Signing and Signature Verification with an ECDSA Key Pair

For details about the algorithm specifications, see ECDSA.

Signing

1. Use cryptoFramework.createAsyKeyGenerator and AsyKeyGenerator.generateKeyPair to generate a 256-bit key pair (KeyPair) using ECC.

   In addition to the example in this topic, ECC and Randomly Generating an Asymmetric Key Pair may help you better understand how to generate an ECC asymmetric key pair. Note that the input parameters in the reference documents may be different from those in the example below.

2. Use cryptoFramework.createSign with the string parameter 'ECC256|SHA256' to create a Sign instance. The key type is ECC256, and the MD algorithm is SHA256.

3. Use Sign.init to initialize the Sign instance with the private key (PriKey).

4. Use Sign.update to pass in the data to be signed. Currently, the data to be passed in by a single update() is not size bound. You can determine how to pass in data based on the data volume.

5. Use Sign.sign to generate a signature.

Signature Verification

1. Use cryptoFramework.createVerify with the string parameter 'ECC256|SHA256' to create a Verify instance. The key type is ECC256, and MD algorithm is SHA256.

2. Use Verify.init to initialize the Verify instance using the public key (PubKey).

3. Use Verify.update to pass in the data to be verified. Currently, the data to be passed in by a single update() is not size bound. You can determine how to pass in data based on the data volume.

4. Use Verify.verify to verify the data signature.

import cryptoFramework from '@ohos.security.cryptoFramework';
import buffer from '@ohos.buffer';
// The plaintext is split into input1 and input2.
let input1: cryptoFramework.DataBlob = { data: new Uint8Array(buffer.from("This is Sign test plan1", 'utf-8').buffer) };
let input2: cryptoFramework.DataBlob = { data: new Uint8Array(buffer.from("This is Sign test plan2", 'utf-8').buffer) };
async function signMessagePromise(priKey: cryptoFramework.PriKey) {
  let signAlg = "ECC256|SHA256";
  let signer = cryptoFramework.createSign(signAlg);
  await signer.init(priKey);
  await signer.update(input1); // If the plaintext is short, you can use sign() to pass in the full data at a time.
  let signData = await signer.sign(input2);
  return signData;
}
async function verifyMessagePromise(signMessageBlob: cryptoFramework.DataBlob, pubKey: cryptoFramework.PubKey) {
  let verifyAlg = "ECC256|SHA256";
  let verifier = cryptoFramework.createVerify(verifyAlg);
  await verifier.init(pubKey);
  await verifier.update(input1); // If the plaintext is short, you can use verify() to pass in the full data at a time.
  let res = await verifier.verify(input2, signMessageBlob);
  console.info("verify result is " + res);
  return res;
}
async function main() {
  let keyGenAlg = "ECC256";
  let generator = cryptoFramework.createAsyKeyGenerator(keyGenAlg);
  let keyPair = await generator.generateKeyPair();
  let signData = await signMessagePromise(keyPair.priKey);
  let verifyResult = await verifyMessagePromise(signData, keyPair.pubKey);
  if (verifyResult == true) {
    console.info('verify success');
  } else {
    console.error('verify failed');
  }
}