Commit 7c8ae5f6 authored by Steven Fackler's avatar Steven Fackler
Browse files

Better docs for AEAD tag

parent aa7c2753

openssl/src/symm.rs

+10 −0
Original line number Diff line number Diff line
@@ -287,6 +287,10 @@ impl Crypter { 
    /// as AES GCM.

    ///

    /// When encrypting data with an AEAD cipher, this must be called after `finalize`.

    ///

    /// The size of the buffer indicates the required size of the tag. While some ciphers support a

    /// range of tag sizes, it is recommended to pick the maximum size. For AES GCM, this is 16

    /// bytes, for example.

    pub fn get_tag(&self, tag: &mut [u8]) -> Result<(), ErrorStack> {

        unsafe {

            assert!(tag.len() <= c_int::max_value() as usize);
@@ -370,6 +374,10 @@ pub fn encrypt_aead(t: Cipher, 
///

/// Additional Authenticated Data can be provided in the `aad` field, and the authentication tag

/// should be provided in the `tag` field.

///

/// The size of the `tag` buffer indicates the required size of the tag. While some ciphers support

/// a range of tag sizes, it is recommended to pick the maximum size. For AES GCM, this is 16 bytes,

/// for example.

pub fn decrypt_aead(t: Cipher,

                    key: &[u8],

                    iv: Option<&[u8]>,
@@ -650,6 +658,8 @@ mod tests { 
             f4fc97416ee52abe";

        let tag = "e20b6655";



        // this tag is smaller than you'd normally want, but I pulled this test from the part of

        // the NIST test vectors that cover 4 byte tags.

        let mut actual_tag = [0; 4];

        let out = encrypt_aead(Cipher::aes_128_gcm(),

                               &key.from_hex().unwrap(),