strong impact on decrypt performance, 20-25%. One probably should consider
switching between slower and faster routines depending on how much data
we were asked to process.

those referencing compact, 256-byte, S-boxes.

For S/MIME multipart/signed type the signature is calculated on the fly.

For other detached data forms the stream isn't used after the single pass to
calculate signatures.

For non-detached the data is stored in a memory BIO.

supplied list.

Send ctrls to EVP_PKEY_METHOD during signing of PKCS7 structure so
customisation is possible.

PR: 1071

EVP_PKEY_cmp().