EVP_chacha20, EVP_chacha20_poly1305 - EVP ChaCha20 stream cipher
#include <openssl/evp.h> const EVP_CIPHER *EVP_chacha20(void); const EVP_CIPHER *EVP_chacha20_poly1305(void);
The ChaCha20 stream cipher for EVP.
The ChaCha20 stream cipher. The key length is 256 bits, the IV is 128 bits long. The first 64 bits consists of a counter in little-endian order followed by a 64 bit nonce. For example a nonce of:
With an initial counter of 42 (2a in hex) would be expressed as:
Authenticated encryption with ChaCha20-Poly1305. Like EVP_chacha20(), the key is 256 bits and the IV is 96 bits. This supports additional authenticated data (AAD) and produces a 128-bit authentication tag. See the "AEAD Interface" in EVP_EncryptInit(3) section for more information.
Developers should be aware of the negative performance implications of calling these functions multiple times and should consider using EVP_CIPHER_fetch(3) instead. See "Performance" in crypto(7) for further information.
RFC 7539 uses a 32 bit counter and a 96 bit nonce for the IV.
These functions return an EVP_CIPHER structure that contains the implementation of the symmetric cipher. See EVP_CIPHER_meth_new(3) for details of the EVP_CIPHER structure.
evp(7), EVP_EncryptInit(3), EVP_CIPHER_meth_new(3)
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