RSA, Elliptic Curve, DSA, and Elgamal ECES Practice Questions (Page 5)

Questions 21–25

1. 21foundation · easy

   In elliptic curve cryptography, what is the result of adding two distinct points P and Q on an elliptic curve over a finite field?

   • AThe average of the x-coordinates of P and Q
   • BThe point at infinity, regardless of P and Q
   • CA third point R on the curve, computed by drawing a line through P and Q and reflecting the intersection point across the x-axis
   • DThe product of the x-coordinates of P and Q
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2. 22foundation · easy

   In RSA key generation, which two values are used to compute the modulus n?

   • AThe totient φ(n) and the private exponent d
   • BTwo distinct large prime numbers p and q
   • CThe public exponent e and the private exponent d
   • DA prime p and a generator g
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4. 23foundation · easy

   Which of the following is a required step in ECDSA signature verification?

   • AEncrypt the signature with the public key
   • BCompute w = s⁻¹ mod n and use it with the public key and the hash to derive a point
   • CCompute the private key from the signature
   • DDecrypt the message with the private key
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5. 24expert · medium

   A security architect is comparing RSA and ECC for a new PKI. The PKI will issue certificates for millions of IoT devices, and the certificates will be stored on the devices. The architect must minimize certificate size and signing time. Which approach is best?

   • AUse Elgamal with 2048-bit keys, because it supports both encryption and signatures
   • BUse RSA with 2048-bit keys, because RSA signing is faster than ECC signing
   • CUse DSA with 1024-bit keys, because it is a federal standard
   • DUse ECC with a 256-bit curve, because it provides smaller certificates and faster signing
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6. 25expert · medium

   A company is evaluating encryption schemes for a new secure email system. The system requires public-key encryption and must support both encryption and digital signatures. The team is considering Elgamal and RSA. Which consideration is most important when choosing between them?

   • AElgamal provides better security because it is based on the discrete logarithm problem
   • BRSA is more widely supported and standardized for both encryption and signatures
   • CElgamal is faster for encryption because it uses modular exponentiation
   • DRSA is more efficient for key generation because it only requires prime selection
   Reveal Solution Discussion Select an answer first