chacha_ctx
chacha_ctx rs_chacha; /* chacha context for random keystream */
chacha_keysetup(chacha_ctx *x,const u8 *k,u32 kbits)
chacha_ivsetup(chacha_ctx *x,const u8 *iv)
chacha_encrypt_bytes(chacha_ctx *x,const u8 *m,u8 *c,u32 bytes)