Class PEMEncoder

java.lang.Object

java.security.PEMEncoder

public final class PEMEncoder
extends Object

PEMEncoder is a preview API of the Java platform.

Programs can only use PEMEncoder when preview features are enabled.

Preview features may be removed in a future release, or upgraded to permanent features of the Java platform.

PEMEncoder implements an encoder for Privacy-Enhanced Mail (PEM) data. PEM is a textual encoding used to store and transfer security objects, such as asymmetric keys, certificates, and certificate revocation lists (CRL). It is defined in RFC 1421 and RFC 7468. PEM consists of a Base64-formatted binary encoding enclosed by a type-identifying header and footer.

Encoding may be performed on Java API cryptographic objects that implement DEREncodable^PREVIEW. The encode(DEREncodable) and encodeToString(DEREncodable) methods encode a DEREncodable into PEM and return the data in a byte array or String.

Private keys can be encrypted and encoded by configuring a PEMEncoder with the withEncryption(char[]) method, which takes a password and returns a new PEMEncoder instance configured to encrypt the key with that password. Alternatively, a private key encrypted as an EncryptedKeyInfo object can be encoded directly to PEM by passing it to the encode or encodeToString methods.

PKCS #8 2.0 defines the ASN.1 OneAsymmetricKey structure, which may contain both private and public keys. KeyPair objects passed to the encode or encodeToString methods are encoded as a OneAsymmetricKey structure using the "PRIVATE KEY" type.

When encoding a PEMRecord^PREVIEW, the API surrounds the PEMRecord.pem()^PREVIEW with the PEM header and footer from PEMRecord.type()^PREVIEW. PEMRecord.leadingData()^PREVIEW is not included in the encoding. PEMRecord will not perform validity checks on the data.

The following lists the supported DEREncodable classes and the PEM types that each are encoded as:

• X509Certificate : CERTIFICATE
• X509CRL : X509 CRL
• PublicKey: PUBLIC KEY
• PrivateKey : PRIVATE KEY
• PrivateKey (if configured with encryption): ENCRYPTED PRIVATE KEY
• EncryptedPrivateKeyInfo : ENCRYPTED PRIVATE KEY
• KeyPair : PRIVATE KEY
• X509EncodedKeySpec : PUBLIC KEY
• PKCS8EncodedKeySpec : PRIVATE KEY
• PEMRecord : PEMRecord.type()

This class is immutable and thread-safe.

Here is an example of encoding a PrivateKey object:

    PEMEncoder pe = PEMEncoder.of();
    byte[] pemData = pe.encode(privKey);

Here is an example that encrypts and encodes a private key using the specified password:

    PEMEncoder pe = PEMEncoder.of().withEncryption(password);
    byte[] pemData = pe.encode(privKey);

Implementation Note:

An implementation may support other PEM types and DEREncodables.

Since:

25

External Specifications

• RFC 1421: Privacy Enhancement for Internet Electronic Mail
• RFC 7468: Textual Encodings of PKIX, PKCS, and CMS Structures

See Also:

• PEMDecoder^PREVIEW
• PEMRecord^PREVIEW
• EncryptedPrivateKeyInfo

Method Summary

Modifier and Type	Method	Description
byte[]	encode(DEREncodablePREVIEW de)	Encodes the specified DEREncodable and returns the PEM encoding in a byte array.
String	encodeToString(DEREncodablePREVIEW de)	Encodes the specified DEREncodable and returns a PEM encoded string.
static PEMEncoderPREVIEW	of()	Returns an instance of PEMEncoder.
PEMEncoderPREVIEW	withEncryption(char[] password)	Returns a new PEMEncoder instance configured for encryption with the default algorithm and a given password.

Methods declared in class Object

clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

Method Details

of

public static PEMEncoderPREVIEW of()

Returns an instance of PEMEncoder.

Returns:

a PEMEncoder

encodeToString

public String encodeToString(DEREncodablePREVIEW de)

Encodes the specified DEREncodable and returns a PEM encoded string.

Parameters:

de - the DEREncodable to be encoded

Returns:

a String containing the PEM encoded data

Throws:

IllegalArgumentException - if the DEREncodable cannot be encoded

NullPointerException - if de is null

See Also:

• withEncryption(char[])

encode

public byte[] encode(DEREncodablePREVIEW de)

Encodes the specified DEREncodable and returns the PEM encoding in a byte array.

Parameters:

de - the DEREncodable to be encoded

Returns:

a PEM encoded byte array

Throws:

IllegalArgumentException - if the DEREncodable cannot be encoded

NullPointerException - if de is null

See Also:

• withEncryption(char[])

withEncryption

public PEMEncoderPREVIEW withEncryption(char[] password)

Returns a new PEMEncoder instance configured for encryption with the default algorithm and a given password.

Only PrivateKey objects can be encrypted with this newly configured instance. Encoding other DEREncodable^PREVIEW objects will throw an IllegalArgumentException.

Implementation Note:

The default password-based encryption algorithm is defined by the jdk.epkcs8.defaultAlgorithm security property and uses the default encryption parameters of the provider that is selected. For greater flexibility with encryption options and parameters, use EncryptedPrivateKeyInfo.encryptKey(PrivateKey, Key, String, AlgorithmParameterSpec, Provider, SecureRandom)^PREVIEW and use the returned object with encode(DEREncodable).

Parameters:

password - the encryption password. The array is cloned and stored in the new instance.

Returns:

a new PEMEncoder instance configured for encryption

Throws:

NullPointerException - when password is null