learning the mechanics of signing with RSA and I have a block of code that works below.
var privateRSAKey = File.ReadAllText("RSAPrivateKey.txt").Trim();
Regex privateRSAKeyRegex = new Regex(@"-----(BEGIN|END) RSA PRIVATE KEY-----[\W]*");
privateRSAKey = privateRSAKeyRegex.Replace(privateRSAKey, "");
//byte[602]
byte[] rsaPrivateKeyBytes = Convert.FromBase64String(privateRSAKey);
RSA rsa = RSA.Create();
rsa.ImportRSAPrivateKey(new ReadOnlySpan<byte>(rsaPrivateKeyBytes), out _);
But a similar block won't work for replacing the public key on another rsa object.
publicRSAKey = File.ReadAllText("RSAPublicKey.txt").Trim();
Regex publicRSAKeyRegex = new Regex(@"-----(BEGIN|END) PUBLIC KEY-----[\W]*");
publicRSAKey = publicRSAKeyRegex.Replace(publicRSAKey, "");
//byte[162]
byte[] rsaPublicKeyBytes = Convert.FromBase64String(publicRSAKey);
RSA recipientRSA = RSA.Create();
recipientRSA.ImportRSAPublicKey(new ReadOnlySpan<byte>(rsaPublicKeyBytes), out _);
I just want to replace the public rsa key from a string file with but i get the error
An unhandled exception of type 'System.Security.Cryptography.CryptographicException' occurred in System.Security.Cryptography.Algorithms.dll
ASN1 corrupted data.
CodePudding user response:
I found this literally after posting https://vcsjones.dev/key-formats-dotnet-3/
To summarize each PEM label and API pairing:
“BEGIN RSA PRIVATE KEY” => RSA.ImportRSAPrivateKey
“BEGIN PRIVATE KEY” => RSA.ImportPkcs8PrivateKey
“BEGIN ENCRYPTED PRIVATE KEY” => RSA.ImportEncryptedPkcs8PrivateKey
“BEGIN RSA PUBLIC KEY” => RSA.ImportRSAPublicKey
“BEGIN PUBLIC KEY” => RSA.ImportSubjectPublicKeyInfo
My issue was that my key was in the format -----BEGIN PUBLIC KEY-----
and I was using ImportRSAPublicKey
.
I switched to .ImportSubjectPublicKeyInfo
and all is well