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org.bouncycastle.bcpg

public Class S2K

extends BCPGObject
Class Inheritance
Imports
java.io.DataInputStream, .IOException, .InputStream, java.security.SecureRandom, org.bouncycastle.crypto.CryptoServicesRegistrar
Parameter specifier for the PGP string-to-key password based key derivation function.

In iterated mode, S2K takes a single byte iteration count specifier, which is converted to an actual iteration count using a formula that grows the iteration count exponentially as the byte value increases.

e.g. 0x01 == 1088 iterations, and 0xFF == 65,011,712 iterations.

Nested and Inner Type Summary

Modifier and TypeClass and Description
public static class
S2K.Argon2Params

Parameters for Argon2 S2K.

public static class
S2K.GNUDummyParams

Parameters for the GNU_DUMMY_S2K method.

Field Summary

Modifier and TypeField and Description
pack-priv int
algorithm

public static final int
ARGON_2

Memory-hard, salted key generation using Argon2 hash algorithm.

private static final int
EXPBIAS

public static final int
GNU_DUMMY_S2K

public static final int
GNU_PROTECTION_MODE_DIVERT_TO_CARD

public static final int
GNU_PROTECTION_MODE_NO_PRIVATE_KEY

pack-priv int
itCount

pack-priv byte[]
iv

pack-priv int
memorySizeExponent

pack-priv int
parallelism

pack-priv int
passes

pack-priv int
protectionMode

public static final int
SALTED

Salted key generation.

public static final int
SALTED_AND_ITERATED

Salted and iterated key generation.

public static final int
SIMPLE

Simple key generation.

pack-priv int
type

Constructor Summary

AccessConstructor and Description
pack-priv
S2K(InputStream in)

public
S2K(int
the digest algorithm to use.
algorithm)

Constructs a specifier for a simple S2K generation.

public
S2K(int
the digest algorithm to use.
algorithm, byte[]
the salt to apply to input to the key generation.
iv)

Constructs a specifier for a salted S2K generation.

public
S2K(int
the digest algorithm to iterate.
algorithm, byte[]
the salt to apply to input to the key generation.
iv, int
the single byte iteration count specifier.
itCount)

Constructs a specifier for a salted and iterated S2K generation.

public
S2K(S2K.Argon2Params
argon2 parameters
argon2Params)

Constructs a specifier for an S2K method using Argon2.

public
S2K(S2K.GNUDummyParams
GNU_DUMMY_S2K parameters
gnuDummyParams)

Construct a specifier for an S2K using the GNU_DUMMY_S2K method.

Method Summary

Modifier and TypeMethod and Description
public static S2K

Returns:

S2K
argon2S2K(S2K.Argon2Params
argon2 parameters
parameters)

Return a new S2K instance using the ARGON_2 method, using the given argon2 

parameters
public void
encode(BCPGOutputStream out)

Implements abstract org.bouncycastle.bcpg.BCPGObject.encode.

public int
getHashAlgorithm()

Gets the hash algorithm for this S2K.

public long
getIterationCount()

Gets the actual (expanded) iteration count.

public byte[]
getIV()

Gets the iv/salt to use for the key generation.

public int

Returns:

memory size exponent
getMemorySizeExponent()

Gets the memory size exponent - only if ARGON_2

public int

Returns:

parallelism
getParallelism()

Gets the degree of parallelism - only if ARGON_2

public int

Returns:

number of passes
getPasses()

Return the number of passes - only Argon2

public int
getProtectionMode()

Gets the protection mode - only if GNU_DUMMY_S2K

public int
getType()

Gets the digest algorithm specified.

public static S2K

Returns:

S2K
gnuDummyS2K(S2K.GNUDummyParams
GNU Dummy S2K parameters
parameters)

Return a new S2K instance using the GNU_DUMMY_S2K method, using the given GNU Dummy S2K 

parameters
public static S2K

Returns:

S2K
saltedAndIteratedS2K(int
hash algorithm tag
algorithm, byte[]
salt
salt, int
number of iterations
iterationCount)

Return a new S2K instance using the SALTED_AND_ITERATED method, using the given hash 

algorithm
public static S2K

Returns:

S2K
saltedS2K(int
hash algorithm tag
algorithm, byte[]
salt
salt)

Return a new S2K instance using the SALTED method, using the given hash 

algorithm
public static S2K

Returns:

S2K
simpleS2K(int
hash algorithm tag
algorithm)

Return a new S2K instance using the SIMPLE method, using the given hash 

algorithm
private void
writeOneOctetOrThrow(BCPGOutputStream
output stream
out, int
value
val, String
name of the value for the error message
valName)

Throw an IllegalArgumentException if the value cannot be encoded, otherwise write the value to the output stream.

Inherited from org.bouncycastle.bcpg.BCPGObject:
getEncoded

Field Detail

algorithmback to summary
pack-priv int algorithm
ARGON_2back to summary
public static final int ARGON_2

Memory-hard, salted key generation using Argon2 hash algorithm.

EXPBIASback to summary
private static final int EXPBIAS
GNU_DUMMY_S2Kback to summary
public static final int GNU_DUMMY_S2K
GNU_PROTECTION_MODE_DIVERT_TO_CARDback to summary
public static final int GNU_PROTECTION_MODE_DIVERT_TO_CARD
GNU_PROTECTION_MODE_NO_PRIVATE_KEYback to summary
public static final int GNU_PROTECTION_MODE_NO_PRIVATE_KEY
itCountback to summary
pack-priv int itCount
ivback to summary
pack-priv byte[] iv
memorySizeExponentback to summary
pack-priv int memorySizeExponent
parallelismback to summary
pack-priv int parallelism
passesback to summary
pack-priv int passes
protectionModeback to summary
pack-priv int protectionMode
SALTEDback to summary
public static final int SALTED

Salted key generation. A single iteration of a hash function with a (unique) salt

SALTED_AND_ITERATEDback to summary
public static final int SALTED_AND_ITERATED

Salted and iterated key generation. Multiple iterations of a hash function, with a salt

SIMPLEback to summary
public static final int SIMPLE

Simple key generation. A single non-salted iteration of a hash function

typeback to summary
pack-priv int type

Constructor Detail

S2Kback to summary
pack-priv S2K(InputStream in) throws IOException
S2Kback to summary
public S2K(int algorithm)

Constructs a specifier for a simple S2K generation.

Parameters
algorithm:int

the digest algorithm to use.

S2Kback to summary
public S2K(int algorithm, byte[] iv)

Constructs a specifier for a salted S2K generation.

Parameters
algorithm:int

the digest algorithm to use.

iv:byte[]

the salt to apply to input to the key generation.

S2Kback to summary
public S2K(int algorithm, byte[] iv, int itCount)

Constructs a specifier for a salted and iterated S2K generation.

Parameters
algorithm:int

the digest algorithm to iterate.

iv:byte[]

the salt to apply to input to the key generation.

itCount:int

the single byte iteration count specifier.

S2Kback to summary
public S2K(S2K.Argon2Params argon2Params)

Constructs a specifier for an S2K method using Argon2.

Parameters
argon2Params:S2K.Argon2Params

argon2 parameters

S2Kback to summary
public S2K(S2K.GNUDummyParams gnuDummyParams)

Construct a specifier for an S2K using the GNU_DUMMY_S2K method.

Parameters
gnuDummyParams:S2K.GNUDummyParams

GNU_DUMMY_S2K parameters

Method Detail

argon2S2Kback to summary
public static S2K argon2S2K(S2K.Argon2Params parameters)

Return a new S2K instance using the ARGON_2 method, using the given argon2 

parameters
.
Parameters
parameters:S2K.Argon2Params

argon2 parameters

Returns:S2K

S2K

encodeback to summary
public void encode(BCPGOutputStream out) throws IOException

Implements abstract org.bouncycastle.bcpg.BCPGObject.encode.

getHashAlgorithmback to summary
public int getHashAlgorithm()

Gets the hash algorithm for this S2K.

getIterationCountback to summary
public long getIterationCount()

Gets the actual (expanded) iteration count.

getIVback to summary
public byte[] getIV()

Gets the iv/salt to use for the key generation.

getMemorySizeExponentback to summary
public int getMemorySizeExponent()

Gets the memory size exponent - only if ARGON_2

Returns:int

memory size exponent

getParallelismback to summary
public int getParallelism()

Gets the degree of parallelism - only if ARGON_2

Returns:int

parallelism

getPassesback to summary
public int getPasses()

Return the number of passes - only Argon2

Returns:int

number of passes

getProtectionModeback to summary
public int getProtectionMode()

Gets the protection mode - only if GNU_DUMMY_S2K

getTypeback to summary
public int getType()

Gets the digest algorithm specified.

gnuDummyS2Kback to summary
public static S2K gnuDummyS2K(S2K.GNUDummyParams parameters)

Return a new S2K instance using the GNU_DUMMY_S2K method, using the given GNU Dummy S2K 

parameters
.
Parameters
parameters:S2K.GNUDummyParams

GNU Dummy S2K parameters

Returns:S2K

S2K

saltedAndIteratedS2Kback to summary
public static S2K saltedAndIteratedS2K(int algorithm, byte[] salt, int iterationCount)

Return a new S2K instance using the SALTED_AND_ITERATED method, using the given hash 

algorithm
, 
salt
and 
iterationCount
.
Parameters
algorithm:int

hash algorithm tag

salt:byte[]

salt

iterationCount:int

number of iterations

Returns:S2K

S2K

saltedS2Kback to summary
public static S2K saltedS2K(int algorithm, byte[] salt)

Return a new S2K instance using the SALTED method, using the given hash 

algorithm
and 
salt
.
Parameters
algorithm:int

hash algorithm tag

salt:byte[]

salt

Returns:S2K

S2K

simpleS2Kback to summary
public static S2K simpleS2K(int algorithm)

Return a new S2K instance using the SIMPLE method, using the given hash 

algorithm
.
Parameters
algorithm:int

hash algorithm tag

Returns:S2K

S2K

writeOneOctetOrThrowback to summary
private void writeOneOctetOrThrow(BCPGOutputStream out, int val, String valName) throws IOException

Throw an IllegalArgumentException if the value cannot be encoded, otherwise write the value to the output stream.

Parameters
out:BCPGOutputStream

output stream

val:int

value

valName:String

name of the value for the error message

Exceptions
IOException:
potentially thrown by BCPGOutputStream#write(int)
IllegalArgumentException:
if the value cannot be encoded
org.bouncycastle.bcpg back to summary

public Class S2K.Argon2Params

extends Object
Class Inheritance
Parameters for Argon2 S2K.

Field Summary

Modifier and TypeField and Description
private final int
memSizeExp

private final int
parallelism

private final int
passes

private final byte[]
salt

Constructor Summary

AccessConstructor and Description
public
Argon2Params()

Uniformly safe and recommended parameters not tailored to any hardware.

public
Argon2Params(SecureRandom secureRandom)

Uniformly safe and recommended parameters not tailored to any hardware.

public
Argon2Params(int
number of iterations, must be greater than 0
passes, int
number of lanes, must be greater 0
parallelism, int
exponent for memory consumption, must be between 3+ceil(log_2(p)) and 31
memSizeExp, SecureRandom
secure random generator to initialize the salt vector
secureRandom)

Create customized Argon2 S2K parameters.

public
Argon2Params(byte[]
16 bytes of random salt
salt, int
number of iterations, must be greater than 0
passes, int
number of lanes, must be greater 0
parallelism, int
exponent for memory consumption, must be between 3+ceil(log_2(p)) and 31
memSizeExp)

Create customized Argon2 S2K parameters.

Method Summary

Modifier and TypeMethod and Description
public int

Returns:

memory size exponent
getMemSizeExp()

Return the exponent indicating the memory size 

m
public int

Returns:

parallelism
getParallelism()

Return the factor of parallelism 

p
public int

Returns:

number of passes
getPasses()

Return the number of passes 

t
public byte[]

Returns:

salt
getSalt()

Return a 16-byte byte array containing the salt 

S
public static S2K.Argon2Params

Returns:

safe parameters for memory constrained environments
memoryConstrainedParameters()

Recommended parameters for memory constrained environments (64MiB RAM).

private static byte[]

Returns:

salt
mineSalt(SecureRandom
random number generator instance
secureRandom)

Generate 16 bytes of random salt.

public static S2K.Argon2Params
universallyRecommendedParameters()

Uniformly safe and recommended parameters not tailored to any hardware.

Inherited from java.lang.Object:
cloneequalsfinalizegetClasshashCodenotifynotifyAlltoStringwaitwaitwait

Field Detail

memSizeExpback to summary
private final int memSizeExp
parallelismback to summary
private final int parallelism
passesback to summary
private final int passes
saltback to summary
private final byte[] salt

Constructor Detail

Argon2Paramsback to summary
public Argon2Params()

Uniformly safe and recommended parameters not tailored to any hardware. Uses Argon2id, 1 pass, 4 parallelism, 2 GiB RAM.

See Also
RFC 9106: §4. Parameter Choice
Argon2Paramsback to summary
public Argon2Params(SecureRandom secureRandom)

Uniformly safe and recommended parameters not tailored to any hardware. Uses Argon2id, 1 pass, 4 parallelism, 2 GiB RAM.

See Also
RFC 9106: §4. Parameter Choice
Argon2Paramsback to summary
public Argon2Params(int passes, int parallelism, int memSizeExp, SecureRandom secureRandom)

Create customized Argon2 S2K parameters.

Parameters
passes:int

number of iterations, must be greater than 0

parallelism:int

number of lanes, must be greater 0

memSizeExp:int

exponent for memory consumption, must be between 3+ceil(log_2(p)) and 31

secureRandom:SecureRandom

secure random generator to initialize the salt vector

Argon2Paramsback to summary
public Argon2Params(byte[] salt, int passes, int parallelism, int memSizeExp)

Create customized Argon2 S2K parameters.

Parameters
salt:byte[]

16 bytes of random salt

passes:int

number of iterations, must be greater than 0

parallelism:int

number of lanes, must be greater 0

memSizeExp:int

exponent for memory consumption, must be between 3+ceil(log_2(p)) and 31

Method Detail

getMemSizeExpback to summary
public int getMemSizeExp()

Return the exponent indicating the memory size 

m
.
Returns:int

memory size exponent

getParallelismback to summary
public int getParallelism()

Return the factor of parallelism 

p
.
Returns:int

parallelism

getPassesback to summary
public int getPasses()

Return the number of passes 

t
.
Returns:int

number of passes

getSaltback to summary
public byte[] getSalt()

Return a 16-byte byte array containing the salt 

S
.
Returns:byte[]

salt

memoryConstrainedParametersback to summary
public static S2K.Argon2Params memoryConstrainedParameters()

Recommended parameters for memory constrained environments (64MiB RAM). Uses Argon2id with 3 passes, 4 lanes and 64 MiB RAM.

Returns:S2K.Argon2Params

safe parameters for memory constrained environments

See Also
RFC9106: §4. Parameter Choice
mineSaltback to summary
private static byte[] mineSalt(SecureRandom secureRandom)

Generate 16 bytes of random salt.

Parameters
secureRandom:SecureRandom

random number generator instance

Returns:byte[]

salt

universallyRecommendedParametersback to summary
public static S2K.Argon2Params universallyRecommendedParameters()

Uniformly safe and recommended parameters not tailored to any hardware. Uses Argon2id, 1 pass, 4 parallelism, 2 GiB RAM.

See Also
RFC 9106: §4. Parameter Choice
org.bouncycastle.bcpg back to summary

public Class S2K.GNUDummyParams

extends Object
Class Inheritance
Parameters for the GNU_DUMMY_S2K method.

Field Summary

Modifier and TypeField and Description
private final int
protectionMode

Constructor Summary

AccessConstructor and Description
private
GNUDummyParams(int protectionMode)

Method Summary

Modifier and TypeMethod and Description
public static S2K.GNUDummyParams

Returns:

params
divertToCard()

Factory method for a GNU Dummy S2K indicating a private key located on a smart card.

public int

Returns:

protection method
getProtectionMode()

Return the GNU Dummy S2K protection method.

public static S2K.GNUDummyParams

Returns:

params
noPrivateKey()

Factory method for a GNU Dummy S2K indicating a missing private key.

Inherited from java.lang.Object:
cloneequalsfinalizegetClasshashCodenotifynotifyAlltoStringwaitwaitwait

Field Detail

protectionModeback to summary
private final int protectionMode

Constructor Detail

GNUDummyParamsback to summary
private GNUDummyParams(int protectionMode)

Method Detail

divertToCardback to summary
public static S2K.GNUDummyParams divertToCard()

Factory method for a GNU Dummy S2K indicating a private key located on a smart card.

Returns:S2K.GNUDummyParams

params

getProtectionModeback to summary
public int getProtectionMode()

Return the GNU Dummy S2K protection method.

Returns:int

protection method

noPrivateKeyback to summary
public static S2K.GNUDummyParams noPrivateKey()

Factory method for a GNU Dummy S2K indicating a missing private key.

Returns:S2K.GNUDummyParams

params