Wouldn't strings(1) have worked for this?
By default, strings needs a run of 4+ (printable|ascii) characters. This sounds like it was 1 ascii character at a time in a sea of random data (with other alpha chars removed).
alt Hacker News
By default, strings needs a run of 4+ (printable|ascii) characters. This sounds like it was 1 ascii character at a time in a sea of random data (with other alpha chars removed).