OK, I’ve worked out what’s going on. Leonidas is right, it’s not just the hash that gets encrypted (in the case of the Cipher class method), it’s the ID of the hash algorithm concatenated with the digest: DigestInfo ::= SEQUENCE { digestAlgorithm AlgorithmIdentifier, digest OCTET STRING } Which is why the encryption by the Cipher … Read more
i wanted to point out something as a response to a comment by ala asking if: Public Key = modulus + exponent That is exactly correct. There are a few ways of storing this exponent + modulus. The first attempt at a standard was in RFC 3447 (Public-Key Cryptography Standards (PKCS) #1: RSA Cryptography Specifications … Read more
You don’t need to export existing parameters then re-import over top of them. That forces your machine to generate an RSA key then throw it away. So specifying a keysize to the constructor doesn’t matter (if you don’t use the key it won’t generate one… usually). The public key file is a DER encoded blob. … Read more
Run the following command to retrieve the SHA256 fingerprint of your SSH key (-l means “list” instead of create a new key, -f means “filename”): $ ssh-keygen -lf /path/to/ssh/key So for example, on my machine the command I ran was (using RSA public key): $ ssh-keygen -lf ~/.ssh/id_rsa.pub 2048 00:11:22:33:44:55:66:77:88:99:aa:bb:cc:dd:ee:ff /Users/username/.ssh/id_rsa.pub (RSA) To get the … Read more
Java does not come with out-of-the-box support for PKCS1 keys. You can however use Bouncycastle PEMParser pemParser = new PEMParser(new FileReader(privateKeyFile)); JcaPEMKeyConverter converter = new JcaPEMKeyConverter().setProvider(“BC”); Object object = pemParser.readObject(); KeyPair kp = converter.getKeyPair((PEMKeyPair) object); PrivateKey privateKey = kp.getPrivate();
You have an OpenSSH format key and want a PEM format key. It is not intuitive to me, but the suggested way to convert is by changing the password for the key and writing it in a different format at the same time. The command looks like this: ssh-keygen -p -N “” -m pem -f … Read more
I have tried RSA Encryption and Decryption for NSString. Here is the code: Add Security.Framework to your project bundle. ViewController.h code is as follows: #import <UIKit/UIKit.h> #import <Security/Security.h> @interface ViewController : UIViewController { SecKeyRef publicKey; SecKeyRef privateKey; NSData *publicTag; NSData *privateTag; } – (void)encryptWithPublicKey:(uint8_t *)plainBuffer cipherBuffer:(uint8_t *)cipherBuffer; – (void)decryptWithPrivateKey:(uint8_t *)cipherBuffer plainBuffer:(uint8_t *)plainBuffer; – (SecKeyRef)getPublicKeyRef; – … Read more
RSA encrypts a single message which has a length which is somewhat smaller than the modulus. Specifically, the message is first “padded”, resulting in a sequence of bytes which is then interpreted as a big integer between 0 and n-1, where n is the modulus (a part of the public key) — so the padded … Read more
(Expanding more than I feel is appropriate for an edit.) PKCS1, available in several versions as rfcs 2313 2437 3447 and 8017, is primarily about using the RSA algorithm for cryptography including encrypting decrypting signing and verifying. But since crypto is often used between systems or at least programs it is convenient to have a … Read more
Thanks to jwilleke, I have got a solution. To verify the RS256 signature of a JWT, it is needed to use the RSAPKCS1SignatureDeformatter class and its VerifySignature method. Here is the exact code for my sample data: string tokenStr = “eyJraWQiOiIxZTlnZGs3IiwiYWxnIjoiUlMyNTYifQ.ewogImlzcyI6ICJodHRwOi8vc2VydmVyLmV4YW1wbGUuY29tIiwKICJzdWIiOiAiMjQ4Mjg5NzYxMDAxIiwKICJhdWQiOiAiczZCaGRSa3F0MyIsCiAibm9uY2UiOiAibi0wUzZfV3pBMk1qIiwKICJleHAiOiAxMzExMjgxOTcwLAogImlhdCI6IDEzMTEyODA5NzAsCiAiY19oYXNoIjogIkxEa3RLZG9RYWszUGswY25YeENsdEEiCn0.XW6uhdrkBgcGx6zVIrCiROpWURs-4goO1sKA4m9jhJIImiGg5muPUcNegx6sSv43c5DSn37sxCRrDZZm4ZPBKKgtYASMcE20SDgvYJdJS0cyuFw7Ijp_7WnIjcrl6B5cmoM6ylCvsLMwkoQAxVublMwH10oAxjzD6NEFsu9nipkszWhsPePf_rM4eMpkmCbTzume-fzZIi5VjdWGGEmzTg32h3jiex-r5WTHbj-u5HL7u_KP3rmbdYNzlzd1xWRYTUs4E8nOTgzAUwvwXkIQhOh5TPcSMBYy6X3E7-_gr9Ue6n4ND7hTFhtjYs3cjNKIA08qm5cpVYFMFMG6PkhzLQ”; string[] tokenParts = tokenStr.Split(‘.’); RSACryptoServiceProvider rsa = new RSACryptoServiceProvider(); rsa.ImportParameters( new RSAParameters() { Modulus … Read more