Len and Finney shared one very rare and relevant skillset: they both were developers of the remailer technology that was a precursor to Bitcoin.
Satoshi’s second post about Bitcoin stated that pay-to-send email was Bitcoin’s first working use case.
[Adam] Back’s own interest in cryptocurrency started from running a remailer, and he created the HashCash proof of work system for remailer operators to combat spam and DDOS attacks.
Interestingly, Back himself has suggested that Satoshi might have been a remailer developer, noting that the devs would “[practice] their own technology” to pseudonymously contribute to cryptographic protocol discussions.
This next one was a weird claim to make, I didn't see where it was confirmed..
Unlike many Cypherpunks discussed, we know that Len made extensive pseudonymous contributions to the Cypherpunk mailing list via remailers.
... the list goes on ...
Len’s Ph.D. advisor at COSIC was none other than “father of digital currency” David Chaum. While Chaum laid the groundwork for the entire Cypherpunk movement and all cryptocurrencies, few could claim to have worked with him directly.
Len’s research was focused on developing privacy-enhancing protocols with “real-world applicability” and working code.
Satoshi’s code contributions and comments ramped up heavily during summer and winter break, but tapered off in late spring and the end of year, when an academic would have been taking and/or grading finals.
The idiosyncratic construction of Bitcoin’s code also suggests that Satoshi had an academic background. It has been described as “brilliant but sloppy”, eschewing conventional software development practices like unit testing but exhibiting cutting-edge security architecture and an expert understanding of academic cryptography and economics.
Satoshi’s writing exhibits spelling and word choices idiosyncratic of British English such as “bloody difficult”, “flat”, “maths”, grey”, as well as the dd/mm/yyyy date format. However, Satoshi also refers to Euros rather than pounds.
Analysis of Satoshi’s posting history suggests they were a European ‘night owl’ who worked on Bitcoin after returning from a job or school during the day. At one point, Satoshi also stated that an increase in mining difficulty happened “yesterday”, which would not have been true if they lived in the US.
And when we examine Len’s tweet history, we see that timestamps of Satoshi’s posts and code commits correspond closely to Len’s own hours of late-night activity.