Skip to main content
The OpenSSL backend can operate with a FIPS 140-2 capable OpenSSL library. This enables SoftHSM v2 to restrict cryptographic operations to FIPS-approved algorithms and enforce the self-test requirements mandated by FIPS 140-2.
FIPS mode is only available with the OpenSSL backend. The Botan backend does not support FIPS 140-2 operation.

​
Overview

FIPS 140-2 support in OpenSSL is provided through a validated cryptographic module (the “FIPS canister”). To use it, you must:
  1. Build a FIPS-capable OpenSSL static library with position-independent code (PIC).
  2. Use the fipsld linker script (supplied by OpenSSL) as your C and C++ compiler wrapper when building SoftHSM.
Read the OpenSSL FIPS 140 SecurityPolicy and UserGuide documents before proceeding — they describe the exact requirements for a validated build.

​
Building a FIPS-capable OpenSSL

1

Obtain a validated OpenSSL source

Download an OpenSSL source release that carries a FIPS 140-2 validation (e.g. OpenSSL 1.0.1e or a later validated version). Consult the CMVP certificate for the exact version.
2

Build with PIC

The libsofthsm2.so shared library requires all statically linked code to be compiled as position-independent code. Pass the PIC flag when configuring OpenSSL:
./config shared fips -fPIC --prefix=/opt/openssl-fips
make
make install
The FIPS module canister is already compiled with PIC, but the surrounding OpenSSL code must be as well.
3

Install fipsld

After make install, the fipsld script is placed under the OpenSSL installation. Locate it:
find /opt/openssl-fips -name fipsld

​
Using fipsld as the compiler

fipsld is a shell script that wraps the linker to inject FIPS integrity checks into the final binary. You must set both CC and CXX to fipsld when running ./configure or cmake: 
export CC=/opt/openssl-fips/bin/fipsld
export CXX=/opt/openssl-fips/bin/fipsld
./configure --with-crypto-backend=openssl --with-openssl=/opt/openssl-fips
make

​
Handling the C/C++ compiler mismatch

A common problem is that the C++ compiler (g++) does not compile .c files as C code. You can verify this with a quick test: 
/* foo.c */
foo() { char *x = "ab"; }
Compile with both compilers and compare the warnings: 
gcc -Wall foo.c      # no warning about missing return type
g++ -Wall foo.c      # raises a warning or error about missing type and char* constant
When this mismatch causes errors inside the fipsld script, you need a wrapper that inserts -x c and -x none around each .c file in C++ compiler invocations.

​
Wrapper script

Create a wrapper script (e.g. /usr/local/bin/fipsld-wrapper) that calls fipsld but handles .c files correctly: 
#!/bin/sh

commands="g++"

for elem in $@
do
  case $elem in
    *.c) commands+=" -x c $elem -x none";;
    *)   commands+=" $elem";;
  esac
done

exec $commands
Make it executable: 
chmod +x /usr/local/bin/fipsld-wrapper
Then set CXX to your wrapper instead of fipsld directly: 
export CC=/opt/openssl-fips/bin/fipsld
export CXX=/usr/local/bin/fipsld-wrapper
./configure --with-crypto-backend=openssl --with-openssl=/opt/openssl-fips
make
You must set both CC and CXX to fipsld (or the wrapper) in all cases. Failing to do so will produce a binary that does not pass the FIPS integrity check at runtime.

​
Self-test status

At startup, OSSLCryptoFactory runs the FIPS self-tests required by the module. You can query the result through the CryptoFactory interface: 
bool ok = CryptoFactory::i()->getFipsSelfTestStatus();
If the self-tests fail, this returns false and SoftHSM will refuse to perform cryptographic operations.

Build docs developers (and LLMs) love

Get started for freeTalk to us