Comment Re:How secure is that connection string? (Score 1) 124
Even if BTSync were to process one connection string per CPU clock cycle, it would still take 1e20 years to try all the possible 20-character Base64 strings that BTSync uses by default. If you choose a longer string, then it will take even more time. In otherwords, the standard strings have 120 bits of entropy, and you can increase that to up to 240 bits. This is less than is typically used for encryption these days, but btsync doesn't have to deal with offline attacks.
Rather than key size, I would be more concerned about whether the client potentially leaks data through timing attacks, or any MITM/sniffing attacks that speed up the cracking faster than brute force.