Interface DigestContext

All Superinterfaces:

AutoCloseable, Closeable, CryptoContext, TagEngine<byte[]>

All Known Implementing Classes:

JcaDigestContext

public non-sealed interface DigestContext
extends TagEngine<byte[]>, CryptoContext

Context for computing unkeyed message digests and extendable-output functions (XOFs) in streaming pipelines.

A DigestContext combines digest/XOF state with the TagEngine contract: the wrapped input stream passes bytes through while updating the computation; at end-of-file, a fixed-length tag is appended (produce mode) or compared with an expected tag (verify mode).

Operation

• Produce mode: TagEngine.wrap(java.io.InputStream) emits the original data, then appends the digest (or configured-length XOF output) as a trailer.
• Verify mode: Provide the expected tag via TagEngine.setExpectedTag(byte[]); the engine compares the computed tag at EOF using the configured verification approach.

Usage

Digest trailer

TagEngine<byte[]> eng = TagEngineBuilder.digest(DigestSpec.sha256()).get();
try (java.io.InputStream in = eng.wrap(upstream)) {
    in.transferTo(out);
}

Detached verification

TagEngine<byte[]> eng = TagEngineBuilder.digest(DigestSpec.sha256()).get();
eng.setExpectedTag(expectedDigest);
try (java.io.InputStream in = eng.wrap(bodyWithoutTrailer)) {
    in.transferTo(java.io.OutputStream.nullOutputStream());
}

Security considerations

• Unkeyed digests do not provide authenticity; use MacContext or SignatureContext for that.
• For XOFs, choose an output length appropriate for your security level.
• Implementations are stateful and not guaranteed to be thread-safe.

Since:

1.0

Field Summary

Fields inherited from interface TagEngine

LOG

Method Summary

Methods inherited from interface CryptoContext

algorithm, close, key

Methods inherited from interface TagEngine

getVerificationCore, setExpectedTag, setVerificationApproach, tagLength, wrap