Compatibility between Silver Key versions

Silver Key 4 introduced a new parcel format – more secure and tamper-proof, offering a lot of new features, such as parcel analyzing, partial decryption, digital signatures, and FIPS 140-2 compliance mode.

There is a drawback, though: older Silver Key versions don't know anything about this cool new format. If you try to decrypt a 4.x parcel with an older Silver Key version, you will see this message box:

Compatibility error message

which means that this particular parcel needs a newer decryptor.

What Can Be Done Here?

There are several ways to solve this problem:


A rather obvious solution and also the best one. However if upgrading is out of the question, there are other methods.

Using self-decrypting parcels

Self-decrypting parcels contain an embedded decryptor and so have no compatibility problem.

Using 3.x compatibility mode

Silver Key 4 can create old-style parcels that are decryptable by older versions. Select the compatibility mode (or ask your correspondent to if you are on the receiving side): Start / All Programs / Silver Key / Settings / Cipher / 3.x compatibility engine.

Decrypting using Free Edition

You can encrypt with your older version 3.x (and so have all the features of a commercial version), and decrypt with Silver Key 4 Free Edition. Basically, Silver Key 4.x is a completely different program and so can coexist with an older version. Few conflicts can be easily resolved.

First conflict is caused by the same desktop icon and program group. Another conflict happens because of the same command names in Explorer's right-click menu.

  1. Install Silver Key Free Edition.
  2. Double-click Silver Key desktop icon to make sure the installation has been completed.
  3. Open Crypto Settings and disable desktop icon and all the right-click commands except Decrypt.
  4. Delete Silver Key program group in the Start / All Programs menu
  5. Re-install (repair) the older version to restore its desktop icon and program group.
  6. Open the older version's Crypto Settings panel and disable right-click Decrypt command.