OpenSSL PKCS#5 v1.5 EVP_BytesToKey

This KDF was added in v0.4.0.

This KDF is provided for compatibility with data encrypted using OpenSSL's default PBE, known as EVP_BytesToKey. This is a single iteration of MD5 over the concatenation of the password and 8 bytes of random ASCII salt. OpenSSL recommends using PBKDF2 for key derivation but does not expose the library method necessary to the command-line tool, so this KDF is still the de facto default for command-line encryption.