How to use the command 'argon2' (with examples)

Argon2 is a command-line utility that allows you to calculate Argon2 cryptographic hashes. Argon2 is a password hashing algorithm that is resistant to both side-channel attacks and GPU cracking attacks, making it a strong choice for securely storing passwords. In this article, we will explore different use cases of the argon2 command and provide examples for each case.

Use case 1: Calculate a hash with a password and a salt with the default parameters

Code:

echo "password" | argon2 "salt_text"

Motivation: This use case allows you to calculate a hash using the default parameters of Argon2. This is useful when you don’t need to customize the iteration, memory usage, or parallelism of the hash calculation.

Explanation:

• echo "password": This command is used to pass the password to the argon2 command. You can replace "password" with the actual password you want to hash.
• argon2 "salt_text": This command calculates the Argon2 hash using the provided password and salt. Replace "salt_text" with the actual salt you want to use.

Example output:

$ echo "password" | argon2 "salt_text"
Type:   Argon2id
Iterations:  3
Memory:      4096 KiB
Parallelism: 1
Hash:        cb9fd854f3946da97e7b4784cc3cd57d89312142f5b997e72fcbd8c581ead2c8
Encoded:     $argon2id$v=19$m=4096,t=3,p=1$c2FsdF90ZXh0$y536VOOWaemXe0h4TMzVfYkxIUNbWZ-I_8vejFF63c4

Use case 2: Calculate a hash with the specified algorithm

Code:

echo "password" | argon2 "salt_text" -d|i|id

Motivation: This use case allows you to specify the algorithm you want to use for the Argon2 hash calculation. You can choose from argoni2d, argon2i, or argon2id. This allows you to customize the security level and performance of the hash.

Explanation:

• echo "password": This command is used to pass the password to the argon2 command.
• argon2 "salt_text": This command calculates the Argon2 hash using the provided password and salt. Replace "salt_text" with the actual salt you want to use.
• -d|i|id: This option allows you to specify the algorithm to be used. Choose either d for Argon2d, i for Argon2i, or id for Argon2id.

Example output (using -id option):

$ echo "password" | argon2 "salt_text" -id
Type:       Argon2id
Iterations:  3
Memory:      4096 KiB
Parallelism: 1
Hash:        cb9fd854f3946da97e7b4784cc3cd57d89312142f5b997e72fcbd8c581ead2c8
Encoded:     $argon2id$v=19$m=4096,t=3,p=1$c2FsdF90ZXh0$y536VOOWaemXe0h4TMzVfYkxIUNbWZ-I_8vejFF63c4

Use case 3: Display the output hash without additional information

Code:

echo "password" | argon2 "salt_text" -e

Motivation: Sometimes, you may only want to retrieve the final hash without any additional information. This use case allows you to easily obtain the hash without any extra output.

Explanation:

• echo "password": This command is used to pass the password to the argon2 command.
• argon2 "salt_text": This command calculates the Argon2 hash using the provided password and salt. Replace "salt_text" with the actual salt you want to use.
• -e: This option tells the argon2 command to display only the output hash without any additional information.

Example output:

$ echo "password" | argon2 "salt_text" -e
cb9fd854f3946da97e7b4784cc3cd57d89312142f5b997e72fcbd8c581ead2c8

Use case 4: Calculate a hash with given iteration [t]imes, [m]emory usage, and [p]arallelism parameters

Code:

echo "password" | argon2 "salt_text" -t 5 -m 20 -p 7

Motivation: This use case is useful when you want to explicitly set the iteration times, memory usage, and parallelism parameters for the Argon2 hash calculation. This allows you to fine-tune the security level and performance of the hash.

Explanation:

• echo "password": This command is used to pass the password to the argon2 command.
• argon2 "salt_text": This command calculates the Argon2 hash using the provided password and salt. Replace "salt_text" with the actual salt you want to use.
• -t 5: This option sets the iteration times to 5. Adjust the value to suit your security requirements.
• -m 20: This option sets the memory usage to 20 MiB. Increase or decrease the value based on the memory capacity of your system.
• -p 7: This option sets the parallelism factor to 7. The higher the parallelism factor, the faster the hash calculation, but it may require more system resources.

Example output:

$ echo "password" | argon2 "salt_text" -t 5 -m 20 -p 7
Type:       Argon2id
Iterations:  5
Memory:      20480 KiB
Parallelism: 7
Hash:        49d869ffb2ca97c999699a76bfb4480b95b2f5f13903eb6c18ec7198fb1f37a7
Encoded:     $argon2id$v=19$m=20480,t=5,p=7$c2FsdF90ZXh0$Sdpv_7KclaOTmplr77RIC5Wy