Search code examples
pythonpython-3.xrsa

Import String Public Key to RSA Public Key in Python

I am using Python RSA to do RSA encryption and decryption

I have public/private key in string format and the above mentioned library expects it in format class of type rsa.PublicKey

I am not able to convert my string public/private key to required format(class)

Public Key:

MIIBIjANBgkqhkiG9w0BAQEFAAOCAQ8AMIIBCgKCAQEAt14jQ0+D8+gpsCPIrCoWVgw8qmH6izDXQTSqHngcGkjuuK58TOOgUo/lari7uTAg5s0ng42WYwQw3uXqa4aKOUMfcLvmn9pALNY3q9oXZa9plxemGR9itlTrY6ZKOX2FrRTB42K6F6YUnMTtjotw/6E3lNQJpFYwyT1EhLV/TP2ds7NVbNEMX+kRcelxD9Cwwigfv+2eljUJP/lQUoNTEJr6oQRibPMSBCRBbljUq5fDSxGrm0WKFLcxDwcf57/qekeWeFkysdzOTSlOQfGs8WLGho3pMNal0uCzEi2SIVPnkg3cNs6nCJ/Y3LCwUcOk1kRJqyZqk46s4iFzEElGqQIDAQAB
Solution

  • The posted key is a Base64 encoded, DER encoded RSA public key in X.509/SPKI format (this can be verified in an ASN.1 parser, e.g. https://lapo.it/asn1js/).

    Python-RSA supports for public RSA keys both formats (i.e. X.509/SPKI and PKCS#1) and encodings (i.e. PEM and DER) with the respective methods of the rsa.PublicKey class, e.g. the posted Base64 encoded, DER encoded X.509/SPKI key can be imported with load_pkcs1_openssl_der() as follows:

    import rsa
import base64

publicKeySpkiDer = base64.b64decode('MIIBIjANBgkqhkiG9w0BAQEFAAOCAQ8AMIIBCgKCAQEAt14jQ0+D8+gpsCPIrCoWVgw8qmH6izDXQTSqHngcGkjuuK58TOOgUo/lari7uTAg5s0ng42WYwQw3uXqa4aKOUMfcLvmn9pALNY3q9oXZa9plxemGR9itlTrY6ZKOX2FrRTB42K6F6YUnMTtjotw/6E3lNQJpFYwyT1EhLV/TP2ds7NVbNEMX+kRcelxD9Cwwigfv+2eljUJP/lQUoNTEJr6oQRibPMSBCRBbljUq5fDSxGrm0WKFLcxDwcf57/qekeWeFkysdzOTSlOQfGs8WLGho3pMNal0uCzEi2SIVPnkg3cNs6nCJ/Y3LCwUcOk1kRJqyZqk46s4iFzEElGqQIDAQAB')
publicKey = rsa.PublicKey.load_pkcs1_openssl_der(publicKeySpkiDer)

    A PEM encoded X.509/SPKI key can be imported with load_pkcs1_openssl_pem().

    A PKCS#1 public key can be imported with load_pkcs1(). In the second parameter the encoding is specified (with 'PEM' or 'DER').