io.jsonwebtoken

Interface Header

All Superinterfaces:

Map<String,Object>

All Known Subinterfaces:

JweHeader, JwsHeader, ProtectedHeader

public interface Header
extends Map<String,Object>

A JWT JOSE header.

This is an immutable JSON map with convenient type-safe getters for JWT standard header parameter names.

Because this interface extends Map<String, Object>, you can use standard Map accessor/iterator methods as desired, for example:

 header.get("someKey");

However, because Header instances are immutable, calling any of the map mutation methods (such as Map.put, etc) will result in a runtime exception.

Security

The Header interface itself makes no implications of integrity protection via either digital signatures or encryption. Instead, JwsHeader and JweHeader represent this information for respective Jws and Jwe instances.

Since:

0.1

See Also:

ProtectedHeader, JwsHeader, JweHeader

Nested Class Summary

Nested classes/interfaces inherited from interface java.util.Map

Map.Entry<K,V>

Field Summary

Fields

Modifier and Type	Field and Description
static String	ALGORITHM Deprecated. since 0.12.0 in favor of getAlgorithm().
static String	COMPRESSION_ALGORITHM Deprecated. since 0.12.0 in favor of getCompressionAlgorithm()
static String	CONTENT_TYPE Deprecated. since 0.12.0 in favor of getContentType().
static String	DEPRECATED_COMPRESSION_ALGORITHM Deprecated. use COMPRESSION_ALGORITHM instead.
static String	JWT_TYPE Deprecated. since 0.12.0 - this constant is never used within the JJWT codebase.
static String	TYPE Deprecated. since 0.12.0 in favor of getType().

Method Summary

Methods

Modifier and Type	Method and Description
String	getAlgorithm() Returns the JWT alg (Algorithm) header value or null if not present.
String	getCompressionAlgorithm() Returns the JWT zip (Compression Algorithm) header parameter value or null if not present.
String	getContentType() Returns the cty (Content Type) header value or null if not present.
String	getType() Returns the typ (Type) header value or null if not present.

Methods inherited from interface java.util.Map

clear, containsKey, containsValue, entrySet, equals, get, hashCode, isEmpty, keySet, put, putAll, remove, size, values

Field Detail

JWT_TYPE

@Deprecated
static final String JWT_TYPE

Deprecated. since 0.12.0 - this constant is never used within the JJWT codebase.

JWT Type (typ) value: "JWT"

See Also:

Constant Field Values

TYPE

@Deprecated
static final String TYPE

Deprecated. since 0.12.0 in favor of getType().

JWT Type header parameter name: "typ"

See Also:

Constant Field Values

CONTENT_TYPE

@Deprecated
static final String CONTENT_TYPE

Deprecated. since 0.12.0 in favor of getContentType().

JWT Content Type header parameter name: "cty"

See Also:

Constant Field Values

ALGORITHM

@Deprecated
static final String ALGORITHM

Deprecated. since 0.12.0 in favor of getAlgorithm().

JWT Algorithm header parameter name: "alg".

See Also:

JWS Algorithm Header, JWE Algorithm Header, Constant Field Values

COMPRESSION_ALGORITHM

@Deprecated
static final String COMPRESSION_ALGORITHM

Deprecated. since 0.12.0 in favor of getCompressionAlgorithm()

JWT Compression Algorithm header parameter name: "zip"

See Also:

Constant Field Values

DEPRECATED_COMPRESSION_ALGORITHM

@Deprecated
static final String DEPRECATED_COMPRESSION_ALGORITHM

Deprecated. use COMPRESSION_ALGORITHM instead.

JJWT legacy/deprecated compression algorithm header parameter name: "calg"

See Also:

Constant Field Values

Method Detail

getType

String getType()

Returns the typ (Type) header value or null if not present.

Returns:

the typ header value or null if not present.

getContentType

String getContentType()

Returns the cty (Content Type) header value or null if not present.

The cty (Content Type) Header Parameter is used by applications to declare the IANA MediaType of the content (the payload). This is intended for use by the application when more than one kind of object could be present in the Payload; the application can use this value to disambiguate among the different kinds of objects that might be present. It will typically not be used by applications when the kind of object is already known. This parameter is ignored by JWT implementations (like JJWT); any processing of this parameter is performed by the JWS application. Use of this Header Parameter is OPTIONAL.

To keep messages compact in common situations, it is RECOMMENDED that producers omit an application/ prefix of a media type value in a cty Header Parameter when no other '/' appears in the media type value. A recipient using the media type value MUST treat it as if application/ were prepended to any cty value not containing a '/'. For instance, a cty value of example SHOULD be used to represent the application/example media type, whereas the media type application/example;part="1/2" cannot be shortened to example;part="1/2".

Returns:

the typ header parameter value or null if not present.

getAlgorithm

String getAlgorithm()

Returns the JWT alg (Algorithm) header value or null if not present.

• If the JWT is a Signed JWT (a JWS), the alg (Algorithm) header parameter identifies the cryptographic algorithm used to secure the JWS. Consider using Jwts.SIG.get(id) to convert this string value to a type-safe SecureDigestAlgorithm instance.
• If the JWT is an Encrypted JWT (a JWE), the alg (Algorithm) header parameter identifies the cryptographic key management algorithm used to encrypt or determine the value of the Content Encryption Key (CEK). The encrypted content is not usable if the alg value does not represent a supported algorithm, or if the recipient does not have a key that can be used with that algorithm. Consider using Jwts.KEY.get(id) to convert this string value to a type-safe KeyAlgorithm instance.

Returns:

the alg header value or null if not present. This will always be non-null on validly constructed JWT instances, but could be null during construction.

Since:

0.12.0

getCompressionAlgorithm

String getCompressionAlgorithm()

Returns the JWT zip (Compression Algorithm) header parameter value or null if not present.

Compatibility Note

While the JWT family of specifications only defines the zip header in the JWE (JSON Web Encryption) specification, JJWT will also support compression for JWS as well if you choose to use it. However, be aware that if you use compression when creating a JWS token, other libraries may not be able to parse the JWS. However, compression when creating JWE tokens should be universally accepted for any library that supports JWE.

Returns:

the zip header parameter value or null if not present.

Since:

0.6.0