public class KeyBasedPersistenceTokenService extends Object implements TokenService, InitializingBean
TokenService
that is compatible with clusters and across machine restarts,
without requiring database persistence.
Keys are produced in the format:
Base64(creationTime + ":" + hex(pseudoRandomNumber) + ":" + extendedInformation + ":" + Sha512Hex(creationTime + ":" + hex(pseudoRandomNumber) + ":" + extendedInformation + ":" + serverSecret) )
In the above, creationTime
, tokenKey
and extendedInformation
are equal to that stored in Token
. The Sha512Hex
includes the same payload,
plus a serverSecret
.
The serverSecret
varies every millisecond. It relies on two static server-side secrets. The first
is a password, and the second is a server integer. Both of these must remain the same for any issued keys
to subsequently be recognised. The applicable serverSecret
in any millisecond is computed by
password
+ ":" + (creationTime
% serverInteger
). This approach
further obfuscates the actual server secret and renders attempts to compute the server secret more
limited in usefulness (as any false tokens would be forced to have a creationTime
equal
to the computed hash). Recall that framework features depending on token services should reject tokens
that are relatively old in any event.
A further consideration of this class is the requirement for cryptographically strong pseudo-random numbers.
To this end, the use of SecureRandomFactoryBean
is recommended to inject the property.
This implementation uses UTF-8 encoding internally for string manipulation.
Constructor and Description |
---|
KeyBasedPersistenceTokenService() |
Modifier and Type | Method and Description |
---|---|
void |
afterPropertiesSet() |
Token |
allocateToken(String extendedInformation)
Forces the allocation of a new
Token . |
void |
setPseudoRandomNumberBits(int pseudoRandomNumberBytes)
Deprecated.
|
void |
setPseudoRandomNumberBytes(int pseudoRandomNumberBytes) |
void |
setSecureRandom(SecureRandom secureRandom) |
void |
setServerInteger(Integer serverInteger) |
void |
setServerSecret(String serverSecret) |
Token |
verifyToken(String key)
Permits verification the <
Token.getKey() was issued by this TokenService and
reconstructs the corresponding Token . |
public Token allocateToken(String extendedInformation)
TokenService
Token
.allocateToken
in interface TokenService
extendedInformation
- the extended information desired in the token
(cannot be null
, but can be empty)TokenService.verifyToken(String)
at any future time.public Token verifyToken(String key)
TokenService
Token.getKey()
was issued by this TokenService
and
reconstructs the corresponding Token
.verifyToken
in interface TokenService
key
- as obtained from Token.getKey()
and created by this implementationnull
if the token was not issued by this TokenService
public void setServerSecret(String serverSecret)
serverSecret
- the new secret, which can contain a ":" if desired (never being sent to the client)public void setSecureRandom(SecureRandom secureRandom)
public void setPseudoRandomNumberBits(int pseudoRandomNumberBytes)
setPseudoRandomNumberBytes(int)
pseudoRandomNumberBytes
- changes the number of bytes issued (must be >= 0; defaults to
256)public void setPseudoRandomNumberBytes(int pseudoRandomNumberBytes)
pseudoRandomNumberBytes
- changes the number of bytes issued (must be >= 0; defaults to 256 for passivity reasons)public void setServerInteger(Integer serverInteger)
public void afterPropertiesSet() throws Exception
afterPropertiesSet
in interface InitializingBean
Exception