# Big data and modern crypto systems

Throughout history, some cryptographic systems were broken by finding patterns in encrypted messages (like frequent chars in a particular language), and thereby discovering the cipher. These classic systems, which relied on algorithms unknown to the attacker, were broken by analyzing the messages and detecting patterns. This allowed attackers to induce the algorithm that was used.

The security of modern cryptography is based on a large key and applying non-reversible mathematics to a message to obtain an encrypted message. In these modern systems it is impossible to apply reverse engineering to a message because it requires more computational capacity than available.

Since there is currently a lot of storage capacity to store an giant amount of encrypted messages, knowing that it was generated with the same key and the same algorithm, it is not possible to analyze them, for instance by finding repetitive patterns, to be able to deduce the key?

• In general, if the design of the algorithm is right, you can not find patterns, for instance in AES (until now), no such pattern was found. But, there are algorithms, for instance in RC4, where such patterns exist (see en.wikipedia.org/wiki/RC4). The "giant" store that you can make today I don't think that is really giant and capable for the cryptanalysis of modern cryptosystems. – 111 Jan 21 '17 at 13:07
• If you try really hard I can see $2^{64}$ (128 EiB) cipher texts being stored for analysis. However chances are you'll never see that many under a single key. Though this storage may be useful for some time-memory trade-offs chances are there are easier ways to get where you want (eg by "hacking" the participants or htting them with a wrench). – SEJPM Jan 21 '17 at 13:21