My oath ceremony for naturalization is in a few days. I have a question about how to sign the certificate of naturalization that I should get after the oath. I heard that you are supposed to sign your full name completely and legibly without any abbreviations. My usual signature (on my driver's license, credit cards, and current non-US passport etc) is a kind of illegible scrawl using my initials. Which signature should go on the naturalization certificate? If the full/complete name, then subsequent to naturalization do I have to keep signing that way too? e.g. when applying for a US passport, do I use my current signature or the full/complete signature?(Comment after oath) On the certificate, they have printed my (usual) signature next to my photograph. The officer at the oath instructed me that I need to sign the certificate in the same way, and that for security reasons it was important that the two signatures should match. So I have signed the certificate that way.