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# JWTGenerateKeyPair

Generates an asymmetric key pair appropriate for the given JWS algorithm. Returns a struct with `privateKey` and `publicKey` as PEM-encoded strings.

## Method Signature

```
JWTGenerateKeyPair( [algorithm] )
```

### Arguments

| Argument    | Type     | Required | Description                                     | Default |
| ----------- | -------- | -------- | ----------------------------------------------- | ------- |
| `algorithm` | `string` | No       | Target algorithm. Determines key type and size. | `RS256` |

### Supported Algorithms

| Algorithm         | Key Type   | Key Size |
| ----------------- | ---------- | -------- |
| `RS256` / `RS384` | RSA        | 2048-bit |
| `RS512`           | RSA        | 4096-bit |
| `ES256`           | EC (P-256) | —        |
| `ES384`           | EC (P-384) | —        |
| `ES512`           | EC (P-521) | —        |

### Returns

A `struct` with:

* `privateKey` — PEM string
* `publicKey` — PEM string

## Examples

```javascript
rsaKeys = jwtGenerateKeyPair( "RS256" );
token   = jwtCreate( { sub: "u1" }, rsaKeys.privateKey, "RS256" );
payload = jwtVerify( token, rsaKeys.publicKey, "RS256" );

ecKeys  = jwtGenerateKeyPair( "ES256" );
token   = jwtCreate( { sub: "u1" }, ecKeys.privateKey, "ES256" );
payload = jwtVerify( token, ecKeys.publicKey, "ES256" );

// Persist keys for production
fileWrite( "/etc/keys/private.pem", rsaKeys.privateKey );
fileWrite( "/etc/keys/public.pem",  rsaKeys.publicKey  );
```

## Related

* [JWTGenerateSecret()](/boxlang-framework/modularity/jwt/reference/built-in-functions/jwtgeneratesecret.md) — symmetric HMAC secret
* [Key Management Guide](/boxlang-framework/modularity/jwt/key-management.md)
* [Algorithms](/boxlang-framework/modularity/jwt/reference/algorithms.md)


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