# llSHA1String

*LSL function*

```lsl
string string llSHA1String(string src);
```

- `string src`: Source string to hash.

- Returns: `string`
- Energy: 10

Returns a string of 40 hex characters representing the SHA-1 security hash of src.

Returns a [string](https://wiki.secondlife.com/wiki/string) of 40 hex characters that is the [SHA-1](https://en.wikipedia.org/wiki/SHA-1) security hash of **src**.

```lsl title="How to use" frame="terminal"
string result = llSHA1String("");
```

## 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 appended to the byte value (hence 0x0080-0x00FF become 0xC280-0xC2FF inside the `llSHA1String()` routine). A JIRA has been filed for this.

## Examples

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

```lsl
llSay(0, llSHA1String("Hello, Avatar!")); // returns 2E73318E547AF1B28CC0C96F95DDC9B1EE906B8D
```

</details>

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

#### Linux Example

```lsl
$ echo -n 'Hello, Avatar!' | openssl sha1
2E73318E547AF1B28CC0C96F95DDC9B1EE906B8D
```

</details>

## History

- SVN:1291 r98903 Trunk Initial introduction.
- SVN:1298 r99021 Branch:OpenAL

Integration into OpenAL branch.

- Date of Release [2008-10-31](https://wiki.secondlife.com/wiki/Release_Notes/Second_Life_Beta_Server/1.25#server-release-notes-2c-second-life-beta-server-1-25-0)

## See also

### Functions

- [llMD5String](/functions/llMD5String/)
- [llSHA256String](/functions/llSHA256String/)

### Articles

- [SHA-1](https://wiki.secondlife.com/wiki/SHA-1) (script implementation)

---

*Source: [LlSHA1String](https://wiki.secondlife.com/wiki/LlSHA1String) on the Second Life Wiki. Content from the Second Life Wiki articles LlSHA1String (revision 1215834, 2023-12-09), Template:Wikipedia (revision 1212086, 2022-09-19) and Template:LSL Function/warning (revision 1168838, 2012-06-11), CC BY-SA 3.0.*

---

From lsl.dev: https://lsl.dev/functions/llSHA1String/