Converting Binary Data into an Asymmetric Key Pair

This topic uses RSA, ECC, and SM2 as an example to describe how to convert binary data into an asymmetric key pair (KeyPair). That is, convert a piece of external or internal binary data into a KeyPair object for subsequent operations, such as encryption and decryption.

NOTE

The asymmetric key conversion must comply with the following requirements:

The public key must use the ASN.1 syntax and DER encoding format and comply with X.509 specifications.

The private key must use the ASN.1 syntax and DER encoding format and comply with PKCS#8 specifications.

Converting Binary Data into an RSA Key Pair

For details about the algorithm specifications, see RSA.

Obtain the binary data of the RSA public key or private key and encapsulate the data into a DataBlob object.

Either the public key or private key can be passed in. In this example, the public key is passed in.
Use cryptoFramework.createAsyKeyGenerator with the string parameter 'RSA1024' to create an asymmetric key generator (AsyKeyGenerator) object for a 1024-bit RSA key with two primes.

The default number of primes for creating an RSA asymmetric key is 2. The PRIMES_2 parameter is omitted in the string parameter here.
Use AsyKeyGenerator.convertKey to convert the binary data into an asymmetric key pair (KeyPair).

Example: Convert binary data into an RSA key pair (using callback-based APIs).

import cryptoFramework from '@ohos.security.cryptoFramework';

function convertAsyKey() {
  let rsaGenerator = cryptoFramework.createAsyKeyGenerator('RSA1024');
  let pkVal = new Uint8Array([48, 129, 159, 48, 13, 6, 9, 42, 134, 72, 134, 247, 13, 1, 1, 1, 5, 0, 3, 129, 141, 0, 48, 129, 137, 2, 129, 129, 0, 174, 203, 113, 83, 113, 3, 143, 213, 194, 79, 91, 9, 51, 142, 87, 45, 97, 65, 136, 24, 166, 35, 5, 179, 42, 47, 212, 79, 111, 74, 134, 120, 73, 67, 21, 19, 235, 80, 46, 152, 209, 133, 232, 87, 192, 140, 18, 206, 27, 106, 106, 169, 106, 46, 135, 111, 118, 32, 129, 27, 89, 255, 183, 116, 247, 38, 12, 7, 238, 77, 151, 167, 6, 102, 153, 126, 66, 28, 253, 253, 216, 64, 20, 138, 117, 72, 15, 216, 178, 37, 208, 179, 63, 204, 39, 94, 244, 170, 48, 190, 21, 11, 73, 169, 156, 104, 193, 3, 17, 100, 28, 60, 50, 92, 235, 218, 57, 73, 119, 19, 101, 164, 192, 161, 197, 106, 105, 73, 2, 3, 1, 0, 1]);
  let pkBlob: cryptoFramework.DataBlob = { data: pkVal };
  rsaGenerator.convertKey(pkBlob, null, (err, keyPair) => {
    if (err) {
      console.error(`convertKey failed, ${err.code}, ${err.message}`);
      return;
    }
    console.info('convertKey success');
  });
}

Converting Binary Data into an ECC Key Pair

For details about the algorithm specifications, see ECC.

Obtain the binary data of the ECC public key or private key and encapsulate the data into a DataBlob object.

Either the public key or private key can be passed in. As shown in the following example, the public key and private key are passed in separately.
Use cryptoFramework.createAsyKeyGenerator with the string parameter 'ECC256' to create an asymmetric key generator (AsyKeyGenerator) object for a 256-bit ECC key pair.
Use AsyKeyGenerator.convertKey to convert the binary data into an asymmetric key pair (KeyPair).

Example: Convert binary data into an ECC key pair (using callback-based APIs).

import cryptoFramework from '@ohos.security.cryptoFramework';

function convertEccAsyKey() {
  let pubKeyArray = new Uint8Array([48, 89, 48, 19, 6, 7, 42, 134, 72, 206, 61, 2, 1, 6, 8, 42, 134, 72, 206, 61, 3, 1, 7, 3, 66, 0, 4, 83, 96, 142, 9, 86, 214, 126, 106, 247, 233, 92, 125, 4, 128, 138, 105, 246, 162, 215, 71, 81, 58, 202, 121, 26, 105, 211, 55, 130, 45, 236, 143, 55, 16, 248, 75, 167, 160, 167, 106, 2, 152, 243, 44, 68, 66, 0, 167, 99, 92, 235, 215, 159, 239, 28, 106, 124, 171, 34, 145, 124, 174, 57, 92]);
  let priKeyArray = new Uint8Array([48, 49, 2, 1, 1, 4, 32, 115, 56, 137, 35, 207, 0, 60, 191, 90, 61, 136, 105, 210, 16, 27, 4, 171, 57, 10, 61, 123, 40, 189, 28, 34, 207, 236, 22, 45, 223, 10, 189, 160, 10, 6, 8, 42, 134, 72, 206, 61, 3, 1, 7]);
  let pubKeyBlob: cryptoFramework.DataBlob = { data: pubKeyArray };
  let priKeyBlob: cryptoFramework.DataBlob = { data: priKeyArray };
  let generator = cryptoFramework.createAsyKeyGenerator('ECC256');
  generator.convertKey(pubKeyBlob, priKeyBlob, (error, data) => {
    if (error) {
      console.error(`convertKey failed, ${error.code}, ${error.message}`);
      return;
    }
    console.info('convertKey success');
  });
}

Converting Binary Data into an SM2 Key Pair

For details about the algorithm specifications, see SM2.

Obtain the binary data of the SM2 public key or private key and encapsulate the data into a DataBlob object.

Either the public key or private key can be passed in. As shown in the following example, the public key and private key are passed in separately.
Use cryptoFramework.createAsyKeyGenerator with the string parameter 'SM2_256' to create an asymmetric key generator (AsyKeyGenerator) object for a 256-bit SM2 key pair.
Use AsyKeyGenerator.convertKey to convert the binary data into an asymmetric key pair (KeyPair).

Example: Convert binary data into an SM2 key pair (using callback-based APIs).

import cryptoFramework from '@ohos.security.cryptoFramework';

function convertSM2AsyKey() {
  let pubKeyArray = new Uint8Array([48, 89, 48, 19, 6, 7, 42, 134, 72, 206, 61, 2, 1, 6, 8, 42, 129, 28, 207, 85, 1, 130, 45, 3, 66, 0, 4, 90, 3, 58, 157, 190, 248, 76, 7, 132, 200, 151, 208, 112, 230, 96, 140, 90, 238, 211, 155, 128, 109, 248, 40, 83, 214, 78, 42, 104, 106, 55, 148, 249, 35, 61, 32, 221, 135, 143, 100, 45, 97, 194, 176, 52, 73, 136, 174, 40, 70, 70, 34, 103, 103, 161, 99, 27, 187, 13, 187, 109, 244, 13, 7]);
  let priKeyArray = new Uint8Array([48, 49, 2, 1, 1, 4, 32, 54, 41, 239, 240, 63, 188, 134, 113, 31, 102, 149, 203, 245, 89, 15, 15, 47, 202, 170, 60, 38, 154, 28, 169, 189, 100, 251, 76, 112, 223, 156, 159, 160, 10, 6, 8, 42, 129, 28, 207, 85, 1, 130, 45]);
  let pubKeyBlob: cryptoFramework.DataBlob = { data: pubKeyArray };
  let priKeyBlob: cryptoFramework.DataBlob = { data: priKeyArray };
  let generator = cryptoFramework.createAsyKeyGenerator('SM2_256');
  generator.convertKey(pubKeyBlob, priKeyBlob, (error, data) => {
    if (error) {
      console.error(`convertKey failed, ${error.code}, ${error.message}`);
      return;
    }
    console.info('convertKey success');
  });
}