Retrieval of Ice Samples Using the Ice Drone

The ecological impacts of meltwater produced by icebergs and sea ice in the waters around Greenland are poorly understood, due in part to limited observations. Current field sampling methods are resource and labor-intensive, and not without significant risk. We developed a small, unoccupied, and robotic platform to retrieve ice samples, while simultaneously eliminating safety risks to scientists and their support infrastructure. The IceDrone consists of a modified commercial hexcopter that retrieves ice samples. We describe the design requirements, construction, and testing of the IceDrone. IceDrone's capabilities were validated in the laboratory and during a field test in January 2019 near Nuuk (southwest Greenland). IceDrone retrieved samples in hard and dry glacial ice in harsh winter conditions. The field test led to modifications in the drilling head design and drilling process that enable it to retrieve samples in thin sea ice. All design files and software are provided in an attempt to rapidly enhance our collective understanding of ice-ocean interactions while improving the safety and productivity of field sampling campaigns

Pseudo-cryptanalysis of the Original Blue Midnight Wish

The hash function Blue Midnight Wish (BMW) is a candidate in the SHA-3 competition organised by the U.S. National Institute of Standards and Technology (NIST). BMW was selected for the second round of the competition, but the algorithm was tweaked in a number of ways. In this paper we describe cryptanalysis on the original version of BMW, as submitted to the SHA-3 competition in October 2008. When we refer to BMW, we therefore mean the original version of the algorithm. The attacks described are (near-)collision, preimage and second preimage attacks on the BMW compression function. These attacks can also be described as pseudoattacks on the full hash function, i.e., as attacks in which the adversary is allowed to choose the initial value of the hash function. The complexities of the attacks are about 2 14 for the near-collision attack, about 2 3n/8+1 for the pseudo-collision attack, and about 2 3n/4+1 for the pseudo-(second) preimage attack, where n is the output length of the hash function. Memory requirements are negligible. Moreover, the attacks are not (or only moderately) affected by the choice of security parameter for BMW

The Grindahl Hash Functions

Abstract. In this paper we propose the Grindahl hash functions, which are based on components of the Rijndael algorithm. To make collision search suf-ficiently difficult, this design has the important feature that no low-weight characteristics form collisions, and at the same time it limits access to the state. We propose two concrete hash functions, Grindahl-256 and Grindahl-512 with claimed security levels with respect to collision, preimage and sec-ond preimage attacks of 2128 and 2256, respectively. Both proposals have lower memory requirements than other hash functions at comparable speeds and security levels