The old "low-level" API is deprecated, and doesn't support hardware acceleration. And this makes the code simpler, too.
Discussion:
5ff4a67 Use OpenSSL EVP API for symmetric encryption in pgcrypto.
contrib/pgcrypto/openssl.c | 554 ++++++++++++++------------------------------
1 file changed, 178 insertions(+), 376 deletions(-)
Upstream: git.postgresql.org