Security of AES ECB for 128 bit random data I am using AES ECB mode to encrypt and decrypt 128 random data. I have read on drawbacks on using ECB but it seems that it is feasible to use it for random data. However my concern is that my implementation provides an oracle. What i am concerned is key extraction. Would it be possible in reasonable time or possible at all? Again the data is random, basically server generates 128 random bits and sends it to client, the clien then encrypts it and sends it back to server. However client and server communicate via a third party (tethered way) so third party can see both plaintext and ciphertext.

My two questions are:
is it safe to use AES ECB when both plaintext and ciphertext are visible to a third party? (random data, replay is not a concern)

Also there is a case where it becomes an oracle (if i am using it correctly) anyone can send 128 bits data and get cipher of it back.. (possible but not that practical, though i am wondering of its implications)?
AES is designed so that it is infeasible to derive the key with only the plaintext and ciphertext. It's part of the definition of a strong cipher.  

At the risk of sounding like a broken record, the real problem with ECB is that the same input blocks produce the same output blocks. This is devastating if your data is more than 128 bits. Other modes prevent this by adding in some randomness as well as having previous blocks affecting future blocks.  

Another security feature added by some modes is authentication. They provide a way to prove your data came from the place you expect it did, and to prove it wasn't tampered with. Without authentication, attackers could corrupt a single block of your data without you being able to directly tell (barring non cryptographic methods, such as checking if the decrypted data makes sense, but thats a lot less strong).  

If all you need is secrecy, and integrity and authentication is of absolutely no concern to your threat model, and you guarantee the same block isn't ever encrypted twice, then encrypting 16 bytes (128 bits) of random data with AES ECB is okay.