IDEA 832 bits Block cipher encryption source code in C. International Data Encryption Algorithm 832 bits.

IDEA uses 128-bit keys. However, the internal keys are much larger. IDEA uses the 128-bit key to generate the 52 * 16-bit subkeys, or 832 bits. The 128-bit limitation of the key is artificial, so it can be enlarged up to 832 bits.

After the patent expired in 2012, IDEA-832 was released. It uses the same principle as IDEA-128 but the 52 subkeys are generated by a one-way hash function.

The result is an algorithm that works at the same speed as the IDEA-128 but with a 832-bit key.

Note that weak keys do not exist in IDEA-832 since subkeys are generated by a one-way hash function.