1# Converting a PEM String into an Asymmetric Key Pair (ArkTS)
2
3
4This topic walks you through on how to convert a string in PEM format into an RSA asymmetric key pair (**KeyPair**).
5
6
7> **NOTE**
8>
9> The **convertPemKey** operation must comply with the following requirements:
10>
11> - The public key must comply with X.509 specifications, PKCS\#1 specifications, and PEM encoding format.
12>
13> - The private key must comply with the PKCS\#8 or PKCS\#1 specifications and the PEM encoding format.
14>
15> - Currently, only RSA asymmetric keys can be converted.
16
17
18## Converting a String in PEM Format into an RSA Key Pair
19
20For details about the algorithm specifications, see [RSA](crypto-asym-key-generation-conversion-spec.md#rsa).
21
221. Use [cryptoFramework.createAsyKeyGenerator](../../reference/apis-crypto-architecture-kit/js-apis-cryptoFramework.md#cryptoframeworkcreateasykeygenerator) with the string parameter **'RSA1024'** to create an asymmetric key generator (**AsyKeyGenerator**) object for a 1024-bit RSA key with two primes.
23
24   The default number of primes for creating an RSA asymmetric key is **2**. The **PRIMES_2** parameter is omitted in the string parameter here.
25
262. Use [AsyKeyGenerator.convertPemKey](../../reference/apis-crypto-architecture-kit/js-apis-cryptoFramework.md#convertpemkey12) to convert the binary data into an asymmetric key pair (**KeyPair**).
273. Use [AsyKeyGenerator.getEncodedPem](../../reference/apis-crypto-architecture-kit/js-apis-cryptoFramework.md#getencodedpem12) to convert the public key in the asymmetric key object into PKCS #1 or X.509 format and convert the private key into PKCS #1 or PKCS #8 format.
28
29- Example: Convert a string in PEM format into an RSA key pair (using promise-based APIs).
30
31  ```ts
32  import { cryptoFramework } from '@kit.CryptoArchitectureKit';
33
34  let priKeyPkcs1Str1024: string  =
35    "-----BEGIN RSA PRIVATE KEY-----\n"
36    + "MIICXQIBAAKBgQCwIN3mr21+N96ToxnVnaS+xyK9cNRAHiHGgrbjHw6RAj3V+l+W\n"
37    + "Y68IhIe3DudVlzE9oMjeOQwkMkq//HCxNlIlFR6O6pa0mrXSwPRE7YKG97CeKk2g\n"
38    + "YOS8YEh8toAvm7xKbiLkXuuMlxrjP2j/mb5iI/UASFSPZiQ/IyxDr0AQaQIDAQAB\n"
39    + "AoGAEvBFzBNa+7J4PXnRQlYEK/tvsd0bBZX33ceacMubHl6WVZbphltLq+fMTBPP\n"
40    + "LjXmtpC+aJ7Lvmyl+wTi/TsxE9vxW5JnbuRT48rnZ/Xwq0eozDeEeIBRrpsr7Rvr\n"
41    + "7ctrgzr4m4yMHq9aDgpxj8IR7oHkfwnmWr0wM3FuiVlj650CQQDineeNZ1hUTkj4\n"
42    + "D3O+iCi3mxEVEeJrpqrmSFolRMb+iozrIRKuJlgcOs+Gqi2fHfOTTL7LkpYe8SVg\n"
43    + "e3JxUdVLAkEAxvcZXk+byMFoetrnlcMR13VHUpoVeoV9qkv6CAWLlbMdgf7uKmgp\n"
44    + "a1Yp3QPDNQQqkPvrqtfR19JWZ4uy1qREmwJALTU3BjyBoH/liqb6fh4HkWk75Som\n"
45    + "MzeSjFIOubSYxhq5tgZpBZjcpvUMhV7Zrw54kwASZ+YcUJvmyvKViAm9NQJBAKF7\n"
46    + "DyXSKrem8Ws0m1ybM7HQx5As6l3EVhePDmDQT1eyRbKp+xaD74nkJpnwYdB3jyyY\n"
47    + "qc7A1tj5J5NmeEFolR0CQQCn76Xp8HCjGgLHw9vg7YyIL28y/XyfFyaZAzzK+Yia\n"
48    + "akNwQ6NeGtXSsuGCcyyfpacHp9xy8qXQNKSkw03/5vDO\n"
49    + "-----END RSA PRIVATE KEY-----\n";
50  let publicPkcs1Str1024: string  =
51    "-----BEGIN RSA PUBLIC KEY-----\n"
52    + "MIGJAoGBALAg3eavbX433pOjGdWdpL7HIr1w1EAeIcaCtuMfDpECPdX6X5ZjrwiE\n"
53    + "h7cO51WXMT2gyN45DCQySr/8cLE2UiUVHo7qlrSatdLA9ETtgob3sJ4qTaBg5Lxg\n"
54    + "SHy2gC+bvEpuIuRe64yXGuM/aP+ZvmIj9QBIVI9mJD8jLEOvQBBpAgMBAAE=\n"
55    + "-----END RSA PUBLIC KEY-----\n";
56  async function TestPkcs1ToPkcs8ByPromise() {
57    let asyKeyGenerator = cryptoFramework.createAsyKeyGenerator('RSA1024');
58    let keyPair = await asyKeyGenerator.convertPemKey(publicPkcs1Str1024, priKeyPkcs1Str1024);
59    let priPemKey = keyPair.priKey;
60    let pubPemKey = keyPair.pubKey;
61    let priString = priPemKey.getEncodedPem('PKCS8');
62    let pubString = pubPemKey.getEncodedPem('X509');
63    console.info("[promise]TestPkcs1ToPkcs8ByPromise priString output is " + priString);
64    console.info("[promise]TestPkcs1ToPkcs8ByPromise pubString output is " + pubString);
65  }
66  ```
67
68- Example: Convert a string in PEM format into an RSA key pair (using the synchronous API [convertPemKeySync](../../reference/apis-crypto-architecture-kit/js-apis-cryptoFramework.md#convertpemkeysync12)).
69
70  ```ts
71  import { cryptoFramework } from '@kit.CryptoArchitectureKit';
72
73  let priKeyPkcs1Str1024: string  =
74    "-----BEGIN RSA PRIVATE KEY-----\n"
75    + "MIICXQIBAAKBgQCwIN3mr21+N96ToxnVnaS+xyK9cNRAHiHGgrbjHw6RAj3V+l+W\n"
76    + "Y68IhIe3DudVlzE9oMjeOQwkMkq//HCxNlIlFR6O6pa0mrXSwPRE7YKG97CeKk2g\n"
77    + "YOS8YEh8toAvm7xKbiLkXuuMlxrjP2j/mb5iI/UASFSPZiQ/IyxDr0AQaQIDAQAB\n"
78    + "AoGAEvBFzBNa+7J4PXnRQlYEK/tvsd0bBZX33ceacMubHl6WVZbphltLq+fMTBPP\n"
79    + "LjXmtpC+aJ7Lvmyl+wTi/TsxE9vxW5JnbuRT48rnZ/Xwq0eozDeEeIBRrpsr7Rvr\n"
80    + "7ctrgzr4m4yMHq9aDgpxj8IR7oHkfwnmWr0wM3FuiVlj650CQQDineeNZ1hUTkj4\n"
81    + "D3O+iCi3mxEVEeJrpqrmSFolRMb+iozrIRKuJlgcOs+Gqi2fHfOTTL7LkpYe8SVg\n"
82    + "e3JxUdVLAkEAxvcZXk+byMFoetrnlcMR13VHUpoVeoV9qkv6CAWLlbMdgf7uKmgp\n"
83    + "a1Yp3QPDNQQqkPvrqtfR19JWZ4uy1qREmwJALTU3BjyBoH/liqb6fh4HkWk75Som\n"
84    + "MzeSjFIOubSYxhq5tgZpBZjcpvUMhV7Zrw54kwASZ+YcUJvmyvKViAm9NQJBAKF7\n"
85    + "DyXSKrem8Ws0m1ybM7HQx5As6l3EVhePDmDQT1eyRbKp+xaD74nkJpnwYdB3jyyY\n"
86    + "qc7A1tj5J5NmeEFolR0CQQCn76Xp8HCjGgLHw9vg7YyIL28y/XyfFyaZAzzK+Yia\n"
87    + "akNwQ6NeGtXSsuGCcyyfpacHp9xy8qXQNKSkw03/5vDO\n"
88    + "-----END RSA PRIVATE KEY-----\n";
89  let publicPkcs1Str1024: string  =
90    "-----BEGIN RSA PUBLIC KEY-----\n"
91    + "MIGJAoGBALAg3eavbX433pOjGdWdpL7HIr1w1EAeIcaCtuMfDpECPdX6X5ZjrwiE\n"
92    + "h7cO51WXMT2gyN45DCQySr/8cLE2UiUVHo7qlrSatdLA9ETtgob3sJ4qTaBg5Lxg\n"
93    + "SHy2gC+bvEpuIuRe64yXGuM/aP+ZvmIj9QBIVI9mJD8jLEOvQBBpAgMBAAE=\n"
94    + "-----END RSA PUBLIC KEY-----\n";
95  function TestPkcs1ToPkcs8BySync() {
96    let asyKeyGenerator = cryptoFramework.createAsyKeyGenerator('RSA1024');
97    try {
98      let keyPairData = asyKeyGenerator.convertPemKeySync(publicPkcs1Str1024, priKeyPkcs1Str1024);
99      if (keyPairData != null) {
100        console.info('[Sync]: convert pem key pair success');
101      } else {
102        console.error("[Sync]: convert pem key pair result fail!");
103      }
104      let priPemKey = keyPairData.priKey;
105      let pubPemKey = keyPairData.pubKey;
106      let priString = priPemKey.getEncodedPem('PKCS8');
107      let pubString = pubPemKey.getEncodedPem('X509');
108      console.info("[Sync]TestPkcs1ToPkcs8BySync priString output is " + priString);
109      console.info("[Sync]TestPkcs1ToPkcs8BySync pubString output is " + pubString);
110    } catch (e) {
111      console.error(`Sync error, ${e.code}, ${e.message}`);
112    }
113  }
114  ```
115