# llSHA256String

*LSL function*

```lsl
string string llSHA256String(string src);
```

- `string src`: Source string to hash.

- Returns: `string`
- Energy: 10

Returns a string of 64 hex characters representing the SHA-256 security hash of src.

Returns a [string](https://wiki.secondlife.com/wiki/string) of 64 hex characters that is the [SHA-256](https://en.wikipedia.org/wiki/SHA-2) security hash of **src**.

```lsl title="How to use" frame="terminal"
string result = llSHA256String("");
```

## Specification

LSL strings are stored in the UTF-8 format.

## Caveats

There's no way to input a zero-byte value into this function, nor any byte value from 128-255, therefore it's currently broken for many purposes (like HMAC-SHA1). The reason is because LSL strings cannot have a unicode null character (U+0000) in them, and LSL has no escape code for the null character (many programming languages use \\0 but LSL does not have this feature). `llEscapeURL("%00")` yields an empty string. As well, inside this function, each character with a Unicode integer value over U+0127 / 007F are dealt with in UTF-8 fashion: in the hex values, 0xC2 is prepended to the byte value (hence 0x0080-0x00FF become 0xC280-0xC2FF inside the `llSHA256String()` routine).

## Examples

<details open>
<summary>Example 1</summary>

```lsl
llSay(0, llSHA256String("Hello, Avatar!")); // returns 3a9f9d2e4360319a62139d19bd425c16fb8439b832d74d5221ca75b54c35b4f2
```

</details>

<details>
<summary>Example 2</summary>

#### Linux Example

```lsl
$ echo -n 'Hello, Avatar!' | openssl sha256
3a9f9d2e4360319a62139d19bd425c16fb8439b832d74d5221ca75b54c35b4f2
```

</details>

## See also

### Functions

- [llMD5String](/functions/llMD5String/)
- [llSHA1String](/functions/llSHA1String/)

### Articles

- [SHA-2](https://wiki.secondlife.com/wiki/SHA-2)

---

*Source: [LlSHA256String](https://wiki.secondlife.com/wiki/LlSHA256String) on the Second Life Wiki. Content from the Second Life Wiki article LlSHA256String (revision 1211956, 2022-09-16), CC BY-SA 3.0.*

---

From lsl.dev: https://lsl.dev/functions/llSHA256String/