Improve crypto/digest/md32_common.h mechanism.

The documentation in md32_common.h is now (more) correct with respect
to the most important details of the layout of |HASH_CTX|. The
documentation explaining why sha512.c doesn't use md32_common.h is now
more accurate as well.

Before, the C implementations of HASH_BLOCK_DATA_ORDER took a pointer
to the |HASH_CTX| and the assembly language implementations tool a
pointer to the hash state |h| member of |HASH_CTX|. (This worked
because |h| is always the first member of |HASH_CTX|.) Now, the C
implementations take a pointer directly to |h| too.

The definitions of |MD4_CTX|, |MD5_CTX|, and |SHA1_CTX| were changed to
be consistent with |SHA256_CTX| and |SHA512_CTX| in storing the hash
state in an array. This will break source compatibility with any
external code that accesses the hash state directly, but will not
affect binary compatibility.

The second parameter of |HASH_BLOCK_DATA_ORDER| is now of type
|const uint8_t *|; previously it was |void *| and all implementations
had a |uint8_t *data| variable to access it as an array of bytes.

This change paves the way for future refactorings such as automatically
generating the |*_Init| functions and/or sharing one I-U-F
implementation across all digest algorithms.

Change-Id: I30513bb40b5f1d2c8932551d54073c35484b3f8b
Reviewed-by: Adam Langley <>
10 files changed
tree: 656151ba243139bf71ee1cfa1712c7fb75ee4c60
  1. crypto/
  2. decrepit/
  3. include/
  4. ssl/
  5. tool/
  6. util/
  7. .clang-format
  8. .gitignore
  10. CMakeLists.txt
  11. codereview.settings


BoringSSL is a fork of OpenSSL that is designed to meet Google's needs.

Although BoringSSL is an open source project, it is not intended for general use, as OpenSSL is. We don't recommend that third parties depend upon it. Doing so is likely to be frustrating because there are no guarantees of API or ABI stability.

Programs ship their own copies of BoringSSL when they use it and we update everything as needed when deciding to make API changes. This allows us to mostly avoid compromises in the name of compatibility. It works for us, but it may not work for you.

BoringSSL arose because Google used OpenSSL for many years in various ways and, over time, built up a large number of patches that were maintained while tracking upstream OpenSSL. As Google's product portfolio became more complex, more copies of OpenSSL sprung up and the effort involved in maintaining all these patches in multiple places was growing steadily.

Currently BoringSSL is the SSL library in Chrome/Chromium, Android (but it's not part of the NDK) and a number of other apps/programs.

There are other files in this directory which might be helpful:

  • how to port OpenSSL-using code to BoringSSL.
  • how to build BoringSSL
  • rules and guidelines for coding style.
  • include/openssl: public headers with API documentation in comments. Also available online.