𝐭𝐚𝐫 (𝐓𝐚𝐩𝐞 𝐀𝐫𝐜𝐡𝐢𝐯𝐞) 𝐢𝐬 𝐚 𝐂𝐋𝐈 𝐭𝐨𝐨𝐥 𝐭𝐡𝐚𝐭 𝐛𝐮𝐧𝐝𝐥𝐞𝐬 𝐦𝐮𝐥𝐭𝐢𝐩𝐥𝐞 𝐟𝐢𝐥𝐞𝐬/𝐝𝐢𝐫𝐞𝐜𝐭𝐨𝐫𝐢𝐞𝐬 𝐢𝐧𝐭𝐨 𝐨𝐧𝐞 𝐬𝐢𝐧𝐠𝐥𝐞 𝐚𝐫𝐜𝐡𝐢𝐯𝐞 𝐟𝐢𝐥𝐞 (.𝐭𝐚𝐫), 𝐩𝐫𝐞𝐬𝐞𝐫𝐯𝐢𝐧𝐠 𝐩𝐞𝐫𝐦𝐢𝐬𝐬𝐢𝐨𝐧𝐬, 𝐭𝐢𝐦𝐞𝐬𝐭𝐚𝐦𝐩𝐬, 𝐚𝐧𝐝 𝐬𝐭𝐫𝐮𝐜𝐭𝐮𝐫𝐞. 𝐈𝐭 𝐜𝐚𝐧 𝐚𝐥𝐬𝐨 𝐜𝐨𝐦𝐩𝐫𝐞𝐬𝐬 𝐭𝐡𝐚𝐭 𝐛𝐮𝐧𝐝𝐥𝐞 𝐢𝐧𝐥𝐢𝐧𝐞 𝐮𝐬𝐢𝐧𝐠 𝐚𝐥𝐠𝐨𝐫𝐢𝐭𝐡𝐦𝐬 𝐥𝐢𝐤𝐞 𝐠𝐳𝐢𝐩 (-𝐳 → .𝐭𝐚𝐫.𝐠𝐳) 𝐨𝐫 𝐛𝐳𝐢𝐩2 (-𝐣 → .𝐭𝐚𝐫.𝐛𝐳2).

𝐖𝐡𝐚𝐭 𝐢𝐭'𝐬 𝐚𝐜𝐭𝐮𝐚𝐥𝐥𝐲 𝐝𝐨𝐢𝐧𝐠:

- 𝐀𝐫𝐜𝐡𝐢𝐯𝐢𝐧𝐠 → 𝐜𝐨𝐥𝐥𝐞𝐜𝐭𝐢𝐧𝐠 𝐟𝐢𝐥𝐞𝐬 𝐢𝐧𝐭𝐨 𝐨𝐧𝐞 𝐛𝐥𝐨𝐛 (𝐧𝐨 𝐜𝐨𝐦𝐩𝐫𝐞𝐬𝐬𝐢𝐨𝐧 𝐛𝐲 𝐝𝐞𝐟𝐚𝐮𝐥𝐭)
- 𝐂𝐨𝐦𝐩𝐫𝐞𝐬𝐬𝐢𝐨𝐧 → 𝐨𝐩𝐭𝐢𝐨𝐧𝐚𝐥 𝐟𝐥𝐚𝐠 𝐭𝐨 𝐬𝐡𝐫𝐢𝐧𝐤 𝐭𝐡𝐞 𝐛𝐥𝐨𝐛
- 𝐄𝐱𝐭𝐫𝐚𝐜𝐭𝐢𝐨𝐧 → 𝐮𝐧𝐩𝐚𝐜𝐤𝐢𝐧𝐠 𝐭𝐡𝐞 𝐛𝐥𝐨𝐛 𝐛𝐚𝐜𝐤 𝐢𝐧𝐭𝐨 𝐭𝐡𝐞 𝐨𝐫𝐢𝐠𝐢𝐧𝐚𝐥 𝐟𝐢𝐥𝐞𝐬

𝐆𝐨𝐨𝐠𝐥𝐞 𝐀𝐧𝐭𝐢𝐠𝐫𝐚𝐯𝐢𝐭𝐲 𝐢𝐬 𝐚𝐧 𝐚𝐠𝐞𝐧𝐭𝐢𝐜 𝐬𝐨𝐟𝐭𝐰𝐚𝐫𝐞 𝐝𝐞𝐯𝐞𝐥𝐨𝐩𝐦𝐞𝐧𝐭 𝐩𝐥𝐚𝐭𝐟𝐨𝐫𝐦. 𝐈𝐧𝐬𝐭𝐞𝐚𝐝 𝐨𝐟 𝐚𝐜𝐭𝐢𝐧𝐠 𝐥𝐢𝐤𝐞 𝐚 𝐭𝐫𝐚𝐝𝐢𝐭𝐢𝐨𝐧𝐚𝐥 𝐜𝐨𝐝𝐢𝐧𝐠 𝐚𝐬𝐬𝐢𝐬𝐭𝐚𝐧𝐭 𝐭𝐡𝐚𝐭 𝐨𝐧𝐥𝐲 𝐬𝐮𝐠𝐠𝐞𝐬𝐭𝐬 𝐜𝐨𝐝𝐞, 𝐢𝐭 𝐥𝐞𝐭𝐬 𝐲𝐨𝐮 𝐚𝐬𝐬𝐢𝐠𝐧 𝐡𝐢𝐠𝐡-𝐥𝐞𝐯𝐞𝐥 𝐭𝐚𝐬𝐤𝐬 𝐭𝐨 𝐀𝐈 𝐚𝐠𝐞𝐧𝐭𝐬 𝐭𝐡𝐚𝐭 𝐜𝐚𝐧 𝐫𝐞𝐬𝐞𝐚𝐫𝐜𝐡, 𝐰𝐫𝐢𝐭𝐞 𝐜𝐨𝐝𝐞, 𝐫𝐮𝐧 𝐭𝐞𝐬𝐭𝐬, 𝐮𝐬𝐞 𝐚 𝐛𝐫𝐨𝐰𝐬𝐞𝐫, 𝐢𝐧𝐭𝐞𝐫𝐚𝐜𝐭 𝐰𝐢𝐭𝐡 𝐭𝐞𝐫𝐦𝐢𝐧𝐚𝐥𝐬, 𝐦𝐚𝐧𝐚𝐠𝐞 𝐟𝐢𝐥𝐞𝐬, 𝐚𝐧𝐝 𝐜𝐨𝐨𝐫𝐝𝐢𝐧𝐚𝐭𝐞 𝐰𝐢𝐭𝐡 𝐨𝐭𝐡𝐞𝐫 𝐚𝐠𝐞𝐧𝐭𝐬. 𝐌𝐮𝐥𝐭𝐢𝐩𝐥𝐞 𝐚𝐠𝐞𝐧𝐭𝐬 𝐜𝐚𝐧 𝐰𝐨𝐫𝐤 𝐢𝐧 𝐩𝐚𝐫𝐚𝐥𝐥𝐞𝐥 𝐨𝐧 𝐝𝐢𝐟𝐟𝐞𝐫𝐞𝐧𝐭 𝐩𝐚𝐫𝐭𝐬 𝐨𝐟 𝐚 𝐩𝐫𝐨𝐣𝐞𝐜𝐭.

𝐑𝐞𝐠𝐮𝐥𝐚𝐫 𝐄𝐱𝐩𝐫𝐞𝐬𝐬𝐢𝐨𝐧𝐬 (𝐑𝐞𝐠𝐞𝐱) 𝐢𝐧 𝐏𝐲𝐭𝐡𝐨𝐧 & 𝐍𝐨𝐝𝐞.𝐣𝐬
𝐀 𝐑𝐞𝐠𝐮𝐥𝐚𝐫 𝐄𝐱𝐩𝐫𝐞𝐬𝐬𝐢𝐨𝐧 (𝐑𝐞𝐠𝐞𝐱) 𝐢𝐬 𝐚 𝐬𝐞𝐪𝐮𝐞𝐧𝐜𝐞 𝐨𝐟 𝐜𝐡𝐚𝐫𝐚𝐜𝐭𝐞𝐫𝐬 𝐭𝐡𝐚𝐭 𝐝𝐞𝐟𝐢𝐧𝐞𝐬 𝐚 𝐬𝐞𝐚𝐫𝐜𝐡 𝐩𝐚𝐭𝐭𝐞𝐫𝐧. 𝐈𝐭 𝐢𝐬 𝐜𝐨𝐦𝐦𝐨𝐧𝐥𝐲 𝐮𝐬𝐞𝐝 𝐟𝐨𝐫 𝐬𝐞𝐚𝐫𝐜𝐡𝐢𝐧𝐠, 𝐯𝐚𝐥𝐢𝐝𝐚𝐭𝐢𝐧𝐠, 𝐞𝐱𝐭𝐫𝐚𝐜𝐭𝐢𝐧𝐠, 𝐚𝐧𝐝 𝐫𝐞𝐩𝐥𝐚𝐜𝐢𝐧𝐠 𝐭𝐞𝐱𝐭.

const text = "Contact me at john@example.com";

const regex = /[A-Za-z0-9._%+-]+@[A-Za-z0-9.-]+\.[A-Za-z]{2,}/;

const match = text.match(regex);

if (match) {
    console.log(match[0]); // output: john@example.com
}

ᴀ ʜᴀsʜ ғᴜɴᴄᴛɪᴏɴ ɪs ᴀ ᴍᴀᴛʜᴇᴍᴀᴛɪᴄᴀʟ ᴀʟɢᴏʀɪᴛʜᴍ ᴛʜᴀᴛ ᴛᴀᴋᴇs ᴀɴ ɪɴᴘᴜᴛ ᴏғ ᴀɴʏ sɪᴢᴇ (ᴄᴀʟʟᴇᴅ ᴀ ᴍᴇssᴀɢᴇ ᴏʀ ᴅᴀᴛᴀ) ᴀɴᴅ ᴘʀᴏᴅᴜᴄᴇs ᴀ ғɪxᴇᴅ-sɪᴢᴇ ᴏᴜᴛᴘᴜᴛ ᴋɴᴏᴡɴ ᴀs ᴀ ʜᴀsʜ ᴠᴀʟᴜᴇ, ᴅɪɢᴇsᴛ, ᴏʀ ᴄʜᴇᴄᴋsᴜᴍ. ᴏɴᴇ ᴏғ ᴛʜᴇ ᴍᴏsᴛ ɪᴍᴘᴏʀᴛᴀɴᴛ ᴘʀᴏᴘᴇʀᴛɪᴇs ᴏғ ᴀ ʜᴀsʜ ғᴜɴᴄᴛɪᴏɴ ɪs ᴛʜᴀᴛ ᴇᴠᴇɴ ᴛʜᴇ sᴍᴀʟʟᴇsᴛ ᴄʜᴀɴɢᴇ ɪɴ ᴛʜᴇ ɪɴᴘᴜᴛ—sᴜᴄʜ ᴀs ᴄʜᴀɴɢɪɴɢ ᴀ sɪɴɢʟᴇ ᴄʜᴀʀᴀᴄᴛᴇʀ—ʀᴇsᴜʟᴛs ɪɴ ᴀ ᴄᴏᴍᴘʟᴇᴛᴇʟʏ ᴅɪғғᴇʀᴇɴᴛ ʜᴀsʜ. ʜᴀsʜ ғᴜɴᴄᴛɪᴏɴs ᴀʀᴇ ᴅᴇᴛᴇʀᴍɪɴɪsᴛɪᴄ, ᴍᴇᴀɴɪɴɢ ᴛʜᴇ sᴀᴍᴇ ɪɴᴘᴜᴛ ᴡɪʟʟ ᴀʟᴡᴀʏs ᴘʀᴏᴅᴜᴄᴇ ᴛʜᴇ sᴀᴍᴇ ᴏᴜᴛᴘᴜᴛ, ʙᴜᴛ ᴛʜᴇʏ ᴀʀᴇ ᴅᴇsɪɢɴᴇᴅ ᴛᴏ ᴍᴀᴋᴇ ɪᴛ ᴄᴏᴍᴘᴜᴛᴀᴛɪᴏɴᴀʟʟʏ ɪɴғᴇᴀsɪʙʟᴇ ᴛᴏ ʀᴇᴄᴏɴsᴛʀᴜᴄᴛ ᴛʜᴇ ᴏʀɪɢɪɴᴀʟ ɪɴᴘᴜᴛ ғʀᴏᴍ ɪᴛs ʜᴀsʜ.

ᴛʜᴇ ᴄᴏɴᴄᴇᴘᴛ ᴏғ ʜᴀsʜɪɴɢ ᴏʀɪɢɪɴᴀᴛᴇᴅ ɪɴ ᴄᴏᴍᴘᴜᴛᴇʀ sᴄɪᴇɴᴄᴇ ᴀs ᴀ ᴡᴀʏ ᴛᴏ ᴇғғɪᴄɪᴇɴᴛʟʏ ᴏʀɢᴀɴɪᴢᴇ ᴀɴᴅ ʀᴇᴛʀɪᴇᴠᴇ ᴅᴀᴛᴀ. ᴇᴀʀʟʏ ʜᴀsʜ ғᴜɴᴄᴛɪᴏɴs ᴡᴇʀᴇ ᴅᴇᴠᴇʟᴏᴘᴇᴅ ғᴏʀ ʜᴀsʜ ᴛᴀʙʟᴇs, ᴀʟʟᴏᴡɪɴɢ ᴘʀᴏɢʀᴀᴍs ᴛᴏ ʟᴏᴄᴀᴛᴇ ᴅᴀᴛᴀ ɪɴ ɴᴇᴀʀʟʏ ᴄᴏɴsᴛᴀɴᴛ ᴛɪᴍᴇ (ᴏ(1) ᴏɴ ᴀᴠᴇʀᴀɢᴇ). ᴀs ᴄᴏᴍᴘᴜᴛɪɴɢ ᴇᴠᴏʟᴠᴇᴅ, ᴄʀʏᴘᴛᴏɢʀᴀᴘʜɪᴄ ʜᴀsʜ ғᴜɴᴄᴛɪᴏɴs ᴡᴇʀᴇ ɪɴᴛʀᴏᴅᴜᴄᴇᴅ ᴛᴏ sᴏʟᴠᴇ sᴇᴄᴜʀɪᴛʏ ᴘʀᴏʙʟᴇᴍs sᴜᴄʜ ᴀs ᴘᴀssᴡᴏʀᴅ sᴛᴏʀᴀɢᴇ, ᴅɪɢɪᴛᴀʟ sɪɢɴᴀᴛᴜʀᴇs, sᴏғᴛᴡᴀʀᴇ ɪɴᴛᴇɢʀɪᴛʏ ᴠᴇʀɪғɪᴄᴀᴛɪᴏɴ, ᴀɴᴅ ʙʟᴏᴄᴋᴄʜᴀɪɴ ᴛᴇᴄʜɴᴏʟᴏɢʏ. ᴜɴʟɪᴋᴇ ᴏʀᴅɪɴᴀʀʏ ʜᴀsʜ ғᴜɴᴄᴛɪᴏɴs, ᴄʀʏᴘᴛᴏɢʀᴀᴘʜɪᴄ ʜᴀsʜᴇs ᴀʀᴇ ᴅᴇsɪɢɴᴇᴅ ᴛᴏ ʀᴇsɪsᴛ ᴀᴛᴛᴀᴄᴋs sᴜᴄʜ ᴀs ᴄᴏʟʟɪsɪᴏɴs ᴀɴᴅ ʀᴇᴠᴇʀsᴇ ᴇɴɢɪɴᴇᴇʀɪɴɢ.

ᴀ ʜᴀsʜ ғᴜɴᴄᴛɪᴏɴ ᴡᴏʀᴋs ʙʏ ᴘʀᴏᴄᴇssɪɴɢ ᴛʜᴇ ɪɴᴘᴜᴛ ᴛʜʀᴏᴜɢʜ ᴍᴜʟᴛɪᴘʟᴇ ᴍᴀᴛʜᴇᴍᴀᴛɪᴄᴀʟ ᴛʀᴀɴsғᴏʀᴍᴀᴛɪᴏɴs, ɪɴᴄʟᴜᴅɪɴɢ ʙɪᴛᴡɪsᴇ ᴏᴘᴇʀᴀᴛɪᴏɴs, ᴍᴏᴅᴜʟᴀʀ ᴀʀɪᴛʜᴍᴇᴛɪᴄ, sᴜʙsᴛɪᴛᴜᴛɪᴏɴs, ᴀɴᴅ ᴘᴇʀᴍᴜᴛᴀᴛɪᴏɴs. ᴛʜᴇ ʀᴇsᴜʟᴛɪɴɢ ᴏᴜᴛᴘᴜᴛ ʜᴀs ᴀ ғɪxᴇᴅ ʟᴇɴɢᴛʜ ʀᴇɢᴀʀᴅʟᴇss ᴏғ ᴛʜᴇ ɪɴᴘᴜᴛ sɪᴢᴇ. ᴍᴏᴅᴇʀɴ ᴀʟɢᴏʀɪᴛʜᴍs sᴜᴄʜ ᴀs sʜᴀ-256 ᴜsᴇ ᴍᴀɴʏ ʀᴏᴜɴᴅs ᴏғ ᴄᴏᴍᴘʟᴇx ᴛʀᴀɴsғᴏʀᴍᴀᴛɪᴏɴs ᴛᴏ ᴀᴄʜɪᴇᴠᴇ ᴛʜᴇ ᴀᴠᴀʟᴀɴᴄʜᴇ ᴇғғᴇᴄᴛ, ᴡʜᴇʀᴇ ᴄʜᴀɴɢɪɴɢ ᴊᴜsᴛ ᴏɴᴇ ʙɪᴛ ɪɴ ᴛʜᴇ ɪɴᴘᴜᴛ ᴅʀᴀsᴛɪᴄᴀʟʟʏ ᴄʜᴀɴɢᴇs ᴛʜᴇ ғɪɴᴀʟ ʜᴀsʜ. ᴛʜɪs ᴍᴀᴋᴇs ʜᴀsʜ ғᴜɴᴄᴛɪᴏɴs ɪᴅᴇᴀʟ ғᴏʀ ᴠᴇʀɪғʏɪɴɢ ᴅᴀᴛᴀ ɪɴᴛᴇɢʀɪᴛʏ ʙᴇᴄᴀᴜsᴇ ɪᴅᴇɴᴛɪᴄᴀʟ ɪɴᴘᴜᴛs ᴀʟᴡᴀʏs ᴘʀᴏᴅᴜᴄᴇ ɪᴅᴇɴᴛɪᴄᴀʟ ʜᴀsʜᴇs, ᴡʜɪʟᴇ ᴍᴏᴅɪғɪᴇᴅ ᴅᴀᴛᴀ ᴘʀᴏᴅᴜᴄᴇs ᴀɴ ᴇɴᴛɪʀᴇʟʏ ᴅɪғғᴇʀᴇɴᴛ ᴅɪɢᴇsᴛ.

import hashlib

text = "Hello, World!".encode()

# =========================
# MD5 (128-bit)
# =========================
print("MD5       :", hashlib.md5(text).hexdigest())

# =========================
# SHA-1 (160-bit)
# =========================
print("SHA-1     :", hashlib.sha1(text).hexdigest())

# =========================
# SHA-224 (224-bit)
# =========================
print("SHA-224   :", hashlib.sha224(text).hexdigest())

# =========================
# SHA-256 (256-bit)
# =========================
print("SHA-256   :", hashlib.sha256(text).hexdigest())

# =========================
# SHA-384 (384-bit)
# =========================
print("SHA-384   :", hashlib.sha384(text).hexdigest())

# =========================
# SHA-512 (512-bit)
# =========================
print("SHA-512   :", hashlib.sha512(text).hexdigest())

# =========================
# SHA3-224
# =========================
print("SHA3-224  :", hashlib.sha3_224(text).hexdigest())

# =========================
# SHA3-256
# =========================
print("SHA3-256  :", hashlib.sha3_256(text).hexdigest())

# =========================
# SHA3-384
# =========================
print("SHA3-384  :", hashlib.sha3_384(text).hexdigest())

# =========================
# SHA3-512
# =========================
print("SHA3-512  :", hashlib.sha3_512(text).hexdigest())

# =========================
# BLAKE2b (512-bit)
# =========================
print("BLAKE2b   :", hashlib.blake2b(text).hexdigest())

# =========================
# BLAKE2s (256-bit)
# =========================
print("BLAKE2s   :", hashlib.blake2s(text).hexdigest())

# =========================
# SHAKE-128 (Variable Length)
# 32 bytes = 64 hex characters
# =========================
print("SHAKE-128 :", hashlib.shake_128(text).hexdigest(32))

# =========================
# SHAKE-256 (Variable Length)
# 64 bytes = 128 hex characters
# =========================
print("SHAKE-256 :", hashlib.shake_256(text).hexdigest(64))

# =========================
# Show all available algorithms
# =========================
print("\nAvailable Algorithms:")
print(hashlib.algorithms_available)

# =========================
# Show guaranteed algorithms
# =========================
print("\nGuaranteed Algorithms:")
print(hashlib.algorithms_guaranteed)