Security

AES encryption has become the industry standard for data security. AES comes in 128-bit, 192-bit, and 256-bit implementations, with AES 256 being the most secure. AES has been adopted by the U.S. government. The algorithm described by AES is a symmetric-key algorithm, meaning the same key is used for both encrypting and decrypting the data.

SecurePDF offers 2 levels of encryption AES-128 bit and AES-256 bit. The last three digits represent the length of the secret key, a 256-bit secret key is obviously better. The longer the secret key, the harder it is for an attacker to guess via brute force attack. Both algorithms are considered secure against modern and anticipated future threats.

By default SecurePDF is set to use AES-128, which is compatible with Acrobat Reader 5.0 and above, while AES-256 is compatible with Adobe Reader 9.0 and above. The main reason AES-128 is used is we have found that some Apple iPhones can not view password protected PDF files which are encrypted with AES-256.

If you prefer to use AES-256 its easily changed quickly and simply.