convert string to private and public key (RSA)

Question

The two strings that are the private and public keys are :

 static String Public = "MIGfMA0GCSqGSIb3DQEBAQUAA4GNADCBiQKBgQDH+wPrKYG1KVlzQUVtBghR8n9d" + "/n" + "zcShSZo0+3KgyVdOea7Ei7vQ1U4wRn1zlI5rSqHDzFitblmqnB2anzVvdQxLQ3Uq" + "/n" + "EBKBfMihnLgCSW8Xf7MCH+DSGHNvBg2xSNhcfEmnbLPLnbuz4ySn1UB0lH2eqxy5" + "/n"+ "0zstxhTY0binD9Y+rwIDAQAB"+ "/n"; static String Private = "MIICxjBABgkqhkiG9w0BBQ0wMzAbBgkqhkiG9w0BBQwwDgQIr5NQ/LYPG/UCAggA" +"/n"+ "MBQGCCqGSIb3DQMHBAiLh89iGSkmoASCAoBCpAo9/IzDE3yGhvWr9RgozE7revOo" +"/n"+ "V2OXmU+d0+WYAAx2GYVaUCbFVrmgiVmrbiTgLUMXAGIpvxQ2rzyIvRHW/RN3Gcky" +"/n"+ "qR/AwBatzixqrnoS4aD1/Ovjr4hwde4XHYbPEilZZuVAJFiznhy73qm/So4XghSY........." ;

I have read the other questions and tried their solutions but nothing worked....I have a public and private key both as strings.. I need to convert them to 'Key' but i keep getting java.security.spec.InvalidKeySpecException: java.security.InvalidKeyException ..at generatePublic and generatePrivate functions.. also the keys are just for testing therefore, it is ok if they are known to others...

 public static Key loadPublicKey(String stored) throws GeneralSecurityException, IOException { byte[] data = Base64.getDecoder().decode((stored.getBytes())); X509EncodedKeySpec spec = new X509EncodedKeySpec(data); KeyFactory fact = KeyFactory.getInstance("RSA"); return fact.generatePublic(spec); } public static Key loadPrivateKey(String key64) throws GeneralSecurityException, IOException { byte[] clear = Base64.getDecoder().decode(key64.getBytes()); PKCS8EncodedKeySpec keySpec = new PKCS8EncodedKeySpec(clear); KeyFactory fact = KeyFactory.getInstance("RSA"); PrivateKey priv = fact.generatePrivate(keySpec); Arrays.fill(clear, (byte) 0); return priv; }

still the same issue .. am getting java.security.spec.InvalidKeySpecException: java.security.InvalidKeyException: I changed the public key to :"MIGfMA0GCSqGSIb3DQEBAQUAA4GNADCBiQKBgQDH+wPrKYG1KVlzQUVtBghR8n9dzcShSZo0+3KgyVdOea7Ei7vQ1U4wRn1zlI5rSqHDzFitblmqnB2anzVvdQxLQ3UqEBKBfMihnLgCSW8Xf7MCH+DSGHNvBg2xSNhcfEmnbLPLnbuz4ySn1UB0lH2eqxy50zstxhTY0binD9Y+rwIDAQAB" — Haya Raed
– Haya Raed, Commented Apr 12, 2017 at 14:17
I have tried it by my own with the public key and it is working — Jens
– Jens, Commented Apr 12, 2017 at 14:19
Line feeds are \n, not /n. In a string, this would look like "\\n". — Artjom B.
– Artjom B., Commented Apr 12, 2017 at 18:06
Necroed but for info: aside from the extraneous /n, your Public is indeed base64 of X.509-SPKI publickey suitable for Java X509EncodedKeySpec, but your Private is (base64 of beginning of) an encrypted PKCS8 private key (EncryptedPrivateKeyInfo) while PKCS8EncodedKeySpec must be unencrypted or here decrypted. If you have the password and (can) use BouncyCastle see stackoverflow.com/questions/49932334/… otherwise it's rather complicated. — dave_thompson_085
– dave_thompson_085, Commented Dec 17, 2021 at 11:48

Jens · Accepted Answer · 2017-04-12 14:23:44Z

Remove the line Feeds in the string declaration. That is not part of the key:

static String Public = "MIGfMA0GCSqGSIb3DQEBAQUAA4GNADCBiQKBgQDH+wPrKYG1KVlzQUVtBghR8n9d" + "zcShSZo0+3KgyVdOea7Ei7vQ1U4wRn1zlI5rSqHDzFitblmqnB2anzVvdQxLQ3Uq" + "EBKBfMihnLgCSW8Xf7MCH+DSGHNvBg2xSNhcfEmnbLPLnbuz4ySn1UB0lH2eqxy5" + "0zstxhTY0binD9Y+rwIDAQAB"; static String Private = "MIICxjBABgkqhkiG9w0BBQ0wMzAbBgkqhkiG9w0BBQwwDgQIr5NQ/LYPG/UCAggA" + "MBQGCCqGSIb3DQMHBAiLh89iGSkmoASCAoBCpAo9/IzDE3yGhvWr9RgozE7revOo" + "V2OXmU+d0+WYAAx2GYVaUCbFVrmgiVmrbiTgLUMXAGIpvxQ2rzyIvRHW/RN3Gcky" + "qR/AwBatzixqrnoS4aD1/Ovjr4hwde4XHYbPEilZZuVAJFiznhy73qm/So4XghSY........." ;

I have tried it with the following code:

 public static void main(String[] args) throws GeneralSecurityException, IOException { System.out.println(loadPublicKey(Public)); } public static Key loadPublicKey(String stored) throws GeneralSecurityException, IOException { byte[] data = Base64.getDecoder().decode((stored.getBytes())); X509EncodedKeySpec spec = new X509EncodedKeySpec(data); KeyFactory fact = KeyFactory.getInstance("RSA"); return fact.generatePublic(spec); }

And Output is:

Sun RSA public key, 1024 bits modulus: 140431102839105138202102866401190456107365606715815288536913018579006717438700259314092212104831553250527764925385527697411165705192297577022746989837839401358787285684108054389360182109284048524426941021357601686464156659759470495649944686235380003772357268264646549523784880655065600797504478771675703688879 public exponent: 65537

@zaph it is a string of multiple lines .. it cannot be written as is ... unless it is all placed in one line
@HayaRaed It can not be. I have tried it by my own with public key and no exception
@Jens really!! Why am I getting.... Exception in thread "main" java.security.spec.InvalidKeySpecException: java.security.InvalidKeyException: IOException : DER input, Integer tag error at sun.security.rsa.RSAKeyFactory.engineGeneratePrivate(Unknown Source) at java.security.KeyFactory.generatePrivate(Unknown Source) at Main.loadPrivateKey(Main.java:144) at Main.main(Main.java:185) Caused by: java.security.InvalidKeyException: IOException : DER input, Integer tag error at sun.security.pkcs.PKCS8Key.decode(Unknown Source)
@HayaRaed You refer the private key part. I can not check it, because you have not shown it completly

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