Function EverCrypt_AEAD_decrypt 

pub unsafe extern "C" fn EverCrypt_AEAD_decrypt(
    s: *mut EverCrypt_AEAD_state_s,
    iv: *mut u8,
    iv_len: u32,
    ad: *mut u8,
    ad_len: u32,
    cipher: *mut u8,
    cipher_len: u32,
    tag: *mut u8,
    dst: *mut u8,
) -> EverCrypt_Error_error_code

Verify the authenticity of ad || cipher and decrypt cipher into dst.

@param s Pointer to the The AEAD state created by EverCrypt_AEAD_create_in. It already contains the encryption key. @param iv Pointer to iv_len bytes of memory where the nonce is read from. @param iv_len Length of the nonce. Note: ChaCha20Poly1305 requires a 12 byte nonce. @param ad Pointer to ad_len bytes of memory where the associated data is read from. @param ad_len Length of the associated data. @param cipher Pointer to cipher_len bytes of memory where the ciphertext is read from. @param cipher_len Length of the ciphertext. @param tag Pointer to TAG_LEN bytes of memory where the tag is read from. The length of the tag must be of a suitable length for the chosen algorithm: Spec_Agile_AEAD_AES128_GCM (TAG_LEN=16) Spec_Agile_AEAD_AES256_GCM (TAG_LEN=16) Spec_Agile_AEAD_CHACHA20_POLY1305 (TAG_LEN=16) @param dst Pointer to cipher_len bytes of memory where the decrypted plaintext will be written to.

@return EverCrypt_AEAD_decrypt returns …

EverCrypt_Error_Success

… on success and either of …

EverCrypt_Error_InvalidKey (returned if and only if the s parameter is NULL), EverCrypt_Error_InvalidIVLength (see note about requirements on IV size above), or EverCrypt_Error_AuthenticationFailure (in case the ciphertext could not be authenticated, e.g., due to modifications)

… on failure (EverCrypt_error.h).

Upon success, the plaintext will be written into dst.