HomeGuides :: AssemblageEncryption and Passoword Protection for Email AttachmentsEncryption Strength

1. Encryption Strength

Encryption is critically important to any sort of security because a file that only has a password on it and is not encrypted can be opened and read by anyone with the right skills. That is worse than no security at all, because it gives a false impression of security.  When you apply a password to an attachment in the Assemblage Emailer tool, the contents of the file are actually encrypted.  Without the password, the decryption keys are not known, so the content cannot be recovered by an attacker.

The size of the encryption key is usually measured in 'bits'.  Most encrypted traffic that goes over the Internet uses 128-bit encryption.  Generally speaking, the larger the key, the stronger the encryption - but you have to be a bit careful with this.  A modern computer would require many, many thousands of years to try every combination of a 128-bit encryption key (this is called a 'brute force' attack).  By going to 256-bit encryption, you can change that to millions and millions of years.  But the *effective* security is the same.  128-bit key lengths have been found by the security community to provide a nice balance of encryption that would take a really, really long time to crack with brute force techniques, without the key becoming ridiculously long.

When you password protect email attachments in the Assemblage Emailer Tool, the software takes the password and turns it into a 128 (or 256) bit key using an algorithm called a one-way hashing algorithm.  If you input the same password, you get the same 128 or 256-bits of effectively random data.  But it is not possible to start with the 128-bits of data and obtain the password.
 
The files generated by Assemblage are actually not password protected.  In fact, the password isn't part of the file at all.  Instead, the contents are encrypted using a symmetric algorithm.  The key for the symmetric algorithm is obtained by taking the password and processing it with a one-way hashing algorithm.
 
When a user opens the attachment, they are prompted for a password.  The password is not compared against any value in the attachment.  The password is used to mathematically obtain the decryption key.

Assemblage offers 4 different levels of Encryption.  See PDF Compatibility Levels for more information on the level of encryption for each version of Adobe.

The higher the level of encryption you use, the more secure the attachments will be from attackers.  That being said, certain versions of Adobe are required to decrypt the attachments as well.

In Assemblage versions 2.02 and higher the default setting is to apply AES 128 bit encryption, if you wish to use a different level of encryption, please notify your Trumpet Consultant.

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