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authorAntonio Nino Diaz <antonio.ninodiaz@arm.com>2017-05-24 14:11:07 +0100
committerAntonio Nino Diaz <antonio.ninodiaz@arm.com>2017-05-24 14:17:02 +0100
commitd77b98cabf228b277af2bc5e5ea9c4b221a6cd7b (patch)
treeb3a175b0c131de46d6920c670bb767d7c1ca34e0 /docs
parentab1794f57659a77ad66defbc7ea5cb8afb920b2f (diff)
mbedtls: Use `MBEDTLS_SHA256_SMALLER` in ARM platforms
This options enables an implementation of SHA-256 that has a smaller code footprint (~1.6 KB less) but is also ~30% slower. For ARM platforms, code size is currently considered more important than execution speed in the mbed TLS crypto module. Added a small note about this option to the documentation of the authentication framework. Change-Id: I4c0b221ea5d3466465261316ba07b627fa01b233 Signed-off-by: Antonio Nino Diaz <antonio.ninodiaz@arm.com>
Diffstat (limited to 'docs')
-rw-r--r--docs/auth-framework.md6
1 files changed, 5 insertions, 1 deletions
diff --git a/docs/auth-framework.md b/docs/auth-framework.md
index 531505bf..b416acfc 100644
--- a/docs/auth-framework.md
+++ b/docs/auth-framework.md
@@ -909,9 +909,13 @@ int verify_hash(void *data_ptr, unsigned int data_len,
```
The key algorithm (rsa, ecdsa) must be specified in the build system using the
-`MBEDTLS_KEY_ALG` variable, so the Makefile can include the corresponding
+`TF_MBEDTLS_KEY_ALG` variable, so the Makefile can include the corresponding
sources in the build.
+Note: If code size is a concern, the build option `MBEDTLS_SHA256_SMALLER` can
+be defined in the platform Makefile. It will make mbed TLS use an implementation
+of SHA-256 with smaller memory footprint (~1.5 KB less) but slower (~30%).
+
- - - - - - - - - - - - - - - - - - - - - - - - - -
_Copyright (c) 2015, ARM Limited and Contributors. All rights reserved._