What type of font is this?

Question

I am trying to find the type of fonts from this definition . Specially for the words: Combine,Reveal,gen,enc,dec. An experienced user might know this font

Answer 1

That "gen" is obtained with \mathsf, while "Reveal" with \mathtt. Here's a way to write that passage; I added some personal commands in order to abstract the font assignments, so that changing them is a matter of only changing the definition in the preamble.

\documentclass{article}
\usepackage{amsmath,amssymb}

\newtheorem{definition}{Definition}

\newcommand{\afunc}[1]{\operatorname{\mathsf{#1}}}
\newcommand{\bfunc}[1]{\operatorname{\mathtt{#1}}}
\newcommand{\contract}[1][\mathcal{C}]{\mathcal{#1}}
\newcommand{\Set}[1]{\mathbb{#1}}

\begin{document}

\begin{definition}
A contract function \(f_{\contract}\colon\Set{P}^{*}\to\Set{R}\) is said
to support cryptodatabases processing under the encryption scheme
\(\langle\afunc{gen},\afunc{enc},\afunc{dec}\rangle\) if the following
condition holds: there exist two functions \(\bfunc{Combine}\) and
\(\bfunc{Reveal}\) so that, for any \(n\in\Set{N}\) and any
\(m_{1},\dots,m_{n}\in\afunc{D}_{\contract}\), if
\(\langle pk,sk\rangle\gets\afunc{gen}(1^n)\),
\(c_{i}\gets\afunc{enc}(pk,m_{i})\) for \(i=1,\dots,n\) and
\(c\gets\bfunc{Combine}(c_{1},\dots,c_{n})\), then we have
\(\bfunc{Reveal}(sk,c)=f_{\contract}(m_{1},\dots,m_{n})\).
\end{definition}

\end{document}