JWT

A JSON Web Token (JWT) is an open standard (RFC 7519 - JSON Web Token (JWT) (ietf.org)) that defines a compact and self-contained way for securely transmitting information between parties as a JSON object. It is often used for representing claims between a client and a server or between multiple services.

JWTs are commonly used for:

• Authentication: After a user logs in, the server can create a JWT and send it to the client. The client can then include this token in subsequent requests to prove their identity.
• Authorization: JWTs can contain information about what a user is allowed to do, including access control and permissions.
• Information Exchange: JWTs can be used as a secure way to transmit data between different parts of an application.

JWT Characteristics

JWTs have several characteristics that make them useful in various scenarios:

• Compact: JWTs are designed to be compact, making them suitable for transmission in HTTP headers or URL query parameters.
• Self-contained: JWTs contain all the information needed to verify their authenticity, reducing the need for additional database lookups.
• Stateless: Each JWT is self-contained, so the server does not need to keep track of session state.
• Tamper-Evident: JWTs can be signed, ensuring that their content has not been tampered with.

JWT Structure

JWTs consist of three parts: a header, a payload, and a signature. Each part is Base64Url-encoded and separated by periods ('.').

Header

The header typically consists of two parts:

• Type (typ): This indicates that the token is a JWT. For example, "typ": "JWT".
• Signing Algorithm (alg): This specifies the cryptographic algorithm used to sign the token. Common algorithms include RS256 (RSA signature with SHA-256) and HS256 (HMAC-SHA-256).

Here's an example header:

{ 
    "typ": "JWT", 
    "alg": "HS256" 
}        

What is the role of RSA and SHA256 in RS256 algorithm :

In the RS256 (RSA signature with SHA-256) algorithm, both RSA (Rivest–Shamir–Adleman) and SHA-256 (Secure Hash Algorithm 256-bit) play distinct roles in the signing and verification process of a JWT (JSON Web Token).

RS256 combines the strengths of RSA and SHA-256. RSA provides the asymmetric cryptography for secure key pair management, while SHA-256 provides a cryptographic hash function to ensure the integrity of the token's content. Together, they ensure that RS256-signed JWTs are both secure and tamper-evident.

Here's a breakdown of their roles:

1. RSA (Rivest–Shamir–Adleman):Signing: In RS256, RSA is primarily responsible for the digital signature part of JWTs. When you create a JWT, you use a private RSA key to sign the token. This private key is known only to the entity creating the JWT.Verification: On the receiving side, when someone receives the JWT, they use the corresponding public RSA key to verify the signature. This is a crucial step in ensuring the integrity and authenticity of the token. If the verification is successful, it means that the JWT has not been tampered with and was indeed signed by the entity with the private key.
2. SHA-256 (Secure Hash Algorithm 256-bit):Digest Algorithm: SHA-256 is used as a digest algorithm in RS256. Before signing the JWT, the content of the token is hashed using SHA-256. This produces a fixed-length hash value (256 bits or 32 bytes).Signing Process: The hash value obtained from SHA-256, along with other header and payload information, is used as the input for the RSA signature algorithm. RSA signs this hash value using the private key, creating the digital signature.Verification Process: When verifying the JWT, the recipient hashes the header and payload of the received token using SHA-256. This produces a hash value. They then use the public key to verify the digital signature created by the sender. If the recalculated hash matches the one from the received JWT, it means the token has not been tampered with.

BTW let me give very brief description of what Digest means :

Digest:

A "digest" refers to a fixed-length string of characters (usually in hexadecimal format) generated by applying a cryptographic hash function to a piece of data. A digest is also commonly referred to as a "hash" or "hash value."

A "digest algorithm" (or hash algorithm) is a mathematical function that takes an input (or "message") and produces a fixed-length string of characters, which is the digest. The key properties of a good digest algorithm include:

1. Deterministic: For the same input, the algorithm always produces the same digest.
2. Fast Computation: It should be computationally efficient to calculate the digest.
3. Pre-image Resistance: Given a digest, it should be computationally infeasible to reverse the process and find the original input (pre-image) that produced the digest.
4. Collision Resistance: It should be extremely unlikely for two different inputs to produce the same digest (a collision).
5. Avalanche Effect: A small change in the input should result in a significantly different digest.

Digest algorithms are widely used in various aspects of computer security and cryptography, including:

• Data Integrity: To ensure that data has not been tampered with during transmission or storage. If the digest of the received data matches the expected digest, it's highly likely that the data has not been altered.
• Password Storage: Storing passwords securely by storing the hash of the password instead of the password itself.
• Digital Signatures: In digital signatures, the digest of a message is signed, ensuring that the message has not been altered since the signature was created.
• Cryptography Protocols: In various cryptographic protocols, digest algorithms are used for message authentication codes (MACs) and other security checks.

Commonly used digest algorithms include SHA-256 (part of the SHA-2 family), SHA-1 (less secure and deprecated for many applications), and MD5 (generally considered weak and not recommended for security-critical purposes). The choice of digest algorithm depends on the specific security requirements of the application and the level of security needed.

let's go to original discussion of JWT structure and payload.

Payload

The payload contains claims. Claims are statements about an entity (typically, the user) and additional data. There are three types of claims:

• Registered Claims: These are predefined claims, such as iss (issuer), sub (subject), aud (audience), exp (expiration time), and iat (issued at).,nbf, These claims have specific meanings and are commonly used.
• Public Claims: These claims are defined by the JWT standard but are not mandatory. They are typically used to convey information about the user or application.
• Private Claims: These claims are custom and created for a specific application. They are agreed upon between the parties using the JWT such as server and client.

Here's an example payload with some registered claims:

{ 
    "sub": "Hello There", 
    "name": "Amit Nadiger", 
    "iat": 1516239022 
  ...
}        

Signature

The signature is used to verify that the sender of the JWT is who it says it is and to ensure that the message wasn't changed along the way. The signature is created by taking the encoded header, encoded payload, a secret (for HMAC-based algorithms), and the algorithm specified in the header. The result is a string of bytes, which is then Base64Url-encoded.

Here's an example signature:

HMACSHA256(
  base64UrlEncode(header) + "." +
  base64UrlEncode(payload),
  secret
)        

What is Base64?

Base64 is a binary-to-text encoding scheme that represents binary data in an ASCII string format. It's commonly used in computing and data transmission to ensure that data is transmitted and stored in a format that's both safe and efficient. Base64 encoding is designed to be machine-readable and human-readable, making it suitable for use in text-based protocols such as email, HTML, and URLs and of course JWT.

Here's how Base64 encoding works in detail:

1. Binary Data: In computing, data is often represented in binary format, which consists of sequences of 0s and 1s. This binary data can represent various types of information, including images, files, and more.
2. Grouping Bits: Base64 encoding groups binary data into sets of 6 bits each. This grouping makes it easier to convert binary data into a text-based format.
3. Mapping to Characters: Each group of 6 bits is then mapped to a corresponding character in the Base64 character set. The Base64 character set typically consists of 64 characters, which include uppercase and lowercase letters (A-Z, a-z), digits (0-9), and two additional characters, often '+', and '/'. In some contexts, different characters may be used, but the principle remains the same.
4. Padding: If the binary data doesn't divide evenly into groups of 6 bits, padding characters ('=') are added to the end of the Base64-encoded string to ensure it has a length that is a multiple of 4.

Here's a simple example to illustrate the process:

Let's say you have a binary sequence: 01001001 01010011 00100000. To encode this binary data in Base64:

Group the binary data into sets of 6 bits each:

010010 010101 001100 100000        

Convert each group of 6 bits to decimal:

18 21 12 32        

Map the decimal values to the Base64 character set:

S V M g        

Combine the Base64 characters into a string:

SVMg        

So, the Base64-encoded representation of the binary data 01001001 01010011 00100000 is SVMg.

Below is base 64 mapping:

  0 A     17 R     34 i     51 z
  1 B     18 S     35 j     52 0
  2 C     19 T     36 k     53 1
  3 D     20 U     37 l     54 2
  4 E     21 V     38 m     55 3
  5 F     22 W     39 n     56 4
  6 G     23 X     40 o     57 5
  7 H     24 Y     41 p     58 6
  8 I     25 Z     42 q     59 7
  9 J     26 a     43 r     60 8
  10 K    27 b     44 s     61 9
  11 L    28 c     45 t     62 +
  12 M    29 d     46 u     63 /
  13 N    30 e     47 v
  14 O    31 f     48 w
  15 P    32 g     49 x
  16 Q    33 h     50 y        

Base64 is commonly used in various applications, including:

• JWT creation.
• Email Attachments: To encode binary attachments in email messages.
• URLs: To encode data within URLs where certain characters are not allowed.
• Data Serialization: In web services and APIs for encoding and decoding data.
• Binary to Text Conversion: When binary data needs to be represented as text, e.g., in XML or JSON.
• Password Storage: In some cases, passwords are Base64-encoded before storage, although this is not secure and should be avoided in favor of secure hashing.

Please note that while Base64 encoding makes data more human-readable and suitable for text-based transmission, it does not provide encryption or security. It's not intended for securing sensitive data but for encoding it in a consistent and portable way.

Below base64_url_encode that takes a string as input which is already base64 encoded but it is not base64url compactable and this function performs Base64 URL encoding. Base64 URL encoding is a variant of Base64 encoding used for URL-safe transmission of data, and it replaces certain characters with others to make them safe for use in URLs.

fn main() {
    let original_data = "Hello+World/123==";
    let encoded_data = base64_url_encode(original_data);
    println!("Encoded Data: {}", encoded_data);
}

fn base64_url_encode(data: &str) -> String {
    let base64_url = data
        .chars()
        .map(|c| match c {
            '+' => '-',
            '/' => '_',
            '=' => ' ', // Omit the '=' character
            _ => c,
        })
        .collect::<String>()
        .replace(" ", ""); 
        // Remove any remaining spaces (due to omitted '=')
    base64_url
}
/*
O/P
Encoded Data: Hello-World_123
*/        

3. How to create JWTs

JWTs can indeed be created and validated using various algorithms, depending on the security requirements of the application. The choice of algorithm depends on factors like the level of security needed, the infrastructure in use, and whether we prioritize simplicity or complexity.

Here are some common JWT signing and verification algorithms and their roles:

1. HMAC (Hash-based Message Authentication Code):Role: HMAC algorithms use a shared secret key to both create and verify the signature. They are symmetric, meaning the same secret key is used for both signing and verifying.Use Case: HMAC is suitable for cases where the issuer and the verifier share a secret key. It's often used for server-to-server communication or in situations where the JWT is intended to be used internally within a trusted environment. Example: HS256 (HMAC-SHA-256) is a widely used HMAC algorithm.
2. RSA (Rivest–Shamir–Adleman):Role: RSA algorithms use a pair of public and private keys. The private key is used for signing, and the public key is used for verification. It's an asymmetric approach, providing stronger security.Use Case: RSA is suitable for scenarios where the issuer and the verifier do not share a secret key. It's often used in public key infrastructure (PKI) environments and scenarios where third-party verification is necessary. Example: RS256 (RSA with SHA-256) is a common RSA-based algorithm.
3. ECDSA (Elliptic Curve Digital Signature Algorithm):Role: ECDSA is another asymmetric algorithm that uses elliptic curve cryptography. Like RSA, it involves a pair of public and private keys for signing and verification.Use Case: ECDSA is known for its efficiency and is suitable for resource-constrained environments, such as IoT devices. It provides strong security with shorter key lengths compared to RSA. Example: ES256 (ECDSA with SHA-256) is a commonly used ECDSA algorithm.
4. None (Insecure):Role: It's worth mentioning that JWTs can also be created without any signature. In this case, the token is not secure, and anyone can tamper with the claims or impersonate users.Use Case: This should only be used in scenarios where security is not a concern, such as in development or testing environments.

What is Preferred Algorithm

The preferred algorithm depends on your specific use case and security requirements:

• For most web applications, especially those involving user authentication, RSA-based algorithms like RS256 are preferred because they offer strong security, support public key infrastructure, and allow for third-party verification.
• HMAC-based algorithms like HS256 are suitable for internal communication between trusted services that share a secret key.
• ECDSA-based algorithms like ES256 are a good choice for resource-constrained environments or when shorter key lengths are desirable.
• It's essential to avoid using the "None" algorithm in production, as it provides no security.

When choosing an algorithm, consider factors like the sensitivity of the data being transmitted, the potential impact of a security breach, the resources available for key management, and the compatibility of algorithms with your technology stack. Additionally, stay informed about best practices and security updates related to JWTs and the algorithms you use, as security is an evolving field.

There are several Rust crates available for creating JWTs using HMAC (Hash-based Message Authentication Code) algorithms, such as jsonwebtoken, jwt-compact, jwt, and jwt-simple. These crates provide straightforward ways to generate JWTs with HMAC, and they are well-documented and widely used in the Rust ecosystem.

Reference:

Keats/jsonwebtoken: JWT lib in rust (github.com)

jwt_compact - Rust (docs.rs)

jwt - Rust (docs.rs)

However, when it comes to creating JWTs using RSA (Rivest–Shamir–Adleman) algorithms in Rust, the landscape is a bit more complex. While Rust has a strong cryptography ecosystem, generating JWTs with RSA signing does require more involved setup due to the need for managing public and private keys, which are fundamental to RSA-based cryptography.

To create JWTs with RSA in Rust, we typically need to use the rsa - Rust (docs.rs) crate or a similar cryptography library. The rsa crate allows you to work with RSA keys and provides the tools necessary for signing and verifying JWTs. The process involves loading or generating RSA keys, defining JWT claims, signing the JWT with a private key, and then encoding the JWT.

Steps to create the JWT and sign using RSA :

I will take the below parameters as input :

// Keys
#[derive(Default, Clone)]
pub struct CustomKeys {
    pub signing_key: Option<SigningKey<Sha256>>,
    verifying_key: Option<VerifyingKey<Sha256>>
}

fn create_rsa_key(
        algorithm: &str,
        rsa_keys:&CustomKeys,
        sub: &str,
        iss: &str,
        expires_in: i64,
        aud: &str,
        additional_claims: BTreeMap<String, String>) -> Result<String, Box<dyn std::error::Error>> {        

Prepare Your Payload (Claims): Define the claims you want to include in your JWT. Claims can include the subject (sub), issuer (iss), expiration time (exp), audience (aud), and any custom claims specific to your application.

let time_options = TimeOptions::default();

        let mut custom_claims = Claims::new(CustomClaims::new(sub, aud, iss,expires_in))
            .set_duration_and_issuance(&time_options, Duration::seconds(expires_in))
            .set_not_before(Utc::now() - Duration::hours(1));

        // Add additional claims to the custom claims struct.
        for (key, value) in additional_claims.iter() {
            custom_claims.custom.add_claim(key, value);
        }
        

Create a Payload JSON: Serialize the claims into a JSON string. This JSON string will become the payload of your JWT.

 let payload = serde_json::to_string(&custom_claims).unwrap();        

Create a Header: JWTs have a header that specifies the signing algorithm and token type. The header is also serialized into a JSON string.

let header = serde_json::json!({"alg": "RS256","typ": "JWT"}).to_string();        

Base64-Encode Header and Payload: Encode the header and payload separately using Base64Url encoding. This creates two separate strings.

 let encoded_header = base64url_encode(header.as_bytes());

 let header_payload = format!("{}.{}", encoded_header, encoded_payload);        

Combine Header and Payload: Combine the Base64-encoded header and payload with a period ('.') separator to form the unsigned token.

 let header_payload = format!("{}.{}", encoded_header, encoded_payload);        

Create the RsaPrivatekey using the private key and rsa crate.

pub rsa_keys: CustomKeys,

let rsa_result = RsaPrivateKey::from_pkcs1_pem(RSA_PKCS1_PRIVATE_KEY_2048);

rsa_keys.signing_key = match rsa_result {
    Ok(rsa_signing_key) => {           
        Some(SigningKey::<Sha256>::new(rsa_signing_key))
    },
        Err(err) => {
        return true;
    },
}        

Sign the Token: Use your RSA private key to sign the token. This involves applying a cryptographic signature algorithm (e.g., RS256) to the token. The signature is typically applied to the concatenated header and payload.

 // Sign
let mut rng = rand::thread_rng();
let signature = rsa_keys.signing_key.as_ref().expect("Signing Key has not been created").sign_with_rng(&mut rng,   header_payload.as_bytes());

assert_ne!(signature.to_bytes().as_ref(), header_payload.as_bytes());        

Base64-Encode the Signature: Encode the signature generated in the previous step using Base64Url encoding.

let encoded_signature = base64url_encode(&signature.to_bytes().as_ref());        

Combine Signature with Token: Append the Base64-encoded signature to the unsigned token, again separated by a period ('.').

let jwt = format!("{}.{}", header_payload, encoded_signature);        

Our JWT is Ready: We now have a JWT consisting of three parts: the Base64Url-encoded header, the Base64Url-encoded payload, and the Base64Url-encoded signature. These three parts are separated by periods.

Here's a general overview of what a JWT might look like after these steps:

Base64Url(header).Base64Url(payload).Base64Url(signature)        

Base64Url(header).Base64Url(payload).Base64Url(signature)

• Base64Url(header) is the Base64Url-encoded header.
• Base64Url(payload) is the Base64Url-encoded payload.
• Base64Url(signature) is the Base64Url-encoded signature.

It's important to note that the header and payload are not encrypted; they are only Base64-encoded. The security of the JWT relies on the cryptographic signature, which can only be verified with the corresponding public key.

When validating a JWT, we'll need to:

1. Split the JWT: Separate the header, payload, and signature by splitting at the periods.
2. Decode Base64Url: Decode the Base64Url-encoded header and payload to retrieve the JSON content.
3. Verify the Signature: Use the public key associated with the private key used to sign the JWT to verify the signature. If the signature is valid, you can trust the contents of the JWT.

JWT libraries in various programming languages simplify these steps and handle the details for you, but understanding the underlying process is important for implementing JWT-based authentication and security correctly.

Below is complete code which generates the JWT(Hmac and RSA) using Rust:

NadigerAmit/jwtGenerator: Generates the JWT using HMAC and RSA (github.com)

The above generates the jwt token as below :

hmac_token = eyJhbGciOiJIUzI1NiJ9.eyJleHAiOjE2OTQzMzU2MDMsIm5iZiI6MTY5NDMyODQwMywiaWF0IjoxNjk0MzMyMDAzLCJzdWIiOiJUb2tlbkNyZWF0ZWlvbkRlbW8iLCJpc3MiOiJKYWlTaHJlZVJhbSIsImF1ZCI6IkphaUJhanJhbmdCYWxpIiwiZXhwIjozNjAwLCJHb2QxIjoiSmFpQmFqcmFuZ2JhbGkiLCJHb2QyIjoiSGFyZUtyaXNoYW5hIn0.mA8PtGur-Kp8RO4hGowRsOlMuBeZ8o6KbIDKJR_HSvw

For now RSA private key is hardcoaded
rsa_pkcs1_token = eyJhbGciOiJSUzI1NiIsInR5cCI6IkpXVCJ9.eyJleHAiOjE2OTQzMzU2MDMsIm5iZiI6MTY5NDMyODQwMywiaWF0IjoxNjk0MzMyMDAzLCJzdWIiOiJUb2tlbkNyZWF0ZWlvbkRlbW8iLCJpc3MiOiJKYWlTaHJlZVJhbSIsImF1ZCI6IkphaUJhanJhbmdCYWxpIiwiZXhwIjozNjAwLCJHb2QxIjoiSmFpQmFqcmFuZ2JhbGkiLCJHb2QyIjoiSGFyZUtyaXNoYW5hIn0.EKYiJ4WF668bFiVSB82yV5uonjERqOLaemoZGklLgFkK0ywAfO1dZBFXZi4GlJRaxa2y32OaKRsb7f5R4BucGQ7tkUEPjYYy3VXQDCD9b4mBLxZeUcdjoQ2hags3axGLrmYgGYDhZvBOiNewX8vxoWEOfW2xrmh7G5CXlSZ8QqNHfJ7G4D3Md3Y2YsmFcXAF0QKP0U3Id7sq62QHtJhPL6rc32MTxr8nSF16OU5BJWdVue4Wh0gEszAfrUMPy9bI0kEypcYzXVCGA9yuy2M-2UGJoUbnVERWF-C5F0UzE43OseHOujRirq4d41YqolGPivvdhwHiDtvDvDjFJkQglA

For now RSA private key is hardcoaded
rsa_pkcs8_token = eyJhbGciOiJSUzI1NiIsInR5cCI6IkpXVCJ9.eyJleHAiOjE2OTQzMzU2MDMsIm5iZiI6MTY5NDMyODQwMywiaWF0IjoxNjk0MzMyMDAzLCJzdWIiOiJUb2tlbkNyZWF0ZWlvbkRlbW8iLCJpc3MiOiJKYWlTaHJlZVJhbSIsImF1ZCI6IkphaUJhanJhbmdCYWxpIiwiZXhwIjozNjAwLCJHb2QxIjoiSmFpQmFqcmFuZ2JhbGkiLCJHb2QyIjoiSGFyZUtyaXNoYW5hIn0.EKYiJ4WF668bFiVSB82yV5uonjERqOLaemoZGklLgFkK0ywAfO1dZBFXZi4GlJRaxa2y32OaKRsb7f5R4BucGQ7tkUEPjYYy3VXQDCD9b4mBLxZeUcdjoQ2hags3axGLrmYgGYDhZvBOiNewX8vxoWEOfW2xrmh7G5CXlSZ8QqNHfJ7G4D3Md3Y2YsmFcXAF0QKP0U3Id7sq62QHtJhPL6rc32MTxr8nSF16OU5BJWdVue4Wh0gEszAfrUMPy9bI0kEypcYzXVCGA9yuy2M-2UGJoUbnVERWF-C5F0UzE43OseHOujRirq4d41YqolGPivvdhwHiDtvDvDjFJkQglA
amit:~/OmRustPractice/jwt-generator$        

If you have seen the code I think you might have noticed there are different types of keys as PKCS1 and PKCS2.

The PKCS (Public-Key Cryptography Standards) family is a set of standards and specifications for various aspects of public-key cryptography. PKCS standards are developed and maintained by RSA Data Security, Inc., which is now part of the EMC Corporation. These standards cover a wide range of cryptographic operations, including key management, digital signatures, encryption, and more.

Two commonly referenced PKCS standards are PKCS #1 and PKCS #8, which serve different purposes in the context of public-key cryptography:

1. PKCS #1Purpose: PKCS #1, or Public-Key Cryptography Standards #1, primarily defines the standards for RSA encryption, digital signatures, and key management using the RSA algorithm.Components:RSA Key Formats: PKCS #1 defines key formats for RSA keys, including private and public key representations.RSA Encryption: It specifies the format and process for RSA encryption, including padding schemes like RSAES-PKCS1-v1_5.RSA Digital Signatures: PKCS #1 outlines the format and procedures for creating and verifying RSA digital signatures using schemes like RSASSA-PKCS1-v1_5 and RSASSA-PSS.Key Management: The standard covers RSA key pair generation and conversion between different key formats.Versions: There are multiple versions of PKCS #1, each corresponding to different updates and improvements in RSA-based cryptographic operations.
2. PKCS #3: Diffie-Hellman Key Agreement StandardPurpose: PKCS #3 defines the standard for Diffie-Hellman key exchange, which enables two parties to securely agree on a shared secret over an insecure communication channel.Components:Key Agreement: Describes the key exchange process using the Diffie-Hellman algorithm.Use Cases: PKCS #3 is used for secure key agreement in various protocols, including secure communication and key establishment in public-key cryptography.
3. PKCS #5: Password-Based Cryptography StandardPurpose: PKCS #5 focuses on password-based encryption and key derivation. It defines methods for securely deriving cryptographic keys from passwords.Components:Key Derivation Functions: Specifies key derivation functions (KDFs) for generating cryptographic keys from passwords.Password-Based Encryption: Describes techniques for encrypting data using passwords.Use Cases: PKCS #5 is commonly used for encrypting sensitive data with passwords, such as securing stored passwords or creating encrypted archives.
4. PKCS #7: Cryptographic Message Syntax StandardPurpose: PKCS #7 defines a syntax for cryptographic messages. It is commonly used for secure email, digital signatures, and certificates.Components:Message Format: Specifies the format for enveloped data, digital signatures, certificates, and other cryptographic constructs.Use Cases: PKCS #7 is used in various applications, including Secure/Multipurpose Internet Mail Extensions (S/MIME) for secure email and cryptographic message formats.
5. PKCS #8Purpose: PKCS #8, or Public-Key Cryptography Standards #8, focuses on defining a standard format for encoding private keys in a way that is independent of the underlying cryptographic algorithm. It is used to represent private keys, making them easier to exchange between systems.Components:Private Key Format: PKCS #8 specifies a standardized format for encoding private keys, including private key information and the associated algorithm.Algorithm Independence: One of the key features of PKCS #8 is that it allows the representation of private keys in a way that is algorithm-independent. This means that it can be used with various cryptographic algorithms, not just RSA.Use Cases: PKCS #8 private key encoding is commonly used for storing and exchanging private keys for various cryptographic algorithms, including RSA, DSA, and ECDSA.ASN.1 Encoding: PKCS #8 private keys are encoded using ASN.1 (Abstract Syntax Notation One) encoding, which is a standard for representing data structures in a machine-independent way.
6. PKCS #9: Selected Attribute TypesPurpose: PKCS #9 defines a set of attribute types that are used in various cryptographic standards. It provides a common framework for attribute representation.Components:Attribute Types: Specifies attribute types and their usage in cryptographic contexts.
7. PKCS #10: Certification Request Syntax StandardPurpose: PKCS #10 defines the syntax for certification requests, which are used to request digital certificates from certificate authorities (CAs).Components:Certification Request Format: Specifies the format for certification requests, including public key information and certificate attributes.
8. PKCS #11: Cryptographic Token Interface (Cryptoki)Purpose: PKCS #11 defines an API for cryptographic hardware tokens, such as hardware security modules (HSMs). It allows software applications to interface with cryptographic hardware.Components:Cryptographic Functions: Provides functions for cryptographic operations, key management, and token management.
9. PKCS #12: Personal Information Exchange Syntax StandardPurpose: PKCS #12 defines a format for securely storing and exchanging personal identity information, including private keys, certificates, and passwords.Components:PFX Format: Specifies the Personal Information Exchange (PFX) format for storing cryptographic information.
10. PKCS #15: Cryptographic Token Information Format StandardPurpose: PKCS #15 specifies a data structure for cryptographic tokens, enabling interoperability between cryptographic devices and systems.Components:Token Information Format: Defines a standardized data structure for cryptographic tokens.

Both PKCS #1 and PKCS #8 are important standards in the field of public-key cryptography. PKCS #1 primarily deals with RSA-specific operations, while PKCS #8 provides a standardized way to represent private keys, making them interoperable across different cryptographic systems. These standards help ensure consistency and compatibility in cryptographic operations across various software and platforms.

Thanks for reading and please comment of you have any.