diff options
Diffstat (limited to 'linux-x86/include/openssl/chacha.h')
-rw-r--r-- | linux-x86/include/openssl/chacha.h | 6 |
1 files changed, 6 insertions, 0 deletions
diff --git a/linux-x86/include/openssl/chacha.h b/linux-x86/include/openssl/chacha.h index cfbaa75..2868c29 100644 --- a/linux-x86/include/openssl/chacha.h +++ b/linux-x86/include/openssl/chacha.h @@ -29,6 +29,12 @@ extern "C" { // CRYPTO_chacha_20 encrypts |in_len| bytes from |in| with the given key and // nonce and writes the result to |out|. If |in| and |out| alias, they must be // equal. The initial block counter is specified by |counter|. +// +// This function implements a 32-bit block counter as in RFC 8439. On overflow, +// the counter wraps. Reusing a key, nonce, and block counter combination is not +// secure, so wrapping is usually a bug in the caller. While it is possible to +// wrap without reuse with a large initial block counter, this is not +// recommended and may not be portable to other ChaCha20 implementations. OPENSSL_EXPORT void CRYPTO_chacha_20(uint8_t *out, const uint8_t *in, size_t in_len, const uint8_t key[32], const uint8_t nonce[12], uint32_t counter); |