Memory Wipe

Wipe data from memory.

Synopsis

#include <monocypher.h>

void crypto_wipe(void *secret, size_t secret_size);

Description

crypto_wipe() securely erases sensitive data in memory.

Sensitive data (such as cryptographic keys or secret plaintexts) should be erased from memory as early as possible, to minimise the window in which it can be leaked. Standard functions like memset and bzero are not safe to use, as the compiler may decide they have no effect and optimise them out.

The arguments are:

• secret: The buffer to erase.

• secret_size: The number of bytes to erase from the buffer. Normally this is the size of the entire buffer.

Monocypher will wipe its context structs when finalizing an operation such as signing or decrypting. When using direct interfaces like crypto_lock(), these context structs are invisible to you. They are exposed in incremental interfaces like crypto_lock_init(). The original key buffer does not get automatically wiped. When using incremental interfaces, you may want to wipe the original key buffers immediately after calling the respective init function.

Using crypto_wipe() alone may not suffice for security. It is recommended to lock down relevant memory regions as well. Refer to the introduction for instructions on how to lock down memory on common operating systems.

Return values

This function returns nothing.