I'm not sure what you mean by this. Quoting from the author of MD5 in the RFC specifying it (https://tools.ietf.org/html/rfc1321):
"The MD5 algorithm is intended for digital signature applications, where a large file must be 'compressed' in a secure manner before being encrypted with a private (secret) key under a public-key cryptosystem such as RSA."
I'm not sure what you mean by this. Quoting from the author of MD5 in the RFC specifying it (https://tools.ietf.org/html/rfc1321):
"The MD5 algorithm is intended for digital signature applications, where a large file must be 'compressed' in a secure manner before being encrypted with a private (secret) key under a public-key cryptosystem such as RSA."