Adobe ACROBAT READER 7.0 Manual page 153

Creating digital IDs
If you're not using a third-party digital ID, you can create your own self-signed digital ID.
The resulting file stores an encrypted private key used for signing or decrypting
documents, and a public key contained in a certificate, which is used for validating
signatures and encrypting documents.
You can create either a PKCS#12 digital ID, which is a standard encryption format, or a
Windows Default Certificate digital ID, which is stored in the Windows Certificate Store.
PKCS#12 file extensions are .pfx in Windows and .p12 in Mac OS.
To create a self-signed digital ID:
1. Choose Document > Security Settings.
2. Select Digital IDs on the left, and then click Add.
3. Select Create A Self-Signed Digital ID, and then click Next. Click Next again.
4. Select one of the following to specify where to store your digital ID, and then click Next:
New PKCS#12 Digital ID File stores the information in a file that you can send to others.
Windows Certificate Store (Windows only) stores the file where other Windows
applications can also retrieve it.
5. Type a name and other personal information for your digital ID. When you certify or sign
a document, the name appears in the Signatures tab and in the signature field.
6. (Optional) To use Unicode values for extended characters, select Enable Unicode Support,
and then specify Unicode values for the appropriate fields.
7. Choose a key algorithm from the menu. 2048-bit RSA offers more security than 1024-bit
RSA, but 1024-bit RSA is more universally compatible.
8. From the Use Digital ID menu, choose whether you want to use the digital ID for digital
signature, data encryption, or both.
9. Click Next, and specify a a file name and location for the digital ID file.
10. Type a password; passwords are case-sensitive, must contain at least six characters, and
may not contain double quotation marks or the following characters: ! @ # $ % ^ & * , | \ ;
< > _. Type the same password in both the Choose A Password and Confirm Password
boxes. Click Next.
11. Click Finish.
You can export and send your certificate file to those who need to validate your signature.
(See Managing digital ID certificates.)