Overview (Bouncy Castle Library 1.85 API Specification)

Lightweight Crypto Packages
Package	Description
org.bouncycastle.crypto	Base classes for the lightweight API.
org.bouncycastle.crypto.agreement	Basic key agreement classes.
org.bouncycastle.crypto.agreement.ecjpake	Support classes for Elliptic Curve Password Authenticated Key Exchange by Juggling (EC J-PAKE) key exchange.
org.bouncycastle.crypto.agreement.jpake	Support classes for Password Authenticated Key Exchange by Juggling (J-PAKE) key exchange.
org.bouncycastle.crypto.agreement.kdf	Support classes for KDF based key derivation functions.
org.bouncycastle.crypto.agreement.owl	Support classes for the Owl augmented PAKE (Hao, Bag, Chen, Lopez 2024).
org.bouncycastle.crypto.agreement.owl.test
org.bouncycastle.crypto.agreement.srp	Support classes for Secure Remote Password (SRP) protocol.
org.bouncycastle.crypto.agreement.test
org.bouncycastle.crypto.bls	BLS signatures over the BLS12-381 curve, per draft-irtf-cfrg-bls-signature.
org.bouncycastle.crypto.commitments	Classes for supporting commitment calculation.
org.bouncycastle.crypto.constraints	Crypto-services-constraint framework: lets callers limit which cryptographic primitives the lightweight API will produce (by key size, by allowlist, by purpose).
org.bouncycastle.crypto.digests	Message digest classes.
org.bouncycastle.crypto.ec	Utility classes for support Elliptic Curve cryptographic transforms.
org.bouncycastle.crypto.ec.test
org.bouncycastle.crypto.encodings	Block encodings for asymmetric ciphers.
org.bouncycastle.crypto.engines	Basic cipher classes.
org.bouncycastle.crypto.fpe	Format-Preserving Encryption per NIST SP 800-38G: FF1 and FF3-1 modes that produce ciphertext in the same alphabet (digits / strings) as the input plaintext.
org.bouncycastle.crypto.generators	Generators for keys, key pairs and password based encryption algorithms.
org.bouncycastle.crypto.hash2curve	Hash to curve implementation
org.bouncycastle.crypto.hash2curve.data
org.bouncycastle.crypto.hash2curve.impl
org.bouncycastle.crypto.hash2curve.test
org.bouncycastle.crypto.hash2curve.test.impl
org.bouncycastle.crypto.hpke	Hybrid Public Key Encryption (HPKE) per RFC 9180.
org.bouncycastle.crypto.io	Classes for doing "enhanced" I/O with Digests and MACs.
org.bouncycastle.crypto.kems	Key Encapsulation Mechanisms.
org.bouncycastle.crypto.kems.cmce	The Classic McEliece key encapsulation mechanism as standardised in ISO/IEC 18033-2:2006/Amd 2:2026 (Clause 13): lightweight engine internals for the non-pc and pc ("plaintext confirmation") parameter sets, each in a plain and a semi-systematic ("f") key-generation variant.
org.bouncycastle.crypto.kems.frodo	The FrodoKEM key encapsulation mechanism as standardised in ISO/IEC 18033-2:2006/Amd 2:2026 (Clause 14): lightweight engine internals for the salted "FrodoKEM" and ephemeral "eFrodoKEM" SHAKE parameter sets.
org.bouncycastle.crypto.kems.mlkem	ML-KEM (FIPS 203) bindings of the lightweight KEM API (`EncapsulatedSecretGenerator` / `EncapsulatedSecretExtractor`) sitting on top of the `org.bouncycastle.pqc.crypto.mlkem` primitives.
org.bouncycastle.crypto.macs	Classes for creating MACs and HMACs.
org.bouncycastle.crypto.modes	Modes for symmetric ciphers.
org.bouncycastle.crypto.modes.gcm	GCM mode support classes.
org.bouncycastle.crypto.modes.kgcm	Lookup tables for KGCM (the GCM analogue used by the Ukrainian DSTU 7624 Kalyna cipher).
org.bouncycastle.crypto.paddings	Paddings for symmetric ciphers.
org.bouncycastle.crypto.params	Classes for parameter objects for ciphers and generators.
org.bouncycastle.crypto.parsers	Helper classes for parsing "on the wire" public keys.
org.bouncycastle.crypto.prng	Lightweight psuedo-random number generators and SecureRandom builders.
org.bouncycastle.crypto.prng.drbg	SP800-90A deterministic random bit generators, can be used stand alone or in conjunction with SP800SecureRandomBuilder class.
org.bouncycastle.crypto.prng.test
org.bouncycastle.crypto.signers	Basic signers.
org.bouncycastle.crypto.signers.mldsa	ML-DSA (FIPS 204) bindings of the lightweight signer API.
org.bouncycastle.crypto.signers.slhdsa	SLH-DSA (FIPS 205) bindings of the lightweight signer API.
org.bouncycastle.crypto.test	Example code and test classes for the lightweight API.
org.bouncycastle.crypto.test.cavp
org.bouncycastle.crypto.test.speedy
org.bouncycastle.crypto.threshold	Threshold-cryptography helpers — Shamir secret sharing over GF(2⁸) and supporting polynomial arithmetic.
org.bouncycastle.crypto.threshold.test
org.bouncycastle.crypto.tls	Legacy lightweight TLS support — predates and is largely superseded by the standalone `org.bouncycastle.tls` TLS / JSSE module.
org.bouncycastle.crypto.util	Some general utility/conversion classes.

ASN.1 Support Packages
Package	Description
org.bouncycastle.asn1	A library for parsing and writing ASN.1 objects.
org.bouncycastle.asn1.anssi	Support classes for the French ANSSI EC curves.
org.bouncycastle.asn1.bc	ASN.1 classes specific to the Bouncy Castle APIs.
org.bouncycastle.asn1.bsi	ASN.1 classes specific to the Bundesamt für Sicherheit in der Informationstechnik (BSI) standards.
org.bouncycastle.asn1.cmc	Support classes for Certificate Management over CMS (CMC) - RFC 5272 and RFC 6402.
org.bouncycastle.asn1.cmc.test
org.bouncycastle.asn1.cmp	Support classes useful for encoding and supporting PKIX-CMP as described RFC 4210.
org.bouncycastle.asn1.cmp.test
org.bouncycastle.asn1.cms	Support classes useful for encoding and supporting Cryptographic Message Syntax as described in PKCS#7 and RFC 3369 (formerly RFC 2630).
org.bouncycastle.asn1.cms.ecc	Support classes for CMS ECC - RFC 5753/3278.
org.bouncycastle.asn1.cms.test
org.bouncycastle.asn1.crmf	Support classes useful for encoding and supporting PKIX-CRMF as described RFC 4211.
org.bouncycastle.asn1.crmf.test
org.bouncycastle.asn1.cryptlib	Object identifier constants from the cryptlib OID arc (Peter Gutmann's cryptlib).
org.bouncycastle.asn1.cryptopro	Support classes for CRYPTO-PRO related objects - such as GOST identifiers.
org.bouncycastle.asn1.dvcs	Support classes useful for encoding and processing Data Validation and Certification Server (DVCS) protocols as described in RFC 3029.
org.bouncycastle.asn1.dvcs.test
org.bouncycastle.asn1.eac	ASN.1 classes specific to the Bundesamt für Sicherheit in der Informationstechnik (BSI) Technical Guideline Advanced Security Mechanisms for Machine Readable Travel Documents.
org.bouncycastle.asn1.edec	Object identifier constants for the Edwards-curve EdDSA algorithms per RFC 8410 (id-X25519, id-X448, id-Ed25519, id-Ed448).
org.bouncycastle.asn1.esf	Support classes useful for encoding and supporting [ESF] RFC3126 Electronic Signature Formats for long term electronic signatures.
org.bouncycastle.asn1.esf.test
org.bouncycastle.asn1.ess	Support classes useful for encoding and supporting Enhanced Security Services for S/MIME as described RFC 2634 and RFC 5035.
org.bouncycastle.asn1.ess.test
org.bouncycastle.asn1.est	Support classes for Enrollment over Secure Transport (EST) - RFC 7030.
org.bouncycastle.asn1.gm	Support classes for Chinese Standard (GM) standard curves and algorithms.
org.bouncycastle.asn1.gnu	Object identifier constants from the GNU project's OID arc, including the OIDs used by GnuPG for the Camellia and Brainpool curves.
org.bouncycastle.asn1.iana	Object identifier constants from the IANA-allocated PKIX OID registry — currently covering the HMAC-SHA-1 OID used by IKE / IPsec.
org.bouncycastle.asn1.icao	ICAO ASN.1 classes for electronic passport.
org.bouncycastle.asn1.icao.test
org.bouncycastle.asn1.isara	Object identifier constants from ISARA Corporation's quantum-safe OID arc — most notably the XMSS / XMSS-MT signature OIDs they registered.
org.bouncycastle.asn1.isismtt	Support classes for the ISIS-MTT Project.
org.bouncycastle.asn1.isismtt.ocsp	Support classes for the ISIS-MTT profile for OCSP.
org.bouncycastle.asn1.isismtt.test
org.bouncycastle.asn1.isismtt.x509	Support classes for the ISIS-MTT X.509 Certificate Extensions.
org.bouncycastle.asn1.iso	Support classes for various ISO Standards.
org.bouncycastle.asn1.kisa	Support classes for the Korea Information Security Agency (KISA) standard - SEED algorithm.
org.bouncycastle.asn1.microsoft	Support for Microsoft specific ASN.1 classes and object identifiers.
org.bouncycastle.asn1.microsoft.test
org.bouncycastle.asn1.misc	Miscellaneous object identifiers and objects.
org.bouncycastle.asn1.misc.test
org.bouncycastle.asn1.mod
org.bouncycastle.asn1.mozilla	ASN.1 types and OID constants for Mozilla's SignedPublicKeyAndChallenge (SPKAC) form — the browser-side certificate-enrolment structure historically emitted by `<keygen>` elements.
org.bouncycastle.asn1.nist	Support classes for NIST related objects.
org.bouncycastle.asn1.nsri	Support classes algorithms from the Korean National Security Research Institute.
org.bouncycastle.asn1.ntt	ASN.1 classes relevant to the standards produced by Nippon Telegraph and Telephone.
org.bouncycastle.asn1.ocsp	Support classes useful for encoding and supporting OCSP objects.
org.bouncycastle.asn1.oiw	Objects and OID for the support of ISO OIW.
org.bouncycastle.asn1.pkcs	Support classes useful for encoding and supporting the various RSA PKCS documents.
org.bouncycastle.asn1.plants	ASN.1 types for the IETF PLANTS working group's Merkle Tree Certificate work (`draft-ietf-plants-merkle-tree-certs`), including the `MerkleTreeCertEntry` and `MTCProof` structures.
org.bouncycastle.asn1.rosstandart	Support classes algorithms from the Russian Federal Agency on Technical Regulating and Metrology - Rosstandart.
org.bouncycastle.asn1.sec	Classes for support of the SEC standard for Elliptic Curve.
org.bouncycastle.asn1.smime	Support classes useful for encoding and supporting S/MIME.
org.bouncycastle.asn1.smime.test
org.bouncycastle.asn1.teletrust	Support classes for TeleTrust related objects.
org.bouncycastle.asn1.test	Test programs for the ASN.1 package.
org.bouncycastle.asn1.tsp	Support classes useful for encoding and supporting Time Stamp Protocol as described RFC 3161.
org.bouncycastle.asn1.ua	Support classes for the Ukrainian DSTU standard.
org.bouncycastle.asn1.util	An ASN.1 dump utility.
org.bouncycastle.asn1.util.test
org.bouncycastle.asn1.x500	Support classes for the creation and processing of object based on X.500 names.
org.bouncycastle.asn1.x500.style	Template classes for the common styles used for converting X.500 names to strings and back.
org.bouncycastle.asn1.x509	Support classes useful for encoding and processing X.509 certificates.
org.bouncycastle.asn1.x509.qualified	Support classes useful for encoding and processing messages based around RFC3739
org.bouncycastle.asn1.x509.sigi	Support classes for the German SigI (Signature Interoperability Specification) standard.
org.bouncycastle.asn1.x9	Support classes useful for encoding and supporting X9.62 elliptic curve.

Utility Packages
Package	Description
org.bouncycastle.math	The Bouncy Castle math package.
org.bouncycastle.math.ec	Math support for Elliptic Curve.
org.bouncycastle.math.ec.custom.djb	Experimental implementation of curve25519.
org.bouncycastle.math.ec.custom.gm	Custom implementation of SM2 EC curve, SM2-P256V1.
org.bouncycastle.math.ec.custom.sec	Custom implementations of (most of) the curves over Fp from the SEC specification.
org.bouncycastle.math.ec.custom.sec.test
org.bouncycastle.math.ec.endo	Endomorphism support for the EC math classes — the GLV / GLS decomposition tables that accelerate scalar multiplication on suitable curves (secp256k1, etc.).
org.bouncycastle.math.ec.rfc7748	Constant-time scalar-multiplication implementations for the Curve25519 and Curve448 elliptic curves per RFC 7748.
org.bouncycastle.math.ec.rfc7748.test
org.bouncycastle.math.ec.rfc8032	Constant-time implementations of the Ed25519 and Ed448 signature schemes per RFC 8032, sitting on top of the Curve25519 / Curve448 scalar-multiplication in `org.bouncycastle.math.ec.rfc7748`.
org.bouncycastle.math.ec.rfc8032.test
org.bouncycastle.math.ec.test
org.bouncycastle.math.ec.tools	Standalone tools for working with elliptic curves — discrete log calculators, curve parameter generators, and table-generation utilities used to bootstrap the named curves in `org.bouncycastle.math.ec`.
org.bouncycastle.math.field	Polynomial-field math (GF(2^m) with various basis representations) used to back the F2m elliptic curves in `org.bouncycastle.math.ec`.
org.bouncycastle.math.raw	Math support for raw multi-precision calculations.
org.bouncycastle.math.raw.test
org.bouncycastle.math.test
org.bouncycastle.util	General purpose utility classes used throughout the APIs.
org.bouncycastle.util.encoders	Classes for producing and reading Base64 and Hex strings.
org.bouncycastle.util.encoders.test
org.bouncycastle.util.io	General purpose I/O helper classes and wrappers.
org.bouncycastle.util.io.pem	Classes for reading and writing raw PEM objects.
org.bouncycastle.util.io.pem.test
org.bouncycastle.util.io.test
org.bouncycastle.util.test	Light weight test API.
org.bouncycastle.util.utiltest

Post-Quantum Lightweight Crypto Packages
Package	Description
org.bouncycastle.pqc.crypto	Root of the lightweight Post-Quantum Cryptography implementations.
org.bouncycastle.pqc.crypto.aimer	Lightweight implementation of AIMer, an MPC-in-the-Head signature scheme built on the AIM2 one-way function, in the NIST PQC additional-digital-signatures round.
org.bouncycastle.pqc.crypto.cmce	Lightweight implementation of Classic McEliece (Round 4 NIST PQC KEM finalist).
org.bouncycastle.pqc.crypto.crystals.dilithium	Lightweight implementation of CRYSTALS-Dilithium (the NIST Round 3 submission that was subsequently standardised as ML-DSA / FIPS 204).
org.bouncycastle.pqc.crypto.faest	Lightweight implementation of FAEST — symmetric-primitive digital signature scheme based on AES and the VOLE-in-the-Head proof system.
org.bouncycastle.pqc.crypto.falcon	Lightweight implementation of Falcon, the NTRU-lattice-based signature scheme selected for standardisation by NIST.
org.bouncycastle.pqc.crypto.frodo	Lightweight implementation of FrodoKEM (a learning-with-errors KEM that did not advance past Round 3 of the NIST PQC process; retained as a conservative reference).
org.bouncycastle.pqc.crypto.haetae	Lightweight implementation of HAETAE, a module-lattice-based signature scheme in the NIST PQC additional-digital-signatures round.
org.bouncycastle.pqc.crypto.hawk	Lightweight implementation of Hawk, an NTRU-lattice-based signature scheme in the NIST PQC additional-digital-signatures round.
org.bouncycastle.pqc.crypto.hqc	Lightweight implementation of HQC (Hamming Quasi-Cyclic), a code-based KEM that NIST selected for standardisation as a backup to ML-KEM.
org.bouncycastle.pqc.crypto.lms	Lightweight implementation of LMS and the HSS multi-tree variant per RFC 8554 (hash-based stateful signatures).
org.bouncycastle.pqc.crypto.mayo	Lightweight implementation of MAYO, a UOV-based signature scheme in the NIST PQC additional-digital-signatures round.
org.bouncycastle.pqc.crypto.mldsa	Lightweight implementation of ML-DSA (Module-Lattice-Based Digital Signature Algorithm) as standardised by NIST FIPS 204.
org.bouncycastle.pqc.crypto.mlkem	Lightweight implementation of ML-KEM (Module-Lattice-Based Key-Encapsulation Mechanism) as standardised by NIST FIPS 203.
org.bouncycastle.pqc.crypto.mqom	Lightweight implementation of MQOM ("MQ on my Mind"), an MPC-in-the-Head signature scheme in the NIST PQC additional-digital-signatures round.
org.bouncycastle.pqc.crypto.newhope	Low level implementation of the NewHope key exchange algorithm.
org.bouncycastle.pqc.crypto.ntru	The NTRU algorithm based on the round 3 submission of the NIST post-quantum cryptography.
org.bouncycastle.pqc.crypto.ntruplus	Lightweight implementation of NTRU+ (Korean post-quantum KEM submission).
org.bouncycastle.pqc.crypto.ntruprime	Lightweight implementation of NTRU Prime — the streamlined-NTRU and NTRU LPRime KEM variants from the NIST PQC Round 3 alternates.
org.bouncycastle.pqc.crypto.qruov	Lightweight implementation of QR-UOV, a quotient-ring variant of the UOV multivariate signature scheme in the NIST PQC additional-digital-signatures round.
org.bouncycastle.pqc.crypto.saber	Lightweight implementation of SABER, a module-lattice KEM from the NIST PQC Round 3 finalists.
org.bouncycastle.pqc.crypto.sdith	Lightweight implementation of SDitH ("Syndrome Decoding in the Head"), a code-based MPC-in-the-Head signature scheme in the NIST PQC additional-digital-signatures round.
org.bouncycastle.pqc.crypto.slhdsa	Lightweight implementation of SLH-DSA (Stateless Hash-Based Digital Signature Algorithm) as standardised by NIST FIPS 205, succeeding the SPHINCS+ submission in `org.bouncycastle.pqc.legacy.sphincsplus`.
org.bouncycastle.pqc.crypto.snova	Lightweight implementation of SNOVA, a UOV-variant signature scheme in the NIST PQC additional-digital-signatures round.
org.bouncycastle.pqc.crypto.sphincs	Low level implementation of the SPHINCS-256 signature algorithm.
org.bouncycastle.pqc.crypto.sqisign	Lightweight implementation of SQIsign (Short Quaternion and Isogeny Signature), an isogeny-based signature scheme in the NIST PQC additional-digital-signatures round.
org.bouncycastle.pqc.crypto.uov	Lightweight implementation of UOV (Unbalanced Oil and Vinegar), a multivariate-quadratic signature scheme in the NIST PQC additional-digital-signatures round.
org.bouncycastle.pqc.crypto.util	Shared PQC factory utilities — `PublicKeyFactory`, `PrivateKeyFactory`, `SubjectPublicKeyInfoFactory`, `PrivateKeyInfoFactory` and the OID lookup helpers that route PQC parameter sets between the wire-format ASN.1 layer and the lightweight `Parameters` types.
org.bouncycastle.pqc.crypto.xmss	Low level implementation of the XMSS and XMSS^MT signature algorithms.
org.bouncycastle.pqc.crypto.xwing	Lightweight implementation of X-Wing, the hybrid KEM combining X25519 and ML-KEM-768 (draft-connolly-cfrg-xwing-kem).

Package	Description
org.bouncycastle.pqc.math.ntru	Contains the polynomial classes used in the NTRU round 3 algorithm.
org.bouncycastle.pqc.math.ntru.parameters	Parameter sets and supporting polynomial arithmetic for the NTRU-family KEM implementations.
org.bouncycastle.pqc.math.ntru.test