Stark

Stark Industries is a technology company that develops and manufactures advanced weapon and defense technologies.

The Stark repository is a collection of tools related to cryptanalysis.

Key scheduling reversers

DES

DES key scheduling reverser can

• print all round keys from the DES key;
• bruteforce the DES key from the first round key and a pair of plaintext/ciphertext.

Round keys (or subkeys) are 48-bit large and split into eight 6-bit values for mixing with the expanded state. So there are typically two possible representation of a subkey:

• one 48-bit word
• eight 6-bit words

Usage:

des_keyschedule DES_key_in_hex
des_keyschedule Round1_key_in_hex plaintext_in_hex ciphertext_in_hex
des_keyschedule R1.1 R1.2 R1.3 R1.4 R1.5 R1.6 R1.7 R1.8 plaintext_in_hex ciphertext_in_hex

Examples:

des_keyschedule 3032343234363236
des_keyschedule 502CACC603C7 1122334455667788 c403d32e2bc6cfee
des_keyschedule 14 02 32 2C 31 20 0F 07 1122334455667788 c403d32e2bc6cfee

AES

AES key scheduling reverser can

• print all round keys from the AES key;
• print all round keys from any intermediate or final round key(s).

Usage:

aes_keyschedule AES_key_in_hex
aes_keyschedule Round_key(s)_in_hex Initial_round_key_number_between_0_and_10#11#13

The AES key size is deduced from the size of the parameter, so

• for AES-128, provide one round key and its index
• for AES-192, provide one round key concatenated with the first half of the next round key and the index of the starting round key
• for AES-256, provide two concatenated round keys and the index of the starting round key

Examples:

• AES-128: (provide 1 round key)

aes_keyschedule B1BA2737C83233FE7F7A7DF0FBB01D4A
aes_keyschedule 97F926D5677B324AC439D77C8B03FDF8 5
aes_keyschedule FAEF63792F9A97A1FB78C88C4CA7048F 10

• AES-192: (provide 1.5 round keys)

aes_keyschedule B1BA2737C83233FE7F7A7DF0FBB01D4A7835FA62BE9726A1
aes_keyschedule D42AAFEB1510F368D8AA1354A707697696D6CC20F7737995 5
aes_keyschedule 504B601C4EEB5C33B3D208B8E4966BA37B07118538961350 11

• AES-256: (provide 2 round keys)

aes_keyschedule B1BA2737C83233FE7F7A7DF0FBB01D4A7835FA62BE9726A1BB39F261BAC4729C
aes_keyschedule F2E96B6FD53C1BBB49D0990E6FF86927DF8F909C21310695C43D2751C133AC12 5
aes_keyschedule 4D69A4975189FCA00DB0AC8F686EE58C033BE6307A3C13C226DF38591EEAC857 13

SM4

SM4 key scheduling reverser can

• print all round keys from the SM4 key;
• print all round keys from any 4 consecutive intermediate or final round keys.

Usage:

sm4_keyschedule SM4_key_in_hex
sm4_keyschedule Round_keys_in_hex Initial_round_key_number_between_0_and_32

The SM4 key is first XORed with constants FKs, so we also display the value of the key itself.

Example:

sm4_keyschedule 01234567 89ABCDEF 12345678 9ABCDEF0
sm4_keyschedule FA3386F7 7814E4E0 37128B07 BB1231C6 23
sm4_keyschedule C337204D D1C1C4AF 19237F5D AB6618FE 32