• SHA-1:

   CREATE OR REPLACE  
    FUNCTION SHA1(plain_text VARCHAR2) RETURN VARCHAR2  
    AS  
    BEGIN  
     RETURN UTL_RAW.CAST_TO_VARCHAR2(UTL_ENCODE.BASE64_ENCODE(DBMS_CRYPTO.HASH (src => utl_i18n.string_to_raw (plain_text, 'AL32UTF8'), typ => DBMS_CRYPTO.HASH_SH1)));  
    END;  
  

• MD5:

   CREATE OR REPLACE  
    FUNCTION MD5(plain_text VARCHAR2) RETURN VARCHAR2 IS  
    BEGIN  
     RETURN RAWTOHEX(DBMS_OBFUSCATION_TOOLKIT.MD5(INPUT => TL_RAW.CAST_TO_RAW(plain_text) ));  
    END;
  

import java.math.BigInteger;

import java.security.MessageDigest;
import java.security.NoSuchAlgorithmException;

public class CryptoUtils {

    private final static char[] ALPHABET =
        "ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz0123456789+/".toCharArray();

    public static String sha1(String plain) {
        try {
            MessageDigest md = MessageDigest.getInstance("sha");
            md.update(plain.getBytes());
            byte[] digest = md.digest();

            return encode(digest);
            /* Альтернативные варианты:
            return javax.xml.bind.DatatypeConverter.printBase64Binary(digest);
            или
            return com.sun.org.apache.xml.internal.security.utils.Base64.encode(digest);
            */
        } catch (NoSuchAlgorithmException e) {
            e.printStackTrace();
            return null;
        }
    }

    public static String md5(String raw) {
        try {
            MessageDigest md = MessageDigest.getInstance("MD5");
            md.update(raw.getBytes(), 0, raw.length());
            return new BigInteger(1, md.digest()).toString(16);
        } catch (NoSuchAlgorithmException e) {
            e.printStackTrace();
            return null;
        }
    }

    public static String encode(byte[] buf) {
        int size = buf.length;
        char[] ar = new char[((size + 2) / 3) * 4];
        int a = 0;
        int i = 0;
        while (i < size) {
            byte b0 = buf[i++];
            byte b1 = (i < size) ? buf[i++] : 0;
            byte b2 = (i < size) ? buf[i++] : 0;

            int mask = 0x3F;
            ar[a++] = ALPHABET[(b0 >> 2) & mask];
            ar[a++] = ALPHABET[((b0 << 4) | ((b1 & 0xFF) >> 4)) & mask];
            ar[a++] = ALPHABET[((b1 << 2) | ((b2 & 0xFF) >> 6)) & mask];
            ar[a++] = ALPHABET[b2 & mask];
        }
        switch (size % 3) {
        case 1:
            ar[--a] = '=';
        case 2:
            ar[--a] = '=';
        }
        return new String(ar);
    }
}