Converting a string private key to PrivateKey type

Question

I am having below RSA private key in string format.

String privatekey = -----BEGIN RSA PRIVATE KEY-----
MIIEpAIBAAKCAQEAqAKCCMKqboM8ywSuNvmf2zuT0e2elxntdEe5msv22         


        

Answer 1

BEGIN RSA PRIVATE KEY means your key is pkcs#1 format and not pkcs#8. Reading pkcs#1 keys is not natively supported by Java. You need to use bouncycastle library ( see Read RSA private key of format PKCS1 in JAVA )or use any of these solutions Getting RSA private key from PEM BASE64 Encoded private key file

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if your key were pkcs#8, it would have the header BEGIN PRIVATE KEY. In that case, for your code to work correctly you would need additionally decode the key content from base64

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To convert a pkcs#1 key to pkcs#8 you can use openssl

  openssl pkcs8 -topk8 -inform PEM -outform PEM -nocrypt -in pkcs1.key -out pkcs8.key