Bouncy Castle

Health v2 · maintenance only

Flags: no_releases

Adoption not part of the score

2683 stars · 1268 forks observed · 2026-08-28

What it is AI-extracted, prompt v1, taxonomy v1, 2026-08-30, confidence not recorded

Bouncy Castle is a comprehensive open-source cryptographic library for Java (and C#/.NET) implementing a wide range of algorithms, a JCA/JCE provider, and protocols such as TLS, DTLS, OpenPGP, CMS/S/MIME, and X.509/PKIX. It includes lightweight APIs for constrained environments and supports post-quantum algorithms, with separately licensed FIPS-certified editions.

Use cases

• implement TLS 1.3 in a Java application
• sign and encrypt files with OpenPGP
• generate and validate X.509 certificates and CSRs
• add a JCE crypto provider with more algorithms than the JDK
• use post-quantum cryptography algorithms in Java
• build S/MIME or CMS signed messages
• do cryptography in C#/.NET without platform dependencies
• implement DTLS for a UDP-based protocol

When to choose

• you need algorithms or protocols (PGP, CMS, OCSP, CMP, post-quantum) not covered by the standard JDK or .NET crypto APIs
• you need a lightweight crypto API usable in constrained environments like J2ME/Android
• you need fine-grained control over certificate parsing, path validation, or PKI message formats
• you want a permissively licensed, widely audited, long-established crypto library

When to avoid

• you only need basic TLS/HTTPS - use the platform's built-in TLS stack instead
• you require FIPS 140 compliance - the general edition is not FIPS certified; you need the separate FIPS version
• you want a high-level API that hides crypto details - Bouncy Castle is low-level and requires cryptographic expertise to use safely
• you need crypto in a language other than Java, C#, or Kotlin

Facets

library · maturity stable

cryptography security sdk security developer-tools backend apis jvm dotnet cross-platform tls openpgp x509 pkix post-quantum-cryptography jce-provider fips dtls cms smime android

Member repositories

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