3.3.5.2.2.5 Compute Message Digest

The message digest MUST be computed using the SHA1 algorithm, as defined in [RFC3174] by following these steps:

  1. Compute a digest of the serialized message using the SHA1 algorithm.

  2. Compute the digest of the digest produced in step 1 using the SHA1 algorithm.

Then the digest produced in step 2 is ready to be signed using RSA as specified in section 3.3.5.2.2.6.

The message digest MUST include the serialized header element (as defined in section 3.3.5.2.2.4).