diff options
Diffstat (limited to 'templates/nonce-reuse.html')
| -rw-r--r-- | templates/nonce-reuse.html | 160 |
1 files changed, 87 insertions, 73 deletions
diff --git a/templates/nonce-reuse.html b/templates/nonce-reuse.html index 9761955..2637d50 100644 --- a/templates/nonce-reuse.html +++ b/templates/nonce-reuse.html @@ -32,6 +32,88 @@ forge arbitrary ciphertext. </p> <br> + {% if form.errors %} + <div class="errors"> + Errors: + <ul> + {% for name, errors in form.errors.items() %} + {% for error in errors %} + <li> {{name}}: {{ error }} </li> + {% endfor %} + {% endfor %} + </ul> + </div> + {% endif %} + <form action="/forbidden-salamanders/nonce-reuse" method="post"> + <div><em> + Roseacrucis chooses a key, a nonce, and two messages. He encrypts both messages under the same nonce. + </em></div><br> + + <div> + <label for="key">Key (16 bytes in hex)</label> + <input name="key" id="key" type="text" value="{{ key if key else '746c6f6e6f7262697374657274697573' }}" minlength=32 maxlength=32 required> + </div> + + <div> + <label for="nonce">Nonce (12 bytes in hex)</label> + <input name="nonce" id="nonce" type="text" value="{{ nonce if nonce else '4a4f5247454c424f52474553' }}" minlength=24 maxlength=24 required> + </div> + + <div> + <label for="m1">First intercepted message</label> + <input name="m1" id="m1" type="text" required maxlength=64 value="{{m1 if m1 else 'The universe (which others call the Library)'}}"> + </div> + + <div> + <label for="m2">Second intercepted message</label> + <input name="m2" id="m2" type="text" required maxlength=64 value="{{m2 if m2 else 'From any of the hexagons one can see, interminably'}}"> + </div> + + <br><div><em> + After intercepting the ciphertexts, you choose a new message to forge under the same key and nonce. + </em></div><br> + + <div> + <label for="mf">Forged message; shorter than the first message</label> + <input name="mf" id="mf" type="text" required maxlength=64 value="{{mf}}"> + </div> + + <div> + <button type="submit">Recover authentication key and forge MAC</button> + </div> + </form> + <form action="/forbidden-salamanders/nonce-reuse" method="get"> + <div> + <button type="submit">Reset</button> + </div> + </form> + {% if macs %} + <div class="solution"> + <p> + Forged ciphertext: <code>{{ c_forged.hex() }}</code> + {% if macs|length == 1 %} + <br> + Forged MAC: <code>{{macs[0][2].hex()}}</code> + <br> + Authentication key: <code>{{macs[0][0].hex()}}</code></li> + {% endif %} + </p> + {% if macs|length != 1 %} + Forged MAC candidates: + <ul> + {% for h, _, mac in macs %} + <li> + MAC: <code>{{mac.hex()}}</code> + <ul class="inner-ul"> + <li>Authentication key: <code>{{h.hex()}}</code></li> + </ul> + </li> + {% endfor %} + </ul> + {% endif %} + </div> + {% endif %} + <br> <details> <summary> Attack outline. @@ -84,61 +166,6 @@ in this case, one can check each possibility online. </p> </details> - <br> - <form action="/forbidden-salamanders/nonce-reuse" method="post"> - <div> - <label for="key">Key (16 bytes in hex)</label> - <input name="key" id="key" type="text" value="{{ key.hex() if key else '59454c4c4f575f5355424d4152494e45' }}" minlength=32 maxlength=32> - </div> - - <div> - <label for="nonce">Nonce (12 bytes in hex)</label> - <input name="nonce" id="nonce" type="text" value="{{ nonce.hex() if nonce else '4a4f5247454c424f52474553' }}" minlength=24 maxlength=24> - </div> - - <div> - <label for="m1">First intercepted message (in ASCII)</label> - <input name="m1" id="m1" type="text" required maxlength=100 value="{{m1}}"> - </div> - - <div> - <label for="m2">Second intercepted message (in ASCII)</label> - <input name="m2" id="m2" type="text" required maxlength=100 value="{{m2}}"> - </div> - - <div> - <label for="mf">Forged message; shorter than the first message (in ASCII)</label> - <input name="mf" id="mf" type="text" required maxlength=100 value="{{mf}}"> - </div> - - <div> - <button type="submit">Recover authentication key and forge MAC</button> - </div> - </form> - {% if macs %} - <div> - <p> - Forged ciphertext: <code>{{ c_forged.hex() }}</code> - </p> - Forged MAC candidates: - <ul> - {% for h, _, mac in macs %} - <li> - MAC: <code>{{mac.hex()}}</code> - <ul> - <li>Authentication key: <code>{{h.hex()}}</code></li> - </ul> - </li> - {% endfor %} - </ul> - <form action="/forbidden-salamanders/nonce-reuse" method="get"> - <div> - <button type="submit">Reset</button> - </div> - </form> - </div> - {% endif %} - <br> <details> <summary> Show me the code. @@ -148,10 +175,8 @@ from <a href="/git/forbidden-salamanders">aesgcmanalysis</a> import xor, gmac, g k = b"tlonorbistertius" nonce = b"jorgelborges" -m1 = b"The universe (which others call the Library)" -aad1 = b"The Anatomy of Melancholy" -m2 = b"From any of the hexagons one can see, interminably" -aad2 = b"Letizia Alvarez de Toledo" +m1, aad1 = b"The universe (which others call the Library)", b"" +m2, aad2 = b"From any of the hexagons one can see, interminably", b"" c1, mac1 = gcm_encrypt(k, nonce, aad1, m1) c2, mac2 = gcm_encrypt(k, nonce, aad2, m2) @@ -161,21 +186,10 @@ possible_secrets = nonce_reuse_recover_secrets(nonce, aad1, aad2, c1, c2, mac1, # Forge the ciphertext m_forged = b"As was natural, this inordinate hope" -assert len(m_forged) <= len(m1) -c_forged = xor(c1, xor(m1, m_forged)) -aad_forged = b"You who read me, are You sure of understanding my language?" +c_forged, aad_forged = xor(c1, xor(m1, m_forged)), b"" -# Check possible candidates for authentication key -succeeded = False for h, s in possible_secrets: - mac_forged = gmac(h, s, aad_forged, c_forged) - try: - assert gcm_decrypt(k, nonce, aad_forged, c_forged, mac_forged) == m_forged - succeeded = True - print(c_forged.hex(), mac_forged.hex()) - except AssertionError: - pass -assert succeeded</pre></details> + print("MAC candidate": gmac(h, s, aad_forged, c_forged))</pre></details> <details> <summary> Show me the math. @@ -219,7 +233,7 @@ for factor, _ in p.factor(): </p> <ul> <li>The gcd of two polynomials is unique only up to multiplication by a non-zero constant because “greater” is defined for polynomials in terms of degree. When used in algorithms, gcd refers to the <em>monic</em> gcd, which is unique.</li> - <li>The <a href="https://math.stackexchange.com/a/943626/1084004">inverse Frobenius automorphism</a> (i.e., square root) in \(\mathbb{F}_{2^{128}}\) is given by \(\sqrt{x} = x^{2^{127}})\).</li> + <li>The <a href="https://math.stackexchange.com/a/943626/1084004">inverse Frobenius automorphism</a> (i.e., square root) in \(\mathbb{F}_{2^{128}}\) is given by \(\sqrt{x} = x^{2^{127}}\).</li> </ul> </details> <script> |