Schneier has been around for a long time, knows the industry well and has made significant contributions. Not everyone get's things right all the time including Schneier.
Credibility wise he ..
- has a master's degree in computer science
- was awarded an honorary Ph.D from the University of Westminster in London
- is chief technology officer of BT Managed Security Solutions
15 publications, 6 notable books -
- Applied Cryptograph
- Cryptography Engineering
- Secrets and Lies: Digital Security in a Networked World
- Beyond Fear: Thinking Sensibly About Security in an Uncertain World
- Liars and Outliers: Enabling the Trust that Society Needs to Thrive
- Data and Goliath: The Hidden Battles to Collect Your Data and Control Your World
Reference: https://en.wikipedia.org/wiki/Bruce_Schneier