nothing-up-my-sleeve number

In reference to magic tricks in which the performer may have something concealed in a sleeve (or may demonstrate to the audience that they do not).

nothing-up-my-sleeve number (plural nothing-up-my-sleeve numbers)

1. (cryptography) A number which, by its construction, is above suspicion of having hidden properties; used in creating cryptographic functions such as hashes and ciphers.
   • 2014 May, Mr. Ajay Bhaisare, “Data Protection Outsourcing of Cloud Data to Maintain Trust between Cloud Service and Data Owner Using RC5 Algorithm”, in IJCSMC, volume 3, number 5, page 608:

     The key schedule, however, expanding the key using an essentially one-way method, is more complex, with the binary expansions of both e and the golden ratio of "nothing up my sleeve numbers".

   • 2017, Manul Laphroaig, PoC or GTFO:

     Anyway, they make the same point: “The BADA55-VPR curves illustrate the fact that 'verifiably pseudorandom' curves with 'systematic' seeds generated from 'nothing-up-my-sleeve numbers' also do not stop the attacker from generating a curve with a one-in-a-million weakness.”