[vc_row height=”medium” us_bg_overlay_color=”#f5f5f5″ us_shape_show_bottom=”1″ us_shape_color_bottom=”#ffffff” css=”%7B%22default%22%3A%7B%22background-color%22%3A%22%23f5f5f5%22%7D%7D”][vc_column width=”5/6″][vc_column_text css=”%7B%22default%22%3A%7B%22color%22%3A%22%23023047%22%7D%7D”]

STAP block ciphers

[/vc_column_text][us_separator][/vc_column][vc_column width=”1/6″][/vc_column][/vc_row][vc_row height=”small” us_bg_overlay_color=”#ffffff”][vc_column][vc_column_text css=”%7B%22default%22%3A%7B%22color%22%3A%22%23023047%22%2C%22font-family%22%3A%22Source%20Code%20Pro%22%2C%22background-color%22%3A%22%23ffffff%22%7D%7D”]Given a key k, a block cipher E_k is a family of permutations that takes a fixed-sized block as input and returns an encrypted message of the same size.[/vc_column_text][/vc_column][/vc_row][vc_row height=”small” color_scheme=”alternate” us_bg_overlay_color=”#ffffff” css=”%7B%22default%22%3A%7B%22background-color%22%3A%22%23ffffff%22%7D%7D”][vc_column width=”1/12″][/vc_column][vc_column us_bg_overlay_color=”#ffffff” link=”%7B%22url%22%3A%22%22%7D” width=”11/12″][vc_column_text css=”%7B%22default%22%3A%7B%22color%22%3A%22%231a1a1a%22%7D%7D”]Block ciphers are usually built by iterating a round function; a process that is repeated r times (sub-keys might optionally be derived from a key schedule algorithm applied to the master key), where r is chosen such that the cipher offers a good security margin and efficiency when evaluating the function.[/vc_column_text][vc_row_inner][vc_column_inner width=”1/2″][us_image image=”1345″ size=”medium” link=”%7B%22url%22%3A%22%22%7D”][/vc_column_inner][vc_column_inner width=”1/2″][us_image image=”1346″ size=”us_600_600″ link=”%7B%22url%22%3A%22%22%7D”][/vc_column_inner][/vc_row_inner][vc_row_inner][vc_column_inner][vc_column_text css=”%7B%22default%22%3A%7B%22color%22%3A%22%231a1a1a%22%7D%7D”]A block cipher is said to be secure if E_k, with a randomly chosen key, is indistinguishable from a random permutation. Thus, each round in the iterated construction must bring some confusion (such that changing the input has an unpredictable effect on the output) and diffusion (such that changing a few entries in the input changes many entries in the output).

The most common round function constructions are Feistel networks and Substitution Permutation Networks (SPNs).[/vc_column_text][/vc_column_inner][/vc_row_inner][/vc_column][/vc_row][vc_row height=”small” color_scheme=”alternate” us_bg_overlay_color=”#ffffff” css=”%7B%22default%22%3A%7B%22background-color%22%3A%22%23ffffff%22%7D%7D”][vc_column us_bg_overlay_color=”#ffffff” link=”%7B%22url%22%3A%22%22%7D”][vc_custom_heading text=”Constructions” font_container=”tag:h2|font_size:42|text_align:left|color:%23219ebc” google_fonts=”font_family:ABeeZee%3Aregular%2Citalic|font_style:400%20regular%3A400%3Anormal”][us_separator size=”small”][vc_row_inner][vc_column_inner width=”1/2″][vc_column_text css=”%7B%22default%22%3A%7B%22color%22%3A%22%23023047%22%2C%22font-size%22%3A%2230px%22%7D%7D”]

Feistel networks

[/vc_column_text][vc_column_text css=”%7B%22default%22%3A%7B%22color%22%3A%22%231a1a1a%22%7D%7D”]In a Feistel network, the input x is divided into two parts: x_L and x_R, each of size n/2 bits.[/vc_column_text][us_image image=”1349″ align=”center” size=”medium” link=”%7B%22url%22%3A%22%22%7D”][us_separator size=”small”][us_image image=”1348″ align=”center” size=”medium” link=”%7B%22url%22%3A%22%22%7D”][us_separator size=”small”][vc_column_text css=”%7B%22default%22%3A%7B%22color%22%3A%22%231a1a1a%22%7D%7D”]A well-known Feistel cipher is the Data Encryption Standard (DES), which is no longer used because of its small key space, allowing a systematic attack in a reasonable amount of time.[/vc_column_text][/vc_column_inner][vc_column_inner width=”1/2″][vc_column_text css=”%7B%22default%22%3A%7B%22color%22%3A%22%23023047%22%2C%22font-size%22%3A%2230px%22%7D%7D”]

SPNs

[/vc_column_text][vc_column_text css=”%7B%22default%22%3A%7B%22color%22%3A%22%231a1a1a%22%7D%7D”]An SPN comprises three components: an S-box layer S, a diffusion layer M, and a sub-key addition AddK.[/vc_column_text][us_separator size=”small”][us_image image=”1350″ align=”center” size=”medium” link=”%7B%22url%22%3A%22%22%7D”][us_separator][vc_column_text css=”%7B%22default%22%3A%7B%22color%22%3A%22%231a1a1a%22%7D%7D”]The most widely used block cipher (and best-known symmetric encryption) is the Advanced Encryption Standard (AES), considered the most secure in the community.[/vc_column_text][/vc_column_inner][/vc_row_inner][/vc_column][/vc_row][vc_row height=”small” color_scheme=”alternate” us_bg_overlay_color=”#f5f5f5″ css=”%7B%22default%22%3A%7B%22background-color%22%3A%22_header_middle_bg%22%7D%7D”][vc_column link=”%7B%22url%22%3A%22%22%7D” css=”%7B%22default%22%3A%7B%22background-color%22%3A%22%23f5f5f5%22%7D%7D”][vc_row_inner content_placement=”middle” css=”%7B%22default%22%3A%7B%22background-color%22%3A%22%23f5f5f5%22%2C%22border-style%22%3A%22solid%22%2C%22border-color%22%3A%22%231a1a1a%22%7D%7D”][vc_column_inner width=”1/12″][/vc_column_inner][vc_column_inner us_bg_overlay_color=”#f5f5f5″ link=”%7B%22url%22%3A%22%22%7D” css=”%7B%22default%22%3A%7B%22background-color%22%3A%22%23f5f5f5%22%2C%22border-radius%22%3A%225px%22%2C%22border-style%22%3A%22double%22%2C%22border-left-width%22%3A%2255%22%2C%22border-top-width%22%3A%2244%22%2C%22border-bottom-width%22%3A%2255%22%2C%22border-right-width%22%3A%2255%22%2C%22border-color%22%3A%22%23023047%22%2C%22box-shadow-blur%22%3A%223px%22%2C%22box-shadow-color%22%3A%22%23023047%22%7D%7D” width=”10/12″][vc_custom_heading text=”STAP Lounge” font_container=”tag:h2|font_size:42|text_align:center|color:%23219ebc” google_fonts=”font_family:ABeeZee%3Aregular%2Citalic|font_style:400%20regular%3A400%3Anormal”][vc_column_text css=”%7B%22default%22%3A%7B%22color%22%3A%22%23333333%22%7D%7D”]

The STAP Zoo currently collects information about the following list of STAP block ciphers:

◊ Arion
◊ Chaghri
◊ GMiMC
◊ Grendel
◊ Griffin
◊ LowMC
◊ MARVELlous design (Jarvis)
◊ Marvellous designs (Rescue and Vision)
◊ MiMC
◊ Poseidon variants (HadesMiMC)
◊ RAIN
◊ Small-pSquare

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