Return the EVP_CIPHER for AES-256 in XTS mode (IEEE 1619 / NIST SP 800-38E).
Declared in <openssl/evp.h>
<openssl/evp.h>
EVP_CIPHER const* EVP_aes_256_xts();
Pointer to the cipher method (expects a 512-bit key), or NULL if unavailable in this build.