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# EcdsaLib

## EcdsaLib

### compressPublicKey

```solidity
function compressPublicKey(bytes32 x, bytes32 y) internal pure returns (bytes)
```

Converts public key X and Y coordinates (32-byte each) to a compressed public key (33-byte). Compressed public key is X coordinate prefixed with `02` or `03` based on the Y coordinate parity. It is expected that the uncompressed public key is stripped (i.e. it is not prefixed with `04`).

#### Parameters

| Name | Type    | Description                         |
| ---- | ------- | ----------------------------------- |
| x    | bytes32 | Wallet's public key's X coordinate. |
| y    | bytes32 | Wallet's public key's Y coordinate. |

#### Return Values

| Name | Type  | Description                                                  |
| ---- | ----- | ------------------------------------------------------------ |
| \[0] | bytes | Compressed public key (33-byte), prefixed with `02` or `03`. |


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