I did a quick search in a PRPC72 system for 'hash' , 'checksum' , 'md5' in the Expression Builder - but I didn't find anything.

I also checked the JavaDocs ("PegaRULES Java Engine v07.10 - Public API") : and didn't find anything.

However: the standard Java API contains the required functionality to generate Hashes.

Here's a standalone bit of Java to generate a Hash (I just used 'SHA1' here; but you can swap this out for 'SHA256' (longer) or 'MD5' (NB: broken!) of a password stored in a file compared with an attempted Password.

package com.pega.gcs.generatehash;
import java.io.ByteArrayOutputStream;
import java.io.InputStream;
import java.security.MessageDigest;
import java.security.NoSuchAlgorithmException;
import java.util.Arrays;

public class HashChecker {
    private static final String passwordFile="secret.txt";
    private final byte[] passwordHash;
    private final byte[] passwordAttemptHash;
   
    private byte[] getBytesFromStream(InputStream is) throws Exception {
        ByteArrayOutputStream buffer = new ByteArrayOutputStream();
        int nRead;
        byte[] data = new byte[16384];

        while ((nRead = is.read(data, 0, data.length)) != -1) {
            buffer.write(data, 0, nRead);
        }
        buffer.flush();
        return buffer.toByteArray();
    }
   
    private byte[] GetHash(byte[] inBytes, String Algorithm) throws NoSuchAlgorithmException {
        MessageDigest hash = MessageDigest.getInstance(Algorithm);
        hash.update(inBytes);
        return hash.digest();
    }
   
   
    public HashChecker(String passwordAttempt, String Algorithm) throws Exception {
        this.passwordHash=GetHash(getBytesFromStream (this.getClass().getResourceAsStream(passwordFile) ) , Algorithm);
        this.passwordAttemptHash=GetHash( passwordAttempt.getBytes("UTF8"), Algorithm);
        }
   
    public boolean PasswordCheck() {
        return Arrays.equals(passwordHash, passwordAttemptHash);
    }
   
    public static void main(String[] args) throws Exception {
        HashChecker hashchecker=new HashChecker("Llanfairpwllgwyngyllgogerychwyrndrobwllllantysiliogogogoch\r\n", "SHA1");
        if (hashchecker.PasswordCheck()) {
            System.out.println("The password matched");
        }
        else {
            System.out.println("The password did not match !");
        }
    }
}

<?xml version="1.0" encoding="UTF-8"?>
<project xmlns="http://maven.apache.org/POM/4.0.0" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xsi:schemaLocation="http://maven.apache.org/POM/4.0.0 http://maven.apache.org/xsd/maven-4.0.0.xsd">
    <modelVersion>4.0.0</modelVersion>
    <groupId>com.pega.gcs</groupId>
    <artifactId>GenerateHash</artifactId>
    <version>1.0-SNAPSHOT</version>
    <packaging>jar</packaging>
    <properties>
        <project.build.sourceEncoding>UTF-8</project.build.sourceEncoding>
        <maven.compiler.source>1.7</maven.compiler.source>
        <maven.compiler.target>1.7</maven.compiler.target>
    </properties>
</project>

I haven't done it myself: but the code should work from within a PRPC Function (or possibly split across a few smaller functions) without much bother.

[ Note: since I created my password in a text file in notepad on Windows: I had to add in the '\r\n' bit to the password that is checked. This is just an oddity of using files - using a DB shouldn't present this minor complication here ]