I realize servers such as Google, Yahoo, which use RSA has 2048 bits public key. After comparing those keys, I realize that the public keys share a common property, that is first 9 bytes and last 5 bytes are always the same. Since those public keys have 270 bytes altogether, this means there are only 256 useful bytes, which is 2048 bits. Is this 2048 bits of key secure? I google online and found that it takes a very long time to break 2048 bits of key as mentioned here. But I am not convincing enough. Can anyone explain to me?
1$\begingroup$ FYI, the extra 14 bytes are due to the file format used to store the key, as explained here. $\endgroup$– Matt NordhoffNov 2, 2014 at 4:30
2$\begingroup$ What kind of explaining would it take to convince you? You've already read explanations. What can we say? Have you read other related questions on this website or IT Security? $\endgroup$– Matt NordhoffNov 2, 2014 at 4:59
$\begingroup$ This site gives you the ability to look up the recommended key sizes from various orgs. With regard to asymmetric keys, the estimates for the security of 2048-bit keys (i.e., when there is a reasonable chance they will no longer be safe) is between 2020 and 2030. $\endgroup$– sjuNov 2, 2014 at 15:30