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DuckDB Extensions All extensions Crypto

Key Derivation functions in the Crypto DuckDB extension

Function category

Key Derivation

4 functions

Password hashing and key derivation with Argon2, scrypt, PBKDF2 and HKDF. Use Argon2 or scrypt to store passwords, and HKDF to derive several keys from one high-entropy secret.

crypto_argon2

Scalar function Key Derivation
Signature
crypto_argon2( variant: VARCHAR, password: BLOB | VARCHAR, salt: BLOB | VARCHAR, iterations: BIGINT, memory_kib: BIGINT, parallelism: BIGINT, length: BIGINT ) → BLOB
Arguments (Positional)
Argument variant Type VARCHAR Mode Positional Description
Argument password Type BLOB | VARCHAR
2 concrete types
BLOBVARCHAR
Mode Positional Description
Argument salt Type BLOB | VARCHAR
2 concrete types
BLOBVARCHAR
Mode Positional Description
Argument iterations Type BIGINT Mode Positional Description
Argument memory_kib Type BIGINT Mode Positional Description
Argument parallelism Type BIGINT Mode Positional Description
Argument length Type BIGINT Mode Positional Description
Description

Argon2 password hashing (RFC 9106). variant is 'argon2id' (recommended), 'argon2i' or 'argon2d' (case-insensitive); memory_kib is the memory cost in KiB (at least 32) and parallelism the number of lanes. The salt must be at least 8 bytes; output is length bytes (up to 1 MiB). Password and salt accept VARCHAR or BLOB. Working memory is reserved against DuckDB's memory_limit before it is allocated.

1 Argon2id with 2 iterations, 64 MiB and 4 lanes 
SELECT lower(to_hex(crypto_argon2('argon2id', 'password', 'somesalt', 2, 65536, 4, 32))) AS hash;

Output

hash
1a9677b0afe81fda7b548895e7a1bfeb8668ffc19a530e37e088a668fab1c02a
2 A small, fast configuration for tests 
SELECT lower(to_hex(crypto_argon2('argon2id', '', 'somesalt', 1, 64, 1, 16))) AS hash;

Output

hash
83b7ea15e3a517fe0455cbe091d0931c
Related functions

crypto_hkdf

Scalar function Key Derivation
Signature
crypto_hkdf( algorithm: VARCHAR, key: BLOB | VARCHAR, salt: BLOB | VARCHAR, info: BLOB | VARCHAR, length: BIGINT ) → BLOB
Arguments (Positional)
Argument algorithm Type VARCHAR Mode Positional Description
Argument key Type BLOB | VARCHAR
2 concrete types
BLOBVARCHAR
Mode Positional Description
Argument salt Type BLOB | VARCHAR
2 concrete types
BLOBVARCHAR
Mode Positional Description
Argument info Type BLOB | VARCHAR
2 concrete types
BLOBVARCHAR
Mode Positional Description
Argument length Type BIGINT Mode Positional Description
Description

HKDF extract-and-expand (RFC 5869). Derives length bytes from high-entropy input key material, an optional salt, and a context info string; length is at most 255 × the digest length (8,160 bytes for sha2-256). Key, salt and info accept VARCHAR or BLOB. HKDF is fast, so it is for deriving keys from a secret, not for hashing passwords.

1 RFC 5869 test case 1 
SELECT lower(to_hex(crypto_hkdf('sha2-256',
         unhex('0b0b0b0b0b0b0b0b0b0b0b0b0b0b0b0b0b0b0b0b0b0b'),
         unhex('000102030405060708090a0b0c'),
         unhex('f0f1f2f3f4f5f6f7f8f9'),
         42))) AS okm;

Output

okm
3cb25f25faacd57a90434f64d0362f2a2d2d0a90cf1a5a4c5db02d56ecc4c5bf34007208d5b887185865
2 RFC 5869 test case 3: empty salt and info 
SELECT lower(to_hex(crypto_hkdf('sha2-256', unhex('0b0b0b0b0b0b0b0b0b0b0b0b0b0b0b0b0b0b0b0b0b0b'), '', '', 42))) AS okm;

Output

okm
8da4e775a563c18f715f802a063c5a31b8a11f5c5ee1879ec3454e5f3c738d2d9d201395faa4b61a96c8
Related functions

crypto_pbkdf2

Scalar function Key Derivation
Signature
crypto_pbkdf2( algorithm: VARCHAR, password: BLOB | VARCHAR, salt: BLOB | VARCHAR, iterations: BIGINT, length: BIGINT ) → BLOB
Arguments (Positional)
Argument algorithm Type VARCHAR Mode Positional Description
Argument password Type BLOB | VARCHAR
2 concrete types
BLOBVARCHAR
Mode Positional Description
Argument salt Type BLOB | VARCHAR
2 concrete types
BLOBVARCHAR
Mode Positional Description
Argument iterations Type BIGINT Mode Positional Description
Argument length Type BIGINT Mode Positional Description
Description

PBKDF2-HMAC key derivation (RFC 8018). Derives length bytes (1 to 1,048,576) from a password and salt with the given HMAC algorithm and iteration count (at least 1). Password and salt accept VARCHAR or BLOB. blake3 is not supported. Prefer crypto_argon2 for new password storage; use PBKDF2 where FIPS compliance or interoperability requires it.

1 RFC 6070 test vector (PBKDF2-HMAC-SHA1, 4096 iterations) 
SELECT lower(to_hex(crypto_pbkdf2('sha1', 'password', 'salt', 4096, 20))) AS dk;

Output

dk
4b007901b765489abead49d926f721d065a429c1
2 PBKDF2-HMAC-SHA256, 40-byte output 
SELECT lower(to_hex(crypto_pbkdf2('sha2-256', 'passwordPASSWORDpassword', 'saltSALTsaltSALTsaltSALTsaltSALTsalt', 4096, 40))) AS dk;

Output

dk
348c89dbcbd32b2f32d814b8116e84cf2b17347ebc1800181c4e2a1fb8dd53e1c635518c7dac47e9
Related functions

crypto_scrypt

Scalar function Key Derivation
Signature
crypto_scrypt( password: BLOB | VARCHAR, salt: BLOB | VARCHAR, n: BIGINT, r: BIGINT, p: BIGINT, length: BIGINT ) → BLOB
Arguments (Positional)
Argument password Type BLOB | VARCHAR
2 concrete types
BLOBVARCHAR
Mode Positional Description
Argument salt Type BLOB | VARCHAR
2 concrete types
BLOBVARCHAR
Mode Positional Description
Argument n Type BIGINT Mode Positional Description
Argument r Type BIGINT Mode Positional Description
Argument p Type BIGINT Mode Positional Description
Argument length Type BIGINT Mode Positional Description
Description

scrypt password-based key derivation (RFC 7914). n is the CPU/memory cost and must be a power of 2, r the block size and p the parallelism; output is length bytes (up to 1 MiB). Password and salt accept VARCHAR or BLOB. Working memory (128 × n × r bytes) is reserved against DuckDB's memory_limit before it is allocated.

1 RFC 7914 test vector (n = 1024, r = 8, p = 16) 
SELECT lower(to_hex(crypto_scrypt('password', 'NaCl', 1024, 8, 16, 64))) AS dk;

Output

dk
fdbabe1c9d3472007856e7190d01e9fe7c6ad7cbc8237830e77376634b3731622eaf30d92e22a3886ff109279d9830dac727afb94a83ee6d8360cbdfa2cc0640
Related functions