Digital Signature — Java

A digital signature is legally binding and can be equivalent to an ink pen signature on paper contracts and other documents.

Unlike electronic signatures, digital signatures have a unique digital ID that identifies the signer's identity. Digital signatures can get information about whether the signature is trustworthy and whether the document has been modified after the signature, thereby ensuring the legal validity of the document.

Benefits of ComPDFKit PDF Digital Signature SDK

• Authentication: Digital signatures can accurately identify the creator and the signer of a document.
• Integrity: Digital signatures allow users to easily verify whether the document's content has been altered after signing.
• Non-Repudiation: When the signature is valid, it can prove the signer's intent to sign, they can't deny that they have signed the document.
• Built-in Certificate Support: Full support for PFX and P12 certificates.
• Custom Appearance: Customize the appearance of signatures through drawn, image, or typed signatures.
• Fast UI Integration: Achieve rapid integration and customization through extensible UI components.

Guides for Digital Signatures

• Create Digital Certificates: Create a PKCS#12 signing identity.
• Create Digital Signatures: Create a field and sign it with a certificate.
• Read Digital Signature Information: Inspect signer and certificate information.
• Verify Digital Certificates: Check certificate trust.
• Verify Digital Signatures: Check integrity, permissions, and trust.
• Trust Certificate: Configure certificates trusted by the application.
• Remove Digital Signatures: Remove signature data and optionally its appearance while retaining the field.
• Invisible Digital Signatures: Sign with a widget rectangle of zero.
• Long-Term Validation and PAdES: Create or prolong evidence and inspect full validation reports.
• AWS KMS Signing: Use the supported KMS key configuration and certificate.
• Two-Phase External Signing: Persist preparation and complete it after the external signer responds.
• Signature and Document Timestamps: Use embedded timestamps, document timestamps, and TSA tokens.

The advanced signature APIs below require an SDK JAR that contains the corresponding classes. Initialize and license the SDK before use. The code examples use these imports as needed:

import com.compdfkit.core.android.graphics.RectF;
import com.compdfkit.core.annotation.form.CPDFSignatureWidget;
import com.compdfkit.core.annotation.form.CPDFWidget;
import com.compdfkit.core.document.CPDFDocument;
import com.compdfkit.core.page.CPDFPage;
import com.compdfkit.core.signature.*;
import java.nio.file.Files;
import java.nio.file.Paths;
import java.util.Arrays;
import java.util.Base64;