According to this Matasano Crypto challenge, the NIST "likes" the following prime modulus, which appears to be expressed in hexadecimal:
I have a few questions about it:
Is this number specified anywhere? I tried Googling it, both in decimal and in hexadecimal, hoping to find it somewhere, maybe in a NIST document, but I couldn't find it anywhere.
Why was this particular number picked? I know that Diffie-Hellman requires a prime modulus, and it should be big enough to prevent certain factoring attacks, and it should also be a safe prime, also to prevent certain factoring attacks, but there are lots of numbers with these properties. Was that number chosen somewhat arbitrarily, or were there any other criteria used to pick it?
Is this number used for anything other than Diffie-Hellman, like maybe RSA or elliptic curve algorithms?