Cisco Certified Network Associate (CCNA) Practice Exam

What is the key length range for SSL?

1. 128 - 256

2. 256 - 512

3. 40 - 128

4. 10 - 40

The correct answer is: 40 - 128

The key length range for SSL (Secure Sockets Layer) cryptographic protocols typically starts at 40 bits and can go up to 128 bits. This range is significant because it ensures a balance between security and performance. A key length of 40 bits provides a basic level of encryption, which can be susceptible to attacks, while 128 bits offers a much stronger level of security against modern threats. In practical applications, SSL implementations often use key lengths such as 128 bits and 256 bits, but the existence of 40-bit keys historically appears within SSL as a part of older encryption standards. However, modern usage has shifted away from these weaker keys due to the significant vulnerabilities associated with them. In comparing the ranges offered in the other choices, the higher ranges do not reflect the typical SSL key length requirements. Hence, the selection that best matches the commonly recognized key length for SSL is the one that includes 40 to 128 bits.