Cryptographic standards like the PKCS#1-v1.5 signature scheme for RSA are essential for secure digital communications, yet cryptographic libraries remain vulnerable. Fuzzing, a security testing technique, often struggles to detect memory-safety bugs in these libraries due to the need for context-sensitive inputs—those with complex semantic relationships between their fields. This paper presents a preliminary study that evaluates 7 uzzers for their ability to generate such inputs across 5 libraries implementing the PKCS#1-v1.5 signature verification scheme. Our findings reveal performance variations among the fuzzers and highlight their limitations with context-sensitive inputs.