docs/reference/syscalls/cprng_add_entropy.md

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# zx_cprng_add_entropy

## Summary

Add entropy to the kernel CPRNG.

## Declaration

```c
#include <zircon/syscalls.h>

zx_status_t zx_cprng_add_entropy(const void* buffer, size_t buffer_size);
```

## Description

`zx_cprng_add_entropy()` mixes the given entropy into the kernel CPRNG.
a privileged operation.  It will accept at most **ZX_CPRNG_ADD_ENTROPY_MAX_LEN**
bytes of entropy at a time.

## Rights

None.

## Return value

`zx_cprng_add_entropy()` returns **ZX_OK** on success.

## Errors

**ZX_ERR_INVALID_ARGS** *buffer_size* is too large, or *buffer* is not a valid
userspace pointer.

## BUGS

This syscall should be very privileged.

## See also

 - [`zx_cprng_draw()`]

[`zx_cprng_draw()`]: cprng_draw.md