JDK 1.4 supports the following digital signature algorithms:

• MD2/RSA
• MD5/RSA
• SHA1/DSA
• SHA1/RSA

We'll examine two examples in this section. The first, the hard way (see Digital signature code example: The hard way), uses the primitives already discussed for message digests and public key cryptography to implement digital signatures. The second, the easy way (see Digital signature code example: The easy way), uses the Java language's direct support for signatures.