ATick for .NET#

Sign PDFs with confidence

ATick for .NET is the standalone PDF digital-signature library for C# — PAdES & CMS signing, deferred / remote-key signing and a green-tick appearance Adobe shows as valid, in one NuGet package.

Get started →

API reference

using Aniketc068.ATick;

byte[] pdf = File.ReadAllBytes("doc.pdf");
byte[] pfx = File.ReadAllBytes("my.pfx");

byte[] signed = Atick.SignPfx(pdf, pfx,
    "{\"password\":\"••••\",\"cn\":\"Aniket Chaturvedi\",\"reason\":\"Approved\"," +
    "\"green_tick\":true,\"page\":1,\"rect\":[300,55,575,175]," +
    "\"pades\":true,\"timestamp\":true,\"ltv\":true}");   // PAdES-B-LT

File.WriteAllBytes("signed.pdf", signed);

Everything you need to sign PDFs#

Sign anywhere

PFX/P12 or PEM files directly, and tokens / HSMs / the Windows store via the deferred flow and your own provider — one consistent API.

Signing »

Full PAdES

B-B, B-T, B-LT, B-LTA with RFC-3161 timestamps and long-term validation — recognised by Adobe Acrobat as “PAdES Signature Level”.

PAdES levels »

Deferred / eSign

Two-step Prepare → external CMS → Embed for remote keys (eSign ESP, HSM, token) — the InputHash is just the SHA-256 of the bytes-to-sign.

Deferred / eSign »

Rich appearance

Logo or CN-on-the-left, the validity mark (? / green tick), distinguished name, custom text, invisible signatures, any date format.

Appearance »

Trust & control

Certification (DocMDP), field-locking (FieldMDP), pre-sign expiry / CRL / OCSP checks, password protection and metadata.

Certification »

Built for scale

A revocation cache speeds up batch signing, multi-signatory documents stay valid, and every error is a clean .NET exception.

Fast signing »

The green tick your readers trust#

ATick draws a verified-signature appearance with a green tick. When the certificate is valid and trusted, Adobe Reader / Acrobat shows “Signed and all signatures are valid.”

Adobe Reader — signed and all signatures are valid, with the ATick green tick

Why ATick#

	ATick for .NET
External services	none — the crypto, PKCS#12/PEM, image decode, timestamping and LTV are all built into the engine
Install	one NuGet package `ATick` (the native engine is included)
Build step	none on your side — P/Invoke to the bundled engine, no C compiler
Platforms	Windows (64/32-bit), Linux (x64/ARM64/ARM) and macOS — one cross-platform package
Errors	every failure is an `AtickException` you can catch