clarify LTC_PAD_PKCS7

Author: sjaeckel

doc/crypt.tex

@@ -7462,7 +7462,7 @@ \subsection{Padding mode argument}
 \begin{center}
 \begin{tabular}{|l|l|}
      \hline \textbf{mode} & \textbf{Standard} \\
-     \hline LTC\_PAD\_PKCS7  & RFC-5652 / PKCS \#7 \\
+     \hline LTC\_PAD\_PKCS7  & a.k.a CMS; best described in RFC-5652 / PKCS \#7; also mentioned in PKCS \#5 which refers to RFC-1423 \\
      \hline LTC\_PAD\_ISO\_10126 & ISO/IEC 10126 \footnote{\textit{ISO/IEC 10126} support is only available when the library is built with \textit{rng\_get\_bytes()} support} \\
      \hline LTC\_PAD\_ANSI\_X923 & ANSI X.923 \\
      \hline LTC\_PAD\_ONE\_AND\_ZERO & ISO/IEC 7816-4 \\