keygenme-py

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#============================================================================#

#============================ARCANE CALCULATOR===============================#

#============================================================================#

  

import hashlib

from cryptography.fernet import Fernet

import base64

  
  
  

# GLOBALS --v

arcane_loop_trial = True

jump_into_full = False

full_version_code = ""

  

username_trial = "BENNETT"

bUsername_trial = b"BENNETT"

  

key_part_static1_trial = "picoCTF{1n_7h3_kk3y_of_"

key_part_dynamic1_trial = "xxxxxxxx"

key_part_static2_trial = "}"

key_full_template_trial = key_part_static1_trial + key_part_dynamic1_trial + key_part_static2_trial

  

star_db_trial = {

"Alpha Centauri": 4.38,

"Barnard's Star": 5.95,

"Luhman 16": 6.57,

"WISE 0855-0714": 7.17,

"Wolf 359": 7.78,

"Lalande 21185": 8.29,

"UV Ceti": 8.58,

"Sirius": 8.59,

"Ross 154": 9.69,

"Yin Sector CL-Y d127": 9.86,

"Duamta": 9.88,

"Ross 248": 10.37,

"WISE 1506+7027": 10.52,

"Epsilon Eridani": 10.52,

"Lacaille 9352": 10.69,

"Ross 128": 10.94,

"EZ Aquarii": 11.10,

"61 Cygni": 11.37,

"Procyon": 11.41,

"Struve 2398": 11.64,

"Groombridge 34": 11.73,

"Epsilon Indi": 11.80,

"SPF-LF 1": 11.82,

"Tau Ceti": 11.94,

"YZ Ceti": 12.07,

"WISE 0350-5658": 12.09,

"Luyten's Star": 12.39,

"Teegarden's Star": 12.43,

"Kapteyn's Star": 12.76,

"Talta": 12.83,

"Lacaille 8760": 12.88

}

  
  

def intro_trial():

print("\n===============================================\n\

Welcome to the Arcane Calculator, " + username_trial + "!\n")

print("This is the trial version of Arcane Calculator.")

print("The full version may be purchased in person near\n\

the galactic center of the Milky Way galaxy. \n\

Available while supplies last!\n\

=====================================================\n\n")

  
  

def menu_trial():

print("___Arcane Calculator___\n\n\

Menu:\n\

(a) Estimate Astral Projection Mana Burn\n\

(b) [LOCKED] Estimate Astral Slingshot Approach Vector\n\

(c) Enter License Key\n\

(d) Exit Arcane Calculator")

  

choice = input("What would you like to do, "+ username_trial +" (a/b/c/d)? ")

if not validate_choice(choice):

print("\n\nInvalid choice!\n\n")

return

if choice == "a":

estimate_burn()

elif choice == "b":

locked_estimate_vector()

elif choice == "c":

enter_license()

elif choice == "d":

global arcane_loop_trial

arcane_loop_trial = False

print("Bye!")

else:

print("That choice is not valid. Please enter a single, valid \

lowercase letter choice (a/b/c/d).")

  
  

def validate_choice(menu_choice):

if menu_choice == "a" or \

menu_choice == "b" or \

menu_choice == "c" or \

menu_choice == "d":

return True

else:

return False

  
  

def estimate_burn():

print("\n\nSOL is detected as your nearest star.")

target_system = input("To which system do you want to travel? ")

  

if target_system in star_db_trial:

ly = star_db_trial[target_system]

mana_cost_low = ly**2

mana_cost_high = ly**3

print("\n"+ target_system +" will cost between "+ str(mana_cost_low) \

+" and "+ str(mana_cost_high) +" stone(s) to project to\n\n")

else:

# TODO : could add option to list known stars

print("\nStar not found.\n\n")

  
  

def locked_estimate_vector():

print("\n\nYou must buy the full version of this software to use this \

feature!\n\n")

  
  

def enter_license():

user_key = input("\nEnter your license key: ")

user_key = user_key.strip()

  

global bUsername_trial

if check_key(user_key, bUsername_trial):

decrypt_full_version(user_key)

else:

print("\nKey is NOT VALID. Check your data entry.\n\n")

  
  

def check_key(key, username_trial):

  

global key_full_template_trial

  

if len(key) != len(key_full_template_trial):

return False

else:

# Check static base key part --v

i = 0

for c in key_part_static1_trial:

if key[i] != c:

return False

  

i += 1

  

# TODO : test performance on toolbox container

# Check dynamic part --v

if key[i] != hashlib.sha256(username_trial).hexdigest()[4]:

return False

else:

i += 1

  

if key[i] != hashlib.sha256(username_trial).hexdigest()[5]:

return False

else:

i += 1

  

if key[i] != hashlib.sha256(username_trial).hexdigest()[3]:

return False

else:

i += 1

  

if key[i] != hashlib.sha256(username_trial).hexdigest()[6]:

return False

else:

i += 1

  

if key[i] != hashlib.sha256(username_trial).hexdigest()[2]:

return False

else:

i += 1

  

if key[i] != hashlib.sha256(username_trial).hexdigest()[7]:

return False

else:

i += 1

  

if key[i] != hashlib.sha256(username_trial).hexdigest()[1]:

return False

else:

i += 1

  

if key[i] != hashlib.sha256(username_trial).hexdigest()[8]:

return False

  
  
  

return True

  
  

def decrypt_full_version(key_str):

  

key_base64 = base64.b64encode(key_str.encode())

f = Fernet(key_base64)

  

try:

with open("keygenme.py", "w") as fout:

global full_version

global full_version_code

full_version_code = f.decrypt(full_version)

fout.write(full_version_code.decode())

global arcane_loop_trial

arcane_loop_trial = False

global jump_into_full

jump_into_full = True

print("\nFull version written to 'keygenme.py'.\n\n"+ \

"Exiting trial version...")

except FileExistsError:

sys.stderr.write("Full version of keygenme NOT written to disk, "+ \

"ERROR: 'keygenme.py' file already exists.\n\n"+ \

"ADVICE: If this existing file is not valid, "+ \

"you may try deleting it and entering the "+ \

"license key again. Good luck")

  

def ui_flow():

intro_trial()

while arcane_loop_trial:

menu_trial()

  
  
  

# Encrypted blob of full version

full_version = \

b"""

gAAAAABpRaLynVVsfWihmzH_LerSsmI7O_aFWeZRhgUuxmiqwegf8JxyPBwGgY_wpocHh5BUxHy7qEmJcAI-BxZQeAZ5Ziiwc4UYl4ZNb4avb1vkPlQvhSVzMek4iFNsw0wuDiMrS_4Sz_GhOHPFHp9F8OI7rwh8nteVlUfiGvymXFZQ1CdqnEC3rd-8DQ8Dc9-13ohD4QVmwfeYtRNbPmb3qCzdL20gT064v4PpVgzzQq4o08SSvVDxZEe2ktq1YjEHddm0MMqCn4qxO2x9218HzP2WaMatvuwFw3nWKOx4XQMV0gBzDVuPunoPJ_WOTQa3zUmI2Fin1Ija3oIIrjU6JyC796_quQkg3hw4iV_6pERHujMI_k8Vc6tkSWyMaB5daabBKNN_iHRRb_cyM04GjmLTWY347ec8KBhNF7DiC3VC91y3h-twvMGsbUCmGSbJsUAMiMq0GEv-SXTKcbk2YxYEYcQUDWcsaDeOQ3-P6QklVj5sTtNq7Gu0r2xVHjRjiO4hgUAlppU7xFhYArFzrFzwSRfYGo1AHXFdkkrIoq5Igz3lOwsw3KRK6QdkiG2ZiTr7lKqhE7RoBEx38YTx6S-Ttb7OdlGAo-x2AM0aj3uOLgT_JHU6_I-4EhkjmSm3BeA50jrtXpe5A033LK3sdz4b4X4hRXK9b1vQIi5R5Oz01VzLkcXMaTYTPJw7ajV10ohnckTUKdQ_uYErpDVxi_qh1gAPU0ukO7nYNwD0mISLCaV30kq6EI9JxtrVq6d0nzBjie-Q8Afw-MhRnnh0NCc4cON1P2dEMeTngPqIZGkE2Q7QhH21ptyYQmZFF0r7OeIigEa-40tDmVZLk8c9oXkiSPmL63vl8IzfMFsysj6yeSYIZjFgjH77CMuTY322N_IHvCfZyK224iMU99iiOP2tdy0IqMPgXlXf28dYmFghlc2Wu1Sj10h8hrnk_XBOEDq2NPSaoPWtVOEpB18HyZqRd6dvxCYV9V4Sb8U5k5N314fnh0X5TYrceghtRyuYecZglPg05XGT5nsHWEt6b6AtHN8GEhzMCR6LUODqGohNo2_X2Vr5RRwk5lgbqQe362cy0CPnfNaEg0q3htQNx3Y_YwxfR6pT-S8GEc8g1MpSFWb41uVxgb91FPwUOmRQWxVfxjkjXldOw_NAAR3ufhZd9sCWlOJR61sZ1t99ol5qb5NK_b-gDymRf2G1y7jydKb4z-7XYlJWGNkvZ86VgtoUzxjh0ahAfl5rGNtlJcdk4quMhTT0PzVOUXpSRBHAZOKhcGbawlI8WBNfmhjgqy3LHA0bydUuDvAZqDkjjeIyrvTjCPyXGoJf1F4yDYuINO60gCNN5RMikst7NDRiNXpkxczv237Q8LFAUQAz-kq-jRNoEKRe1Y63lezB69BqGDYp7vhcPWlalGpCNVXzw_1hf8xa7GXX4PYnQ0iPS2obl_Oy6reieoyHd7_4MRClcR1k6tWcI6EDVTNdI7IULCyY38T_ii2jW0C_PX7y7UKhQdReDdRflfmsrLGPQnRTO7OtcApjQiLMRKMhxLPiqFBg9hZ0YpuGcDazMsE0yQ-2yiGzTouzEOpnnNp_VFvLDlTO7ujXnWF0CrrCTXSnZxKYxmnIcwtDM-65tDEyWkvbEaZTIpaU0nPLMq7y5LDuO8vcStxoDGrSDH-I5rtKhQptvvnHeobwMdat1PqfpDX5wDhwPt36rkhaRcvCfih3kIpaNf6smxxZfFdQb66e8jkeVYD0VtfwM9H9PY64yJJ7za1Nt-G9ipEwJCSMUHf8srxKv2uFMVRYiBaacF3UI8UZqOhj1-7KcP7frmAZ8wUxWj7Kjze2jrj5g90Fw8ldZalk2ab_7iCpAlnI1Qm8M7qBE4U3wAWY4hKqxxfgVkPkDUzkVAlJQhp79MCG-Gkrkvx6CmIMkNyWj-jZHboSG8Nm2xz8Zyj_BJAObrOBUrxpiXpOHeJPMI0-2Wfr0Q0vAlxcRoPgZe5m778cq4EV3zYp6aukbIXn5ud8G_k78m9NPRSyt84I7D5fD-RlXVOvyAxBS4QIuMy3QWHfBUf1rsC9JbFnduqaoxnCDLMq2GlSwIzv8IL1TH2MdRR6uEvSw3vQHir_h0Owm3U6p57cfiSkArq81hhuVZNMzqJYcDn_RaSjGzoY1o_QrVH4oXkoBdn0axa-5DAWFqUQnlHeLluxzQIpJyfkTPslUfy048v7vaDn9g71WwRtP7M3_nioksJYzSnCozjKa8iXwL6kXwpJwOMKDGhGym2Y959-bE2Ihk2DzSDObDUEiTJe4zcgl9KWOIYvR5V87u7B-lUf1f2YDd__nnvBf-nkcIcKY0sqk03IoQVnZPteDjEoDsV0qTIQRBXzt5hd_bhy5uZPVv_WweeU9-vstbkc0h1eJbXo5jPanmFqIpX-lWH9oaEfkYOAjDssaYgj9f6VlAez8HynM8m7_PmFNiJmhDd6Y8VmFgnF9hepYLz0l8zyPXYn1k53oRawI3PEMbNPjeujoH2R9SFErZz6CAKHwVsQmFla6dR2UL8jDhs-COG6nwmE-QbCBB4ureuAgKxY_CEeSIqnirL6z9lhJHlaoWqdxwlm_jg9w2y4iNhr68gSwof9Mm62yRc-2nfZTEagxmi2847ENSEuEWWHNgYvSkQjaBgZAQsIMc3WYH9rfIFcbtb3EScgLF05iKjhQ72ebfL-kEjF_0P6Q1eNWOXtRYXKPHoIYZ990ByUUKBERZPPcbGW7Wl8eA-q_2yXfiI9M7Os5iAF1ODMwgYJwfj-fHKSkw5MICkeKcnW9NOnXsJeThoCCtsxotltek8QEwlOhBZFyQRc6zZLS-gjfIJZrj5Txf9G7wS7Sn7Xe4Vfdo5fY3wPJt8mDFaj2kEEhxlcQ8m6fQdfPRbWcqZDEARRolRgRs5js84z-pgh2GzBLRztSf9bvEuAy7oL3INRRPSUwRWNTzVIfuns3I7O4RdVzsU7YR2gTXI7GKKYLMg_tje0uzwrVRXDDr34ridJx37yjLRo756u_PMD8WqmsLzaC3WGzU45cHt0bQL8m9YAeEhHVVf5wEo97Wo9DsfPVozmXu8Vv-yO9t1XnCyBh-PN9-LeX_7R-QamTbqm5IQtVBCO4EQkkwth-8zctCJl5XrKJbY8yTgHsmhlTRkEnyO5MQ0RCKXrLeKuQ55ghAWrPgEXzgDPsmi3PC_abFXQVjm4tUDHl72X6Gv89IOhXpazS75UNSW2SXl5uikaZgqEIwLYxdGofPsVExeuWaxwtrmySpoRKT4ljpSNm-fq837arq39wj-2tp7W1n2VvanL466OrcplwMxf-lYoGxN8uEAXajGEFTHOj2djg6-RyhpRFmWKEjp2rDtK0sVEr8AiIE_eIpTQnwUM9VEkAL-AImbYYqK6s-aAoYqTGYwCPd7Ah7b1ZWgYQ-2WueA0tSdHpUy9ks8apmMNAl97_BYKRkUuhdal5gzgsI0xIr24slj7COVxlIQt7KF-Z-KED5Y4sKv922K6Ts34HHpB9cHCBgJbug8mSBIB9Bc5gijMbRaQskv_2Bq2b9ifbufapOzeCuVOKgxYoDddb7R5dgqQ_NdzOtA3aWwqh5KMLa1flAlIR22nj_TfFUVgnAKGubolLZGwJFFXHYAQneg1WozJPH9geqp6F0AF09sHOE3MfWiKdwbgdj6pcMm8N59NOsr0qBt5zehp03DVCPwVL2Smnm2RqWQPZke-d9o_WBlYvFRQuusXXrTMQQ4k7qAJ47fC85ff1q60sT8PWtdSxMQxTxYUQFwGw1EuzutWOU6OFdgLowiFlvxGB73a5RdEWUd6l25J2qEnmRM9cnP0CFBsWkCM6pIPZzZg9DA6Jg==

"""

  
  
  

# Enter main loop

ui_flow()

  

if jump_into_full:

exec(full_version_code)

Focus on check_key(), the function that validates the key.

The source code provided the static parts of the flag:

key_part_static1_trial = "picoCTF{1n_7h3_kk3y_of_"
key_part_dynamic1_trial = "xxxxxxxx"
key_part_static2_trial = "}"

The xxxxxxxx portion is generated from the SHA-256 hash of the username. The username is defined as:

username_trial = "BENNETT"
bUsername_trial = b"BENNETT"

The code showed how to recover key_part_dynamic1_trial: hash the username “BENNETT” and take the characters at indices 4, 5, 3, 6, 2, 7, 1, and 8.

hashlib.sha256(username_trial).hexdigest()[4]
hashlib.sha256(username_trial).hexdigest()[5]
hashlib.sha256(username_trial).hexdigest()[3]
hashlib.sha256(username_trial).hexdigest()[6]
hashlib.sha256(username_trial).hexdigest()[2]
hashlib.sha256(username_trial).hexdigest()[7]
hashlib.sha256(username_trial).hexdigest()[1]
hashlib.sha256(username_trial).hexdigest()[8]

Use this one-line command to do that:

python3 -c 'import hashlib; h=hashlib.sha256(b"BENNETT").hexdigest(); print(h); print("".join(h[i] for i in [4,5,3,6,2,7,1,8]))'

The value of xxxxxxxx was 08c46aa4.

Insert this value between the static parts of the flag:

picoCTF{1n_7h3_kk3y_of_08c46aa4}

DONE!!!

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