(Perl) Get Ed25519 Key in Different Formats

Demonstrates how to get/save an Ed25519 private key to different formats.

Converting a private key from one format to another is done by loading in one format and saving/getting in another.

Note: This example requires Chilkat v9.5.0.83 or greater.

Chilkat Perl Downloads Perl Module for Windows, MacOS, Linux, Alpine Linux, Solaris

use chilkat();

# This example assumes the Chilkat API to have been previously unlocked.
# See Global Unlock Sample for sample code.

$eddsa = chilkat::CkEdDSA->new();
$prng = chilkat::CkPrng->new();
$privKey = chilkat::CkPrivateKey->new();

# Generates a new ed25519 key and stores it in privKey.
$success = $eddsa->GenEd25519Key($prng,$privKey);
if ($success == 0) {
    print $eddsa->lastErrorText() . "\r\n";
    exit;
}

# ----------------------------------------------------------
# Ed25519 PKCS1 format
# 
# This is the format created by:  openssl genpkey -algorithm X25519 -out xkey.pem
$pkcs1Base64 = $privKey->getPkcs1ENC("base64");
print $pkcs1Base64 . "\r\n";

# Sample output:  MC4CAQAwBQYDK2VuBCIEIB1mwirs+eC6XGbkjPIiZyBwQ7768uSd9v5PHOLFbIXo

# PKCS1 is a binary ASN.1 DER format.  You can examine the contents with two online tools:
# 1) Go to ASN.1 Decoder  and paste the base64 into the online form.
# 2) Or Decode Base64 ASN.1 to XML 

# The PKCS1 ASN.1 format for an Ed25519 key look like this:
#   SEQUENCE
#     INTEGER 0
#     SEQUENCE
#       OBJECT IDENTIFIER 1.3.101.110 curveX25519 (ECDH 25519 key agreement algorithm)
#     OCTET STRING 
#       OCTET STRING (32 byte) 1D66C...

# Save it directly to a file.
$success = $privKey->SavePkcs1File("qa_output/ed25519.key");

# ----------------------------------------------------------
# Ed25519 Unencrypted PKCS8 format
# 
# For ed25519, the ASN.1 output is the same as for PKCS1.
$pkcs8Base64 = $privKey->getPkcs8ENC("base64");
print $pkcs8Base64 . "\r\n";

# PKCS8 is a binary ASN.1 DER format.  You can examine the contents with two online tools:
# 1) Go to ASN.1 Decoder  and paste the base64 into the online form.
# 2) Or Decode Base64 ASN.1 to XML 

# ----------------------------------------------------------
# Ed25519 Encrypted PKCS8 format
# 
# Note: The encrypted output cannot be examined using the above online tools because the ASN.1 is encrypted.
$password = "secret";
$pkcs8EncBase64 = $privKey->getPkcs8EncryptedENC("base64",$password);
print $pkcs8EncBase64 . "\r\n";

# ----------------------------------------------------------
# Ed25519 in PEM format:
# 
$ed25519Pem = $privKey->getPkcs1Pem();
print $ed25519Pem . "\r\n";

# Sample output:

# -----BEGIN PRIVATE KEY-----
# MC4CAQAwBQYDK2VuBCIEIOKPhbULJagBAi7hbRdn1f4AAzh1RqqCHqCAvau7N6yO
# -----END PRIVATE KEY-----

# ----------------------------------------------------------
# Ed25519 in JWK Format
# 
$jwk = $privKey->getJwk();

$json = chilkat::CkJsonObject->new();
$json->Load($jwk);
$json->put_EmitCompact(0);
print $json->emit() . "\r\n";

# Sample output:
# {
#   "kty": "OKP",
#   "crv": "Ed25519",
#   "x": "SE2Kne5xt51z1eciMH2T2ftDQp96Gl6FhY6zSQujiP0",
#   "d": "O-eRXewadF0sNyB0U9omcnt8Qg2ZmeK3WSXPYgqe570",
#   "use": "sig"
# }

# In the above JWK, x is the public key, y is the private key.
# Both are 32 bytes and are base64-url encoded.

# ----------------------------------------------------------
# Ed25519 in XML Format
# 
$ed25519_xml = $privKey->getXml();
print $ed25519_xml . "\r\n";

# Sample output:  <Ed25519KeyValue>w4b/gI0zgYKgjtfWLjNfc4issmP7Qap84uesYNgEefP/WoY3jNOhOzgTYsMtOnuyGn3MdA4NZtsUXVNI1NiTlA==</Ed25519KeyValue>

# The base64 content is composed of the concatenation of the 32-byte private key with the 32-byte public key and then base64 encoded.
# In other words:  Base64(privKey || pubKey)

# ----------------------------------------------------------
# Ed25519 in Raw Hex Format
# 
$sbPubKeyHex = chilkat::CkStringBuilder->new();
$privKeyHex = $privKey->getRawHex($sbPubKeyHex);

# We should have a 32-byte private key (a 64 character hex string).
print "private key = " . $privKeyHex . "\r\n";

# We should have a 32-byte public key (a 64 character hex string).
print "public key = " . $sbPubKeyHex->getAsString() . "\r\n";

# Sample output:
# key type = ed25519
# size in bits = 256
# private key = d4ee72dbf913584ad5b6d8f1f769f8ad3afe7c28cbf1d4fbe097a88f44755842
# public key = 19bf44096984cdfe8541bac167dc3b96c85086aa30b6b6cb0c5c38ad703166e1