let spec: cryptoFramework.ScryptSpec = {
        algName: 'SCRYPT',
        passphrase: '123456',
        salt: new Uint8Array(16),
        n:1024,
        p:16,
        r:8,
        maxMemory:1024 * 16 * 8 * 10, //n * p * r * 10
        keySize: 64
      };
      let kdf = cryptoFramework.createKdf('SCRYPT');
      let secret = kdf.generateSecretSync(spec);
      console.info("[Sync]key derivation output is " + secret.data);
    } catch(error) {
      let e: BusinessError = error as BusinessError;
      console.error('key derivation failed, errCode: ' + e.code + ', errMsg: ' + e.message);
    }
  }